连续刚构梁拱组合桥日照温度效应分析

Solar Temperature Effect Analysis on Bridge with Continuous Rigid Beam-arch Composite Structure

为了对连续刚构梁拱组合桥日照温度效应展开研究,依托陕西省铜川市某在建高墩大跨连续刚构梁拱组合桥,采用现场温度场实测数据、历史气象观测数据与有限元数值模拟相结合的方法,研究高墩大跨连续梁拱组合体系空间温度场及其温度效应。结果表明:通过开展依托工程空心薄壁混凝土高墩温度场现场试验测试,分析混凝土高墩温度分布随时间和空间的变化规律,可以看出混凝土高墩在1 d中内外表面温度测点的温差可达到11.9℃,这说明温度分布沿桥墩壁厚方向的差异显著,为高墩日照温度场数值模型验证提供了试验基础;对比有限元模拟结果与现场实测数据表明,大部分代表性观测点位的温度有限元计算值与温度实测值吻合程度较好,验证了数值模型及气象参数取值的合理性;关键施工阶段温度效应分析表明,主梁合龙口相对高差值随着结构整体升降温变化呈线性变化;在考虑不同主墩温度梯度的情况下,主梁的挠度曲线形式和挠度值与现行桥梁规范中仅考虑主梁温度梯度效应相比均发生了较大变化;当拱肋合龙温差在10℃以内时,可以忽略其对结构内力和线形的影响。

To study the solar temperature effect on continuous rigid beam-arch composite bridges,relying on the continuous rigid beam-arch composite bridge with high-pier and long-span under construction in Tongchuan city,Shaanxi province,the spatial temperature field and its temperature effects of continuous beam-arch composite system with high-pier and long-span are studied by using the combination of on-site temperature field measuring data,historical meteorological observation data,and finite element numerical simulation.The result indicates that by conducting on-site experimental tests on the temperature field of hollow thin-walled concrete high piers based on engineering,the variation rule of temperature spatio-temporal distribution of concrete high piers is analyzed.It is found that the temperature difference between inner and outer surface temperature measuring points of concrete high piers can reach 11.9℃in a day.That indicates significant differences in temperature distribution along the direction of pier wall thickness,and provides an experimental basis for verifying the numerical model for solar temperature field at high piers.The comparison between finite element simulation result and on-site measuring data shows that the temperature finite element calculation values of most of representative observation points are in good agreement with the temperature measuring values.That verifies the rationality of numerical model and meteorological parameter values.The temperature effect analysis during the critical construction stage shows that the relative height difference between main beam and junction is varying linearly with the overall temperature variations of structure.Considering different temperature gradients of main piers,the form and value of main beam deflection curve have undergone significant changes compared to the current specifications,which only consider the temperature gradient effect of main beam.When the temperature difference of arch rib closure is within 10℃,its influence on internal force and linearity of structure can be ignored.