铁道建筑

基于经典解析法与板壳有限元法,对比分析单线偏心活载作用下铁路40 m跨度混凝土简支箱梁畸变应力分布,并通过定义畸变应力比分析截面几何参数对箱梁畸变效应的影响。结果表明:用解析法和板壳有限元法计算得出的畸变翘曲应力相近,ANSYS板壳有限元更适合模拟空间箱梁的真实受力情况;在偏心活载作用下,腹板与顶板交界处的应力比为10%,腹板与底板交界处应力比为13%,顶板悬臂端部应力比最大,可达17%;高跨比和宽跨比的增加会使跨中附近的畸变效应更加明显,壁厚的增加会使畸变效应有减弱趋势,且跨中截面的畸变效应始终大于l/4截面与l/8截面(l为跨度)。

Based on the classical analytical method and the shell finite element method,the distortion stress distribution of railway 40 m span concrete box simply supported girder under single-track eccentric live load was calculated and compared.The influence of sectional geometric parameters on distortion effect of box girder were analyzed by defining the distortion stress ratio.The results show that the results of the distortion warping stress calculated by the analytical method and the shell finite element method are similar.The ANSYS shell finite element is more suitable to simulate the real stress of the space box girder.Under the eccentric live load,the stress ratio at the junction of web and top plate is 10%,the stress ratio at the junction of web and bottom plate is 13%,and the stress ratio at the end of cantilever of roof is the largest,up to 17%.With the increase of height span ratio and width span ratio,the distortion effect near the mid-span becomes more obvious.The increase of wall thickness will weaken the distortion effect,and the distortion effect of mid-span section is always greater than that of l/4 section and l/8 section(l is span).