Experimental response of cold-formed steel stud shear wall with hardboard sheathing under seismic loading

摘要

In the design of cold-formed steel (CFS) buildings, sheathings are used to provide lateral resistance to seismic or wind load. Many researchers have thoroughly studied the basic behavior of different sheathing (including walls sheathed with plywood, oriented strand board, gypsum wallboard, gypsum sheathing board, steel sheet sheathing, and fiberboard) with different thicknesses. However, despite many studies, the examination of existing experimental studies demonstrates that the lateral bracing and stiffness provided by the sheathing are generally ignored, and sheathing is provided as a non-structural component. This study aims at that neglected aspect. In this study, cold-formed steel shear wall (CFSSW) response has been investigated with varied thickness of hardboard sheathing used as a structural element. The main aim was to determine the contribution of sheathing in resisting lateral forces. For this purpose, three full-scale specimens (i) frame without sheathing, (ii) frame sheathed with 4 mm thick hardboard, (iii) frame sheathed with 10 mm thick hardboard were tested using a uni-directional shake table. The sheathing was screw-fastened to the cold-formed studs and tracked for the development of shear stiffness and strength in the wall system. The test results revealed that in addition to increasing the lateral stiffness of the structure, the hardboard sheathing also acts as an efficient bracing system. However, some minor but recoverable damages were also noticed. In addition, stud local buckling failure mode was observed, and it could be caused by the low anchor stiffness of using cleats instead of hold-downs. It is also important to mention that the number of tests performed in the current study was limited, and further similar research needs to be carried out before generalizing the results.