Abstract

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Title:: Low Cyclic Load Experiment of Cold-formed Steel Self Tapping Screw Connection of Keel-plasterboard

Author(s):: CHEN Wei; CHEN Li-wei; CHEN Sheng-gen; ZHANG Yi-dong; SU Yi-ran; LIU Bin; Key Laboratory of Building Fire Protection Engineering and Technology of MPS, Tianjin Fire Research Institute of MPS

Keywords:: cold-formed steel; plasterboard; self tapping screw connection; shear performance; low cyclic load

Abstract:: The experimental research on the cold-formed steel self tapping screw connection of keel-plasterboard was carried out. The low cyclic load experiments of 32 typical specimens were completed. The influences of screw margin and number of surface plates on the shear strength of self tapping screw connections were analyzed, and the simplified formula of shear strength was put forward. The results show that because of the different anti extrusion abilities of plasterboard along the edge of plate and the inside direction of plate, the shear strength of specimen under positive load is generally less than that under negative load. The load-displacement curves of some specimens are abrupt after reaching the peak value of shear strength, which is generally accompanied by rapid cracking of plasterboard or bolt pull-out. The specimen mainly presents the extrusion damage of the plasterboard, and some self tapping screws have a small amount of tilts. When the screw margin is 10-25 mm, the shear strength of specimens increases with the increase of margin. When the screw margin exceeds 25 mm, the shear strength of specimens dont increase obviously. The shear strength of double surface plates specimen is significantly higher than that of single surface plate specimen, but has not reached 2 times of that of the single surface plate specimen. The predicted results by simplified formula of shear strength are in good agreement with the test results.