Evaluation of the Effects of Link Beam in Eccentrically Braced Frames under Frequency-Domain Modal Analyses

Eccentrically brace is one of the new methods in seismic improvement of the structure. Placing the link beam in different zone of the brace changes the seismic performance of the bracing system. Therefore, in the present paper, using the finite element method (FEM) and ABAQUS software, ۳-story steel structures with eccentrically braces will be modeled. Eccentrically braces will have horizontal and vertical link beams. Braced structures will be investigated by modal analyses in the frequency domain method. Three types of eccentrically braces including (a) middle horizontal beam (EBFK), (b) side horizontal beam (EBFD) and vertical beam (EBFV) will be modeled. Also, validation of the models will be done with the paper of Abdul Hamid et al (۲۰۲۲). The results show that the EBFV model, compared to the EBFK and EBFD models, has a better performance in von mises stress and displacement. The EBFV model will reduce the von mises stress by ۶۲.۲۵% and ۶۵.۴۱%, respectively, compared to the EBFK and EBFD models. Also, the EBFV model will reduce the displacement of the structure by ۱۵.۳۳% and ۱۴.۶۴%, respectively, compared to the EBFK and EBFD models. The EBFK model will reduce the rotation of the structure by ۱۰.۱۷% and ۲۵%, respectively, compared to the EBFD and EBFV models.

Keywords:

Steel Structure , Eccentrically Braced Frame , Link Beam , Modal Analysis , ۳D Structure