Influence of Shear Flexibility in Structural Shear Walls on Pushover Analysis

Abstract

The aim of this work is to show the main differences which exist, taking in to account the influence of the type of finite element used, when performing pushover analysis of reinforced concrete structures. The non-linear analysis was performed using FE software SAP2000, and the results were extracted from models including Frame and Shell elements, respectively.

Several reinforced concrete structures were modelled with Frame elements and Shell elements, which will be further presented. Therefore, it was possible to validate the results obtained from the analysis, also to identify certain restrictions according to the type of finite element used in the modelling of the resistant walls.

In the first phase, three isolated structural walls were modelled with distinct geometries. The first one presents a rectangular shape, the second – “L” shape and the third one “U” shape. The application of pushover analysis through the different examples presented in this document, intends to validate the results obtained for the Shell elements.

Subsequently, the same kind of analysis was performed on a building. These examples intend to show that the performance of ductility is strongly dependent from the type of element, which is not taken into account in the pushover analysis nowadays.

N2 method was applied to all examples, in order to understand the differences in the structures seismic design, according to the type of element used in the modelling. The results are compared, and the differences are identified. As well as, the limitations of applicability of Shell elements in the modelling of structural walls were determined.