Scipedia: Documents published in 2018

High Damping Rubber Model for Energy Dissipating Devices

Alex Barbat — Mon, 02 Apr 2018 12:27:42 +0200

This work presents the results of a study carried out to characterize the mechanical response of a high damping rubber to be used in designing and constructing energy dissipating devices and base isolators for controling strong vibrations in civil engineering structures. A new parametric model of the elastomer is proposed to be employed in the design procedure and structural analysis of passive controlled structures. The parameters of the model are calibrated using experimental data obtained from tests on rubber specimens under different loading paths. The main dissipating energy mechanisms of the rubber are identified. The proposed model is able to reproduce those main mechanisms as well as geometric second order effects such as tension stiffening due to the effect of axial strains in the response. The response predicted by the proposed model is compared with that obtained from experimental tests and from the Kelvin and plasticity models.

Earthquake Loss Assessment for Integrated Disaster Risk Management

Alex Barbat — Mon, 02 Apr 2018 12:22:10 +0200

Understanding probable losses and reconstruction costs due to earthquakes creates powerful incentives for countries to develop planning options and tools to cope with risk, including allocating the sustained budgetary resources necessary to reduce those potential damages and safeguard development. A specific catastrophic risk model has been developed to evaluate, building by
building, the probabilistic losses and pure premiums of different portfolios, taking into account the seismic microzonation of cities. This model has been used to evaluate the fiscal contingency liabilities of the government and to build an optimal structure for risk transfer and retention, considering contingent credits, reserve funds, insurance/reinsurance, and cat bonds. Lastly, the model allows the evaluation of an exceedance probability curve of benefit-cost ratio, providing an innovative and ground-breaking tool for decision makers to analyze the net benefits of the risk mitigation strategies, such as earthquake retrofitting and seismic code enforcement. This article describes the model and the derived abovementioned tools, using the results of loss scenarios and the strategies implemented in some earthquake prone urban centers.

Estimation of Probabilistic Seismic Losses and the Public Economic Resilience—An Approach for a Macroeconomic Impact Evaluation

Alex Barbat — Mon, 02 Apr 2018 12:14:33 +0200

The Disaster Deficit Index (DDI) measures country risk from a macroeconomic and financial perspective, according to possible catastrophic events. The DDI captures the relationship between the demand for contingent resources to cover the maximum probable losses and the public sector’s economic resilience; that is, the availability of internal and external funds for restoring affected inventories. For calculating potential losses, the model follows the insurance industry in establishing a probable loss, based on the critical impacts during a given period of exposure, and for the economic resilience the model computes the country’s financial ability to cope with the situation taking into account: the insurance and reinsurance payments; the reserve funds for disasters; the funds that may be received as aid and donations; the possible value of new taxes; the margin for budgetary reallocations; the feasible value of external credit; and the internal credit the country may obtain. Access to these resources has limitations and costs that must be taken into account as feasible values according to the macroeconomic and financial conditions of the country. This article presents the model of DDI and proposes it as a simple way of measuring a country’s fiscal exposure and potential deficit—or contingency liabilities—in case of extreme disasters to guide the governmental decisionmaking from economic, financial, and disaster risk reduction perspectives.

VISCOUS DAMAGE MODEL FOR TIMOSHENKO BEAM STRUCTURES

Alex Barbat — Sun, 01 Apr 2018 21:16:14 +0200

A local damage constitutive model based on Kachanov’s theory is used within a finite element frame and applied to the case of 2D and 3D Timoshenko beam elements. The model takes into account viscous effects, thus allowing damping to be considered in a rigorous way. A damage index based on potential energy criteria, useful in evaluating the behaviour of structures or of parts of structures, is proposed. The procedure is applied to estimate the damage produced by seismic actions in reinforced concrete building structures, whose response is computed by using a non-linear Newmark-type incremental time integration scheme. Three numerical examples are included; one
of them compares results obtained by using the proposed model with results of a laboratory test.

Analysis of Ultra Low Cycle Fatigue problems with the Barcelona plastic damage model and a new isotropic hardening law

Alex Barbat — Sun, 01 Apr 2018 20:55:43 +0200

This paper presents a plastic-damage formulation and a new isotropic hardening law, based on the Barcelona plastic damage model initially proposed by Lubliner et al. (1989) [1], which is capable of predicting steel failure due to Ultra Low Cycle Fatigue (ULCF). This failure mechanism is obtained when the material is subjected to cyclic loads and breaks after applying a very low number of cycles, usually less than hundreds. The failure is driven by the plastic response of the material, and it is often predicted based on the plastic strains applied to it. The model proposed in this work has been formulated with the objective of predicting accurately the plastic behavior of the material, as well as its failure due to ULCF. This is achieved taking into account the fracture energy dissipated during the whole loading process. This approach allows the simulation of ULCF when it takes place due to regular cyclic loads or non-regular
cyclic loads, as it is the case of seismic loads. Several simulations are conducted in order to show the capabilities of the formulation to reproduce the mechanical response of steel when it is subjected to regular and non-regular cyclic loads. The formulation is validated comparing the numerical results with several experimental tests made o n X52 steel specimens. The agreement between the numerical and experimental results asses the validity of the proposed model to predict the plastic behavior of steel and its failure
due to Ultra Low Cycle Fatigue.

Validation on large scale tests of a new hardening–softening law for the Barcelona plastic damage model

Alex Barbat — Sun, 01 Apr 2018 20:13:51 +0200

This paper presents the results of finite element simulations made on a bent pipe subjected to an in-plane variable cyclic displacement combined with internal pressure. Special emphasis is put on the capacity of the model to illustrate different failure modes depending on the internal pressure applied on the pipe. The results of the numerical analyses will be compared to experimental ones. The constitutive model used for the simulation of Ultra Low Cycle Fatigue (ULCF) loading and the hardening–softening law used are only briefly touched upon. The monotonic behavior of a large diameter pipe, as obtained from the constitutive model proposed, is also shown and compared to experimental results under two different loading conditions. The total axial load at failure for this case resulted in less than 10% error as compared to the experiments. Regarding the ULCF in-plane bending simulations conducted on a 16-in. 90º elbow, the results were in good agreement with the experimental test in terms of force–displacement hysteresis loops and total fatigue life of the specimen. An analysis of the dependence of the failure mode to the internal pressure applied has been conducted, showing that the formulation is capable of obtaining both habitual failure types.

Behaviour of the interface between concrete and FRP using serial/ parallel mixing theory

Alex Barbat — Sun, 01 Apr 2018 20:05:49 +0200

Experimental research has shown that one of the key factors affecting the behaviour of reinforced concrete structures strengthened with externally-bonded fibre-reinforced polymer (FRP) is the bonding behaviour between concrete and FRP laminates. As a complement to experimentation, this paper proposed the use of serial/parallel mixing theory in numerical simulation, which is a tool for studying the behaviour of the concrete-FRP epoxy interface. An example is presented which analyses beam test simulation results and compares them with the experimental results.

FINITE ELEMENT ANALYSIS OF BASE ISOLATED BUILDINGS SUBJECTED TO EARTHQUAKE LOADS

Alex Barbat — Sun, 01 Apr 2018 18:53:00 +0200

A finite element formulation modelling hyperelastic quasi-incompressible rubber-like materials (elastomers) is developed which takes into account large displacements and large elastic strains as well as inelastic effects. The capacity of laminated rubber-like materials to support high loads in compression and large displacements in shear is the principal reason for their use in devices for seismic base isolation of structures. The energy-dissipation capacity of these devices is increased by using high damping rubber, which is an elastomer incorporating carbon black particles, or having lead-plug insertion. The Ogden strain energy function has been used as a basis for the material model implemented in a total Lagrangian formulation, the strain being decomposed into its deviatory and volumetric parts and the pressure variable being condensed at element level. Mooney-Rivlin and neo-Hooke strain energy functions can also be used by simply changing the parameters of the model. The stress-strain hysteresis, which appears when these devices are subjected to dynamic or quasi-static cyclic loads, has been modelled by frequency dependent viscoelastic and plastic constitutive models. The bearings have been modelled by means of an equivalent single element capable of describing the composite behaviour of the actual isolation system. The proposed model is validated using available experimental results and it is proved to be a powerful tool in dealing with different bearings. Finally, results for a six-storey base isolated building subjected to the El Centro earthquake are given.

Non-linear seismic analysis of RC structures with energy-dissipating devices

Alex Barbat — Sun, 01 Apr 2018 18:45:49 +0200

The poor performance of some reinforced concrete (RC) structures during strong earthquakes has alerted about the need of improving their seismic behavior, especially when they are designed according to obsolete codes and show low structural damping, important second-order effects and low ductility, among other defects. These characteristics allow proposing the use of energy-dissipating devices for improving their seismic behavior. In this work, the non-linear dynamic response of RC buildings with energy dissipators
is studied using advanced computational techniques. A fully geometric and constitutive non-linear model for the description of the dynamic behavior of framed structures is developed. The model is based on the geometrically exact formulation for beams in finite deformation. Points on the cross section are composed of several simple materials. The mixing theory is used to treat the resulting composite. A specific type of element is proposed for modeling the dissipators including the corresponding constitutive relations. Special attention is paid to the development of local and global damage indices for describing the performance of the buildings. Finally, numerical tests are presented for validating the ability of the model for reproducing the non-linear seismic response of buildings with dissipators.

SSP algorithm for linear and non-linear dynamic response simulation

Alex Barbat — Sun, 01 Apr 2018 18:38:52 +0200

A direct integration algorithm to solve the spatially discretized equations of motion of a structure is proposed. This algorithm formulates the equations of motion in state space and uses their analytical solution to derive a recursive discrete-time equation. The proposed structural state procedure (SSP) can be considered as a generalization for multi-degree-of-freedom systems of the Duhamel's integral used for single-degree-of-freedom systems. It can be noted that the proposed SSP algorithm does not need a previous modal uncoupling of the equations of motion and consequently it does not require any hypothesis about damping. SSP is shown to be stable and to give accurate results with a reasonable computation time. Stability and accuracy essentially depend on the computation of the system matrix. The SSP algorithm is combined with an iterative scheme to obtain the response of structures with non-linear behaviour. Two examples of
application of SSP are included: seismic response of a building structure with linear behaviour and free vibration of a non-linear system with imposed initial conditions.

Comparing observed damages and losses with modelled ones using a probabilistic approach: The Lorca 2011 case

Alex Barbat — Sun, 01 Apr 2018 11:39:09 +0200

A loss and damage assessment was performed for the buildings of Lorca, Spain, considering an earthquake hazard scenario with similar characteristics to those of a real event which occurred on May 11th, 2011, in terms of epicentre, depth and magnitude while also considering the local soil response. This low-to moderate earthquake caused severe damage and disruption in the region and especially on the city. A building by building resolution database was developed and used for damage and loss assessment. The portfolio of buildings was characterized by means of indexes capturing information from a structural point of view such as age, main
construction materials, number of stories, and building class as well as others related to age and vulnerability classes. A replacement cost approach was selected for the analysis in order to calculate the direct losses incurred by the event. Seismic hazard and vulnerability were modelled in a probabilistic way, considering their inherent uncertainties which were also taken into account in the damage and loss calculation process. Losses have been expressed in terms of the mean damage ratio of each dwelling and since the analysis has been performed on a geographical information system platform, the distribution of the damage and its categories was mapped for the entire urban centre. The simulated damages and losses were compared with the observed ones reported by the
local authorities and institutions that inspected the city after the event.

Seismic and wind vulnerability assessment for the GAR-13 global risk assessment

Alex Barbat — Sun, 01 Apr 2018 11:31:48 +0200

A general methodology to evaluate vulnerability functions suitable for a probabilistic global risk assessment is proposed. The methodology is partially based in the methodological approach of the Multi-hazard Loss Estimation Methodology (Hazus) developed by the Federal Emergency Management Agency (FEMA). The vulnerability assessment process considers the resolution, information and limitations established for both the hazard and exposure models adopted. Seismic and wind vulnerability functions are estimated for each one of the building classes defined in typical global exposure databases. They consider possible variations according to the design level in different regions of the world which accounts for variations of the expected quality of construction and the design code compliance level. In addition, a consistent, expert opinion based methodology is proposed in order to assign particular vulnerability functions to building classes according to the development level of each country, the city complexity and the hazard level of the region. The proposed set of vulnerability functions and the assignment procedure were used for the probabilistic global risk assessment made in the framework of the UNISDR’s Global Assessment Report on Disaster Risk Reduction, GAR 2013. Recommendations for the refinement of the methodological approach are included for future global or scaled regional risk assessments.

RETROSPECTIVE ASSESSMENT OF RISK FROM NATURAL HAZARDS

Alex Barbat — Sun, 01 Apr 2018 11:18:58 +0200

The existing disaster databases allow analyzing losses produced by previous events and assessing the risk to natural hazard in a similar way as the insurance industry does for vehicles, health, etc., if the conditions and trends are maintained. Among the existing disaster databases, we selected DesInventar whose vast majority of records correspond to “small” events; this selection is of special interest as these small events are often ignored because, individually, they only stroke a few assets accounting for low economic losses. Nevertheless, their accumulated effect can have a significant impact over the economic and fiscal sustainability of urban areas, regions or countries. Also, considering the difficulties involved in assessing risk for those small disasters, like the lack of general models and the elevated susceptibility to local variables of the results, this approach can give answers so far unavailable. The methodology herein proposed has been applied to the assessment of risk (in the terms of the loss exceedance curve) in 23 countries.

Holistic Disaster Risk Evaluation for the Urban Risk Management Plan of Manizales, Colombia

Alex Barbat — Sun, 01 Apr 2018 10:07:29 +0200

Disaster risk depends on both the physical vulnerability and a wide range of social, economic, and environmental aspects of a society. For a better risk understanding, a holistic or integrated perspective was considered when risk was assessed for the city of Manizales, Colombia. This assessment accounts not only for the expected physical damage and loss, but also for the socioeconomic vulnerability factors that favor second order effects in a disaster. This comprehensive approach allows the identification of different aspects related to physical vulnerability, social fragility, and lack of resilience that can be improved, thus enhancing integrated disaster risk management actions. The outcomes of this comprehensive assessment are currently being used as input to update the disaster risk management plan of Manizales.

