Abstract

The structural monitoring, which is becoming increasingly common, makes it necessary to choose one or more methods of processing and analyzing the obtained data. This choice is key to meeting the objectives of this monitoring. Considering that there are many methods with different capacities and requirements, this choice is a complex problem. This paper presents a methodology for the assessment and selection of methods for the identification of dynamic response properties of buildings using vibration monitoring. In this work, well-known methods based on time domain analysis (subspace-state) and non-parametric methods based on the frequency domain are studied when applied to seismic vibration records for a reinforced concrete building instrumented with a network of tri-axial force-balance accelerometers. For two and a half years, the sensor network has recorded close to 500 sensitive earthquakes. Nonetheless, it only includes those with a magnitude higher than 4.8 (M_L or M_W) and that occurred between September, 2015 and September, 2016. Using six versions of identification methods, modal response parameters are determined for each of the two main directions of the building, considering different levels of information acquired by the sensor network (floor information). An assessment of the performance of each method is conducted based on the number of identified modal frequencies and damping ratios; their variability (coefficient of variation); and the processing time of each method. As a result and conclusion regarding the use of this methodology, it is not only possible to choose the most convenient method for processing vibration records applied to structural health monitoring (SHM) according to its own objective, but also to progressively improve the design of the sensor network.

Abstract

This is the review of the Structural Engineering Update course carried out at the Regional Center for Technological Developments for Seismology and Seismic Engineering Construction (CeDeReTec, Mendoza, Argentina) at the end of the year 2019. The presentations are shown and also reports on the activities carried out within the framework of the Project “Destructive Potential Generated by the Earthquake of Ecuador of April 16, 2016” are reported.

Abstract

Abstract

In this work, a simple and effective Rigid Beam Model is proposed for studying the dynamic behaviour of ancient freestanding stone columns. As well known, monolithic and multi-drum freestanding columns are historical structural elements typical of ancient temples that still can be found in the Mediterranean area. These columns are particularly prone to collapse in case of seismic actions. The dynamic behaviour of freestanding columns has been studied by many authors in the past [1-3], and it is characterized by a strong nonlinearity due to sliding and rocking between the drums. The Rigid Beam Model here described assumes each drum of the column as a rigid beam element and each interface between the drums as a node of the model able to move horizontally. Similar to Housner [1] approach, this model assumes small displacements and no sliding between blocks. Furthermore, the material nonlinearity is considered by means of a moment-rotation constitutive law slightly modified with respect to the bilinear one introduced by Housner. Numerical simulations were performed on monolithic and multi-drum columns modelled using the proposed Rigid Beam Model approach. Results are compared against simulations of the same columns undertaken by means of the Discrete Element Model, which is able to consider large displacements and the possible sliding between the drums, and it has already proven its effectiveness in simulating column behaviour [2-4].