【摘要】 利用三维有限元分析方法,建立具有不同直腹板厚度(25、30、35、40、45 cm)的5个箱形主梁有限元模型,分析其空间应力分布特点,归纳出斜拉桥中此类双箱单室倒梯形截面的薄弱环节及斜拉桥箱梁在不同直腹板厚度下的应力变化。考虑到梁段以外附近区域的作用,在其两端截面上施加由平面杆系结构分析所得的端面内力,另外,索力和预加力(梁纵向、横隔梁横向、斜腹板竖向)也施加在相应的位置,分析不同工况下箱形主梁在施工荷载、自重、索力和预应力作用下的空间应力效应。通过对以上工况计算结果的静力分析,归纳出斜拉桥中此类双箱式截面的应力分布特点,并给出直腹板厚度的合理化建议。分析表明,直腹板厚度为40 cm左右时,主梁的应力分布比较合理。更多还原

【Abstract】 By using the three-dimensional finite element analytical method,five different finite element models were established for box girders of the cable-stayed bridge with vertical webs of different thicknesses(25,30,35,40,45 cm).Three-dimensional stresses distribution characteristics of the models were analyzed.The disadvantages of twin-box single cross hammerhead sections and stresses varying with vertical webs of different thicknesses were specified.Considering the effects of the zone adjacent to the girder section,the internal-forces at the two-end surfacees were obtained by the horizontal shaft system analysis and were exerted in each model respectively.Moreover,the construction load,dead weight of the girder section,cable forcees and pre-stressed forcees along the longitudinal girder and transverse diaphragm and in the inclined web vertical direction were considered.Based on the above,the three-dimensional stresses of the box girder of the cable-stayed bridge with vertical webs of different thicknesses were analyzed.By the results of the above working situations,stresses distribution characteristics of twin-box girders of the cable-stayed bridge were summarized,and the reasonable designs were proposed.Analysis shows that the stress distributions of the main girder are reasonable when the vertical web thickness is around 40cm.更多还原