铁路大跨连续梁-拱组合桥主梁横向受力研究

RESEARCH ON THE MAIN GIRDER TRANSVERSE FORCE OF LONG-SPAN CONTINUOUS GIRDER-ARCH COMPOSITE BRIDGE OF RAILWAY

以跨径(82.9+172+82.9)m预应力混凝土连续梁-钢管混凝土拱组合桥为背景,采用软件MIDAS建立了单箱单室截面连续梁桥和连续梁-拱组合桥两种空间有限元模型,对两种桥梁横向受力及传递规律进行研究。分析结果表明:边跨梁段,连续梁桥与连续梁-拱组合桥横向内力及横向应力基本一致;中跨梁段,连续梁桥的轴力较小,横向弯矩较大,连续梁-拱组合桥应力较小,分布较均匀;边腹板位置处环框模型均可以包络连续梁桥和连续梁-拱桥顶板应力。对于连续梁-拱桥,环框模型在1/8~3/8边跨、1/6~1/2中跨范围内适用,其余位置,环框模型计算结果偏小;拱桥底板拉应力比连续梁桥拉应力大,且大于环梁模型计算结果,设计中应予以注意。

Taking the（82.9＋172＋82.9） m prestressed concrete continuous girder and steel tube concrete-arch composite bridge as an example,the MIDAS software was used to establish 2 kinds of space finite element models of singlebox-single-room-section continuous girder bridge and continuous girder-arch composite bridge,the transverse force and the transfer rules of the 2 bridges were analyzed.The analysis results showed that the transverse force and the stress of the continuous girder bridge and continuous girder-arch composite bridge were almost the same in edge span girder section;in the middle span girder section,the axial force of the continuous girder bridge was smaller,and the transverse bending moment was bigger,the stress of continuous girder-arch composite bridge was less and the distribution was more uniform.The MIDAS-Civil fully moment framed model could be used to calculate the top plate stress at side web position for both bridges;MIDAS-Civil fully moment framed model was applicable for the 1/8～3/8 edge-span,1/6～1/2 mid-span of continuous girder-arch composite bridge,and the calculation results were small at other positions.Special attention should be paid that the tensile stress of the arch bridge was larger than that of the continuous girder-bridge,and it was also larger than the calculation results of MIDAS-Civil fully rigid framed model.