大体积混凝土桥梁承台温度及应力场模拟

Finite element analysis of the temperature field and temperature stress of a concrete bridge deck

为掌握大体积混凝土在龄期范围内的温度及应力分布,为某即建大桥承台施工提供合理、有效的调控措施,采用大型商用软件ANSYS对混凝土承台浇筑后七天内的温度场及温度应力进行数值模拟.结果表明:内部温峰出现在浇筑后的3.5 d左右,表面温峰则出现在第2 d,且先后浇筑的三层混凝土的温度场分布随龄期变化规律有较高的一致性;混凝土内部的最大温度应力出现在浇筑后的7 d,且高于当日混凝土抗拉强度,为避免早期裂缝的发生,在承台施工过程中需在混凝土内部埋设冷凝水管,且要对温度场及温度应力值进行监测.

To know the massive concrete temperature and stress distributions within the age range and provide reasonable and effective control measures for the building of the bridge deck, large commercial software ANSYS is employed to conduct numerical simulation of the temperature field and temperature stress within seven days after the pouring of concrete. Results show that the internal temperature peaks at the 4th day after pouring, surface temperature peak occurs in the second day, and the temperaatre field distributions of three successively poured layers of concrete are highly consistent with age range changes. The maximum temperature stress in concrete appears in the 7th day after pouring and it is larger than the tensile strength of concrete values on that day. In order to avoid early cracking, an internal condensate pipe should be embedded in the concrete during the construction process of bridge deck, and temperature field and temperature stress should also be monitored.