Abstract

This chapter uses a mechanical method that involves non-linear analysis with deterministic and probabilistic approaches, as well as procedures of analysis based on limits states defined by displacements, in order to evaluate the behavior of a low rise RC building with plan irregularity designed according to Venezuelan codes and subjected to seismic actions. By using adequate structural models and computational tools, the seismic behavior of the building is obtained in a suitable way. Among these tools, the quadrants method was chosen, which provides the rapid assessment of the seismic capacity of a structure through its non-linear response. The results of the research show that the current design of this kind of structures is not safe when they are designed for the maximum seismic actions prescribed by codes. Therefore, it is necessary to review the design procedures in order to fulfill the goals of the performance-based design.

Abstract

'''In this paper, a suspended-zipper braced frame (SZBF) equipped with hybrid damper consisting of Added Damping and Stiffness (ADAS) metallic damper and shape memory alloy (SMA) wires is introduced. The proposed seismic-force-resisting system is designed by performance-based plastic design (PBPD) method, which in addition to a significant reduction in the residual displacement of the structure, can increase the collapse displacement amount by providing a suitable lateral strength and ductility compared to the conventional SZBF. A new method for designing the proposed hybrid damper is presented, in which two factors of highest hysteretic energy and the least consumption amount of SMA material is provided. The existing models in this paper are two high-rise 12- and 16-story SZBFs in two cases (a) with the conventional system and designed by force-based design method (b) with proposed hybrid damper and designed by the PBPD method. Seismic assessment of the proposed SZBF (PSZBF) by nonlinear static analysis is performed under two lateral load patterns of parabolic and uniform, in accordance with the FEMA-P695 in OpenSees software. Two parameters of the overstrength factor (Ω) and response modification coefficient (R) are evaluated from the analysis results. It is determined that the PSZBF does not lead to a significant change in the overstrength factor comparing to the conventional SZBF. Also, the PSZBF, in addition to reducing the consumption amount of used steel by about 7%, can increase the R parameter by about 50% compared to the conventional system.

Abstract

In this paper, a suspended-zipper braced frame (SZBF) equipped with hybrid damper consisting of Added Damping and Stiffness (ADAS) metallic damper and shape memory alloy (SMA) wires is introduced. The proposed seismic-force-resisting system is designed by performance-based plastic design (PBPD) method, which in addition to a significant reduction in the residual displacement of the structure, can increase the collapse displacement amount by providing a suitable lateral strength and ductility compared to the conventional SZBF. A new method for designing the proposed hybrid damper is presented, in which two factors of highest hysteretic energy and the least consumption amount of SMA material is provided. The existing models in this paper are two high-rise 12- and 16-story SZBFs in two cases (a) with the conventional system and designed by force-based design method (b) with proposed hybrid damper and designed by the PBPD method. Seismic assessment of the proposed SZBF (PSZBF) by nonlinear static analysis is performed under two lateral load patterns of parabolic and uniform, in accordance with the FEMA-P695 in OpenSees software. Two parameters of the overstrength factor (Ω) and response modification coefficient (R) are evaluated from the analysis results. It is determined that the PSZBF does not lead to a significant change in the overstrength factor comparing to the conventional SZBF. Also, the PSZBF, in addition to reducing the consumption amount of used steel by about 7%, can increase the R parameter by about 50% compared to the conventional system.

Abstract

This study, proposes a new lateral load resisting system for high-rise (Reinforced Concrete) RC frames, which includes friction damper-superelastic SMA wires. The proposed SMA-friction damper can not only regulate the mechanism of frictional energy dissipation components with its self-centering SMA wires according to the design method based on the proposed performance, which is able to provide a hysteretic behavior and high self-centering capacity with the lowest SMA consumption but also has some advantages such as simple configuration and economic application. In this paper, two high-rise 18 and 22-story RC frames were designed in two design modes of common and with the proposed damper. The nonlinear time history analysis subjected to 10 far-field earthquakes performed in Opensees software. The results of the analyses showed that using the proposed SMA-friction damper, in addition to the effective increase in ductility, lateral stiffness and lateral strength, provided an excellent self-centering capacity, which resulted to the significant reduction in the maximum drift and the residual deformations in the structure.

Abstract

Supplementary cementitious materials (SCMs) are widely used for sustainable concrete. However, this is challenged due to the deteriorated resistance towards carbonation-induced corrosion. This paper introduces the establishment of a novel carbonation-induced early corrosion propagation based service life assessment model (CECP-SAM). This model is characterized by considering the early corrosion propagation (incipient cracking) and the use of supplementary cementitious materials. Based on experimental and numerical methods, the effects of binders, water/binder (W/B) ratio, exposure condition, cover thickness, rebar diameter, semi-carbonation zone, cathode-anode ratio on service life are investigated by CECP-SAM. The model is justified by using the results from a field investigation in Hong Kong. Performance-based service life equations are also given based on CECP-SAM.