廊坊市光明道上跨京沪高铁立交桥设计方案比选

廊坊市光明道大跨度立交桥需跨越多股无砟轨道,为减小对既有线路的影响,确保桥跨布设、工期等满足要求,对该桥桥式设计方案进行研究。考虑铁路现状及桥式设计关键点,选择与工程条件较为适宜的(27+115+288+115+27)m自锚式悬索桥、(80+248+75)m钢-混混合梁双塔斜拉桥及(136.4+248+136.4)m连续钢桁梁桥进行比选分析。结果表明,3种桥式均能满足桥梁主跨跨径及桥梁净空等功能要求,但连续钢桁梁桥方案对既有线路影响较小、工期较短、转体(顶推)施工重量较少、后期养护量相对较小,因此选为最终方案。经应力、位移及稳定性验算,该方案结构受力满足设计要求。

Design Schemes Comparison for Interchange Overpassing Beijing-Shanghai High-Speed Railway on Guangming Road in Langfang City

The long-span interchange on Guangming Road in Langfang City overpasses multiple unballasted railway tracks,to reduce the influence of which on the existing railways and ensure that the span distribution and construction schedule meet the requirements,the design schemes were studied.Considering the control conditions for bridge design and challenges of construction,three bridge types fairly meeting the engineering conditions were selected,including the self-anchored suspension bridge with five spans of 27,115,298,115 and 27 m,the two-pylon steel-concrete hybrid girder cable-stayed bridge with three spans of 80,248 and 75 m,and the continuous steel truss girder bridge with three spans of 136.4,248 and 136.4 m.The results show that all the three types of bridge can meet the spanning requirements of the main span and can leave the demanded clearance beneath the deck,but the continuous steel truss girder scheme was finally selected,because of the extraordinary benefits it can bring,for example,minor influence on the existing railways,short construction time,small weight for rotating(pushing)construction,and few late maintenance.The check calculation of stresses,displacement and stability proved that the load bearing capacity of the scheme could meet the design requirements.