Hysteretic model for steel energy dissipation devices and evaluation of a minimal-damage seismic design approach for steel buildings

This paper evaluates an alternative seismic design approach for steel structures that concentrates damage in easy-to-replace steel energy dissipation devices and protects the main structural members from yielding with capacity design rules. This approach can reduce damage repair costs and downtime, and, can be further enhanced by using rate-dependent dampers in parallel to steel devices to achieve drift reduction and protection of drift-sensitive non-structural elements. A model for steel energy dissipation devices is proposed and calibrated against experimental results. In particular, the Bouc-Wen model is modified to capture the combined kinematic and isotropic hardening in the hysteresis of steel devices. The model is found able to accurately predict the experimentally obtained hysteresis and is implemented in the OpenSees software for use in seismic response analysis. A simplified seismic design procedure is proposed and used to design a prototype steel building equipped with steel devices and viscous dampers according to explicitly defined minimal-damage performance objectives. Seismic analyses results indicate the accuracy of the design procedure and confirm that the building is able to achieve immediate occupancy under the design seismic action and rapid return to occupancy under the maximum considered seismic action. The same building is designed as a conventional steel MRF according to EC8. Results of seismic analyses show that repair of damage in the main structural members of the conventional MRF may not be financially viable in the aftermath of the design and maximum considered earthquakes.