Effects of infill walls on load resistance of multi-story RC frames to mitigate progressive collapse

Abstract

To study the effects of infill wall on progressive collapse resistance of reinforced concrete (RC) frames with slabs, a macro finite element (FE) model was built using general purpose software OpenSees. The FE model was validated by existing test results. Then, the model was subsequently used to predict the progressive collapse potential of eight-story RC frame including slabs and infill walls. The numerical studies demonstrated that the inclusion of the slabs and infill walls could increase the ultimate load and initial stiffness by 70% and 169%, respectively, compared with the bare frame. The infill walls not only changed the load resisting path but also effectively improved the load redistribution ability of the frame. To evaluate the reliability of using a two-story sub-structure to investigate the progressive collapse behavior of a multi-story building, the resistance of each story of a multi-story building in case of column missing is compared. It was found that the resistance of each story was similar, except the first story. Finally, a series of parameter studies were carried out to quantify the effects of opening ratio, thickness and compressive strength of the infill walls on the progressive collapse performance of RC frame.