Effect of height on Retrofitting of existing steel frames using Special Concentrically Braced Frames

Recent earthquakes indicate the importance of retrofitting existing structures to achieve an acceptable level of performance. Several different methods for retrofitting of existing structures were used by structural designers; Use of bracing systems is a cost-effective method for seismic retrofitting of existing steel frames. In particular, Special Concentrically Braced Frame (SCBF) system is one of the candidates that are simple to design, effective in resisting lateral forces, and efficient in limiting lateral deformation.In this paper two existing structure with different heights are retrofitted with SCBF. At next stage vulnerability assessment is done according to ASCE 41-06 with pushover analysis by means of SAP-2000 software and compare the seismic parameters with each other to evaluate effect of height on retrofitted buildings with SCBF. By having focus on results, it’s observed that, Stiffness of Four-story building that retrofitted with SCBF is larger than Eight-story but Earthquake energy that dissipated by eight story SCBF is more. It’s seen that, four story SCBF may undergo less lateral displacements than eight story and ductility of eight story is larger, so with increasing height, effective stiffness will decrease but ductility will increase. Performance of four story structure in low to moderate earthquake is better than eight story so SCBF systems shows It’s best seismic response for low-raise building in low to moderate seismicity regions.

کلیدواژه ها:

Bracing System ، Ductile ، Retrofit ، SCB ، Steel Frame