铁路桁架斜交桥的现场试验和有限元模型

Field test and finite element model of railway steel trussed skew bridge

斜交角在许多方面会影响桥梁的几何形状和设计,比如斜交角度大于20°会影响外纵梁的弯矩和剪力。本文对甘肃兰州铁路钢桁架斜交桥进行了全面的荷载试验,给桥的上部结构安装了42个应变传感器,目的是精确测量结构物对118吨重的火车机车的反应,以确定在反应中斜交角产生的影响。同时利用荷载试验中收集的数据建立了三维有限元模型,将实测的内部轴向力与有限元的分析进行了比较,结果令人满意。模型经过校准后的结果表明,斜交角将内部轴向力降低了约16%,这与目前的设计具有可比性。

The skew angle affect the bridge geometry and design in many aspects,such as skew angle is larger than 20 degree will influence bending moment and shear force of longitudinal girders. Comprehensive load tests are carried out on the Gansu- Lanzhou railway steel trussed skew bridge,and 42 strain sensors are installed on the upper structure of the bridge,in order to accurately measure the response of the structure to the 118 ton locomotive. Then he influence of skew angle in the reaction is analyzed. The three- dimensional finite element model is established with the data collected in the load test.Then the internal axial force of field measurement is compared with that of finite element analysis and the results are satisfactory. After model calibration,the result shows that internal axial force is reduced about 16% off by oblique angle,and that is comparable to the current design.