Damage Mechanism And Improvement Measures Of Continuous Pavement For The Simply Supported Cellular

The continuous slab-deck structure of simple supported beam can effectively improve the comfort of driving and enhance the performance of the bridge, therefore it is widely used in small and medium span bridges. However, in the service process, the crack in the transverse direction is occurred at the continuous deck sections of simple supported bridge with continuous slab-deck. In some situation, even the pitch are formed at the bridge pavement; which will bring a lot of influence to normal driving. In the meantime, the design of bridge continuous slab-deck is controlled by certain experience reinforcement without a special design and calculation, so the design is casual. Thus, the study on analyzing reasons of cracks for continuous slab-deck and improve it is of great importance.Firstly,in this paper, the simple supported cellular beam which is widely used in the small and medium bridge is chose as the research object. Based on the cracking phenomenon of bridge continuous slab-deck, the elastic analysis of the stress mechanism of the bridge continuous slab-deck under the vehicle loads is accurately analyzed. Then the stress analysis formula is deduced under various related action. The two span simply supported cellular was established based on finite element analysis software. The stress of concrete and reinforcement in the bridge continuous deck segment under 8 cases of possible working conditions are analyzed by linear elastic theory, and the material nonlinearity analysis is focused on the cracking of top concrete, then the stress of pavement reinforced after cracking is obtained to estimate the crack width. Secondly,consideration of vehicle-bridge coupling vibration, the mid-span and cross joint deflection(bending moment) time-history curve of simple supported cellular with continuous deck and ordinary simple supported cellular are calculated separately, and the deflection dynamic amplification factor(DAF) of mid-span and the bending moment DAF of cross joint. Finally combining the static and dynamic analysis results, the corresponding improvement measures are proposed by using deduced stress analysis formula of bridge continuous deck joints. The results show that:(1) cracks appear in the cross joints where top and bottom concrete of the continuous slab-deck structure under the load actions because its stress is beyond the limit tensile stress;(2) the vehicle-bridge coupling vibration is also unfavorable to the cracking in the cross joint;(3) the methods of the adoption of concrete with low elastic modulus, the pasted strengthening steel plates on the slab top can effectively improve the situation of stress and cracking, the strengthening of carbon fiber sheet and tensioned prestressed steel of deck methods are not adoptable.This research results provides a reference for the assessment and rehabilitation application of practical engineering.