预应力混凝土连续梁桥温度-挠度试验研究

Test and Research on Temperature-deflection for Prestressed Concrete Continuous Girder Bridges

在大跨径预应力混凝土连续梁桥悬臂施工中,通常因温度变化所致主梁产生较大的挠度,给大桥的合拢造成严重的困难。结合工程实例,在龙溪港大桥0#块端部布置温度计,对温度和挠度进行一昼夜的观测;并分析温度和挠度数据,利用最小二乘法进行温度场分布曲线的拟合。然后,建立有限元模型,计算拟合温度场下的理论温度挠度。结果表明,温度对主梁的挠度影响很大,最大值为32 mm;温度变化引起的挠度与外温呈现出相反的变化趋势,并且挠度值随悬臂长度的增大而逐渐增大,因此,选择最佳的合拢时间对大跨径预应力混凝土连续梁桥成桥后的线形和受力至关重要。

In cantilever construction of long span prestressed concrete continuous girder bridge,the change of temperature often generates large deflection of the main girder,and brings serious difficults to closed period. Combined with engineering instance,to decorate thermometer and strain gauge in the Longxigang bridge of 0 block,and observe the temperature and deflection during day and night on the spot. To analyze the data of temperature and deflection,and get temperature field distribution curve fitting according to the least square method. Then,to calculate theoretical temperature deformation under the temperature field according to the finite element mode. The results showed that temperature has a great influence on the deflection,the maximum value is 32 mm. The deflection caused by temperature change and outside temperature are showing the opposite trend,and with the increase of the cantilever,the deflection increases; so it is very important to choose the best closing times on the linear and stress of long span prestressed concrete continuous girder bridge.