考虑施工过程的钢箱—混凝土组合梁桥的徐变效应分析  

Creep Effect Analysis of Steel Box-Concrete Composite Girder Bridge Considering Construction Process

作　　者：吴树广 赵付强 吕力现 高腾飞 苑广浩 WU Shu-guang;ZHAO Fu-qiang;LYU Li-xian;GAO Teng-fei;YUAN Guang-hao(Road&Bridge International Co.Ltd.,Beijing 100027,China)

机构地区：[1]中交路桥建设有限公司,北京市100027

出　　处：《公路》2022年第4期160-166,共7页Highway

基　　金：国家重点研发计划,项目编号2017YFC0806001。

摘　　要：采用ANSYS建立3×50 m的桥梁实体有限元模型,并基于按龄期调整的有效模量法和有限元增量法,使用徐变准则进行徐变等效计算,在考虑施工过程后研究预制板加载龄期为90 d的钢混组合梁桥的徐变效应,并对比预制和现浇两种不同施工方法的桥梁徐变效应。研究结果表明,桥面板中支点负弯矩区徐变应力储备是边支点的7.8倍;跨中徐变应力纵向分布为边跨>中跨,而横向呈现“两边大,中间小”的规律;支点截面呈现明显的正剪力滞现象,且外侧腹板处徐变应力为内侧腹板处的3.5倍。同时,相较于整体现浇桥面板,预制桥面板的边跨正弯矩区徐变应力显著减小,采用龄期180 d的预制板时应力减少了45%;预制比现浇桥面板的剪力滞现象更明显,支点截面龄期180 d的预制板腹板应力为现浇的4.3倍。In the paper,a 3×50 m bridge entity finite element model is established by ANSYS.Based on the effective modulus method and finite element incremental method adjusted by age,the creep criterion is used for the equivalent calculation of creep.After considering the construction process,the creep effect of steel-concrete composite beam bridge with prefabricated plate loading age of 90 d is studied,and the bridge creep effects of prefabricated and cast-in-situ construction methods are compared.The results show that the creep stress reserve in the negative bending moment region of the fulcrum in the bridge deck is 7.8 times that of the edge fulcrum.The longitudinal distribution of creep stress in mid-span is in the order of side span>mid-span,and the transverse distribution shows the rule of‘large on both sides and small in the middle’.The fulcrum section shows obvious positive shear lag,and the creep stress at the outer web is 3.5 times that at the inner web.Meanwhile,compared with the integral cast-in-situ bridge deck,the creep stress in the positive bending moment region of the side span of the prefabricated bridge deck is significantly reduced,and the stress of the prefabricated bridge deck with the age of 180 d is reduced by 45%.The shear lag phenomenon of precast bridge deck is more obvious than that of cast-in-situ bridge deck,and the web stress of precast slab with 180 d age of fulcrum section is 4.3 times that of cast-in-situ bridge deck.

关 键 词：钢混组合梁桥 施工过程 徐变效应 有效模量法 分析 

分 类 号：U441.5[建筑科学—桥梁与隧道工程]