Masoud Mahdavi - Faculty of Civil Engineering, K. N. Toosi University of Technology, Tehran, Iran
Seyyed Reza Hosseini - Faculty of Civil Engineering, K. N. Toosi University of Technology, Tehran, Iran
Abbas Babaafjaei - Faculty of Civil Engineering, K. N. Toosi University of Technology, Tehran, Iran

The seismic performance of a steel structure depends on various factors, such as the design, materials, and dimensions. One important aspect to consider is the span length of the structure, which can influence the seismic response and the overall performance of the structure. In this study, a ۱۰-story steel structure with chevron bracing system was designed with ABAQUS software and finite element method. The structure was subjected to the El Centro earthquake for ۲۵ seconds using the dynamic analysis method. Furthermore, the W index was defined equal to the span length to the story height, and the values of ۰.۶۷, ۱.۶۷, and ۲.۵ were considered for W. The results showed that the increase of the W index has direct relationship with the changes in the seismic parameters of the structure, including the displacement and acceleration, the von mises stress, the acceleration-time, and the displacement-time diagrams in the roof and the base shear force. Changing the index from ۰.۶۷ to ۱.۶۷ and ۲.۵ has caused an increase of ۱۳.۳۴% and ۱۶.۶۷%, respectively. Changing the index from ۰.۶۷ to ۱.۶۷ and ۲.۵ has caused an increase of ۱۰.۱۵% and ۵۲.۲۸%, respectively. Changing the index from ۰.۶۷ to ۱.۶۷ and ۲.۵ has caused an increase of ۴۳.۷۵% and ۱۰۹.۳۷%, respectively. Changing the index from ۰.۶۷ to ۱.۶۷ and ۲.۵ has caused an increase of ۲۰.۸۳% and ۴۷.۹۱%, respectively.

Span Length, Story Height, Seismic Performance, Chevron Brace, Finite element method