DESIGN AND ANALYSIS OF PRESTRESSED REACTIVE POWDER CONCRETE LOW-HEIGHT BOX BEAM

摘要

Reactive Powder Concrete (RPC) is a new generation concrete developed in 1993. RPC has the advantage of high strength, high durability and high toughness. According to the higher performance, RPC can be used in bridge engineering to cut down the beam section and reduce the beam self-weight. RPC can be also used in severe environment to prolong the bridge operation life and lower the maintenance costs.The calculation method for the conventional concrete beam design is modified based on the perfect character of RPC. The ultimate compressive strength of RPC is up to 140MPa and it is difficult for the compressive area to be crushed, unless much more steel bars are wasted. The rectangular failure mode of the conventional reinforcement concrete beam is changed to be triangle mode. It is assumed that the stress is not up to the ultimate compressive strength in compressive area. With the modified failure mode, one 32m prestressed RPC low-height box beam for railway is designed. The box beam is 2.0m high and the height to span ratio is 1/16. The web and the bottom plate are 0.3m, and the top plate is 0.244m. The area of the prestressed steel bar is about 0.02m2. The stress and the deflection results are satisfied with the code requirements. It is the important reference for the low-height beam design.