大型钢管混凝土组合拱肋温度场及效应分析

Temperature field and effect analysis of large concrete-filled steel tube composite arch rib

钢管混凝土组合结构受温度的影响是多方面的,研究其从结构成型至服役全过程的温度分布规律及温度效应,对该结构的设计、施工和运营维护十分重要。通过对全尺寸钢管混凝土从混凝土硬化开始至成型后一段时间的温度进行实时监测,分析温度场规律,再建立有限元模型分析由温度产生的效应。结果表明:钢管混凝土内表温差易引起脱空现象,特别是水化热峰值结束后10 h左右,该段时间需要做好保温措施;太阳辐射产生的温度最大可达到15℃,显著影响着钢管混凝土的温度分布;截面径向温度呈两端低中间高的抛物线型非线性分布;钢管混凝土表面的应变与温度保持异步变化;外包混凝土浇筑后,在其水化热峰值时刻,管内混凝土应力最大达到3 MPa左右,钢管的应力可达到36 MPa,外包混凝土直至硬化完成,最大应力也不到2 MPa。这些结论可为钢管混凝土组合结构的设计、施工优化与病害消除提供借鉴和参考。

The influence of temperature on concrete-filled steel tube(CFST)composite structure is multifaceted.It is very important for the design,construction,operation and maintenance of CFST to study the temperature distribution law and effect of the whole process from structure forming to service.Through real-time monitoring of the temperature of full-size CFST from the beginning of concrete hardening to a period of time after forming,the law of temperature field was analyzed,and then the finite element model was established to analyze the effect of temperature.The results show that the temperature difference between the inner and outer surfaces of CFST is easy to cause the cavitation phenomenon,especially about 10 hours after the end of hydration heat peak,during which the heat preservation measures should be taken.The maximum temperature generated by solar radiation can reach 15℃,which significantly affects the temperature distribution of CFST.The radial temperature of the section presents a parabolic nonlinear distribution with low temperature at both ends and high temperature in the middle.The surface strain and temperature of CFST keep asynchronous changes.After the external wrapped concrete pouring,at the peak of hydration heat,the maximum stress of the concrete in the pipe can reach about 3 MPa,the stress of the steel pipe can reach 36 MPa,and the maximum stress of the outsourcing concrete is less than 2 MPa all the time.These conclusions can provide reference for the design,construction optimization and disease elimination of CFST composite structures.