多梁式组合钢板梁桥荷载横向分布研究

Study on Lateral Load Distribution of Multi-Beam Composite Steel Plate Girder Bridge

多梁式钢混组合板梁主梁高度小,可提高通行净空,装配化施工可节约工期,在城市高架桥建设中具有较好的应用前景。通过实体-板壳三维有限元分析,研究组合钢板梁桥荷载横向分布特性;分析车道荷载横向分布影响线,明确各主梁荷载的横向分担范围与比例;分析不利荷载工况及各主梁荷载横向分布系数,得出受力较大的主梁及其不利荷载作用位置。比较设置与未设跨中横梁的组合梁受力状态,分析跨中横梁对荷载横向分布的影响。研究结果表明:设置跨中横梁使边梁及中梁弯矩影响线竖标值分别减小约20%和36%,而相邻主梁荷载分担作用增大,有利于改善单根主梁的荷载分布特性。在偏心及对称车道荷载作用下,跨中横梁使得组合梁的荷载横向分布趋于平缓,荷载横向分布改善2%~5%。多梁式组合钢板梁桥在实际应用中,可根据汽车荷载情况及所处桥位景观要求,综合考虑是否设置跨中横梁。

The height of the main beam of the multi-beam steel-concrete composite plate girder is small,which can improve the traffic clearance,and the assembly construction can save the construction period.It has a good application prospect in the construction of urban viaducts.Through the 3D finite element analysis of solid plate-shell,the lateral load distribution characteristics of the composite steel plate girder bridge are studied;the influence line of the lateral distribution of the lane load is analyzed,and the lateral sharing range and proportion of the load of each main girder is determined;the unfavorable load conditions and the load of each main girder are analyzed.The lateral distribution coefficient is used to obtain the main girder with greater stress and its unfavorable load action position.The stress state of composite beams with and without mid-span beam is compared,and the influence of mid span beam on the lateral distribution of load is analyzed.The research results show that the setting of the mid-span beam reduces the vertical scale values of the bending moment influence line of the side beam and the middle beam by about 20%and 36%respectively,while the load sharing effect of the adjacent main beam increases,which is beneficial to improve the load distribution characteristic of a single main beam.Under the action of eccentric&symmetrical lane loads,the mid-span beam makes the lateral load distribution of the composite beam tend to be gentle,and the lateral load distribution is improved by 2%-5%.In practical application of multi-girder composite steel plate girder bridges,whether to install mid-span beams can be comprehensively considered according to the vehicle load conditions&the landscape requirements of the bridge location.