Modernist Unreinforced Masonry (URM) Buildings of Barcelona: Seismic Vulnerability and Risk Assessment

Alex Barbat — Sat, 31 Mar 2018 18:20:42 +0200

The main objective of this work is to assess the vulnerability and seismic risk of typical existing modernist unreinforced masonry (URM) modernist buildings and aggregates situated in the Eixample district of Barcelona, part of the architectural heritage of the city. The context of the analysis is the methodology proposed by the Risk-UE project. The buildings are characterized by their capacity spectrum and the earthquake demand is defined by the 5% damped elastic response spectrum, considering deterministic and probabilistic earthquake scenarios. A discussion addresses the basis of the seismic damage states probabilities and the calculated damage index. An important research effort has been focused on the buildings modeling. All the architectural elements and their mechanical properties have been studied and evaluated accurately. It has been evidenced that a detailed and complete knowledge of all the structural elements existing in this type of buildings influence directly their behavior and hence the calculations and the results. The analysis of the isolated buildings and of the aggregate building has been performed for both mentioned seismic scenarios. Finally, a complete discussion of the results is included.

Probabilistic estimation of annual lost economic production due to premature deaths because of earthquakes

Alex Barbat — Sat, 31 Mar 2018 18:09:25 +0200

A methodology to estimate, in a probabilistic way, the annual cost to society of premature deaths because of earthquakes is proposed in this article. The methodology makes use of results obtained by means of prospective and probabilistic seismic risk assessments where expected deaths caused by the collapse of buildings are obtained. Those results, combined with demographic and macroeconomic indicators such as the age distribution, life expectancy at birth, and per capita gross domestic product, are used to estimate the cost to society in terms of lost productivity due to premature mortality because of earthquakes. The proposed methodology does not attempt to estimate nor assign a cost to human lives at any stage, but the one associated to lost productivity at the societal level. One of the descriptors of the methodology is part of the components of the disability adjusted life year, a widely used metric in the public health field that estimates the burden of diseases based mostly on historical data. As an example, the methodology is applied to Medellín, the second largest city of Colombia, finding that the cost of lost productivity due to premature mortality because of earthquakes has a similar order of magnitude to the direct physical losses in the public and private building stock calculated in a previous probabilistic seismic risk assessment.

Holistic Urban Seismic Risk Evaluation of Megacities: Application and Robustness

Alex Barbat — Sat, 31 Mar 2018 17:45:41 +0200

The holistic evaluation of disaster risk is achieved affecting the physical risk with an impact factor, obtained from contextual conditions, such as the socioeconomic fragility and the lack of resilience, that aggravate the initial physical loss scenario. Available data about these conditions at urban level are necessary to apply the method. Abrief explanation of the model is made in this work to illustrate the benefits of this approach that contributes to the effectiveness of disaster risk management, inviting to the action and identifying the hard and soft weaknesses of urban centres.

A laminated structural finite element for the behavior of large non-linear reinforced concrete structures

Alex Barbat — Sat, 31 Mar 2018 11:40:43 +0200

In order to correctly predict the kinematics of complex structures, analysis using three-dimensional finite elements (3DFEs) seems to be the best alternative. However, simulation of large multi-layered structures with many plies can be una ordable with 3DFEs because of the excessive computational cost, especially for non-linear materials. In addition, the discretization of very thin layers can lead to highly distorted FEs carrying numerical issues, therefore, reduced models arise as an a ordable solution. This paper describes a new finite element formulation to perform numerical simulations of laminated reinforced concrete structures. The intention of this work is that the proposed scheme can be applied in the analysis of real-life structures where a high amount of computational resources are needed to fulfill the meshing requirements, hence the resulting formulation has to be a compromise between simplicity and efficiency.
So that, the condensation of a dimension (thickness), mandatory to model three-dimensional structures with twodimensional finite elements (2DFEs), leads to refer all layers contained within such FEs to a plane, which is typically named middle plane or geometrical plane, since its sole function is to serve as a geometrical reference. This work is based on the assumption that the geometrical plane has to be distinguished from a mechanical plane, which is where the resultant sti ness of all layers is contained. It is also assumed in this work that the mechanical plane changes its position due to non-linear response of the component materials.

Energy damage index based on capacity and response spectra

Alex Barbat — Sat, 31 Mar 2018 11:31:35 +0200

To assess the expected seismic damage of a structure, non-linear dynamic analysis and the damage index of Park-Ang have been often used. Depending on the size of the structure and on the duration of the record, the computational effort in dynamic analyses is usually high. In this research a new damage index is proposed based on nonlinear static analysis. The damage index is a linear combination of two energy functions: 1) the strain energy associated to the stiffness variation and the ductility of the structure and 2) the energy dissipated associated to hysteretic cycles. These two energy functions are obtained from the capacity curve of the structure and from the energy balance with the spectral acceleration. To show the ability of the index to represent damage, low-rise steel buildings subjected to seismic actions expected in Mexico City are studied. The results obtained with the new method show a good agreement with those calculated by means of dynamic analyses using the Park-Ang damage index. In average, the Park-Ang damage index is well fitted by the combination of 62% of the strain energy and 38% of the energy dissipated by hysteresis. Moreover, this new damage index allows linking damage to certain characteristics of the seismic actions as, for instance, intensity and duration of the applied seismic action. Therefore, the new approach results in a practice and powerful tool for estimating the seismic damage in buildings, especially when considering probabilistic approaches, where massive computations are needed.

Two-scale approach for the nonlinear dynamic analysis of RC structures with local non-prismatic parts

Alex Barbat — Sat, 31 Mar 2018 11:21:09 +0200

There is general agreement in the fact that fully three-dimensional (3D) numerical techniques provide the most precise tools for simulating the behavior of RC buildings even when their computational costs for real structures became them unpractical. Moreover, one-dimensional formulations (1D) are rather limited for predicting the mechanical behavior of framed structures which present local weakness that can determine their global responses, such as it is the case of poor detailed joints of RC buildings in seismic zones or precast concrete structures. An alternative approach, combining both simplicity and computational efficiency, is given by coupling reduced models for prismatic elements with full 3D models for the zones corresponding to connecting joints. In this work, a two-scale approach is developed for obtaining the nonlinear dynamic response of RC buildings with local non-prismatic parts. At global scale level all the elements are rods; however, if local parts with complex geometry appear, the corresponding elements are analyzed considering fully 3D models which constitute the local scale level. The dimensional-coupling between scales is performed imposing the kinematics hypothesis of the beam model on surface-interfaces of the 3D model. An iterative Newton-Raphson scheme which considers the interaction between scales is developed to obtain the response at global level. The tangential stiffness of the local models are obtained numerically. Computationally, the problem is managed by means of a master-slave approach, where the global scale problem acts as the master and the local models are the slaves; iterative communication between scales considers internal forces and moments as well as tangential tensors. The process stops when global convergence is achieved. From the computational point of view, the developed method is implemented in a parallelized scheme, where the master and slave problems are solved independently by different programs thus minimizing the intervention on existing codes specific for beams and solids. Finally, numerical examples are included.

A compression–tension concrete damage model, applied to a wind turbine reinforced concrete tower

Alex Barbat — Sat, 31 Mar 2018 11:11:11 +0200

Structures subjected to cyclic loads show alternative tension–compression stress states; in such a case, even if certain damage (fracture) is reached during the tension cycle, the computational model of the structure should maintain its capacity to withstand subsequent compression based only on the contact effect in the damaged area (opening, closing and reopening of cracks). In order to control this behavior, a phenomenological constitutive model able to consider the contact as a structural limitation is required. From the constitutive point of view, geomaterials have different damage thresholds for tension and compression and, from the structural point of view, it must be ensured that the material damaged in tension still resist compression. In this case, it is accepted that cracks behave as a contact surface at the structural level. To meet the above mentioned phenomenology, a modification of the damage model
differentiated in tension and compression proposed by Faria et al. [Faria R, Oliver J, Cervera M. A strainbased plastic viscous-damage model for massive concrete structures. Int J Solids Struct 1998; 35:1533–58] is performed in this paper, considering independent strength thresholds in each of these processes, controlled with two independent discontinuity threshold functions. Also, in this work an elasto-plastic constitutive model is used to represent the behaviour of the steel bars.

Equivalent linearization of the Bouc–Wen hysteretic model

Alex Barbat — Sat, 31 Mar 2018 11:01:20 +0200

The smooth endochronic hysteretic Bouc–Wen model is studied from the point of view of random vibration. The sources of the
errors of the method of equivalent linearization applied to this model using the hypothesis of joint Gaussian behaviour are examined.
The method of linearization for softening hysteretic models proposed by the authors, which is based on a combination of Dirac
and Gauss densities, is developed and applied to the Bouc–Wen model under a variety of conditions. It is shown that the method
gives excellent estimations of the response statistics without increasing the computational effort required by the conventional technique.

Seismic damage evaluation of reinforced concrete buildings with slit walls

Alex Barbat — Sat, 31 Mar 2018 09:46:25 +0200

The purpose of this paper is to investigate a reinforced concrete multi-storey building with dissipative structural walls. These walls can improve the behaviour of a tall multi-storey building. The damage of a building with dissipative walls is compared with that of a building with solid walls. The comparative nonlinear dynamic analysis is performed by means of the SAP2000 software, using a layer model. In order to increase the seismic performance of a building with structural walls is to create slit zones with short connections into the walls. The short connections are introduced as a link element with multi-linear pivot hysteretic plasticity behaviour. The hysteretic rules and parameters of these short connections were proposed by the authors and used in this study. Using the proposed computational model for the slit wall, a seismic analysis of a multi-storey building with slit walls was done. From the results obtained, the advantages of the
proposed model are observed. Unlike other studies on slit walls with short connections, which are focused mostly on the nonlinear dynamic behaviour of the short connections, in this paper the authors take into consideration the whole structural system, wall, connections and frames.

Seismic damage evaluation of reinforced concrete slit walls

Alex Barbat — Sat, 31 Mar 2018 09:31:42 +0200

The purpose of this paper is to investigate a dissipative reinforced concrete structural wall that can improve the behavior of a tall multi-storey building, evaluating the damage it undergoes in comparison with that of a solid wall. The comparative nonlinear dynamic analysis between a dissipative and a solid wall is performed by means of SAP2000 software and using a layered model. The solution to increase the seismic performance of a reinforced concrete structural wall is to create a slit zone with short connections. These are introduced as a link element with multi-linear pivot hysteretic plasticity behavior. The behavior of these short connections is modeled
using the finite element software ANSYS 12. The authors propose to evaluate the damage of reinforced concrete slit walls with short connections using seismic analysis. Using the proposed computational model, a seismic analysis of the dissipative wall belonging to a multi-storey building was performed. From the results obtained, the advantages of the proposed model are observed. The proposed computational model consumes low processing resources and reduces the processing time for a dynamic pushover analysis. Unlike other studies on slit walls with short connections, which are focussed mostly on the nonlinear dynamic behavior of the short connections, in this paper the authors take into consideration the whole structural system, wall and connections.

Active control of building structures under measured seismic loads

Alex Barbat — Sat, 31 Mar 2018 08:59:23 +0200

The concept of active control has been introduced in recent years in order to reduce the seismic response of structures. A predictive control methodology is used to formulate a discrete-time structural control algorithm. This algorithm computes the control forces by using not only the information provided by the structural response but also that given by the measurement of the seismic ground acceleration. Results for checking the effectiveness of the control algorithm in reducing the structural response are presented.

Plastic-damage analysis of reinforced concrete frames

Alex Barbat — Sat, 31 Mar 2018 08:51:53 +0200

The purpose of this paper is to develop an improved analytical model for predicting the damage response of multi-storey reinforced concrete frames modelled as an elastic beam-column with two inelastic hinges at its ends. The damage is evaluated in the hinges, using the concentrated damage concepts and a new member damage evaluation method for frame members, which leads to a meaningful global damage index of the structure. A numerical procedure for predicting the damage indices of the structures using matrix structural analysis, plastic theory and continuum damage model is also developed. The method is adequate for the prediction of the failure mechanisms. Using the proposed framework, various numerical examples are included. Based on the obtained results, advantages and limitation of the proposed model are observed. The proposed numerical model is useful to solve multi-storey reinforced concrete frames using a procedure that combines structural finite elements (beams) with moment-curvature constitutive models derived from classic stress-strain ones. It is an inexpensive and reliable procedure to model the frame structures.

FLEXIBILITY-BASED LINEAR DYNAMIC ANALYSIS OF COMPLEX STRUCTURES WITH CURVED-3D MEMBERS

Alex Barbat — Fri, 30 Mar 2018 23:19:02 +0200

A fexibility-based formulation of a new mass matrix for the dynamic analysis of spatial frames consisting of curved elements with variable cross-sections is presented. The main characteristic of such formulations is the exact equilibrium of forces at any interior point, with no additional hypotheses about the distribution of displacements, strains or stresses. Accordingly, the derived element mass matrix takes into account the exact sti ness and mass distribution throughout each element. In validation tests, results obtained with this method are compared with those obtained by other numerical or analytical formulations, showing the accuracy of the proposed method. The comparison of experimental results for a multispan arch bridge subjected to a dynamic load with those achieved by means of the proposed method are nally included to illustrate its eciency in the treatment of complex structures.

A method to estimate intensity occurrence probabilities in low seismic activity regions

Alex Barbat — Fri, 30 Mar 2018 23:11:23 +0200

The estimation of site intensity occurrence probabilities in low seismic activity regions has been studied from different points of view. However, no method has been definitively established because several problems arise when macroseismic historical data are incomplete and the active zones are not well determined. The purpose of this paper is to present a method that estimates site occurrence probabilities and, at the same time, measures the uncertainties inherent in these probabilities in low activity regions. The region to be studied is divided into very broad seismic zones. An exponential intensity probability law is adjusted for each zone and the degree of uncertainty in the assumed incompleteness of the catalogue is evaluated for each intensity. These probabilities are used to establish what may be termed 'prior site occurrence models'. A Bayesian method is used to improve 'prior models' and to obtain the 'posterior site occurrence models'. Epicentre locations are used to recover spatial information lost in the prior broad zoning. This Bayesian correction permits the use of specific attenuation for different events and may take into account, by means of conservative
criteria, epicentre location errors. Following Bayesian methods, probabilities are assumed to be random variables and their distribution may be used to estímate the degree of uncertainty arising from (a) the statistical variance of estimators, (b) catalogue incompleteness and (e) mismatch of data to prior assumptions such as Poisson distribution for events and exponential distribution for intensíties. The results are maps of probability and uncertainty for each intensity. These maps exhibit better spatial definition than those obtained by means of simple, broad zones. Sorne results for Catalonia (NE of Spain) are shown.

