Ultimate Bearing Capacity of Steel-Reactive Powder Concrete Composite Beams

Abstract

Concrete slab in the negative moment area of continuous steel-concrete composite beams is prone to crack due to the low tension strength of common concrete, which could result in the decreasing of the strength and durability. To solve this problem, a method of replacing the concrete slab with reactive powder concrete (RPC) slab which is of super high strength, durability, toughness and volume stabilization is presented. According to the constitutive relation and the high tension strength of RPC, the normal section failure mode is defined as the critical crack state, and the calculation formula of ultimate bearing capacity is deduced. Finally, some parameters that influence the ultimate bearing capacity are analyzed, such as the height ratio of RPC slab to whole beam, width ratio of RPC slab to steel beam, and the ratio of reinforcement of RPC slab. Compared with the steel-concrete composite beams, it is indicated that in the precondition of RPC slab unallowable crack in negative moment area, the ultimate bearing capacity of steel-RPC composite beams can still be increased, and the crack resistance, stiffness and durability can all be enhanced greatly.