钢-混凝土连续结合梁的温度效应

在静定钢-混凝土结合梁温度响应的基础上,求出了单跨超静定结合梁的劲度系数和温度变化时的固端弯矩;根据力矩分配法,并考虑混凝土的受拉区开裂而不能承载的特点,分析了连续结合梁在温度作用下的响应.以京沪高速铁路三跨钢-混凝土连续结合梁为例,计算了在存在温度梯度、温差和骤然降温时的应力、挠度及剪力钉的受力情况.研究结果表明:当混凝土的温度变化大于钢梁的温度变化时,混凝土中的应力均为压应力,钢梁中的应力均为拉应力;当温度变化较大时,连续结合梁将产生不容忽视的应力;在计算连续结合梁的温度响应时若设钢和混凝土的线膨胀系数相等,则会产生较大的误差.

Temperature responses of steel-concrete continuous composite girders

Based on the responses of static composite girders in the action of temperatures, stiffness coefficients and bending moments at fixed ends of hyperstatic composite girders with single span were obtained. Temperature responses of continuous composite girders were developed according to moment distribution method and considering the crack property on the tensile stress area where load cannot be born. The stresses, deflections and shears on studs of a continuous composite girder with three-span in the action of temperature grades, temperature differences and temperature falling suddenly were computed with the formulas obtained in this paper. The results show that if the temperature change of concrete plates is more than that of steel girders, the stresses in concrete plates are all tensile and those in steel girders are compressor, continuous composite girders will produce the stresses which cannot be neglected in the action of major temperature change, and the common method to put lineal expansion coefficient of concrete equaling to that of steel in calculating the temperature responses of composite girders may result in noticeable errors.