Study On Ultimate Bearing Capacity And Optimum Design Of Prestressed RPC Channel Girders

The channel girder can reduce structural height and traffic noise used in engineering. It has obvious superiority for urban bridge, highway bridge or railway bridge which located in urban area. However, channel girder is a trough-type structure, in which the area of tensional zone is much larger than compressive zone. Moreover, the complexity of structure and the difficulty of construction further the limit of its application in engineering. The deficiencies mentioned above can be well overcomed by using Reactive Powder Concrete in the channel girder instead of common concrete. It can not only make full use of materials, but also reduce the structural weight and improve structural safety.In the paper, According to the current railway bridge design criterions and referring to the existing design data of common concrete channel girder, the section of RPC channel girder has been determined. The paper carries out the full-range analysis and parameter analysis on RPC channel girder using ANSYS. Based on the research of bearing capacity, the optimum design of prestressed RPC channel girder is carried out. Then the paper performs the stability analysis aiming at the optimal results.It shows that the load-deflection curves of prestressed RPC channel girders can be divided into three phases: elastic deformation stage, cracking and crack development stage, failure stage. The girder slab thickness and reinforcement ratio have great effect on the girder bearing capacity and stress state, whereas the web dimensions have little effect. But web dimensions have great effect on cracks in web. Research shows that prestressed RPC channel girder has high cracking capacity. But the girder deflection increases rapidly in the cracking moment, and the girder deformation is great at failure stage too. All of those affect the girder's normal use. The paper suggests that designer should use cracking capacity as ultimate bearing capacity for RPC channel girder. This design idea could not only ensure the operation safety, but also reduce the maintenance cost in the later stage.