Abstract

Info

Title:: Study on Flexural Stiffness of Cold-formed Thin-walled Steel Joists-OSB Composite Floors

Author(s):: SHI Yu; ZHOU Xu-hong; SONG Kai; LIU Jian; School of Civil Engineering, Chang’an University

Keywords:: cold-formed thin-walled steel joist; oriented strand board; composite floor; flexural stiffness; failure mode

Abstract:: Two full scale specimens were tested to study the flexural stiffness of cold-formed thin-walled steel joists-oriented strand board (OSB) composite floors, and the effect of the screw spacing between OSB and cold-formed thin-walled steel joists on the flexural stiffness of composite floors was analyzed. Meanwhile, authors used the proposed method of orthotropic plate to calculate the flexural stiffness of composite floors. Based on this, the influences of the thickness of OSB, the spacing and section dimension of joist, etc. on the flexural stiffness of composite floors were analyzed, and the equivalent flexural stiffness calculation method of the common cold-formed thin-walled steel joists-OSB composite floors was put forward. The results indicate the main failure modes of specimens are bendingtorsion buckling of floor joists，and the relative buckling of compression flange, web and crimping．The wave length of bucking is the adjacent screw spacing．Then the OSB is not obviously damaged. Screw spacing almost has little effect to the elastic flexural stiffness of composite floors. However, in the elastic-plastic stage, with the increase of screw spacing, the stiffness degradation of composite floors increases significantly.