Prioritizing interventions to reduce seismic vulnerability in school facilities in Colombia

Alex Barbat — Fri, 30 Mar 2018 22:43:04 +0200

Colombian seismic code NSR-98 establishes the requirement for the seismic vulnerability analysis and, if necessary, the strengthening of public facilities (schools). Due to the investments required by risk reduction programs, it is necessary to establish criteria for assigning priorities for the interventions. This article proposes a methodology for obtaining a Benefit-Cost Ratio (BCR) at the
subnational level, by assessing the expected annual average loss of the built area of public schools and the retrofitting cost. The BCR is estimated as the difference between the estimates of the net present value for status quo and retrofitted states, these two divided by the retrofitting costs. According to the BCR, 47.3% of the total school built area of Colombia should be retrofitted where the retrofitting
costs correspond to 25% of the total investment. Proposed BCR is useful for prioritizing regions in function of the feasibility of reducing the seismic vulnerability of the schools.

Computational Tool for Post-Earthquake Evaluation of Damage in Buildings

Alex Barbat — Fri, 30 Mar 2018 22:32:32 +0200

A method and a computational tool oriented to assist the damage and safety evaluation of buildings after strong earthquakes is described in this article. The input of the model is the subjective and incomplete information on the building state, obtained by inspectors which are possibly not expert professionals of the field of building safety. The damage levels of the structural components are usually described by linguistic qualifications which can be adequately processed by computational intelligence techniques based on neuro-fuzzy systems what facilitate the complex and urgent tasks of engineering decision-making on the building occupancy after a seismic disaster. The hybrid neuro-fuzzy system used is based on a special three-layer feedforward artificial neural network and fuzzy rule bases and is an effective
tool during the emergency response phase providing decisions about safety, habitability, and reparability of the buildings. Examples of application of the computer program are given for two different building classes.

Damage scenarios simulation for seismic risk assessment in urban zones

Alex Barbat — Fri, 30 Mar 2018 22:24:46 +0200

A methodology for simulating seismic damage of unreinforced mansonry buildings for seismic risk assessment of urban areas is presented in this paper. The methodology is based on the Italian vulnerability index and on the results of a post earthqueke damage survey study whose main result was an observed vulnerability function. The Monte Carlo method was than used to simulate damage probability matrices, fragility curves and vulnerability functions, all of which are the basis of a seismic risk study. The simulation process required the generation of thousands of hypothetical buildings, the analysis of their seismic behaviour and probabilistic studies of the computed results. As an example, probable damage scenarios werw developed for an urban area of Barcelona, Spain.

Revealing the socioeconomic impact of small disasters in Colombia using the DesInventar database

Alex Barbat — Fri, 30 Mar 2018 19:57:16 +0200

Small disasters are usually the product of climate variability and climate change. Analysis of them illustrates that they increase difficulties for local development—frequently affecting the livelihoods of poor people and perpetuating their level of poverty and human insecurity—and entail challenges for a country’s development. In contrast to extreme events, small disasters are often invisible at the national level and their effects are not considered as relevant from a macroeconomic standpoint. Nevertheless, their accumulated impact causes economic, environmental and social problems. This paper presents the results of an evaluation of the DesInventar database, developed
in 1994 by the Network for Social Studies in Disaster Prevention in Latin America. In addition, it proposes a new version of the Local Disaster Index developed in 2005 within the framework of the Disaster Risk and Management Indicators Program for the Americas, with the support of the Inter-American Development Bank.

Disaster risk from a macroeconomic perspective: a metric for fiscal vulnerability evaluation

Alex Barbat — Fri, 30 Mar 2018 19:51:09 +0200

The Disaster Deficit Index (DDI) measures macroeconomic and financial risk in a country according to possible catastrophic scenario events. Extreme disasters can generate financial deficit due to sudden and elevated need of resources to restore affected inventories. The DDI captures the relationship between the economic loss that a country could experience when a catastrophic event occurs and the availability of funds to address the situation. The proposed model utilises the procedures of the insurance industry in establishing probable losses, based on critical impacts during a given period of exposure; for economic resilience, the model allows one to calculate the country’s financial ability to cope with a critical impact. There are limitations and costs associated with access to resources that one must consider as feasible values according to the country’s macroeconomic and financial conditions. This paper presents the DDI model and the results of its application to 19 countries of the Americas and aims to guide governmental decision-making in disaster risk reduction.

A numerical procedure simulating RC structures reinforced with FRP using the serial/parallel mixing theory

Alex Barbat — Fri, 30 Mar 2018 18:43:03 +0200

The use of fiber reinforced polymers (FRP) to reinforce and retrofit reinforced concrete (RC) structures has become one of the main
applications of composites in civil engineering. This paper describes a procedure, based on a finite element formulation, that can be used
to perform numerical simulations of RC structures reinforced with FRP. Composites are treated using the serial/parallel mixing theory,
which deduces the composite behavior from the constitutive equations of its components. A new construction-stages algorithm is developed for simulating retrofitted structures. The performance of the proposed formulation is proved comparing numerical and experimental results. Finally, the developed code is used to obtain the optimum FRP reinforcement configuration for a RC frame structure.

Plastic–damage seismic model for reinforced concrete frames

Alex Barbat — Fri, 30 Mar 2018 18:35:43 +0200

A plastic–damage model for reinforced concrete frames is developed in this article, based on the classical plastic model and the continuum damage model. The plastic–damage constitutive law is implemented into a beam model for framed structures, in which these are described by elastic beams and columns with two inelastic hinges at their ends. A numerical procedure for predicting the member and
global damage in framed structures using the matrix analysis is developed. Additionally, the article introduces a damage index useful in
evaluating the state of structural members and a meaningful global damage index for whole structure. The plastic–damage model,
together with the member and global damage indices, are adequate for the computation of the limit load of reinforced concrete frames
subjected to seismic actions. Examples of applications of the methodology to the non-linear analysis of reinforced concrete framed structures are finally given.

EFFECTIVENESS OF BLOCK ITERATIVE SCHEMES IN COMPUTING THE SEISMIC RESPONSE OF BUILDINGS WITH NONLINEAR BASE ISOLATION

Alex Barbat — Fri, 30 Mar 2018 18:30:07 +0200

The conventional form of solving the equations of motion governing the seismic response of building structures with nonlinear base isolation consists of using monolithic step by step integrationmethods. As an alternative, the application of a block iterative scheme is examined in this paper. After describing the particularities of the equations of motion of the structure with base isolation, different block
iterative schemes are described. Their effectiveness is discussed and compared with that of monolithic step by step integration methods. Adequate examples are used with the aim of performing numerical comparisons.

Parameter identification of large-scale magnetorheological dampers in a benchmark building

Alex Barbat — Fri, 30 Mar 2018 18:16:37 +0200

Magnetorheological (MR) dampers are devices that can be used for vibration reduction in structures. However, to use these devices in an effective way, a precise modeling is required. In this sense, in this paper we consider a modified parameter identification method of large-scale magnetorheological dampers which are represented using the normalized Bouc–Wen model. The main benefit of the proposed
identification algorithm is the accuracy of the parameter estimation. The validation of the parameter identification method has been carried out using a black box model of an MR damper in a smart base-isolated benchmark building. Magnetorheological dampers are used in this numerical platform both as isolation bearings as well as semi-active control devices.

Hierarchical semi-active control of base-isolated structures using a new inverse model of magnetorheological dampers

Alex Barbat — Fri, 30 Mar 2018 18:10:29 +0200

Magnetorheological (MR) dampers have received special attention as semi-active devices for mitigation of structural vibrations. Because of the inherent nonlinearity of these devices, it is difficult to obtain a reasonable mathematical inverse model. This paper is concerned with two related concepts. On one hand, it presents a new inverse model of MR dampers based on the normalized Bouc–Wen model. On the other hand, it considers a hybrid seismic control system for building structures, which combines a class of passive nonlinear base isolator with a semi-active control system. In this application, the MR damper is used as a semi-active device in which the voltage is updated by a feedback control loop. The management of MR dampers is performed in a hierarchical way according to the desired control force, the actual force of the dampers and its capacity to react. The control is applied to a numerical three-dimensional benchmark problem which is used by the structural control community as a state-of-the-art model for numerical experiments of seismic control attenuation. The performance indices show that the proposed semi-active controller behaves satisfactorily.

A finite element methodology for local/global damage evaluation in civil engineering structures

Alex Barbat — Fri, 30 Mar 2018 17:54:24 +0200

The paper introduces a new global damage evaluation method which leads to a meaningful global damage index. A numerical procedure for the prediction of local and global damage in civil engineering structures using the finite element method and a continuum damage model, is presented. The method is adequate for the computation of the limit load in reinforced concrete (RC) structures and for the prediction of the failure mechanisms. Details of the applied damage model are given together with a description of the finite element implementation and the procedure for computing the global damage parameters. Examples of applications of the methodology to the nonlinear analysis of a range of RC structures, are presented.

Performance of Buildings under Earthquakes in Barcelona, Spain

Alex Barbat — Fri, 30 Mar 2018 12:40:02 +0200

The seismic risk of the buildings of Barcelona, Spain, is analyzed by using a method based on the capacity spectrum. The seismic hazard in the area of the city is described by means of the reduced 5% damped elastic response spectrum. Obtaining fragility curves for the most important building types of an urban center requires an important amount of information about the structures and the use of nonlinear structural analysis tools. The information on the buildings of Barcelona was obtainedby collecting, arranging, improving, and completing the database of the housing and current buildings. The buildings existing in Barcelona are mainly of two types: unreinforced masonry structures and reinforced concrete buildings with waffled slab floors. In addition, the Arc-View software was used to create a GIS tool for managing the collected information to develop seismic risk scenarios. This study shows that the vulnerability of the buildings is significant and therefore, in spite of the medium to low seismic hazard in the area of the city, the expected seismic risk is considerable.

Static analysis of beam structures under nonlinear geometric and constitutive behavior

Alex Barbat — Fri, 30 Mar 2018 12:28:46 +0200

In this article, the nonlinear constitutive behavior is considered in the geometrically nonlinear formulation for beams proposed by
Simo and Vu-Quoc. The displacement based method is employed in solving the resulting nonlinear problem in the static case. Thermodynamically consistent three-dimensional constitutive laws are used in describing the material behavior, leading to a more precise estimation of the energy dissipated by the structures. The simple mixing rule is also applied in modeling materials which are composed by several simple components. An appropriated cross sectional analysis is implemented under the assumption and limitations of the planarity
of the beam cross sections. Special attention is paid to the development of a method for defining the global damage state of a structure
based on a scalar damage index capable of describing the residual strength and the load carrying capacity. Several numerical examples,
including composite materials and strain localization, are presented and discussed.

Dynamic analysis of beam structures considering geometric and constitutive nonlinearity

Alex Barbat — Fri, 30 Mar 2018 12:22:04 +0200

A fully geometric and constitutive nonlinear model for the description of the dynamic behavior of beam structures is developed. The
proposed formulation is based on the geometrically exact formulation for beams due to Simo but, in this article an intermediate curved
reference configuration is considered. The resulting deformation map belongs to a nonlinear differential manifold and, therefore, an
appropriated version of Newmark’s scheme is used in updating the kinematics variables. Each material point of the cross-section is
assumed to be composed of several simple materials with their own constitutive laws. The mixing rule is used to describe the resulting
composite. An explicit expression for the objective measure of the strain rate acting on each material point is deduced in this article.
Details about its numerical implementation in the time-stepping scheme are also addressed. Viscosity is included at the constitutive level by means of a thermodynamically consistent visco damage model developed in terms of the material description of the First Piola Kirchhoff stress vector. The constitutive part of the tangent tensor is deduced including the effect of rate dependent inelasticity. Finally, several numerical examples, validating the proposed formulation, are given.

Moment–curvature damage model for bridges subjected to seismic loads

Alex Barbat — Fri, 30 Mar 2018 11:50:40 +0200

The evaluation of the damage caused by horizontal loads, such as seismic action, to existing bridges has received an important attention
in recent years, because it is the first step towards reducing casualties and economic losses. In damage detection and evaluation, the
application of simple and reliable models has been prioritized, because they are necessary in further multi-analyses required by Monte
Carlo simulations. A simplified moment–curvature damage evaluation model, capable of evaluating the expected seismic behavior of RC
highway bridges is proposed in this paper. The damage of a pier is related to the reduction of the cross-sectional moment of inertia of the
bridge piers. Therefore, the evaluation of the damage is based on a non-linear analysis determining the changes of the mentioned moment of inertia. The model was validated using experimental results obtained at the JRC Ispra for the Warth Bridge of Austria and also FEM analyses performed by other authors for the same bridge.

Capacity, fragility and damage in reinforced concrete buildings: a probabilistic approach

Alex Barbat — Thu, 29 Mar 2018 23:15:29 +0200

The main goals of this article are to analyze the use of simplified deterministic nonlinear static procedures for assessing the seismic response of buildings and to evaluate the influence that the uncertainties in the mechanical properties of the materials and in the features of the seismic actions have in the uncertainties of the structural response. A reinforced concrete building is used as a guiding case study. In the calculation of the expected spectral displacement, deterministic nonlinear static methods are simple and straightforward. For not severe earthquakes these approaches lead to somewhat conservative but adequate results when compared to more sophisticated procedures involving nonlinear dynamic analyses. Concerning the probabilistic assessment, the strength properties of the materials, concrete and steel, and the seismic action are considered as random variables. TheMonteCarlo method is then used to analyze the structural response of the building. The obtained results show that significant uncertainties are expected; uncertainties in the structural response increase with the severity of the seismic actions. The major influence in the randomness of the structural
response comes from the randomness of the seismic action. A useful example for selected earthquake scenarios is used to illustrate the applicability of the probabilistic approach for assessing expected damage and risk. An important conclusion of this work is the need of broaching the fragility of the buildings and expected damage assessment issues from a probabilistic perspective.

