Experimental study on diagonally stiffened steel plate shear walls with central perforation

• Diagonally stiffened steel shear walls with central opening is studied.
• We examine three ½ scaled specimens to study seismic behavior of the new system.
• Structural properties of the perforated wall are improved using diagonal stiffeners.
• Ductility of the perforated system is 14% greater than un-stiffened solid model.
• Behavior factor for stiffened SPSWs is resulted R = 9 and for un-stiffened type R = 8.

One of the advantages of Steel Plate Shear Walls (SPSWs) is the easiness of openings application in infill plate. The openings are sometimes required for passing utilities, architectural purposes, and/or structural reasons. However, the recent researches on perforated steel plate shear walls have shown that the shear strength and stiffness of an un-stiffened steel shear wall decrease due to perforation of the infill plate. Hence, this paper presents a special combination of diagonal stiffeners with a central perforation. The seismic behavior of the new system is experimentally investigated and compared to the solid infill plate models. Experimental testing is performed on three ½ scaled single-story SPSW specimens under cyclic quasi-static loading. One of the specimens is un-stiffened and the two others are diagonally stiffened, which in one of them, a circular opening with the diameter of ⅓ depth of the panel is cutout from the wall center. It is observed that by means of the proposed stiffening method the shear strength of the perforated shear walls is achieved close to the un-stiffened wall with the solid panel, and the seismic behavior of the system is considerably improved. Test results show that the ductility ratio of the specially perforated specimen is about 14% greater than the un-stiffened specimen. A formula is developed and verified for the estimation of the shear strength of a perforated and diagonally stiffened SPSW. There are good agreements between the experimental outcomes and the theoretical predictions.