全预制快速架设钢-UHPC轻型组合城市桥梁

发布时间：2018-12-13 21:40

【摘要】：为缩短城市高架桥现场作业时间,利用超高性能混凝土良好的力学性能及耐久性,提出一种可整体预制、整跨吊装、快速成桥的钢-UHPC轻型组合桥梁,并针对传统钢-混凝土组合连续梁桥负弯矩区桥面板拉应力过大的情况,提出一种可与梁段整体预制的简支变连续结构。对30m跨径钢-UHPC轻型组合城市桥梁试设计,并与现有方案进行材料用量及经济性能对比;利用MIDAS/Civil软件对试设计桥梁进行荷载组合效应计算,根据计算结果以中国桥梁设计规范为基础,同时借鉴法国UHPC结构设计规程,分别基于塑性设计法和弹性设计法对钢-UHPC轻型组合连续桥梁的承载能力极限状态和正常使用极限状态进行设计计算,并对正常使用极限状态钢筋数量及裂缝宽度的关系进一步探究;建立负弯矩区精细化的局部有限元模型,根据计算结果选择拉应力较大的桥梁纵向接缝进行1∶1足尺模型试验研究。研究结果表明:试设计桥梁在预估价较低的情况下结构高跨比由1/21降低至1/28,自重减至传统钢-混凝土组合桥梁的54%;钢筋数量增加初期,UHPC板裂缝宽度迅速减小,随着钢筋数量继续增大,其对裂缝宽度控制的贡献明显减小;试设计钢-UHPC轻型组合城市桥梁具有足够的抗弯与抗剪承载力,负弯矩区整体应力水平不高,同时试验接缝抗拉强度远大于计算值,满足工程使用要求。
[Abstract]:In order to shorten the working time of urban viaduct, using the good mechanical properties and durability of ultra-high performance concrete, a kind of steel-UHPC light-duty composite bridge which can be prefabricated, hoisted and completed quickly is put forward. Aiming at the situation that the tensile stress of slab in the negative moment region of traditional steel-concrete composite continuous beam bridge is too large, a simple supported variable continuous structure which can be prefabricated with the whole beam segment is proposed. The experimental design of 30m span steel-UHPC light-duty composite city bridge is carried out, and the material dosage and economic performance are compared with the existing scheme. The combined effect of load is calculated by using MIDAS/Civil software. According to the calculation results, the bridge design code of China is used as the basis, and the design code of UHPC structure in France is used for reference at the same time. Based on plastic design method and elastic design method, the limit state of load-carrying capacity and normal use limit state of steel UHPC light-duty composite continuous bridge are designed and calculated, respectively. Furthermore, the relationship between the number of steel bars and crack width in normal service limit state is further explored. The local finite element model with fine negative bending moment region is established. According to the calculated results, the longitudinal joints of bridges with large tensile stress are selected for 1:1 full-scale model test. The results show that the ratio of height to span is reduced from 1 / 21 to 1 / 28, and the deadweight is reduced to 54 parts of the traditional steel-concrete composite bridge. The crack width of UHPC slab decreases rapidly at the beginning of the increase of steel bar quantity, and its contribution to the crack width control decreases obviously with the increase of the number of steel bars. The steel UHPC light-duty composite city bridge has enough flexural and shear bearing capacity, and the overall stress level in the negative moment region is not high. At the same time, the tensile strength of the test joint is far greater than the calculated value, which meets the requirements of engineering application.
【作者单位】：湖南大学土木工程学院;郑州航空港兴港投资集团有限公司;
【基金】：国家自然科学基金项目(51178177,51378194)
【分类号】：U445.4

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