Case Study on the Effects of Plan Irregularities on Seismic Performance of Structures

Geometric configurations, such as large openings, re-entrant corners, and discontinuity in diaphragms, are very common in architectural design but are seen as undesirable for structural performance during earthquakes. The lateral systems in a structure resist the strong forces induced during an earthquake, preventing damage or collapse of the structure. If these systems fail, the structural integrity of the building may fail, which may lead to injury or loss of life. Configuration irregularities also tend to develop torsion in structures, contributing to much uncertainty in structural performance. These conditions often combine, working together to bring down the seismic performance of the building. In order to investigate, two steel mid-rise structures will be carefully designed using the U.S. building codes and RAM. Both structures will have the same square footage and lateral resisting systems, with differences only in geometric configurations so that accurate analysis of the effects of the irregularities may be achieved. Utilizing SAP2000, dynamic responses of two structures were performed and the drift values for both structures were determined. This study intends to present these findings so that a more integrative earthquake-resistant design process may be implemented, creating a safer world. With this in mind, it is important to evaluate the impact that the architectural design of a structure has on the performance during a seismic event, highlighting the importance of incorporating a more integrative earthquake-resistant design.