波形钢腹板预应力组合箱梁长期性能分析与试验研究

Nowadays, few researches have been carried out on the long-term performance of the composite structures with corrugated webs at home and abroad, thus lack of relative experimental data. For this kind of structures, effective analysis and evaluation methods are needed in the long-term performance, camber setting, and prestress loss calculation.Based on the methods, experiences and results obtained in the youth science fund approved in 2009, 800 days’ outdoor long-term performance test will be carried out to the prestressed concrete box-girder, prestressed concrete box-girder with corrugated webs and prestressed reactive powder concrete box-girder with corrugated webs. The key problems about the long-term deformation, prestress loss and stress redistribution caused by shrinkage and creep can be analyzed and evaluated. The long-term deformation calculated methods of prestressed concrete composite box-girder structures with corrugated webs can be established, which depends on the time. Through theoretical analysis and model test, the topic will make clear the variation characteristics of the shrinkage and creep of prestressed concrete composite box-girder with corrugated webs and analyze the change rules creep deformation, prestress loss and stress redistribution depend on the time. According to the different methods by splashing water and salt spreading and so on to prestressed concrete composite box-girder with corrugated webs and prestressed reactive powder concrete composite box-girder with corrugated webs, through long-term performance comparative test and endurance test at the time, the durability properties advantage and characteristic of prestressed reactive powder concrete composite box-girder with corrugated steel webs will be discussed.

目前国内外针对波形钢腹板组合结构的长期性能研究很少，相关的试验研究资料匮乏，此类结构长期性能、预拱度设置、预应力损失计算等缺乏有效的分析评估方法。结合09年立项课题已经取得的经验、方法和成果，拟通过开展普通混凝土腹板箱梁、波形钢腹板箱梁、RPC波形钢腹板箱梁室外800天的长期性能试验，对波形钢腹板箱梁因收缩徐变引起的长期变形、应变重分布、预应力损失等关键问题进行分析评价。建立考虑时效因素的波形钢腹板预应力组合箱梁结构长期变形计算方法，通过理论分析与模型试验，明确波形钢腹板预应力组合箱梁结构的收缩徐变特征，分析徐变变形、预应力损失和应力重分布等随时间变化规律。针对普通混凝土和PRC波形钢腹板箱梁，结合泼水与撒盐等养护手段，通过长期性能对比试验及耐久性指标测试，探讨RPC波形钢腹板箱梁在耐久性能方面的特点与优势。

目前国内外针对波形钢腹板组合结构的长期性能研究很少，相关的试验研究资料匮乏，此类结构长期性能、预拱度设置、预应力损失计算等缺乏有效的分析评估方法。本课题结合09 年立项课题已经取得的经验、方法和成果，按计划开展了项目调研、理论分析、全过程程序编制与开发、试验设计、室内试验和长达819天的室外试验测试工作。经过试验研究，获得得到了该结构的长期变形、预应力损失和顶底板应力等随时间变化的实测数据，明确了混凝土收缩徐变、预应力损失、结构构造特点对波形钢腹板预应力组合箱梁长期变形与应力的影响，掌握了其长期性能随时间的变化规律。在此基础上，提出了基于时效分析理论的波形钢腹板预应力组合箱梁长期变形和应力计算方法，并基于简支梁的弯矩—曲率关系，建立了考虑失效因素的全过程分析方法。结合试验结果，将理论计算结果与实测值进行了对比分析验证。同时，基于ANSYS/CivilFEM计算平台，采用逐步计算法来进行波形钢腹板组合结构的收缩徐变分析，验证了这种方法的可靠性。通过分析可知，波形钢腹板组合箱梁与混凝土腹板箱梁相比，在预应力配置相同的条件下，徐变对波形钢腹板箱梁的变形影响大于混凝土腹板箱梁，徐变引起的预应力损失率差别不大，混凝土顶底板的应力状态有一定差别。此外，针对普通混凝土和PRC 波形钢腹板箱梁，探讨了RPC 波形钢腹板箱梁在耐久性能方面的特点。本课题研究成果，为此类结构的长期性能分析和预测提供了难得的实测数据资料，为后续的科学研究和工程应用奠定基础，为此类结构的收缩徐变计算提供了手段和方法，对于实体工程预拱度的设置、预应力的设计等关键环节能提供较好的参考意义。