短悬臂斜拉桥主梁正应力分布试验研究

宽跨比大于0.5或高跨比大于0.2的梁按简单梁理论计算的正应力误差较大，因而分析短悬臂主梁的受力性能时，应考虑横向弯曲效应。为了研究短悬臂斜拉桥主梁横向弯曲变形对正应力的影响，定义了正应力不均匀系数，并对宽跨比1∶1的有机玻璃节段模型进行荷载横向对称变位试验，采集索力及应变增量数据进行分析。试验和有限元数据对比，可知:荷载横向不同作用位置对索力及剪力滞的影响很小，其引起的顶板横向弯曲变形会改变加载截面附近正应力的大小和分布规律；横弯效应对正应力的影响往自由端逐渐衰减，往固定端先减小后增大；塔根附近主梁应力的大小及不均匀程度与无横弯影响的结果相差很大。

Experimental study on normal stress distribution of main girder in short cantilever cable-stayed bridge

According to the simple beam theory, there is a remarkable error in the positive stress calculation of the beam with width-span ratio greater than 0.5 or depth-span ratio higher than 0.2. Thus, for the  behavior analysis of short cantilever beam under loads, the transverse bending effect should be taken into account. In order to analyze the influence of the lateral bending deformation of main beam on the positive stress of the short cantilever cable-stayed bridge, the non-uniform coefficient of positive stress is defined. And then a loading test with varying lateral loading locations was carried out on a segment model of organic glass with 1∶1 wide-span-ratio. The cable force and strain increment were collected. By comparing the test results and the finite element analysis results, a conclusion is drawn that the influence transverse load position on cable force and shear lag is very small. While, the lateral bending deformation will change the size and distribution of positive stress in the vicinity of loading cross section. The influence of the transverse bending effect on the positive stress gradually reduces to the free end. The development trend change from decrease to increase towards the fixed end. The size and irregularity degree of the main beam stress near the tower are different from that without bending effect.