(一)问题的提出 目前桥梁工程人员都知道,在多水、泥砂质底的河道上建造桥粱,采用高樁承台是特别有利的． 在钢筋混凝土桥梁中,框架体系有一系列的优点:省免支铰,使构造和养护简化;节点弯矩对顶梁弯 矩有卸载作用. 在中、大跨度的装配式桥梁中,会遇到梁—框架式体系。这种体系 (I) Proposing the Problem At present, bridge engineers all know that it is particularly advantageous to construct bridge beams on watery and silt bottom rivers and to use high-pile caps. In the reinforced concrete bridge, the frame system has a series of advantages: the province free support hinge, so that the structure and conservation simplified; node bending moment of the roof beam moment unloading effect .In the long span of the fabricated bridge, will encounter Beam - frame system. This system