Capacity, damage and fragility models for steel buildings: a probabilistic approach

Alex Barbat — Thu, 29 Mar 2018 23:01:23 +0200

Recently proposed capacity-based damage indices and parametric models for capacity curves are applied to frame steel buildings located in soft soils of the Mexico City. To do that, the seismic performance of 2D models of low-, mid- and high-rise buildings is
assessed. Deterministic and probabilistic nonlinear static and incremental dynamic analyses are implemented. Monte Carlo simulations and the Latin Hypercube sampling technique are used. Seismic actions are selected among accelerograms recorded in the study area. Spectral matching techniques are applied, so that the acceleration time histories have a predefined mean response spectrum and controlled error. The design spectrum of the Mexican seismic code for the zone is used as target spectrum. The well-known Park and Ang damage index allows calibrating the capacity-based damage index. Both damage indices take into account the contribution to damage of the stiffness degradation and of the energy dissipation. Damage states and fragility curves are also obtained and discussed in detail. The results reveal the versatility, robustness and reliability of the parametric model for capacity curves, which allow modelling the nonlinear part of the capacity curves by the cumulative integral of a cumulative lognormal function. However, these new capacitybased damage index and capacity models have been tested for and applied to 2D frame buildings only; they have not been applied to 3D building models yet. The Park and Ang and the capacity-based damage indices show that for the analysed buildings, the contribution to damage of the stiffness degradation is in the range 66–77% and that of energy loss is in the range 29–34%. The lowest contribution of energy dissipation (29%) is found for the low-rise, more rigid, building. The energy contribution would raise with the ductility of the building and with the duration of the strong ground motion. High-rise frame buildings in soft soils of Mexico City show the worst performance so that the use of adequate braced frames to control the displacements could be recommended.

Seismic hazard and risk scenarios for Barcelona, Spain, using the Risk-UE vulnerability index method

Alex Barbat — Thu, 29 Mar 2018 22:48:17 +0200

The vulnerability index method, in its version developed in the framework of the European project Risk-UE, has been adapted and applied in this article, to evaluate the seismic risk for the city of Barcelona (Spain) through a GIS based tool. According to this method, which defines five damage states, the action is expressed in terms of the macroseismic intensity and the seismic quality of the buildings by means of a vulnerability index. The probabilities of damage states are obtained considering a binomial or beta-equivalent probability distribution. The most relevant seismic risk evaluation results obtained, for current buildings and monuments of Barcelona, are given in the article as scenarios of expected losses.

Parametric model for capacity curves

Alex Barbat — Thu, 29 Mar 2018 22:37:54 +0200

A parametric model for capacity curves and capacity spectra is proposed. The capacity curve is considered to be composed of a linear part and a nonlinear part. The normalized nonlinear part is modelled by means of a cumulative lognormal function. Instead, the cumulative Beta function can be used. Moreover, this new conceptualization of the capacity curves allows defining stiffness and energy functions relative to the total energy loss and stiffness degradation at the ultimate capacity point. Based on these functions, a new damage index is proposed and it is shown that this index, obtained from nonlinear static analysis, is compatible with the Park and Ang index obtained from dynamic analysis. This capacity based damage index allows setting up a fragility model. Specific reinforced concrete buildings are used to illustrate the adequacy of the capacity, damage and fragility models. The usefulness of the models here proposed is highlighted showing how the parametric model is representative for a family of capacity curves having the same normalized nonlinear part and how important variables can be tabulated as empirical functions of the two main parameters defining the capacity model. The availability of this new mathematical model may be a powerful tool for current earthquake engineering research or practice, especially in probabilistic approaches where massive computations are needed.

Seismic performance of a block of buildings representative of the typical construction in the Eixample district in Barcelona (Spain)

Alex Barbat — Thu, 29 Mar 2018 19:27:17 +0200

Between the late nineteenth century and the early twentieth century, Barcelona was expanded, occupying the terrains connecting the old walled city and the nearby towns of the plateau of Barcelona. At that time, a large number of unreinforced masonry buildings were constructed and nowadays many of them are still used as dwellings. Though built individually, these buildings are connected to adjacent buildings, forming blocks composed of aggregates. In order to analyze the seismic behavior of isolated buildings and aggregates, two typical central buildings and one typical corner building have been chosen. The two central buildings and the corner building are referred as C1, C2, and E buildings. Two corner buildings and two central buildings have been connected in order to simulate a block side. This aggregate is referred as AGG and it is composed by the following sequence of individual buildings: E-C1-C2-E. Original plans and drawings of existing buildings are then used to model these buildings. The modeled buildings have five stories. Standard pushover analyses lead to evaluate their seismic performance by means of capacity spectra and fragility curves. The analysis has been carried out in the parallel (Ux) and transversal (Uy) directions to the street. Then, a capacity spectrum based method is used to analyze the seismic behavior of these buildings considered as individual buildings and as an aggregate. Two earthquake scenarios are considered. The first one is a deterministic scenario which is based on a historical earthquake occurred in 1824, 25 km away from the city and the second one is a probabilistic scenario, which represents the ground motion with a probability of occurrence of 10% in 50 years. The soil local effects have been also considered and both scenarios have been used to assess the expected damage. Four non-null damage states are considered: slight (1), moderate (2), severe (3) and extensive-to-collapse (4). For the type of soil where most of the buildings are, and in the Ux direction, the four buildings show a similar behavior. The mean damage grade is 2.3 for the deterministic scenario and 2.7 for the probabilistic one. This means that moderate to severe damage is expected in both cases; furthermore, in the case of the deterministic scenario more than 10% of the buildings would suffer extensive-to-collapse damage and nearly 20% for the probabilistic scenario, confirming the high vulnerability of such buildings. The differences in the expected damage are due to the significant different characteristics of the response spectra of the earthquake scenarios in the range of the fundamental periods of the buildings.

New methodology for urban seismic risk assessment from a holistic perspective

Alex Barbat — Thu, 29 Mar 2018 19:06:04 +0200

The seismic risk evaluation usually works with a fragmented concept of risk, which depends on the scientific discipline in charge of the assessment. To achieve an effective performance of the risk management, it is necessary to define risk as the potential economic, social and environmental consequences due to a hazardous phenomenon in a period of time. This article presents a methodology which evaluates the seismic risk from a holistic perspective, which means, it takes into account the expected physical damage and also the conditions related to social fragility and lack of resilience, which favour the second order effects when a hazard event strikes an urban centre. This seeks to obtain results which are useful in the decision making process for risk reduction. The proposed method for urban seismic risk evaluation uses the fuzzy sets theory in order to handle qualitative concepts and variables involved in the assessment, the physical risk level and aggravation level, related to the social fragility and the lack of resilience, are evaluated and finally a total risk level is determinate.

Non-linear static procedures applied to high-rise residential URM buildings

Alex Barbat — Thu, 29 Mar 2018 18:39:03 +0200

In this work, the vulnerability of an unreinforced masonry building, evaluated on the one hand by using the incremental dynamic analysis, and on the other hand by using nine representative non-linear static incremental procedures, is compared. For comparison
reasons among the different non-linear static procedures, the obtained incremental dynamic analyses results are used as reference values. The aim of this analysis is to evaluate the applicability and reliability of the diverse non-linear static procedures for unreinforced
masonry buildings, and to propose modifications oriented to improve their use in this typology of structures. For this purpose, a fully representative unreinforced masonry building of the dominating building type in the Eixample district of Barcelona, is analyzed. Furthermore, the conditional spectrum approach procedure has been applied with the aim to conveniently define the seismic demand. Regarding the definition of the fragility curves, two different methodologies were used for each non-linear static procedure and incremental dynamic analyzes. Subsequently, the corresponding damage indices as well as the damage curves were calculated and compared for the different considered peak ground acceleration values. The results of this comparison seem to confirm that the damage curves obtained by performing the NSP and by applying the Risk-UE methodology overestimate the damage corresponding to low values of the PGA and underestimate the damage for higher values of the PGA.

Ground-Shaking Scenarios and Urban Risk Evaluation of Barcelona using the Risk-UE Capacity Spectrum Based Method

Alex Barbat — Thu, 29 Mar 2018 18:11:58 +0200

The Capacity Spectrum Based Method (CSBM) developed in the framework of the European project Risk-UE has been applied to evaluate the seismic risk for the city of Barcelona, Spain. Accordingly, four damage states are defined for the buildings, the action is expressed in terms of spectral values and the seismic quality of the buildings, that is, their vulnerability, is evaluated by means of capacity spectra. The probabilities of the damage states are obtained considering a lognormal probability distribution. The most relevant seismic risk evaluation results obtained for Barcelona, Spain, are given in the article as scenarios of expected losses.

SEISMIC SAFETY OF LOW DUCTILITY STRUCTURES USED IN SPAIN

Alex Barbat — Thu, 29 Mar 2018 17:57:40 +0200

The most important aspects of the design, seismic damage evaluation and safety assessment of structures with low ductility like waffle slabs buildings or flat beams framed buildings are examined in this work. These reinforced concrete structural typologies are the most used in Spain for new buildings but many seismic codes do not recommend them in seismic areas. Their expected seismic performance and safety are evaluated herein by means of incremental non linear structural analysis (pushover analysis) and incremental dynamic analysis which provides capacity curves allowing evaluating their seismic behaviour. The seismic hazard is described by means of the reduced 5% damped elastic response spectrum of the Spanish seismic design code. The most important results of the study are the fragility curves calculated for the mentioned building types, which allow obtaining the probability of different damage states of the structures as well as damage probability matrices. The results, which show high vulnerability of the studied low ductility building classes, are compared with those corresponding to ductile framed structures.

Adaptive Control of Uncertain Coupled Mechanical Systems with Application to Base-Isolated Structures

Alex Barbat — Thu, 29 Mar 2018 11:40:47 +0200

A problem of feedback stabilization is addressed for a class of uncertain nonlinear mechanical systems with n degrees of freedom and nc < n control inputs. Each system of the class has the structure of two coupled subsystems with nc and nr degrees of freedom, respectively, a prototype being an uncertain base isolated building structure with n degrees of freedom actively controlled via actuators applying forces to specific degrees of freedom of the base movement, nc < n in number. A nonlinear adaptive feedback strategy is described, which,
under appropriate assumptions on the system uncertainties, guarantees a form of practical stability of the zero state. Numerical simulations are also presented to illustrate the application of the control strategy to a base isolated building.

APPLICATION OF QUALITATIVE REASONING IN ENGINEERING

Alex Barbat — Thu, 29 Mar 2018 11:25:22 +0200

Qualitative reasoning is an alternative problem-solving technique useful for the conceptual design of structures. Qualitative reasoning represents the relationships between parameters in a model, and a search computation assigns values represented by intervals and relevant points in the behavior. The traditional difference between analysis and design or input and output parameters in a procedural computation is not existent in qualitative reasoning, since all the parameters in a model are equally represented. Qualitative reasoning derives values for parameters even with incomplete and imprecise knowledge about the model. This work presents a qualitative structural analysis framework, suitable for the evaluation of conceptual designs as well as for tutoring systems. The framework has been implemented in a computer program called Agrippa using the computer language Prolog. Based on a representation of fundamental principles of equilibrium, compatibility, and force-deformation and an incomplete knowledge of geometry and topology, Agrippa derives the signs and relative magnitude of forces and displacements for three-dimensional models of structures.

Quina relació hi ha entre el model econòmic d’una plataforma d’Economia col·laborativa i la seva governança?

Ricard Espelt — Thu, 29 Mar 2018 11:23:01 +0200

L'Economia Col·laborativa (EC), és a dir, el consum col·laboratiu i la producció de capital i mà d'obra entre grups distribuïts recolzats per una plataforma digital, està creixent ràpidament i exponencialment. El seu desenvolupament planteja una sèrie de desafiaments:

L’expectativa generada al voltant de les iniciatives d’EC les augura a contribuir a un desenvolupament sostenible de la societat que, al mateix temps, no sempre contribueix als béns comuns i a una democratització de l'economia.
Al mateix temps que una declaració de la Unió Europea del gener de 2014 subratlla la capacitat d’innovació i d’aportació a l’ecologia de l’EC, és necessària una revisió holística de l’avaluació d’aquestes iniciatives per considerar el seu paper en la transformació social, econòmica i medi ambiental de la societat.
L'impacte pertorbador del model EC més conegut, el de les corporacions com Uber i Airbnb, suscita una enorme controversia, mentre que existeixen models alternatius reeixits, com ara els comuns digitals i el cooperativisme de la plataforma que han rebut una atenció limitada.

En aquest article estudiarem la relació que hi ha entre el model econòmic d’una plataforma d’EC i la seva governança. Per fer-ho analitzarem el model econòmic i de governança de 100 plataformes d’EC amb impacte a la ciutat de Barcelona. Els resultats d’aquesta investigació ens mostren que hi ha una correlació entre el model econòmic d’una plataforma d’EC i el seu model de governança. Aquests resultats ens signifiquen la rellevància que té el govern d’una plataforma digital que promogui l’EC.

Mobilitat Urbana a la Regio Metropolitana de Barcelona. Situació actual, tendencies í perpectives futures

Sergi Saurí — Wed, 28 Mar 2018 23:27:44 +0200

Hi ha tendència a l’augment de la població a les ciutats i un increment de la mobilitat, paral·lel al creixement econòmic, que converteix la congestió i, per consegüent, la pol·lució entre els principals problemes de les ciutats. I en un context on la qualitat de vida a les ciutats s’està convertint, sens dubte, en l’eix vertebrador de les polítiques municipals.

Al mateix temps, s’estan produint en els darrers anys dos importants transformacions: canvi en el model energètic en la mobilitat i un desenvolupament vigorós de les tecnologies de les comunicacions i de la informació. Transformacions que estant tenint i tindran encara una incidència no menyspreable en el comportament i gestió de la mobilitat.

L’objectiu de la ponència és analitzar la mobilitat urbana en les principals ciutats de Catalunya, i especialment en l’àmbit de la Regió Metropolitana de Barcelona, des de l’òptica de la quantia de desplaçaments i repartiment modals fins l’impacte econòmic i ambiental de la mobilitat. L’anàlisi, inclourà així mateix, les tendències i perspectives de canvi en l’àmbit de la mobilitat, fruit, en gran part, d’aquestes transformacions indicades.

A finite element method for hydrodynamic testing of ship forms

Julio García-Espinosa — Wed, 28 Mar 2018 09:56:48 +0200

This paper presents advances in recent work of the authors to derive a fractional step scheme based on the stabilized finite element method that allows overcoming the above mentioned problem, resulting in a efficient time accurate scheme.

