Importance and effectiveness of structural parameters in rapid seismic safety assessment of existing buildings

Abstract

Evaluating the seismic safety of existing buildings in seismically active regions is a challenging task. Especially in metropoles, the volume of building stock requires rapid and sufficiently accurate evaluation processes to be conducted instead of time-taking and costly code-based assessment procedures. To respond to this need, numerous rapid evaluation methods were developed in different countries. The varied structural characteristics of building stocks in different countries necessitate unique approaches, as certain assumptions must be made when considering building typologies. Additionally, the extent of knowledge about structural parameters to be collected from buildings on site should be limited to minimize the time and cost required. To clarify the effects of knowledge on basic structural parameters, a simulation study is conducted on 1113 buildings in Türkiye that have previously been evaluated using the PERA2019 methodology in Istanbul. During the simulation, for various structural parameters, the median or most commonly observed values are assigned to all buildings rather than their actual individual values measured on site, and the resulting errors stemming from these assumptions are calculated. Subsequently, the real values of these parameters measured/determined on site are introduced to the buildings one by one, and the simulations are repeated to identify the most significant and least effective structural parameters by monitoring changes in the total error. Also, the economic consequences of collecting structural parameters at different levels of detail are analyzed. Finally, a case study is conducted on buildings that were exposed to earthquakes. The outcomes showed that critical structural parameters vary remarkably for different construction years due to differences in design regulations and construction/inspection practices valid/common during the construction. The impact of several structural parameters on the accuracy of the results is limited, and spending time to collect these structural parameters isn't efficient. Spending an optimum amount of time to collect only the highly effective critical structural parameters before an earthquake can provide valuable and sufficient information on the seismic performance of the buildings. Based on the outputs, a realistic level of knowledge required for the structural data collection phase for seismic safety of existing buildings is proposed for buildings with different typologies.