合龙段温度场的分区时变温升速率计算方法

A CALCULATION METHOD OF ZONE-PARTITIONING AND TIME-VARYING TEMPERATURE RISE RATE ON CLOSURE SECTION TEMPERATURE FIELD

在桥梁悬臂法施工过程中,合龙段混凝土常由于温度应力而开裂。为采用有限元方法合理的分析合龙段混凝土施工期水化热的温度场,提出了分区时变温升速率计算方法。在该方法中,首先,根据混凝土的浇筑顺序,将合龙段分为n个区域;然后,根据混凝土的绝热温升试验结果和不同区域的浇筑时间,对于每个区域施加不同的随时间变化的温升速率。为验证算法的合理性,对西安市红光路沣河大桥D合龙段进行施工阶段温度场实测。实测和计算的温度结果表明,与不分区相比,分区时变温升速率计算方法的峰值误差和峰值滞后时间更小,温度峰值的计算误差小于5%,可供类似工程施工设计参考。

During the cantilever construction of a bridge, the closure section concrete often cracks due to thermal stress. In order to analyze the temperature field of the closure section concrete caused by hydration heat during the construction using FEM, a calculation method of zone-partitioning and time-varying temperature increase rate is proposed. In this method, the closure section is divided into n areas according to the pouring sequence of concrete. Then, time-varying temperature increase rate of each zone is loaded according to the measured results of adiabatic temperature increase test and its pouring time. In order to verify the rationality of the algorithm, in-situ measurement of the temperature field on the concrete of D closure segment construction of Hongguang Road Fenghe Bridge was carried out. The measured and calculated results show that the peak error and peak lag time of the proposed method is smaller than the non-zone-partitioning method. The temperature peak errors by the method of zone-partitioning and time-varying temperature increase rate are less than 5%.