Epistemic uncertainty of finite element models to predict the seismic response of RC free-plan buildings
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Date
2017
Journal Title
Journal ISSN
Volume Title
Publisher
National Information Centre of Earthquake Engineering
Abstract
This study quantifies the epistemic uncertainty of several modeling assumptions in evaluating the seismic response of six reinforced concrete free-plan office buildings located in Santiago, Chile. The assumptions analyzed are: (1) the in-plane and out-of-plane stiffness of the diaphragms; (2) the simplified soil-structure interaction model; and (3) the level of fixity of the structure. Several detailed finite elements models were elaborated using the ETABS and ANSYS software packages and the seismic response was estimated using response spectrum analysis. The response uncertainty was evaluated by comparing predicted global and local seismic response parameters, such as story shears and drifts, between a predefined reference model commonly used in design with a set of variant models. A statistical evaluation of the modeling uncertainty showed a strong dependency on the response parameter considered, ranged from 11% to 112%. It was concluded also that uncertainties identified in the shear forces of walls at the elevator core were larger than uncertainties in total story shear forces. Additionally, larger uncertainty was identified for shear forces at the basements than shear at upper stories. The out-of-plane diaphragm stiffness was found as one of the most important sources of epistemic uncertainty for the core wall shear and total story shear in upper stories. Finally, the most significant source of uncertainty for the base shear is the one associated with the type of soil-structure interaction model used.
Description
Keywords
Epistemic uncertainty, Free-plan buildings, Diaphragm stiffness, Soil-structure interaction, Basement effect