The key points of ceramsite Concrete composite slabs without middle brace in construction are bearing capacities of trough bottom plates and shear strength of trough contact plane, which are important design parameters. To study bearing capacities of trough bottom plates and composite slabs and evaluate the shear strength of trough contact plane, three bottom plates and three composite slabs are tested and load bearing capacities, crack resistance, elastic restoring capacities of bottom plates and composite slabs are analyzed. The test results and theoretical analysis show that the trough bottom plates and composite slabs have higher resistance to bending, crack resistance and elastic restoring capacities, and application of ceramsite concrete reduces dead load and ensure the feasibility of the trough bottom without brace in construction, in addition trough contact plane has higher shear strength than that of rectangle contact planes. Finally, the application of composite slabs without brace in steel construction has shorter period of construction and better economic indicator compared with cast in place concrete slab.
