混凝土连续梁箱形输水桥日照温度应力分析

根据混凝土箱形输水桥的温度边界特点,给出了箱形输水桥日照温差二次曲线分布形式;针对该日照温度梯度模式,按照温度自约束应力的平衡特点和等效线性化的原则,导出了混凝土箱形输水桥的温度应力计算公式和等效线性化后的特征参数计算公式.对某水库输水桥的计算表明:日照作用下混凝土连续梁箱形输水桥中跨截面下缘将产生较大的拉应力,会降低截面抗裂性,应加强纵向预应力钢筋,提高其抗裂能力.

Analysis of Lengthways Thermal Stress of Concrete Continuous Box-girder Water Birdge by Solar Radiation

According to characteristic of concrete box water bridge thermal boundary,temperature conic distributing is given by solar radiation.Based on balance characteristic of self-restrict stress and the principle of equivalent linearization,calculation formula in allusion to the thermal gradient mode is derived about thermal stress of concrete box water bridge and characteristic coefficient for equivalent linearization.The calculation on the water bridge of one reservoir shows that the lower part of the middle span cross-section will produce large tensile stress,which can reduce the performance of anti-cracking.Therefore,the ability of resisting crack can be improved through the application of the lengthways prestressed reinforcement.