The starting point is the modified governing differential equations for the incompressible turbulent viscous flow and the free surface condition incorporating the necessary stabilization terms via a finite calculus (FIC) procedure developed by the authors . This technique is based on writting the different balance equations over a domain of finite size and retaining higher order terms. These terms incorporate the ingredients for the necessary stabilization of any transient and steady state numerical solution already at the differential equations level.

The resulting stabilized equations are integrated in space using the standard finite element method, and in time using an implicit and uncoupled second order fractional step method.

Els objectius de les Nacions Unides pel desenvolupament sostenible 2016-2030

Daniel Quer — Tue, 27 Mar 2018 17:43:01 +0200

Les Nacions Unides han impulsat el desenvolupament dels països pobres des de els anys seixantes del segle XX tan per l’acció dels seus estats membres com de les agencies intergovernamentals del seu grup com de ONG, altres organismes com l’OCDE i empreses multinacionals implicades en una Responsabilitat Corporativa global. Això s’ha traduït en una sèrie de conferencies internacionals, els Objectius del Mil·lenni de 2000 a 2015, el Global Compact i els Objectius de Desenvolupament Sostenible 2015-2030. En aquestes pagines s’analitza el progres realitzat a través d’aquestes iniciatives que s’han plasmat en 8 Objectius del Mil·lenni (ODM) i 17 Objectius de Desenvolupament Sostenible (ODS)

Energía Limpia para todos los Ciudadanos: ¿hacia dónde va Europa?

Joan Batalla Bejerano — Tue, 27 Mar 2018 17:08:02 +0200

El cambio climático es un hecho fuera de duda que requiere de una transición energética que avance hacia una economía descarbonizada en un escenario a medio y largo plazo con objetivos a 2030 y 2050.

Con este objetivo, el pasado día 30 de noviembre vio la luz el esperado paquete legislativo de energía y clima de la Comisión Europea, bajo el título de “Energía Limpia para todos los Ciudadanos”. Iniciativa comunitaria que comprende varias propuestas de Directivas, Reglamentos y otros documentos que marcarán el rumbo de la política energética de la Unión en los próximos años. La redacción final de todas estas propuestas, en estos momentos en fase de análisis y debate en el Parlamento europeo, sin duda será la herramienta clave para cumplir con los objetivos marcados por la Unión Europea que emanan del Acuerdo de París de 2016.

Una indudable apuesta política por el liderazgo de la Unión Europea en la transición hacia un sistema energético cada vez más respetuoso con el medioambiente, dando prioridad a la eficiencia, al desarrollo de renovables y al papel dinamizador del consumidor en el funcionamiento del mercado eléctrico. Un proceso que debe ser visto como un campo de oportunidad y progreso en la medida que afecta a multitud de sectores como el energético, transporte, industria, edificación, etc. y que exige de un análisis detallada de sus potenciales implicaciones económicas, sociales y medioambientales.

Políticas públicas para una efectiva transformación del sector energético: el papel de la regulación

Joan Batalla Bejerano — Tue, 27 Mar 2018 17:07:02 +0200

El Acuerdo de París, alcanzado en la XXI Conferencia de las Partes (COP21) de la Convención Marco de las Naciones Unidas sobre el Cambio Climático, contempla el compromiso de alcanzar la neutralidad de emisiones de gases de efecto invernadero (GEI) entre 2050 y 2100 para contener el efecto calentamiento de la Tierra. Un objetivo de descarbonización tan ambicioso como este exige de un profundo cambio en las formas de producción y consumo de energía en el horizonte del 2050. En otras palabras, la lucha contra el cambio climático y los efectos que se derivan del mismo, exige cambiar patrones y modos de consumo, incrementar el grado de penetración de las energías renovables, así como mejorar de forma drástica en ámbitos como la eficiencia energética.

Este cambio de modelo económico – sin obviar su relevancia es necesario tener presente que no es una cuestión que se circunscriba exclusivamente en el sector energético – exige de la implicación y concienciación del conjunto de las Administraciones públicas – en la esfera europea, española y catalana –, de las empresas y de los ciudadanos.

El presente paper pretende centrarse en el papel de la regulación económica a la hora de proveer las señales e incentivos correctos en este necesario proceso de transición hacia la hacia la descarbonización de nuestro modelo económico. Es necesario un marco regulatorio y de gobernanza capaz de dar cumplimiento a los objetivos de sostenibilidad medioambiental, todo ello sin obviar otros aspectos clave de la política económica y energética como la seguridad de suministro y la competitividad de nuestro tejido productivo.

Estratègies de futur per a l'agroalimentació catalana

Daniel Quer — Mon, 26 Mar 2018 23:57:12 +0200

El sector agroalimentari català ha demostrat, al llarg dels darrers cinquanta anys, una gran capacitat d’adaptació i creixement en un entorn de dificultat. Tanmateix el segle XXI obre un nou escenari amb noves exigències i nous condicionants. Ens trobem en un moment de grans canvis que requereixen, si més no, revisar les estratègies a fi d’assolir les vies apropiades per a un desenvolupament sostenible capaç de donar resposta als nous desafiaments. El document assenyala els aspectes crítics i proposa estratègies d’avenç al si d’un escenari complex i exigent.

La importància de la universitat per el desenvolupament i la necessitat d’una reforma

Daniel Quer — Mon, 26 Mar 2018 18:53:01 +0200

La universitat té una dimensió com a organització molt important; unes funcions socialment i econòmicament decisives, com son la formació i la creació de coneixement, la transferència, la valorització i el compromís social, i per tant uns reptes de present i de futur de primer nivell. Les dades disponibles constaten una molt notable resposta qualitativa i quantitativa de la universitat catalana que la situen, en la majoria dels àmbits, en els primers llocs entre les universitats espanyoles. Tanmateix ens hem de preguntar si la seva contribució respon suficientment al conjunt de requeriments de la demanda i si està suficientment preparada, o s’està preparant, pel futur. La resposta a aquestes dues qüestions es menys afalagadora i orienta la reflexió en la direcció de la necessitat del canvi i de la capacitat per emprendre una reforma. Diversos elements de caràcter institucional i cultural son barreres a la transformació que faria falta. En una visió optimista, la universitat acabarà reaccionant per si mateixa. Però també pot ser que només canvií i de forma parcial, forçada per la pressió de l’entorn.

Mercados financieros: el "trilema" competencia - calidad - regulación

Daniel Quer — Mon, 26 Mar 2018 18:20:02 +0200

La proliferació de l’automòbil que va començar fa una cinquantena d’anys va portar a una reducció de la utilització del transport públic a les ciutats i a l’eliminació de serveis i, en molts casos, d’alguns modes com el tramvia o els troleibusos. Aquests modes es consideraven sorollosos o antiquats i representaven un impediment a una circulació que es volia tan ràpida com fos possible. Es va acceptar, en definitiva, que els cotxes dominessin els carrers i se n’apropiessin també per a l’aparcament. Aquest paradigma de “modernitat” genera unes externalitats que ara tenim ben identificades (contaminació de l’aire, producció de CO2, soroll, accidents i congestió1, a més d’una inacceptable ocupació de l’espai públic). Poc a poc, aquests efectes indesitjats han anat empenyent als responsables de les ciutats dels països més desenvolupats a posar impediments al trànsit i, en paral·lel, per no perjudicar la mobilitat, a recuperar i millorar els serveis col·lectius de transport urbà.

En aquest context sembla evident la necessitat de planejament del sistema de transport urbà i d’una adequada regulació del seu funcionament per evitar que la situació tendeixi al col·lapse i a uns nivells de contaminació insuportables per una societat moderna i desenvolupada. Aquesta intervenció pública ha de perseguir uns objectius d’eficiència global per a la societat que incorpori el pes de les externalitats. Els plans han de ser de qualitat i acceptats pels ciutadans, però és fonamental que es disposi dels mitjans financers per poder-los materialitzar. Cal doncs tenir clar d’on sortiran aquests mitjans per tal de programar amb realisme les mesures que comporten inversió i per assegurar la cobertura dels dèficits d’explotació que genera el transport públic. També cal preveure el paper que han de tenir les diferents administracions públiques en el finançament del sistema.

La disrupción tecnológica ya está aquí. Cómo afecta a las personas, los gobiernos y las empresas

Daniel Quer — Mon, 26 Mar 2018 12:04:03 +0200

A finales de 2017, siete de las ocho empresas de mayor valor en el mundo eran tecnológicas (hace apenas diez años, sólo había una entre las… ¡veinticinco primeras!). Cuatro de las siete personas más ricas del mundo son fundadoras de empresas tecnológicas. Compañías de publicidad por internet como Google o Facebook valen solas veinte veces lo que vale la principal red de cadenas de televisión en EEUU, la CBS. Un gigante de la distribución por comercio electrónico como Amazon vale en bolsa el doble que la red de grandes almacenes Wal-Mart, y quinientas veces lo que vale otro gran distribuidor, Sears. Se fundan continuamente nuevas empresas de tecnología disruptoras y, algunas de ellas, sin ni si quiera cotizar en bolsa, alcanzan valoraciones de más de mil millones de dólares en poco tiempo. Son las conocidas como “unicornios”. Hoy en día existen ya 215, que valen en conjunto unos 747.000 millones de dólares. La empresa de transporte Uber es un “unicornio”. Hace poco, ha sido valorada en más de 60.000 millones de dólares, más que el valor de todas las compañías de alquiler de coches juntas. La red para compartir pisos Airbnb, que tan sólo tiene ocho años de vida, vale más que el gigante hotelero Marriott, con ochenta años de antigüedad. Recientemente, Softbank lanzó el fondo de venture capital “Vision” para invertir en la revolución tecnológica. Tiene la friolera de 93.000 millones de dólares para invertir. Es posiblemente el mayor fondo de capital privado lanzado nunca.

En 1960, la empresa más valiosa del mundo era General Motors, y empleaba a 600.000 personas para ganar unos 7.600 millones de dólares en dinero actual. Hoy en día, la principal empresa en valor es Apple, que gana 84.000 millones de dólares, más de diez veces lo que ganaba General Motors, pero que emplea tan sólo a 116.000 trabajadores. En otras palabras, el beneficio neto por empleado de Apple multiplica por 57 el que en su momento generaba General Motors, abriendo enormes interrogantes sobre si en el futuro habrá suficientes trabajos para todos. Como dijo Voltaire, el trabajo nos libra de los tres males peores, “el vicio, el aburrimiento y la necesidad”. Podríamos añadir la auto-insatisfacción, pero si nos preocupa el futuro de los trabajos, deberíamos también preocuparnos de los cuatro males inherentes.

Pero, ¿qué está pasando? La confluencia de una multiplicación en la capacidad de procesar datos con el empleo de algoritmos avanzados que permiten tratarlos está acelerando la disrupción tecnológica. Datos que crecen de forma desenfrenada gracias a la popularización de internet (accesible para la mitad de la población), la accesibilidad a los smartphones y los sensores capaces de conectar todo tipo de máquinas a internet. Todo ello constituye el caldo de cultivo de la aceleración de la disrupción tecnológica, proceso que se ha denominado “la cuarta revolución industrial”.

Transformación de los canales de intermediación del ahorro. El papel de las fintech. Una especial consideración a los roboadvisors

Daniel Quer — Sun, 25 Mar 2018 22:18:10 +0200

El endurecimiento de las exigencias de solvencia de las entidades crediticias, en un contexto de tipos de interés en mínimos y de coste de capital en máximos, ha intensificado la transformación del sistema de intermediación del ahorro en el Área euro. Éste transita cada vez menos por las entidades crediticias, que se ven sustituidas por los mercados de capitales. En consecuencia, las necesidades de financiación se cubren cada vez de forma más frecuente mediante la emisión de activos financieros como bonos y acciones, en detrimento de los préstamos bancarios. Nos estamos acercando, aunque todavía estemos muy lejos, a lo que se observa en las economías anglosajonas, especialmente en EEUU. Este nuevo modelo de ahorro/financiación tiene importantes consecuencias para distintos agentes implicados, y no sólo las entidades o los mercados, sino el sector público, las empresas y, especialmente, las familias. Una mayor fracción del ahorro invertido en títulos de renta fija y variable implica la asunción de riesgos de liquidez, de mercado y de crédito que, en ocasiones, puede ser desconocido, excesivo y no recomendable. De esta forma, fórmulas de inversión colectiva como los fondos de inversión o los ETF se configuran como el vehículo idóneo para la materialización del ahorro. Y las fintech, especialmente los roboadvisor, como una opción para el asesoramiento y la planificación financiera.

RESILTRACK-Kick-off-CIMNE

Oscar Fruitos Bickham — Fri, 23 Mar 2018 13:08:02 +0100

El objetivo del RESILTRACK es el de diseñar un sistema que permita conocer el estado de la infraestructura ferroviaria y su afectación ante fenómenos climáticos adversos en tiempo real, así como prever el comportamiento de la misma para actuar donde es necesario obteniendo así infraestructuras ferroviarias resilientes ante los efectos del cambio climático.

Hydrodynamic coefficients estimation for Underwater Autonomous Vehicles using CFD code

José Enrique Gutiérrez Romero — Fri, 23 Mar 2018 10:32:02 +0100

This Master Thesis is focused on the estimation the hydrodynamic coefficients for Underwater Autonomous Vehicle (AUV) by means of CFD code. First a state of art of AUVs development is presented. Second, the sizing process for AUVs is studied. The main decissions on the design of this type of vehicles is showed. Third, hydrodynamic coeffcients required to solid rigid movement of AUV is presented. Fourth, an estimation of these coefficient is carried out using different formulation. Fifth, coefficient for REMUS 100 AUV are estimated using CFD code Tdyn. Then a comparison with experimental results obtained for others authors is showed. Finllay, some interesting conclusions and futher reseach are outlined.

Estimation and comparison of towing tank resistance for round bilge fishing ships using differents numerical techniques

José Enrique Gutiérrez Romero — Fri, 23 Mar 2018 10:23:02 +0100

This degree thesis deals with the estimation of towing tank resistance of fishing vessel with round bilge. First, a state of art of fishing vessel is presented. Second, the usual statistical methods to predict the towing tank resistance of fishing vessel are analyzed. Third, a typical fishing vessel with round bilge is designed. Some parameters of designed fishing vessel are analysed. Fourth, the statistical method are applied to fishing vessel. The results are compared. Fifth, a towing tank analysis with CFD code Tdyn is carried out. The results of CFD and other numerical mentod are compared. Finally some conclusions are presented.

