EFFECTS OF INFILL WALL MODEL ON THE INELASTIC RESPONSES OF A BUILDING

Abstract

Nonlinear Response History Analysis (NLRHA) has been considered as an accurate technique to predict the behavior of buildings subjected to seismic forces. In most applications, the objectives of the analysis are to determine the inelastic responses of the structural members such as columns, beams or structural wall. In general, an infill wall which is a nonstructural component is modeled by an equivalent strut using a line element in order to simplify the analysis. However, the contribution of the strut to the lateral stiffness of the building is much less than the plate action from the actual wall. This effect results in a model that is too flexible, with a higher natural period than the actual building, leading to incorrect inelastic responses. This research examines the effects of modelling of infill walls on the inelastic responses of a building during earthquake. The example building is a 5-story, reinforced concrete moment-resisting frame structure. The 2D lump mass model and the 3D finite element model were investigated. The infill wall was modeled by an equivalent strut. The modulus of elasticity of the strut was used to adjust the elastic natural periods of the building to match the results of ambient vibration test of the building. The responses of the building under different levels of ground motions were analyzed using NLRHA. The effects of infill wall models on the discrepancies of the predicted responses are discussed.