MECHANICAL BEHAVIOUR OF COMPOSITE GIRDERS SUBJECTED TO HOGGING MOMENT: EXPERIMENTAL STUDY

摘要

In continuous composite steel-concrete structures, cracking of the concrete slab in the hogging moment nregion decreases the global stiffness of composite steel-concrete structures and reduces the effect of con-ntinuity, thus making the structural behaviour highly nonlinear even for low stress levels, so special con-nsideration is necessary. An experimental investigation on the behaviour of steel-concrete composite beams nin hogging moment region is presented in this paper. A total of four specimens were tested under point load nin the mid-span. Two of the composite beams with headed studs as the shear connectors, while the other ntwo specimens are using Perfo-Bond Strips (PBLs) as the connection devices between the steel girder and nthe concrete slab. Ultimate load bearing capacity of composite sections in negative moment region was ncalculated and compared with experimental values. Crack formation, crack widths development process nand strain distribution of the composite section before and after cracking were observed and presented in nthis study. Interface slip distribution was also given. Research results indicate that the current specifications nsuch as AASHTO, JSCE, and EUROCODE-4 can provide appropriate values for ultimate strength of a ncomposite girder under negative bending moment.