The use of shear connectors in the steel-concrete structural system is widely used to connect the steel and concrete parts of the system. The push-out test is the standard test used to detect the load capacity of different types of shear connectors. In this study, the push –out test was performed on concrete filled steel tube connected using channel shear connectors. The effect of concrete block strength and the exist of concrete core were investigated. Using concrete filled steel tube with increasing the compressive strength of the slab gain higher loading capacity and less slipping than hollow steel tube and low compressive strength of the concrete block. The experimental results were validated using ABAQUS finite element model. A numerical parametric study was carried out to show the effect of the value of concrete block compressive strength, length of the channel connectors, the strength of CFST and the yield stress of these connectors. It turns out that when increases either the length of shear connector or the concrete block strength or the yield stress of shear connector, the ultimate load increases, while the strength of CFST has no effect on ultimate load.

In this study, three specimens of Warren truss girders composite with concrete deck slab were tested experimentally under a central monotonic load to study the effect of the existence of concrete inside the chords. The load capacity, deflection, slip between the concrete slab and steel tube, and failure modes were reported. Both chords were filled with concrete to the first specimen, only the lower chord was filled with concrete and the upper chord remained hollow to the second specimen and both chords were kept hollow in the third specimen. The result indicated that the existence of concrete inside the chords has a significant effect on the load capacity, failure pattern, and the slip. The steel tubes of the upper chord filled by concrete prevent surface plasticity failure of the upper chord under loading and increase the ultimate load by 6.68 %. Also, filling the lower chord with concrete prevents the surface plasticity failure in the supports zone and caused an increase in the ultimate load by 39.59 %. The slip at the end of the specimen of two chords filled with concrete is less by 71% than the end slip of specimen of hollow top chord and higher by 46.8 % than the specimen of two hollow chords.