ANALYSIS OF INFILL FRAME WITH GAP ELEMENTS USING FINITE ELEMENT APPROACH

Abstract

The rapid urbanisation demands the need of high raised buildings which are always vulnerable to the lateral loads caused due to natural calamities. These lateral loads affect the stability of the structure. The shear walls, which are provided to resist the lateral forces, are not desirable from utility point of view as they come in the way of vehicular movement in the parking floor. In this context the contribution available from wall panels, called infill walls is considered. In this paper, the contribution offered from infill walls to the lateral strength of the building is evaluated using FEM approach. In this approach the infill wall contribution is replaced with two diagonal struts joining the opposite corners of the frame. The general purpose Finite Element package MSC NASTRAN is used to evaluate the infill contribution. Frames with different aspect ratios of span to height with and without wall opening are taken up for the study. On obtaining the strain energy of the infill frame, the infill wall is replaced by equivalent diagonal struts joining the opposite corners of the frame of width to match in strain energy. To make the application more widely applicable, the data obtained from different case studies has been tabulated to train a neural net. The train neural net is expected to offer the width of equivalent strut once the necessary input data is fed. The utility of the study is improved as more data is added.. Later the effect of crack widening in the infill panel was shown by the introduction of gap elements wherever the tensile stress was found more than the permissible value. The failure pattern when a horizontal load, vertical load and rotation each applied in turn at each corner of the infill panel with gap elements is studied