Mitigating Inter-Story Drift Concentration of Concentrically Braced Steel Frames Using Energy-Dissipative Columns

ABSTRACT

Concentrically braced steel frames (CBSF) always suffer from weak-story failure with a large inter-story drift concentrated on the weakest story. A novel system of Energy-Dissipative Column (EDC) is proposed in this paper to improve the seismic behavior of low and mid-rise CBSFs. The EDC system consists of dual hinge supported steel boundary branches and replaceable steel strip dampers between them. Nonlinear dynamic analyses are conducted on 3-story and 6-story benchmark CBSF buildings with and without EDCs. The effectiveness of EDCs with different stiffness ratios on mitigating the seismic responses of CBSFs under design based and maximum considered earthquakes are investigated. The results show that the presence of EDCs in an existing multi-story CBSF can not only dissipate seismic energy to reduce the maximum inter-story drift, but facilitate more uniform inter-story drift distribution by redistributing the seismic forces along the structural height. It is found that the maximum inter-story drift and drift concentration can be reduced by half when the lateral stiffness ratio of EDC to CBSF reaches 0.2.

KEYWORDS:

• Energy-dissipative column
• seismic mitigation
• concentrically braced steel frame
• inter-story drift
• drift concentration
• stiffness ratio

Additional information

Funding

The work presented in this paper was supported by the National Key Research and Development Program of China [Project No. 2017YFC0703607].