Analysis Of Construction Monitoring And Security For Rotating Bridge

Bridges are increasingly utilized to cross over other traffic lines such as railways, highways and rivers, and the swing method of bridge construction is becoming more and more widely used on account of its obvious advantages. Supporting frames, on which concrete will be poured during construction, are built on both sides of the terrain. The beam of the bridge will be swiveled to the correct position by the rotatable structures consisting of ball bearing and slides, without interrupting naval navigation and road traffic. Due to safe and convenient construction and the elimination of the complex high-altitude operations, the swing method has significant socio-economic benefits.Bridge construction monitoring is not only an important part of the bridge construction technology, but also the key to ensuring the macro quality of construction. This paper focuses on the construction of a swing bridge on Qinhuangdao’s West Highway over the Beijing-Harbin Railway. The stress from a cross section of the box girder and swivel pier, and beam deformation after the removal of stents were closely monitored and analyzed based on the calculated values of finite element analysis. Meanwhile, heat of hydration in the cross-section of the swivel pier base was also monitored and calculations of temperature and stress field were simulated by using the finite element software. Reasonable recommendations for controlling the maximum temperature difference between the concrete inside and outside to prevent cracks were given.Due to the inevitable errors in the construction process, the actual center of the rotating body after the removal of stents often does not coincide with the theoretical one. The size of the eccentricity will directly affect whether the rotation could be carried out safely and smoothly. Therefore, it is necessary to have a weighing test and to balance the weight based on the test results before rotation, in order to ensure that the rotating bridge will swivel smoothly.The rotating body gets into a cantilever state after the removal of stents, and needs to stand alone for a short period only relying on the ball hinge before rotation. For that reason, the influence imposed on the bridge by passing trains and wind could not be ignored. Vibration generated by the passing trains was acquired through a field test. When time history analysis method was applied to compute the long cantilever’s vibration response, the influence imposed on the rotating body by passing trains was analyzed. Meanwhile, the influence imposed on the rotating body by wind was also analyzed. The result can provide a reference for the on-site construction control.