Effect of steel and concrete coupling beams on seismic behavior of RC frame accompanied with coupled shear walls

Construction of diagonal reinforcement in concrete coupling beam is difficult; therefore, its replacement is steel coupling beam. A review of the related literature shows that a few studies have considered seismic behavior of RC coupled wall with steel coupling beam. In this paper, the influence of an increase in building height on the seismic nonlinear behavior of dual structural systems in the form of RC frames accompanied with RC coupled shear walls once with concrete, and then with steel coupling beam was investigated. Therefore, the buildings with 7, 14, and 21 stories and containing RC coupled wall systems with concrete and steel coupling beams were used to perform the pushover analysis with different load patterns. Some seismic parameters, such as ductility factor, response modification factor due to ductility, over-strength factor, response modification factor (R), and displacement amplification factor (Cd) were studied. Regarding the results, the response modification factor for the mentioned structural system is higher than the values used in codes of practice for seismic resistant design of buildings. In addition, the displacement amplification factor and the response modification factor increase as the structure height decreases and the values of these factors at steel coupling beam structures are higher than those at concrete coupling beams.