Performance Analysis of Typical Soft Story Infill Wall Frame Structure

Non-continuity of infill walls is one of the causes of soft stories in a structural system. In densely populated areas, the first level of a typical building is used as a parking lot, creating a typical soft story plan where the first floor has fewer walls than the floors above so the walls are not continuous. Modeling of infill walls as one of the load-bearing elements must be done in buildings with a typical soft story plan. This study aims to determine the design results and performance of the four stories existing structure that was analyzed as a structural system of infill wall frame (SRDP) and to compare it with the existing building using SAP 2000 software. The model was analyzed to produce displacement, drift ratio, and reinforcement of slabs, beams, columns, and structural performance. The results showed that the existing building modeled as an SRDP system yields a drift ratio of more than 1.3 at the ground level so it was strengthened by enlarging the dimensions of the ground floor column and reducing the dimensions of the second to fourth floors. It was found that the area of longitudinal reinforcement in the SRDP building was less than in the existing building. On the second-floor column, the flexural reinforcement area is only 20% of the existing reinforcement area, on the third to fourth-floor columns, the flexural reinforcement area is only 30% of the existing reinforcement area. In the beams, the flexural reinforcement area was found to be only 38% to 52% of the existing reinforcement area. The performance level of the SRDP after strengthening is Collapse Prevention (CP) in the x direction and Collapse (C) in the y direction with hinge formation occurring firstly in the beam.