Study On The Experiments Of LGS Square Tube Truss Girder With Z Shaped Clips And LGS-OSB Composite Floor

Light Gauge Steel(LGS) square tube truss girder with Z shaped clips and its OSB composite floor is widely used for its high bearing capacity. But now, there is few experimental data and study on it. In order to understand the force situation and working mechanism of this composite floor accurately and fully, meanwhile to find the main factors affecting its stiffness and bearing capacity, it was very necessary to conduct some esperments and researchs.Based on the thickness of Oriented Strand Board(OSB), thickness of top and bottom chord, span of test specimens these three main parameters, we conducted three experiments on the LGS square tube truss girder and five ones on its OSB composite floor. By means of describing their failure process, phenomenon, mode and load-strain relationship of key sections, in addition to analyzing the impacts of chord and OSB on mechanical and deformation performance, we could know: 1. Normally there were two types of failure modes which are compressive zone local buckling failure and material failure; 2. OSB could significantly increase the plastic stiffness and ultimate bearing capacity of light-gauge steel truss girder, but not elastic stiffness or capacity of normal use; 3. The thickness of OSB had some influence on the stiffness and bearing capacity of composite floor but not obviously; 4. Thickness of top and bottom chord could significantly affect the stiffness and bearing capacity of the beam and composite floor, however top chord influenced ultimate bearing capacity much more than bottom chord.Finally, we checked all specimens’ ultimate bearing capacity based on strength and stability by using Chinese, American and Australian norms to inspect whether the norms are reliable and how accurate they are. The rusults showed that: the calculate value of beam was precise and safe but the calculate value of composite floor was too conservative.