UHPC薄壁盖梁设计、结构试验及施工技术研究

Study on Design, Structural Test and Construction Technique of UHPC Thin-wall Bent Cap

预制桥梁中盖梁重量较大的问题一直困扰着施工,具有轻质高强特点的UHPC可为盖梁轻量化提供解决方案.设计三种采用UHPC的薄壁盖梁,对比断面形式、材料指标及预应力体系;分批次开展结构试验,测试不同缩尺比下的全过程受力状态,分析构件抗裂性、承载力和变形等;比较不同UHPC材料、模板、振捣和养护方法对试件质量的影响.经过研究,UHPC薄壁盖梁设计方案可减轻原结构重量40%以上;UHPC盖梁受力可靠、抗裂性好、变形能力强;UHPC构件生产需严控浇筑过程.

The weight of bent cap is a main problem in the construction of prefabricated bridge.The ultrahigh performance concrete(UHPC)with the features of light weight and high intensity can provide the solution for the light weight of bent cap.Three kinds of UHPC thin-wall bent caps are designed.The sections,material indexes and prestressing systems are compared.The structural tests are carried out in batches to test the whole loading processes with the different scale ratios,and analyze the crack resistances,bearing capacities and deformations of the components.And the influences of the different UHPC materials,templates,vibrating and.maintenances on the quality of the test specimens are compared.The study result shows that UHPC thin-wall bent cap design scheme can reduce the weight of the original structure by more than 40%.UHPC bent cap has the characteristics of reliable stress,good crack resistance and strong deformability.The casting processes must be controlled rigorously in the production of UHPC components.