Verification of SeaFEM - FAST tool capabilities for certification and fully coupled analysis of offshore wind turbines

José Enrique Gutiérrez Romero — Fri, 23 Mar 2018 10:13:02 +0100

This Master thesis is focussed in the verification of the capabilities of SeaFEM - FAST tool to carry out the fully coupled analysis of offshore wind turbines. First, a state of art of fully coupled analysis is presented. Then, rules to clasify and to certificate offshore wind turbines is studied. Design load conditions for OC3- Hywind NREL 5 MW Baseline are computed.

“De les Smart a les Wise Cities: reptes i oportunitats d’un nou paradigma glocal i sostenible per l’economia catalana”

Josep M. Coll — Thu, 22 Mar 2018 23:45:02 +0100

La urbanització, el canvi tecnològic i la incapacitat del sistema capitalista actual per resoldre els grans reptes de la humanitat –pobresa i desigualtat, deteriorament ambiental i gestió dels recursos, robotització i automatització del treball- dibuixen un nou escenari econòmic i polític on el gran eix vertebrador del progrés són les ciutats. Els clústers més innovadors ja no es troben a Europa i els EEUU, sinó a Àsia, que aglutina el major procés urbanitzador i demogràfic del món. Paral·lelament, emergeix un nou paradigma empresarial on les organitzacions necessiten lideratges i cultures capaces d’entendre el seu rol en una realitat complexa, d’adaptar-se al canvi constant i de generar valor per un consumidor més connectat, exigent i conscient de l’impacte del seu comportament en la sostenibilitat. Quines són les oportunitats per l’economia catalana? Paraules clau: ciutats, 4a revolució industrial, nou paradigma, sostenibilitat, consumidor conscient, món VUCA

El impacto de los precios públicos progresivos sobre la tasa de abandono universitario: el caso de Catalunya

Daniel Quer — Thu, 22 Mar 2018 21:02:24 +0100

La valoración de los precios de los servicios públicos no puede realizar en el vacío y, por tanto, sin referencia al sistema impositivo en general y, particularmente su suficiencia financiera y su progresividad. El argumento que señala que la eliminación de los precios públicos de los servicios públicos es una medida favorable a los intereses de los ciudadanos con menos recursos no se puede evaluar sin tener en cuenta los parámetros del resto del sistema fiscal del territorio en el que se quiere implantar la medida. La simplicidad de este tipo de propuestas puede generar que la buena voluntad produzca mayor injusticia social y desigualdad que la existente con anterioridad a la implantación de la medida. Desde esta perspectiva una sociedad con una democracia de calidad debe tener los elementos para argumentar de forma razonable y lo más científica posible, cuál es el nivel de precios más adecuado para los servicios público teniendo en cuenta la estructura social y la configuración general del sistema tributario.. Es fundamental, por tanto, que cualquier propuesta sobre este tema esté fundamentada en los principios de suficiencia y progresividad del sistema tributario en su conjunto. No vale argumentar que la progresividad debería ser superior o los impuestos más altos cuando no existe la voluntad política, ni la capacidad, para producir dichos cambios en la tributación. Y, en cualquier caso, mientras se consigue el consenso político para mejorar la progresividad del sistema la tarifación social de los precios públicos puede colaborar en la mejora de la capacidad redistributiva del sector público. Proponer dos medidas con efectos contrapuestos, prometer aumentar la progresividad en el futuro cuando políticamente sea posible, y pedir la eliminación de los precios públicos con tarifación en función de la renta, es simplemente un reflejo de una política económica incoherente. También es incoherente proponer utilizar el IRPF para aumentar la progresividad del sistema y, simultáneamente, renegar de los sistemas de tarifación social en función de la renta declarada aduciendo que no refleja con precisión la capacidad económica de las familias. El problema de la evasión fiscal, presente todos los países en mayor o menor medida, no puede justificar que el IRPF sea bueno como mecanismo de redistribución de la renta pero un sistema de tarifación social basado en la renta declarada no lo sea. Persiguiendo el problema de la evasión fiscal se resuelven ambos problemas simultáneamente (la falta de recaudación y la mayor justicia en la tarifación social de los precios de los servicios públicos).

Además de contrastar los precios de los servicios públicos con los ingresos tributarios también hay que determinar conjuntamente que servicios públicos tienen mayor beneficio social, que servicios tienen mayor beneficio privado (apropiable por el usuario) y cuáles son esenciales.

Asignatura pendiente: la evaluación de políticas públicas de vivienda

Daniel Quer — Thu, 22 Mar 2018 21:02:03 +0100

En este trabajo se analiza la importancia de realizar evaluaciones detalladas de las políticas públicas, entendidas en sentido amplio (infraestructuras de transportes, infraestructuras científicas, inversión en capital humano, vivienda, etc.), para poder entender el alcance de su impacto y su deseabilidad relativa en términos de sus beneficios sociales. El trabajo se centra en el campo de las políticas de vivienda por motivos de espacio pero se puede aplicar todas las políticas públicas.

“Hasta la fecha ha habido muy poca evaluación de la política de vivienda en Francia a pesar de su elevado coste (40.000 millones en 2010)…” Trannoy y Wasmer (2013)
“Sorprendentemente, a pesar de su volumen, no se ha cuestionado la eficiencia de las ayudas a la vivienda en Francia” G. Fack (2006)
“A pesar de representar casi un 2% del PIB no sabemos prácticamente nada sobre el impacto de la política pública de vivienda en España” García Montalvo y Mas (2000)

Las citas que inician esta sección muestran el significativo peso de la política de vivienda en los presupuestos públicos y la escasez en la evaluación de sus resultados sigue siendo un ejercicio escasamente practicado. El problema de la evaluación no se circunscribe a la política de vivienda: prácticamente no se evalúa ninguna política pública2. Mientras que sería impensable que un nuevo medicamente no pasará por una evaluación estricta de su eficacia comparada y la ausencia de efectos secundarios negativos, en las políticas públicas no se sigue el mismo criterio. En la política educativa, infraestructuras, vivienda, etc. suelen primar los intereses políticos y los “a prioris” por encima de la evidencia científica. En el mejor de los casos muchos gestores públicos tienen buenas intenciones pero pocos conocimientos y mucha ingenuidad. Por desgracia se ha demostrado muchas veces que la aseveración de Camus en “La plaga”: “El mal que hay en el mundo proviene casi siempre de la ignorancia y las buenas intenciones pueden hacer tanto daño como las malas si falta el conocimiento”.

Innovacions de producte i de procés. Caracterització i impacte.

Jordi Angusto — Thu, 22 Mar 2018 20:12:01 +0100

A la tercera edició dels seus principis d’economia política, David Ricardo s’esmenava o complementava a si mateix i donava per bona la possibilitat que el fet de substituir treball per capital, mitjançant la implementació d’una innovació de procés, pogués acabar suposant la destrucció neta de llocs de treball. Ho il·lustrava amb un senzill exemple en què un empresari agrari desenvolupava una màquina nova, gràcies a la qual podia obtenir els mateixos beneficis amb una menor producció i nivell d’ocupació.

Les dades del seu exemple són les següents: l’empresari disposa d’un capital de 20.000, 7.000 en actius fixes i 13.000 en circulant, que destina a pagar a salaris per obtenir un producte de 15.000, amb la venda del qual aconsegueix un marge de beneficis de 2.000 o, el que és el mateix un rendiment del 10% sobre el seu capital. En un moment donat, però, decideix destinar 7.500 del capital circulant al desenvolupament d’una nova màquina, la qual cosa només li deixa per a salaris 5.500; un import que suposa molts menys treballadors però encara prou per produir, gràcies a la màquina, per un import de 7.500 i obtenir els mateixos 2.000 o 10% de beneficis.

Amb això, la producció haurà caigut en un 50%, l’ocupació en un 68%, el quocient capital producte haurà passat de 1,33 a 2,66, la productivitat per treballador haurà passat d’1,15 a 1,36, i la taxa de guanys serà la mateixa. És a dir: tot i l'augment de la productivitat del treball, cauria la total i la participació salarial, que passaria del 86,66% al 73,33% del producte, i les rendes del capital passarien de representar el 13,33% al 26,66% del producte; alhora, l’atur s’hauria incrementat de manera molt significativa i el PIB per càpita hauria disminuït.

Artificial Intelligence and The Future of Finance

Daniel Quer — Thu, 22 Mar 2018 17:55:02 +0100

We provide in this paper an analysis of how Artificial Intelligence (AI) companies are and will be changing the Financial Services Industry. In particular two main areas will be disrupted by AI and Machine Learning (ML) technologies: Financial Marketing and Investing.

Both disciplines are in the middle of a big data revolution: larger, structured and unstructured datasets, modern Data Analysis that makes extensive use of Ai and ML and faster and cheaper computing paradigms.

Financial Marketing is now digital marketing and that means the inevitability of algorithms taking over the value chain process. Consumers want a 24 / 7 easy access to services and products that can be achieved only obviously with a high degree of automation. These are uncharted territories algorithms should help to customize the new digital experience.

Investing is an information processing game, AI and ML will help there in modeling unstructured data using Natural language Processing techniques to measure for example sentiment and some Machine Learning supervised and unsupervised techniques that allow for more flexibility in capturing highly dimensional non-linear data generating processes. All models in financial markets obviously should deal with very noisy data generating processes possibly non-stationary.

All financial services firms should expand their technology / modeling toolbox to these techniques. They will transform finance the only open question is when.

Reempresa: un mercat d’oportunitats

Daniel Quer — Wed, 21 Mar 2018 17:23:02 +0100

El Centre de Reempresa de Catalunya és el mercat de compravenda de petites i mitjanes empreses de Catalunya (www.reempresa.org). És un nou model d’emprenedoria i de creixement empresarial: un mecanisme professional pel qual un o més reemprenedors accedeixen a la propietat d’una empresa d’altres, en funcionament, per a fer-la créixer sense haver de passar per la fase de crear-la.

És una iniciativa de la patronal Cecot (www.cecot.org) i de la fundació Autoocupació (www.autoocupacio.org) i que compta amb el suport de la Generalitat de Catalunya, del Fons Europeu de Desenvolupament Regional (FEDER) de la Comissió Europea i de més d’un centenar d’institucions, ajuntaments i diputacions que fan de la Reempresa un clar exemple de les possibilitats que ofereix la col·laboració público-privada.

Des de finals dels anys 80, diversos països europeus varen començar a donar importància a la consecució d’un entorn favorable per a la transmissió d’empreses, doncs tant important és afavorir la creació de nous negocis, com assegurar la continuïtat dels ja existents i evitar el seu tancament per motius no econòmics. Des de llavors, la Unió Europea ha emès diverses recomanacions als estats membres per tal de millorar la legislació, la fiscalitat i el finançament en relació a la compravenda d’empreses, així com per assegurar l’existència de mercats transparents i serveis de suport als petits i mitjans empresaris que els ajudin al llarg de tot el procés.

L’any 2010, sota un entorn de greu crisi econòmica i una taxa d’atur elevada i creixent, des de Cecot es va creure oportú la creació d’un servei i un marketplace que tingués per objectiu afavorir la compravenda de petites i mitjanes empreses i evitar així la pèrdua de llocs de treball i salvaguardar el teixit empresarial del país. Així, va néixer la Reempresa, que funciona, no solament com un mercat transparent on promocionar i creuar l’oferta i la demanda, sinó com a eina de suport i consultoria a ambdues parts a través d’una metodologia pròpia d’acompanyament a totes les parts implicades.

Creixement inclusiu urbà: desigualtat i risc de pobresa a Catalunya i la metròpoli de Barcelona

Joan Trullén — Wed, 21 Mar 2018 16:43:02 +0100

En els darrers anys institucions com la OCDE i UN-Habitat estan plantejant la necessitat d’activar noves estratègies de creixement inclusiu de naturalesa urbana o metropolitana. La metròpoli de Barcelona des de mitjans dels anys vuitanta fins a la crisi econòmica de 2008-2013 va seguir un model de creixement que va assolir resultats molt importants en termes de creixement de la producció i de l’ocupació, amb avenços molt significatius en la correcció de la desigualtat. Aquest model de creixement inclusiu es reverteix amb la crisi, amb retrocessos molt importants tant en termes de producció i ocupació com en la distribució de la renda. La ponència estudia com la crisi econòmica que afecta tant a la metròpoli de Barcelona com al conjunt de l’economia catalana incideix sobre els principals indicadors de desigualtat a partir de l’explotació de l’Enquesta de Condicions de Vida del INE i Eurostat. Es mesura la desigualtat a Catalunya i Espanya a través del coeficient de Gini pel període 2006-2016 posant el focus en les diferències en el nivell i l’evolució de la desigualtat segons el lloc d’origen de la població (població estrangera). S’estudia també l’evolució de la taxa de risc de pobresa a Catalunya i Espanya, La taxa de risc de pobresa de la població nascuda a l’estranger assoleix uns valors més elevats (entre 20 i 30 punts percentuals més) que els de la població nascuda a Espanya. Es presenten també resultats sobre l’impacte que el lloguer imputat presenta en la desigualtat. Es tracta d’una estimació sobre els guanys que obtenen les famílies pel fet de disposar d’habitatge propi i/o d’habitatge social. Aquesta imputació és molt significativa en diferents països europeus. L’impacte del lloguer imputat millora el coeficient de Gini encara més al conjunt d’Espanya que a Catalunya. La taxa de risc de pobresa després d’aplicar lloguers imputats baixa pel conjunt de la població excepte per a la població nascuda a l’estranger. Finalment, es presenten resultats sobre la taxa de risc de pobresa per Barcelona, l’AMB, la Regió Metropolitana i Catalunya.

RESILTRACK-Kickoff-CIMNE

Oscar Fruitos Bickham — Wed, 21 Mar 2018 13:35:02 +0100

A time-domain finite element method for seakeeping and wave resistance problems

Borja Servan Camas — Wed, 21 Mar 2018 13:21:02 +0100

The objective of this thesis is the research on numerical algorithms to develop numerical tools to simulate seakeeping problems as well as wave resistance problems of ships and floating structures.
The first tool developed is a wave diffraction-radiation solver. It is based on the finite element method (FEM) in order to solve the Laplace equation, as well as numerical schemes based on FEM, streamline integration, and finite difference method tailored for solving the free surface boundary condition.
It has been developed numerical tools to solve solid body dynamics of multibody systems with body links across them. This tool has been integrated with the wave diffraction-radiation solver to solve wave-body interaction problems.
Also it has been tailored coupling algorithms with other numerical tools in order to solve multi-physics problems. In particular, it has been performed coupling with a MEF structural solver to solve fluid-structure interaction problems, with a mooring solver, and with a solver capable of simulating internal flows in tanks to solve couple seakeeping-sloshing problems.
Numerical simulations have been carried out to validate and verify the developed algorithms, as well as to analyze case studies in the areas of marine engineering, offshore engineering, and offshore renewable energy.

