Through study of chemical composition,mechanical properties,grades of inclusions,fractographs and microstructure of the products,it was found that dendritic structures is observed in large ribbed bar with cracks along roots of transverse ribs.

Experimental research on shear resisting properties of cast-in-situ floor slab with cylindrical cavity when stirrup and transverse rib involved

The damage of transverse ribs by scraping during rolling process and cracking during cold bending were analyzed,and then the solutions of changing the transverse rib angles α and β were proposed.

On the basis of the analysis of the damage causes of two rigid bridges with the same size and structure,they are strengthened with transverse steel beams and transverse ribs,which achieves very good effects,and which also suggests that adding transverse ribs to the mid-span of bridges of the same type may produce certain preventive effects.

Through establishing the middle span section space pattern of large span continuous rigid frame,the paper calculates and analyzes by the large universal finite elements procedure ANSYS,compares and studies the influence of box bottom cross rib on direction across bridge stress,so as to reach the controllability of down warping in the main span of continuous rigid frame.

The paper introduced the theoretical model of "method of reinforced stiffness through cross rib" firstly,which the excellent structural capability of reinforced concrete cast-in.