Clayton, Winkley, Berman, and Lowes 2012
The behavior of self- centering steel plate shear wall (SC-SPSW) system was experimentally tested through cyclic loading of four two story subassemblies of this system. It was found that the SC-SPSW system is capable of energy dissipation through the replaceable web plate, and self centering through post- tensioned (PT) strands.
System Concept
The SC-SPSW system consists of thin steel infill plates, or web plates, that yield laterally in order to dissipate seismic energy, along with post- tensioned beam to column connections in order to self center and reduce the residual deformation of the system. The post- tensioned connections are designed to replace the moment resisting connections in the initial design of the SPSW system, which experienced plastic deformations causing costly repairs after an earthquake. The PT connections permit a gap at the beam to column connection and provide the force necessary to recenter the connection and prevent damage at the gaps. The system is designed to effectively dissipate seismic lateral loads, while reducing the cost and time required to repair a specimen post- earthquake.
The specimens within this experiment were four subassemblies of the SC-SPSW system. Each specimen was a two story configuration of the steel plate shear wall system with web plates and post-tensioned connections. One end of the vertical boundary elements was pinned to the ground to prevent column movement, while the other was attached with a roller in order to prevent compressive forces when the gaps opened at the connections. The PT strands were located at the centerline of each horizontal boundary element to self center the system and close gaps at the connections to prevent residual damage, and slotted holes with tight bolts were used in each connection in order to allow for some rotation at the connections.
Experimental Study, Results, and Discussion
The four specimens were designed with different web plate thickness, initial PT forces, and number of PT strands in order to study the effects of these qualities on the stiffness and behavior of the SC-SPSW system. Each specimen was loaded with an actuator, and quantities of force, gap openings, and strain were measured with load cells, potentiometers, and strain gauges, respectfully. Each specimen was loaded cyclically with three cycles to peak displacements up to 2.0% peak drift, then increasing by 0.5% drift up to 4.5% drift.
The results showed that web plate thickness had the strongest effect on the energy dissipation of the system, while the number of PT strands had a strong effect on the recentering stiffness of the system. Greater numbers of PT strands increased the recentering capacity, thus reducing the residual deformation of the system, while thicker web plates increased the residual deformation of the s
Reference
Clayton, P., Winkley, T., Berman, J.W., and Lowes, L.N., (2012). “Experimental Investigation of Self- Centering Steel Plate Shear Walls,” Journal of Structural Engineering, 138, 7, pp. 11.