Clayton et al. 2011
This paper presents an overview of the mechanics and behavior of the SC-SPSW system. This system combines the lateral load resistance of a SPSW with the self-centering capability of PT column-beam connections. The authors propose a performance based design procedure and conduct subassembly tests on the SC-SPSW.
System Concept
This system is composed of a steel infill plate with horizontal and vertical boundary elements and PT beam to column connections. The SC-SPSW system resists lateral load and dissipates energy through development of tension field action and yielding in the thin steel infill panel. PT connections provide a self-centering capability to the system. In the SC-SPSW system, PT connections replace typical MR HBE to VBE connections, allowing the connection to rock about the HBE flange and resulting in the formation of a gap. This gap causes the PT strands in the connection to elongate elastically, so damage at the HBE ends is prevented and self-centering is achieved.
The lateral strength of the SC-SPSW was provided by a web plate, which acts as a replaceable energy-dissipating fuse in the system. HBE distributed forces from the yielding web below and above the HBE act in the direction of the diagonal tension field. If the maximum moment occurs along the HBE, it becomes susceptible to the occurrence of in span flexural hinging. Development of the tension field leads to a reduction of lateral load resistance in the SPSW. Occurrence of in-span hinging in the HBE can be prevented by using PT. PT connections can be designed to ensure that the maximum moment occurs at the end of the HBE at a specified drift level before the beginning of HBE yielding.
Combining the SPSW and PT frame results in flag-shaped hysteresis, where self-centering is provided by SPSW and the re-centering capability is provided by the PT frame.
Experimental Study, Results and Discussion
Seven different 3 and 9-story SC-SPSW buildings were designed according to the performance based design approach. 60 ground motions were used on three different seismic hazard levels. The performance of these models was evaluated by measuring the peak story drift, the residual story drift, the occurrence of PT yielding, and the occurrence of HBE and VBE yielding.
The purpose of initial experimental work on the SC-SPSW subassembly was to capture the effects of the interaction of the PT and web plate forces acting on an intermediate HBE, as well as to validate numerical modeling methods. In the tests, the specimen was able to re-center when loaded up to 4% drift with no damage to the frame and PT members, and exhibited the expected flag-shape hysteresis with re-centering.
The proposed performance based design procedure was capable of producing 3 and 9-story SC-SPSWs that could meet the proposed performance objectives at three different seismic hazard levels
Reference
Clayton, P. M., Dowden, D. M., Purba, R. Berman, J. W., Lowes, N. L., and Bruneau, M. (2011). “Seismic Design and Analysis of Self-Centering Steel Plate Shear Walls,” Proceedings of the Structures Congress Proceedings 2011, Las Vegas, NV, April 14-16.