立交桥多跨连续梁复位监测

Reset Monitoring for the Cross-bridge of Much Across Continuous beam

某立交桥在长期使用中,弯桥处多跨连续梁发生横向滑移近40cm,为此对该梁进行顶升和横移的复位施工。使用位移传感器对多跨连续梁的顶升和降落进行监测和控制,同时使用应变片监测多跨连续梁的应力。监测结果表明,相邻桥墩处的连续梁最大竖向位移差在3.40～7.89mm之间,连续梁产生的最大附加应力在-2.06～1.78MPa之间,连续梁没有裂缝产生,从而确保了多跨连续梁在复位施工中的安全。同时对钢支架的应力进行监测,得出钢管混凝土柱始终处于严重偏心受压状态的结论。在长时间监测中,采取分段测试然后测试数据累加的方法,减小了应变仪连续使用中的漂移问题。该桥的监测方法也可以用于其它桥梁的施工中。

In long-term service of certain cross-bridge, the multi-span continuous beam in the bend of the bridge displaced transversely about 40cm, which was reset by means of rising and horizontal moving. During the reset-construction, the vertical displacement for the continuous beam was monitored using displacement transducers, and the stress on continuous beam using electric-resistance strain gauges. It was found that the maximum difference in the vertical displacement of the continuous beam between nearby bridge piers was about 3.40^(7.89)mm; that being found the maximum additional stress on continuous beam was about -2.06~1.78MPa with no crack on the continuous beam. In addition, the stresses on steel frames were also monitored by strain gauges the conclusion that the steel-pipe concrete columns seriously suffer eccentricity press was obtained. In long time monitoring the excursion of electric-resistance strain instrument was effectively decreased by dividing the measured data into several segments and then adding then up. This monitoring method could be also applied to other bridges′ construction.