Bridge Maintenance Reinforcement Technique Analysis

Nowadays the bridges in each country have general problems of the low capacity of bearing and traffic because of the low standards of primary designing, aging structure and the reduction of the strength in each material. According to the rapid development of social economy and transportation industry in China, a large amount of bridges have been damaged on account of the extended using years and growing load of bridges. As a result, how to take the bridge restoration has become the major issues in bridge engineering at present.This thesis discussed the significance of old bridge restoration and reinforcement, and the old bridge revolution principle as well as the assessment standards. Then it introduced briefly the basic concept and theory, steps and implementing method of bridge restoration, and how to strengthen the daily maintenance, restoration and reinforcement of bridges in order to assure the bearing and traffic capacity, extend the using years, ensure the traffic safety and good operating condition. This thesis studied the restoration and reinforcement methods used for the maintenance and repair for the bridges, such as surface flaws and fracture repair, enlarge section strengthening method, sticking steel plate strengthening method, sticking carbon fiber compound material strengthening method, external prestress strengthening method, changing structural system strengthening method, bridge floor system strengthening and load relief method. It also introduced specific measures and methods in the process of restoration, reinforcement and strengthening, such as the bridge flaw repair, surface flaw repair, inside flaw repair and structure fracture repair. This thesis discusses how to choose the affordable methods for the flaws in bridge structure and its affliated facilities such as bridge deck, bridge deck pavement, expansion seam and support, drainage and railing. It also introduces briefly the strengthening method of arch bridge and its substructure.According to the example of Tanjia Bridge, this thesis introduced the on-site assessment of bridge to judge with data whether to repair or not, the restoration and reinforcement method and how to construct. Built in the year of 1978 and located in Jiyang county of Shandong Provincial road No.239, Tanjia Bridge was under the technical condition of a third level according to the on-site assessment. The restoration and reinforcement method should be taken then. The main construction scheme was:cut the concrete which had the damaged edge, take the derusting measure to the exposed steel bars, repair with mortar to the district which has lower stratum spongiosum and minor disease, repair with mortar to the deep stratum spongiosum with the hole and depth more than 6cm, and stick carbon fiber under the plate; pour glue in the crackle of medium plate, stick carbon fiber under the plate and derust the exposed steel bars under the plate; pour glue in the fracture of abutment coping at the same time; demolish the railing on both side of the bridge and build anti-collision guard rails on the top of bridge deck.Thanks to the exploration and practice in the past decades, the management and maintenance technique of the bridge in China has grown out of nothing and has got some experience in NDT and Strengthening Construction Technology, which laid foundation for the exploration of bridge Strengthening Technology. This development benefits from the advanced construction equipment and complicated analysis technology in the construction of new-built bridges, and it enhances the performance analysis capacity in bridge structure. In the future it will promote the management and maintenance level of the bridge in China.