Assessing the nearly zero-energy building gap in university campuses with a feature extraction methodology applied to a case study in Spain

Jordi Cipriano — Wed, 21 Mar 2018 13:15:02 +0100

Public universities face the challenge of retrofitting the actual campus buildings into nearly zero-energy buildings (NZEB). In this study, a novel methodology for evaluating historical energy use and renewable energy production for all the buildings of a university, including hourly, daily and monthly data assessments is presented. This analysis is useful as a baseline for comparisons with future energy retrofits and enables determining the current gap between actual energy indicators at building and campus levels and the established limits for NZEB non-residential buildings in the European Union. The methodology is applied to a case study at the University of Lleida, a typical average-size university in Spain. Results show a wide variation in energy use among campus buildings, ranging between 50 and 470 kWh/m2 year. Constant or slightly increasing energy use and decreasing trends in renewable energy generation are observed. The daily electricity profiles have shown similar patterns among buildings and substantial potential energy savings during unoccupied periods. In the NZEB analysis, the average non-renewable primary energy use is about 4 times higher than the maximum estimated Spanish threshold range of 45–55 kWh/m2 year. Deep energy renovation strategies are, thus, needed for universities to meet EU NZEB targets.

Constitutive and Geometric Nonlinear Models for the Seismic Analysis of RC Structures with Energy Dissipators

Alex Barbat — Wed, 21 Mar 2018 10:42:10 +0100

Nowadays, the use of energy dissipating devices to improve the seismic response of RC structures constitutes a mature branch of the innovative procedures in earthquake engineering. However, even though the benefits derived from this technique are well known and widely accepted, the numerical methods for the simulation of the nonlinear seismic response of RC structures with passive control
devices is a field in which new developments are continuously preformed both in computational mechanics and earthquake engineering. In this work, a state of the art of the advanced models for the numerical simulation of the nonlinear dynamic response of RC structures with passive energy dissipating devices subjected to seismic loading is made. The most commonly used passive energy dissipating devices are described, together with their dissipative mechanisms as well as with the numerical procedures used in modeling RC structures provided with such devices. The most important approaches for the formulation of beam models for RC structures are reviewed, with emphasis on the theory and numerics of formulations that consider both geometric and constitutive sources on nonlinearity. In the same manner, a more complete treatment is given to the constitutive nonlinearity in the context of fiber-like approaches including the corresponding cross sectional analysis. Special attention is paid to the use of damage indices able of estimating the remaining load carrying capacity of structures after a seismic action. Finally, nonlinear constitutive and geometric
formulations for RC beam elements are examined, together with energy dissipating devices formulated as simpler beams with adequate constitutive laws. Numerical examples allow to illustrate the capacities of the presented formulations.

La Economía Circular: una oportunidad para la Unión Europea

Daniel Quer — Tue, 20 Mar 2018 12:02:02 +0100

En la actualidad, la economía circular ha emergido como uno de los conceptos clave en el establecimiento de un nuevo paradigma económico en el que se desvincula el crecimiento económico del consumo y utilización de recursos naturales. La transición hacia este nuevo modelo basado en un sistema productivo sostenible y respetuoso con el medio ambiente creará nuevos puestos de trabajo y permitirá a la Unión Europea (UE) hacer frente a desafíos medioambientales, económicos y sociales de carácter global. Para la UE, la transición hacia una economía circular es una apuesta clave en la política medioambiental de la próxima década.

La valoración económica de los ecosistemas en la gestión del medio natural.

Daniel Quer — Mon, 19 Mar 2018 18:19:01 +0100

Tal y como sucedió con el Informe Stern que supuso un importante cambio de actitud de la comunidad internacional respecto al cambio climático, el informe TEEB supuso un antes y un después en la puesta en valor de la biodiversidad y de los servicios de los ecosistemas. Este cambio de actitud se produjo, en parte, gracias a la consideración de la valoración económica de los servicios de los ecosistemas y la importancia que su conservación y evitar su pérdida representa para el conjunto de la sociedad.

Integrar la valoración económica en la gestión de las infraestructuras verdes, se convertirá a corto plazo en una necesidad para cubrir las demandas de la sociedad y gracias a herramientas como el Protocolo de Capital Natural que permiten armonizar las metodologías existentes, este proceso se podrá llevar a cabo mediante un proceso reglado.

Impacte socio-econòmic de la implantació de la Nova Oficina Judicial: anàlisi cost-benefici

Alvar Garola — Sun, 18 Mar 2018 20:37:02 +0100

La justícia és un dels pilars de l’estat del benestar i les seves actuacions tenen un gran impacte en termes econòmics. Per tant, és important avaluar les inversions en aquest àmbit per tal de posar en relleu la seva viabilitat.

Aquesta ponència mostra els resultats d’una anàlisi cost-benefici aplicat al projecte de nova oficina judicial impulsat pel Departament de Justícia de la Generalitat de Catalunya. La Nova Oficina Judicial (NOJ) ha estat un dels eixos centrals de l’actuació en l’àmbit de la justícia a Catalunya en els darrers anys. Es tracta d’implantar el nou model d’oficina judicial i fiscal, i desenvolupar les noves tecnologies de comunicació i gestió de la informació a l’àmbit de la Administració de justícia.

Es posa en relleu l’abast de l’impacte que pot tenir la millora de l’eficiència a la justícia. S’explica la metodologia, els resultats obtinguts i la necessitat d'aplicar tècniques d'avaluació econòmica per tal d’avaluar l’impacte tant en els comptes de l’administració com en la societat en el seu conjunt.

Impacte de les noves tecnologies en la mobilitat i les infraestructures de transport

Jonatan Calafí Guasch — Sat, 17 Mar 2018 23:17:14 +0100

Ens trobem davant d’un moment de canvis intensos - alguns en diuen quarta revolució industrial – que tenen com a element comú la ràpida aparició i penetració de noves tecnologies disruptives, que imaginen nous productes, que modifiquen patrons de consum, que creen gegants empresarials tecnològics i empetiteixen algunes empreses centenàries.

Quan parlem de noves tecnologies ens referim al vehicle autònom, elèctric, compartit, al big data, a l’Internet of Things, a la intel·ligència artificial i les seves aplicacions en el transport, a la sensorització, als avenços en els Sistemes Intel·ligents de Transport, a les noves energies, a l’electrificació de la mobilitat, als avenços en les bateries, a les impressores i la fabricació 3D, a la digitalització, als nous materials més sostenibles i més durables com el grafè, al Mobility as a Service (MaaS), al comerç electrònic, al teletreball, a l’economia col·laborativa o a la participació ciutadana en els processos de decisió.

Tots aquests canvis ja alteren múltiples esferes de la nostra vida pública i privada, i evidentment, la manera com ens movem cada dia – la mobilitat - i amb què ens movem, és a dir, les infraestructures de transport.

A diferència d’altres processos històrics on el mitjà de transport és el veritable protagonista – des de l’aparició de la roda, passant pel ferrocarril, el vehicle privat o la globalització a través del transport marítim – és possible que els nous canvis siguin més intensos en els patrons i en la manera com entenem la mobilitat. Cada revolució té els seus mitjans de transport específics i segurament en aquest l’element principal sigui la digitalització.

Davant d’aquest nou paradigma el primer pas és fer-se les preguntes adequades, que ens puguin ajudar no només a estar preparats per a aquest futur incert sinó també per formar-ne part i pilotar aquets canvis en la direcció adequada, canvis que ens haurien de servir per millorar la qualitat de vida, reduir la dependència energètica, augmentar l’eficiència, millorar la sostenibilitat econòmica, financera i ambiental de la mobilitat i incrementar la seguretat.

Quan seran rellevants les noves tecnologies i en quina mesura? Afectaran directament o indirecta els patrons de mobilitat? Com impactaran en les infraestructures de transport i en les diverses fases del cicle de vida, com ara la planificació, el disseny, la construcció o l’explotació? Veurem aparèixer nous models i xarxes d’infraestructures o simplement s’hauran d’actualitzar les actuals als nous canvis? D’altra banda, caldrà una reconversió més profunda on podríem parlar d’obsolescència infraestructural? Es generaran noves necessitats o, en canvi, les noves tecnologies faran molt més amb menys recursos? Com ens poden ajudar a millorar?

Aquest document té la voluntat d’anar desgranant cada una d’aquestes preguntes malgrat la complexitat de fer previsions en aquest context, i més encara, per la pròpia naturalesa disruptiva, caòtica i imprevisible de les noves tecnologies.

Aprendizajes activos para el emprendimiento: Experiencias en el contexto universitario catalán

Javier Asenjo — Fri, 16 Mar 2018 20:52:02 +0100

Esta comunicación explora la educación universitaria para el emprendimiento basada en métodos activos. Se destaca la importancia para el crecimiento económico de la formación en emprendimiento. Esta formación tiene una presencia reciente y aun relativamente menor en nuestras universidades. Se destacan dos experiencias recientes y punteras desarrolladas en Catalunya, en colaboración con otras universidades europeas: el grado oficial LEINN (Liderazgo, Emprendimiento e INNovación) y las metodologías activas basadas en retos desarrolladas en dos másteres del consorcio KIC Innoenergy, ofrecido por la Universitat Politècnica de Catalunya. Se destaca la importancia de promover la formación en emprendimiento basada en la actividad del propio alumno, en línea con las experiencias descritas.

La formació dual: condicionants per assegurar el seu èxit

Ferran Mañe — Fri, 16 Mar 2018 08:04:02 +0100

Un dels efectes més devastadors de la crisi econòmica ha estat l’empitjorament de la situació laboral dels joves, especialment d’aquells amb baix nivell de qualificació. Els seus nivells d’atur han augmentat extraordinàriament i l’ocupació ha esdevingut més precària. Aquesta situació ha posat als sistemes de Formació Professional de nou en el centre del debat ja que es considera que el seu bon funcionament és la clau per assegurar la millora de les oportunitats dels joves que per manca de recursos, qualificacions o motivació no obtenen formació universitària. A més a més, les diferències entre països respecte a la severitat dels problemes d’accés al mercat de treball i a l’ocupació dels joves han estat relacionades amb les característiques i el funcionament del sistema de FP. En concret, la formació professional dual ha esdevingut el paradigma organitzatiu associat als millors resultats i, en conseqüència, diversos organismes internacionals l’han posat en valor com a mesura per fer front al repte de la formació i l’ocupació dels joves. Catalunya no ha estat una excepció en aquesta dinàmica, tant pel que fa a l’empitjorament de la situació laboral dels joves com en el diagnosi de la necessitat d’ajustar el funcionament del sistema de FP amb especial atenció a la formació dual.

El govern de la Generalitat de Catalunya va introduir la formació dual en la formació professional amb el DECRET 284/2011 d’1 de març, regulant la seva organització amb la RESOLUCIÓ ENS/1204/2012. Els objectius especificats es centren al voltant del combat de l’abandonament educatiu prematur, elevar l’atractiu social de la formació professional i la millora de les expectatives d’ocupació dels joves. Actualment ja hi ha tres promocions titulades (2012-14, 2013-15, 2014-16), pel que sembla pertinent abordar un procés de valoració i reflexió sobre com s’està desenvolupant la implantació de la formació dual. Malauradament, no es va establir en el moment de la posada en marxa d’aquesta nova opció formativa un pla específic d’avaluació de procediments ni resultats. En conseqüència, no tenim a la nostra disposició les dades adequades per fer una anàlisi tècnicament correcte. Tanmateix, es poden fer valoracions més generals i adreçades a l’estructuració del sistema amb l’objectiu de poder detectar potencials millores que portin a incrementar la seva eficiència. Aquest treball parteix d’anteriors treballs (Mañé, 2012; Mañé, 2017) que conjuntament amb algunes excel·lents reflexions recents sobre la implantació de l’FP dual a Catalunya (Valiente et al., 2014; Requena, 2016; CTESC, 2017) em serviran per construir les meves pròpies reflexions.

Concretament, aquest treball s’organitza en dos apartats: un primer de contextualització dels reptes respecte al capital humà de l’economia catalana i quina resposta pot donar la formació professional; i un segon amb un repàs de les principals característiques d’un sistema d’FP dual que ens servirà per a fer propostes (posar l’accent) de millora de l’actual organització del sistema a Catalunya.

Emprendre des de les Universitats a Catalunya: sobre models, estereotips i sostenibilitat

Santiago Royo — Thu, 15 Mar 2018 23:21:02 +0100

La present comunicació persegueix discutir les possibilitats i problemes dels models d’emprenedoria des de les universitats. Les universitats catalanes són actors molt significatius de la generació de coneixement al país. Malgrat això, el percentatge d’aquest coneixement que acaba convertit en valor al territori és encara massa modest. L’anàlisi d’aquesta situació permet albirar temes diversos, però que en general poden identificar-se a partir d’una combinació d’aspectes culturals, de gestió de personal, i de model de suport la emprenedoria de les organitzacions. Es plantejaran alguns dels estereotips més importants des del punt de vista de la societat i de la Universitat, i es discutiran alguns dels models d’èxit que estan permetent impulsar el pas al mercat d’aquest coneixement, a partir de l’anàlisi i discussió d’un model d’èxit. El CD6 de la UPC és un centre amb un model propi de gestió i generació del coneixement que orient a la seva activitat de recerca a partir de col.laboracions i projectes amb empreses del país (en aquest cas particular, vinculats a l’enginyeria òptica i la fotònica) el que li ha permès generar fins a 11 empreses spin-off i obtenir un retorn significatiu al se pressupost en forma de royalties. S’analitzarà la importància dels aspectes que permeten impulsar aquests models i el principals entrebancs i amenaces actuals per la pervivència i extensió de models d’emprenedoria sostenible dins les universitats catalanes.

