斜腿刚架桥的受力变形计算方法研究

Study on Calculation of Displacement of Slant Bean Bridge by Force

为了验证斜腿刚架桥的通常计算方法—强迫位移法的计算结果的可靠程度,采用有限元计算手段,对该种桥梁分别按强迫位移法和结构与土共同作用的方法进行了计算比较.结果表明:强迫位移法的计算结果改变了桥上荷载传递的方式,使其应力分布状态与真实应力分布状态有着比较明显的差别.通常情况下采用强迫法能保证桥梁结构的整体安全性,但在桥梁的局部(尤其是跨中位置),该方法会使计算结果偏小,并且在温度变化较大的地区采用该方法进行设计时会使结构产生强大的水平力,甚至导致桥梁基础无法设计,在这种情况下,就必须仔细考虑上下部结构共同作用,来对桥梁进行设计分析.

In order to verify the degree of reliability in the common computing method-forcing displacement of a strutted beam bridge, the FEM was used to calculate the difference between the forcing displacement method and the structure and soil concurrent method. The achievements as follows： the results of the forcing displacement method have changed the way of transference of load on bridge. It has obvious difference between the calculating distribution of stress and the distribution of true stress; generally, it can guarantee the whole security of bridge when using the forcing displacement method. But in the local of the bridge, especially in the middle of the bridge, this method will receive a smaller result. Also in temperature variation drastic zone, using this method, the structure will receive strong horizontal force. Even the fourldation of the bridge can＇t be designed. In such a case, the combine activate of the superstructure and substructure should be consider to design the bridge.