Fabricated Simply Supported Plate Girder Bridge Jack-Up Engineering Control Technology Research

With the rapid development of China transportation infrastructure, due to a variety of reasons, such as the increasing navigation standards and the grade of Beneath Route and the lack of headroom of bridge span caused by the bridge deformation and sinking,It is necessary for bridge to maintain and technical reform. Bridges synchronous jack-up control technology with its low cost, shorten the construction period, less construction waste, do not change the original bridge upper structure mechanical characteristics, etc, have been widely used at home and abroad, especially have incomparable advantages in the treatment of the settlement of bridge offset and the inadequate clearance under the bridge. At the same time, due to the fabricated simply supported girder bridge with low building height, prefabricated convenient, material saving and easy standardization construction, etc, are widely used in small and medium span Bridges.Based on the Chengdu Beixin, interchange the multi-span bridges fabricated simply supported slabs bridge jack-up reconstruction project as the background, detailed the synchronous jack-up control technology, as well as the transformation process and the key technologies of jack-up, and put forward the corresponding improvement scheme and jack-up control technology method. At the same time, using nonlinear finite element software MIDAS FEA to numerical simulation analysis of the stress change sand cracking produced by capping beam and hollow plate hinge joints under the out of sync jack-up situation. For similar bridges jack-up reconstruction project, putting forward the corresponding precautions and control requirements, main conclusions as following:1、Column pier and cover beam joint and the joint cover the top of the beam both were dangerous position in the process of capping beam jack-up, should pay close attention to in the construction monitoring and control process.2、Similar project in the process of jack-up top cover beam around pier height difference should be controlled within±5mm.3、The cracking numerical simulation analysis of the hinge joints in hinged hollow slab, put forward the capping beam jack-up height difference between left and right abutment Δh=KD、L, simple calculation for the similar projects.4、Numerical simulation on the basis of the hinge joints in hinged hollow slab analysis found that Support all escapes has the biggest effect on articulated joints, although it do not produce a crack, but still should be avoided.