Seismic evaluation of reinforced concrete moment frames retrofitted with steel braces using IDA and Pushover methods in the near-fault field

Document Type: Regular Paper

Authors

1 Professor, Faculty of Civil Engineering, Semnan University, Semnan, Iran

2 Associate Professor, Faculty of Civil Engineering, Semnan University, Semnan, Iran

3 Ph.D. Candidate, Faculty of Civil Engineering, Semnan University, Semnan, Iran

Abstract

One of the methods for retrofitting reinforced concrete moment frames is the use of steel braces. In this research, the seismic performance of a double-skinned concrete framing system reinforced with two concentric (CBF) and eccentric (EBF) steel bracing, was investigated under seven near-fault earthquake records of varying intensity. For this purpose, two ten-story concrete frames with five spans were designed according to the rules of procedure and were subjected to increasing dynamical analysis (IDA). Locating the braces in the first and fifth spans. The results indicate that reinforcing concrete frame using CBF and EBF braces increases the frame capacity by 2.3 and 2 times, respectively. The use of EBF braces in a concrete frame reduces up to 7 times the amount of base shear applied to the building relative to the CBF frame. Approximately, the displacement of the roof in the EBF frame in the near-fault area is less than the CBF frame. Also, the softer behavior of the EBF frame against earthquake records increases the safety and level of performance of the concrete bending frame at the immediate occupancy (IO).

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