Study On Concrete Pavement Structural Design Method Of Quick Repair With Precast Concrete SLAB

Quick repair technology of Precast Concrete Slab (PCS) is a new repair method, which replaces the damage area of original cement concrete pavement with precast slabs. The processes of pouring and curing are finished in back court, and only the processes of hoisting and joint treatment are conducted on site, so only 4 to 6 hours are needed before opening to traffic. PCS quick repair technology has great advantages:(1)opening to traffic rapidly; (2)saving maintenance cost; (3)reducing environmental impact; (4)adapting to special climate; (5)improving traffic safety.However, only a little of researches on this technology has been done currently, and an appropriate pavement structural design method of PCS which can be used to guide practice has not been formed. Therefore, it is urgently necessary to study this technology to provide a theoretical basis for the engineering application. In this thesis, the mechanical response of pavement structure and joint load transfer efficiency are analyzed under both static and dynamic load by the finite-element method. Then, the load fatigue stress of PCS is studied. Also, the hoisting of PCS is analyzed, with a reasonable method for hoisting being proposed. At last, the structural design method of PCS is put forward based on the reliability theory.Firstly, the mechanical response of pavement structure and joint load transfer efficiency of PCS are analyzed under static load. The model of pavement structure is established by ABAQUS/Standard, in which the stress and displacement of panels under static load are numerical simulated. The critical load position of PCS is ascertained. Then, the parameter sensitivity of the pavement structure mechanical response and joint load transfer efficiency is analyzed under static load.Secondly, the mechanical response of pavement structure and joint load transfer efficiency of PCS are analyzed under dynamic load. The model of pavement structure is established by ABAQUS/Explicit, with the user subroutine VDLOAD being written by FORTRAN program and being utilized by ABAQUS for simulation of moving constant load. The stress and displacement of slabs under dynamic load are numerical simulated. The most unfavorable driving track of PCS is determined. Then, the parameter sensitivity of the pavement structure mechanical response and joint load transfer efficiency is analyzed under dynamic load. Meanwhile, comparative analysis is performed between static and dynamic models.Thirdly, the load fatigue stress of PCS is studied. On the basis of orthogonal design method and multivariate statistical regression method, the maximum load stress formula of PCS is conducted. Considering the base strength decreases, the load fatigue stress of PCS is analyzed. Also, the maximum vertical displacement formula of PCS is conducted.Then, the hoisting of PCS is analyzed in this thesis. The method of panel bar system is taken for the strength analysis of PCS.Moreover, three dimensional finite element model of hoisting is established by ABAQUS, with the stress of PCS being numerical simulated. Reasonable number and position of hoisting point are determined. At last, rational method of hoisting and process of construction are raised.At last, the structural design method of PCS based on the reliability theory is put forward. On the basis of the previous analysis of load stress calculation method and the temperature stress calculation method in the current specification, the structural design method of PCS is proposed with the base strength decreasing. The specific design process is also given. By analyzing the specific examples, the outcomes by using specification design method and the method given in this thesis are compared, and the application scope of each method is put forward.