New Strategies to Normalize Global Engineering Demand Parameters to Compare Seismic Responses of Complex Buildings

Date: 4/25/2019

Time: 06:00 PM

Room: Grand Ballroom

To assess how differently complex buildings with different shapes and masses and internal rigidity behave under seismic load, it is necessary to introduce standardized engineering demand parameters (EDPs). In this work we compare the seismic response of 15 three-dimensional buildings having different characteristics: typologies (reinforced concrete or post and beam buildings), rigidity distributions, and shapes (rectangular, horizontal L-shape and vertical L-shape). The seismic load is given by 236 real three-component accelerograms covering large range of spectral amplitude level, issued from the ITACA database. The accelerograms are baseline corrected, and rotated (45°, 90°, 135°) to average the impact of motion direction. After testing the correlation between several intensity measures and EDPs, the Euclidean peak ground acceleration is used to describe the seismic input. The 14560 dynamic analyses are performed implementing a transfer function-based method based on the assumption that all the structures behave linearly. The seismic response is assessed in terms of global-standardized EDPs describing the average response of buildings smoothing the local stress concentration. In particular, we introduce two normalization methods. In the first one, the EDPs are expressed by a dimensionless quantity (e.g. the ratio between normal strengths, induced by the seismic load at a given floor, and the weight of the upper floors). In the second method, we standardize each building to a cubic one having the same mass and surface of contact between walls and floor. Comparison between the EDPs issued from the complex buildings and the cubic ones is supposed to catch torsional effects. Comparing the EDPs levels in function of the building shape no relevant differences appear. EDPs for the different typologies or rigidity distributions exhibit clear seismic response differences. Finally, we test the impact of soil-structure interaction that strongly affects all the tested EDPs.

Presenting Author: Arnaud Montabert

Authors