La fiscalitat del segle XXI

Marta Espasa — Thu, 15 Mar 2018 21:14:36 +0100

L’objectiu de la ponència és proposar el disseny d’un sistema fiscal integral que doni respostes als grans reptes de futur com són l’augment de la desigualtat, la sostenibilitat de l’estat del benestar, la lluita contra el canvi climàtic, la globalització, la digitalització i l’evasió i el frau fiscal. Es planteja un sistema fiscal on, a banda d’una reformulació dels principals impostos per a que assoleixin amb la màxima eficàcia els objectius recaptatoris i redistributius, hi juguen un paper important els impostos més innovadors que tenen per missió corregir les fallades de mercat com són les externalitats negatives de caràcter mediambiental, sanitari, social i econòmic.

Fundacions i filantropia

Daniel Quer — Thu, 15 Mar 2018 18:03:02 +0100

Les fundacions espanyoles, en general, i les catalanes, en particular, porten a terme activitats d’interès general sobre la base de la gestió eficients dels seus recursos escassos. Aquestes activitats responen a la voluntat i liberalitat del fundador o fundadors. A la vista dels resultats assolits, és oportú incentivar-les.

Les fundacions també són rellevants des del punt de vista macroeconòmic i perquè cobreixen necessitats no satisfetes per les administracions públiques ni pel sector privat.

Ara, les fundacions compten amb força experiència i directius qualificats. Tanmateix, per a executar la seva tasca amb eficiència, calen reformes en el marc regulador, tant nacional com internacional: des de la reforma de la legislació i la fiscalitat per a incentivar l’altruisme i la creació de fundacions fins la regulació de les fundacions europees i les operacions transfrontereres entre mecenes i fundacions.

Monte Carlo Techniques in Computational Stochastic Mechanics

Alex Barbat — Thu, 15 Mar 2018 13:00:43 +0100

A state of the art on simulation methods in stochastic structural analysis is presented. The purpose of the
paper is to review some of the di erent methods available for analysing the effects of randomness of models
and data in structural analysis. While most of these techniques can be grouped under the general name of
Monte Carlo methods, the several published algorithms are more suitable to some objectives of analysis than
to others in each case. These objectives have been classiffed into the following cathegories: (1), The Statistical
Description of the structural scattering, a primary analysis in which the uncertain parameters are treated as
random variables; (2) The consideration of the spatial variability of the random parameters, that must then
be modelled as Random Fields (Stochastic Finite Elements); (3) The advanced Monte Carlo methods for
calculating the usually very low failure probabilities (Reliability Analysis) and, (4), a deterministic technique
that depart from the random nature of the above methods, but which can be linked with them in some cases,
known as the Response Surface Method. All of these techniques are critically examined and discussed. The
concluding remarks point out some research needs in the field from the authors' point of view.

Economia blava: la necessitat d’un nou model de governança

Iolanda PIEDRA MAÑES — Thu, 15 Mar 2018 12:39:24 +0100

El crecimiento azul puede verse obstaculizado por las presión que la actividad humana realiza en mares y océanos, y las interferencia que se provoca entre actividades que rivalizan por un entorno espacial marítimo.

La ponencia realiza una análisis sobre los modelo de gobernanza y su grado posible de eficacia, a través de un largo recorrido que va, desde la Política Marítima Integral, la Planificación Marítima Espacial y los Planes de Acción desarrollados en el Atlántico para detenerse en plan WestMED del Mediterráneo. Reflexiona y aporta opinión sobre el “modelo de gobernanza” que puede resultar más eficaz para ser adoptado en el Mediterráneo occidental.

Seismic Analysis of Base Isolated Buildings

Alex Barbat — Thu, 15 Mar 2018 12:00:43 +0100

This paper presents a survey of the numerical simulation of base isolation systems for the vibration control of
buildings and their equipment, primarilly against earthquakes. Base isolation has received much attention in
the recent twenty years and many buildings have been protected using this technology. The article focusses
mainly on the different numerical methods used in the analysis of base isolated buildings. The conventional
form of solving the equations of motion governing the seismic response of building structures with nonlinear
base isolation consists of using monolithic step by step integration methods. As an effcient alternative, static
condensation and block iterative schemes can be applied. The particularities of the equations of motion
of buildings equiped with various base isolation systems are described. The linear theory of base isolated
buildings is then presented. After this, numerical solution techniques for the analysis of the seismic response
of buildings with isolation systems are developed in detail in the paper. Finally, numerical results for elastic
and inelastic structures are described. A complete set of references coverning a wide range of studies is
included.

30 anys d'inversions en infraestructures a Catalunya: balanç i perspectives de futur

Cristian Bardají — Wed, 14 Mar 2018 21:43:20 +0100

Els darrers 30 anys s’ha triplicat la dotació de capital en infraestructures de mobilitat a Catalunya, malgrat que encara persisteixen dèficits en la xarxa viària i ferroviària, agreujats a partir de 2011 per la caiguda de la inversió i la baixa participació de Catalunya en el conjunt de la inversió estatal. El context de limitació de recursos públics fa necessari el replantejament de les polítiques d’inversió per tal de prioritzar els criteris d’eficiència i de rendiment social, ambiental i econòmic, la gestió de la demanda, la coordinació entre administracions i la col·laboració públic-privada com a complement a la via pressupostària.

Economia i política per a la seguretat i defensa de la UE

Daniel Quer — Wed, 14 Mar 2018 20:26:02 +0100

S’analitza la situació geo estratègica mundial pel que fa a seguretat i defensa i es relaciona amb la UE. També es detallen els moments més importants i els avenços que s’han fet a l’àmbit de la UE. Es valora el que pensa la ciutadania i s’analitzen les capacitats militars dels estats membres de la UE, dels EUA, de la Xina i d’altres estats, valorant la implicació de l’economia relacionada amb la inversió en seguretat i defensa. I a partir de les anàlisi obtingudes es valora la necessitat i les possibilitats d’una política de seguretat i defensa per a la UE.

Balanç de la productivitat de l’economia catalana des de l’any 2000

Joan Maria Mussons Olivella — Wed, 14 Mar 2018 16:13:14 +0100

Les perspectives sobre el potencial de creixement de l’economia catalana es troben condicionades en bona mesura pel context demogràfic, la qualitat dels factors de producció i el creixement de la productivitat total dels factors (PTF). La baixa productivitat del capital és des de l’any 2000 la principal font de divergència en l’evolució de la PTF de l’economia espanyola respecte a la de les economies més dinàmiques, com la nord-americana (Serrano et al., 2017). Els resultats per al cas català també assenyalen la mateixa tendència, tot i presentar una productivitat del capital destacada dins del conjunt de l’Estat. L’esforç inversor ha disminuït des de l’esclat de la gran crisi, si bé la reorientació del patró inversor ens permet ser més optimistes pel que fa a la productivitat del capital.

Els governs locals de Catalunya: competències i mida òptima

Maite Vilalta — Wed, 14 Mar 2018 15:50:02 +0100

En un Estat compost, on no tot allò que té encomanat el sector públic ho fa un únic govern, cal que el repartiment de les competències entre els diferents nivells de govern, es faci tenint en compte una sèrie de determinants. La literatura econòmica, concretament la teoria del federalisme fiscal, ens ofereix una sèrie de principis que cal tenir en compte a l’hora de decidir la distribució de les competències entre els diferents nivells de govern. Essencialment, es tracta de garantir que els governs puguin prestar els serveis de garantint que es farà de manera eficient i equitativa. I aquesta qüestió està molt relacionada amb la seva mida.
L’objectiu d’aquest escrit és, precisament, analitzar què és el què realment fan els governs locals, fonamentalment els ajuntaments de Catalunya, dins del marc competencial que tenen assignat. Aquesta anàlisi ens permet reflexionar sobre si els nostres municipis tenen la mida òptima per prestar els serveis que els hi han estat assignats. L’anàlisi es realitza a partir de les liquidacions dels pressupostos de despesa dels governs locals corresponents a l’any 2016.
L’escrit s’estructura en 5 apartats a part d’aquesta introducció. A l’apartat 2 es fa un breu repàs a la bibliografia econòmica sobre la mida òptima dels governs. A l’apartat 3 es descriu la configuració del nivell de govern local a Catalunya: es detallen quins són els diferents governs que en formen part, quina mida tenen i quin pes representen dins el conjunt del sector públic català. A l’apartat 4 s’explica què fan els municipis de Catalunya. Concretament, es descriu el seu marc legal competencial i s’analitza la seva despesa, tenint en compte la qüestió de la mida. L’apartat 5 es destina als governs supramunicipals (diputacions, consells comarcals, mancomunitats de municipis i àrea metropolitana de Barcelona); es descriu en què gasten i com gasten. I finalment, el punt 6 conté un apunt final a títol de conclusió.

DIMENSIÓ I DINAMISME EMPRESARIAL DE LA INDÚSTRIA CATALANA. Una aplicació a patir de registres comptables 2003-2015 Modest Guinjoan,

Modest Guinjoan — Wed, 14 Mar 2018 11:44:02 +0100

En aquest treball es proposa una nova mesura del creixement empresarial, l’Indicador Sintètic de Creixement (ISC), compost per tres variables (empleats, ingressos i actiu), com a una alternativa a les mesures més convencionals que només utilitzen un indicador. Establim criteris de classificació en funció del grau de dinamisme relatiu de les empreses i ho apliquem a un univers i un temps específics: pimes industrials catalanes que tenen com a característica la seva permanència (han presentat els seus estats comptable al Registre Mercantil als anys 2003, 2007, 2012 i 2015), i tres subperíodes diferenciats de cicle econòmic (2003-2007, 2007-2012 i 2012-2015). Establim tres nivells de dinamisme i agrupem les 4.627 empreses estudiades en tres categories i constatem que les diferències en el seu ISC són estadísticament significatives en les diferents fases del cicle econòmic. També constatem que el creixement empresarial no depèn, tal i com estableix la llei de Gibrat, de la dimensió inicial, i que les empreses molt dinàmiques (grup A), dinàmiques (grup B) i la resta (grup C) presenten diferències estadísticament significatives entre A i B, i entre B i C. Quan baixem al nivell de 7 sectors industrials, les citades diferències són menys significatives, però segueixen essent-ho si s’agrupa A amb B i es compara amb C. Existeixen indicadors econòmico-financers que presenten un comportament diferenciat en funció del ritme de creixement en els 3 subperíodes. Són l’actiu fix, la rendibilitat econòmica, la rendibilitat financera, la competitivitat, la productivitat i l’any de constitució. Malgrat aquest comportament diferenciat, aquestes variables expliquen un percentatge relativament reduït del creixement empresarial. Efectivament poden afavorir el creixement o veure’s afavorides per un augment de dimensió, però hi ha altres factors que semblen més determinants del creixement empresarial entre el sector manufacturer català.

Reptes i oportunitats per al sistema de recerca a Catalunya

Josep Maria Martorell — Wed, 14 Mar 2018 09:45:02 +0100

El sistema de Recerca català ha obtingut, en els darrers anys, uns resultats remarcables en el context europeu. La majoria d’indicadors utilitzats per mesurar la productivitat científica indiquen un creixement molt important en els darrers 15 anys al nostre país, tant des del punt de vista quantitatiu com qualitatiu. De fet, hom pot demostrar com en gairebé tots els casos els resultats obtinguts pel conjunt d’Universitats i Centres de Recerca catalans és molt superior als resultats esperables, tenint en compte el seu pes poblacional o fins i tot de PIB dins la Unió Europea.

Aquest increment es pot atribuir a un conjunt de polítiques públiques desenvolupades amb un alt grau de consens des de principis del 2000, malgrat que en els darrers anys la crisi econòmica està provocant moltes dificultats en el teixit investigador del país, i fins i tot posa en risc algunes de les fites assolides. Una de les polítiques més destacades és la dels centres de Recerca, emmarcats en el programa CERCA de la Generalitat de Catalunya.

Aquest article té com a objectiu repassar la història recent d’aquestes institucions, determinar quins són els elements clau de l’èxit assolit i identificar els principals reptes de futur per aquest conjunt d’institucions, així com proposar algunes línies de treball per encarar aquests reptes, tenint en compte els escenaris polítics i econòmics actuals i previsibles al futur proper.

En particular, es vol posar el focus en la necessitat d’obertura del sector públic. Sense aquesta obertura, existeix un cert consens en què és molt difícil desenvolupar l’activitat acadèmica amb unes certes garanties, sobretot en comparació amb els nostres col·legues europeus. En canvi, en els darrers anys el conjunt del sector públic ha patit una certa involució, que s’ha notat gairebé tots els nivells de l’administració. En aquest article s’intenta mostrar com la flexibilitat amb què fins ara s’ha gestionat aquest tipus d’institucions és un dels elements claus del seu èxit. I, en el mateix sentit, la mancança actual i futura aquesta flexibilitat podria posar en risc aquests èxits.

La posición competitiva internacional de la economía catalana

Judit Montoriol — Wed, 14 Mar 2018 07:44:06 +0100

La competitividad exterior de las economías española y catalana ha mejorado notablemente a lo largo de las últimas dos décadas, tal y como muestra el hecho que las respectivas cuotas de exportaciones en el comercio global han sido más dinámicas que las de otros países europeos. Para evaluar el grado de sofisticación de los productos exportados, elaboramos el índice de complejidad de las exportaciones (ICE). Observamos que el ICE catalán es significativamente superior al español, lo que refleja una especialización de la economía catalana hacia productos más complejos. Con todo, ambas regiones han experimentado una pérdida de complejidad en los últimos años como consecuencia de la entrada de nuevos exportadores “menos complejos”.

La configuració de les autoritats de competència. Un model per a la regulació d’organismes independents i per a la reforma de l’administració pública

Marc Realp — Tue, 13 Mar 2018 18:01:02 +0100

Una regulació procometitiva que no imposi càrregues innecessàries o desproporcionades i que faciliti un marc igualitari en termes d'oportunitats és clau pel desenvolupament econòmic dels països. L’Autoritat Catalana de la Competència (ACCO) és l’òrgan encarregat de garantir la qualitat normativa des d’aquesta perspectiva. Així, resulta essencial que pugui dur a terme la seva tasca de forma adequada. En conseqüència, cal garantir que disposi dels recursos necessaris així com que tingui una regulació adequada. S’efectuen diverses propostes en relació amb aspectes clau de regulació de l’ACCO. Aquestes reflexions poden tenir interès més enllà del cas particular de l’ACCO.