Study On The Dowel And Tie Bar In Jointed Plain Concrete Pavement

Joints in JPCP(jointed plain concrete pavement) could reduce the environmental stress, but damage the integrity of JPCP. Therefore, dowel and tie bars are installed in transverse and longitudinal joints respectively in order to guarantee the LTA(load transfer ability) of joints.LTA and age of dowel bars have direct relationship with diameter and shape of them. Theoretical investigation about the influence of shape is empty. Tie bars are used to prevent joints open to guarantee LTA. LTA decreases evidently by increase of joints width, but the present design guide does not reflect this trend accurately. Compared with dowel bars, tie bars have not only disadvantage but also advantage on LTA, so it is necessary to analyze the LTA of tie bars accurately.Through the software ANSYS, a large-scale FEM with joints and property of two parameters foundation, considering friction behavior and a part FEM with only one dowel bar and friction element between the bar and concrete, modeling the element direct shear testing, was established respectively. The large-scale FEM was used to analyze the influence of dowel bars on the maximum deflection and flexural stress of the slab and the LTA of tie bars. The part FEM was used to analyze the stress intensity and void in the interface of the dowel bar and concrete.Tie bars were set up by the design guide. Through the analytical solution, the deformation of the longitudinal joint and the tension stress in the middle of slab induced by temperature was calculated considering the bilinear shearing stress-slippage relationship in the interface of slab and base and different kinds of base.In conclusion, shape of dowel bars does not affect the maximum deflection and flexural stress of slab but bearing stress, the principal normal stress, the maximum shearing stress, and shape and height of void in the interface of slab and dowel bars. Tie bars may decrease the maximum deflection and flexural stress of slab evidently. The action of tie bars to reduce the opening width of longitudinal joints is depended on temperature change, and the additional tension stress in the middle slab was caused.