Research On Integral Mechanical Behavior Of Hinged Voied Slab Without The Reinforcement Of Integration Pavement

With the increasing of traffic and overloading,the hinged joint of prefabricated hollow slab bridges is easy to be damaged,which can lead to the failure of transverse connection till the single beam bearing phenomenon appears.But this problem can be solved by the holistic pavement effectively.In order to understand the mechanical behavior the hollow slab bridges reinforced by the holistic pavement and to provide theoretical basis for the reinforcement and reconstruction,experimental study and finite element analysis are carried out.The main work and main conclusion of this paper are listed as follows:(1)The mechanical behavior tests of full-scale model made up of five hollow slab with 8cm and 22cm pavement thickness are proceed,and the feasibility of strengthening method is studied.Comparing the results of two experiments,the results are concluded that the overall stiffness and cracking load of voided slab is improved and the deflection and longitudinal stress is reduced.After the hinge joints crack,the difference of deflection in the middle section of the slabs is small,which shows that the variable load can be distributed to each slab more evenly and the single beam bearing phenomenon is no longer appears.And the results further prove the feasibility of strengthening method.The test results also found that the cracking load of the hinge joint bottom is near,which shows that the mechanical behavior of the hinge joint can not be improved effectively by the holistic pavement.(2)Nonlinear finite element analysis software ABAQUS was used to establish solid model of hollow slab bridges with 8cm and 22cm pavement,and the influence of pavement thickness on the transverse distribution of load,the stress and deflection of slab and the failure model are analyzed.It shows that:the thicker the pavement thickness,the load transverse distribution more uniform;There is a value of pavement thickness between Ocm and 30cm makes the stress and deflection minimum under the same load.The failure model of the hinge joint is vertical shearing failure;The cracking load and the failure load of the hinge joint increase along with the pavement thickness,but the increasing speed is low.(3)The load transverse distribution results of the finite model and the theoretical calculation are compared with each other under the condition of different pavement layer thickness,and the conclusion is that:the more the pavement layer thickness is,the grater the load transverse distribution more uniform,and the grater the difference the calculated calue of hinge plate method.Therefore,a calculation method of load transversion considering the influence of the pavement layer thickness is proposed,and the biggest difference between the finite model and theoretical calculation results is 2.72%which verify the feasibility of the calculation method considering the pavement layer thickness.(4)The finite model of hollow slab bridges with the span of 6m,8m,10m,13m,16m,20m respectively were established.The influence on the stress and deflection of hollow slab by the thickness of pavement layer was analyzed.The result shows that there is an effective thickness of pavement layer making the stress or deflection of different span minimum.Along with the increase of span,the smaller the thickness of pavement layer;when the span increases from 6 m to 20 m,the effective integration pavement layer thickness decrease from 30 cm to 6 cm.