| In China’s highway bridge construction,small and medium-span bridges occupy a great proportion in quantity,and prestressed concrete hollow slab girder bridges are a very popular structural form for small and medium-span bridges with a span of less than 20 m.However,the problem of hinge joints in hollow core girder bridges cannot be ignored.Although the existing hollow-core slab design has been strengthened at the hinge joints by widening,deepening,and pre-buried reinforcement,the problem of hinge joints has not been properly solved according to the data and surveys.Therefore,this paper proposes a design method for wide hollow slab bridges without hinge joints,which aims to avoid longitudinal cracks at the transverse joints of hollow slab main girders from the source design,and has important social and economic significance for guiding the new design and renovation maintenance of hollow slab girder bridges in the future,improving the durability,safety,and traffic comfort of bridges,and reducing maintenance costs.The main research works in this paper are:(1)A design method for hingeless wide hollow core slab bridge is proposed,and the simulation of the 13 m span hingeless wide hollow core slab girder bridge structure is carried out using finite element analysis software,and the stresses of the hingeless wide hollow core slab girder bridge under various combinations of working conditions are verified to meet the design requirements of the code,and the performance is improved in many aspects compared with that of the conventional hollow core slab;(2)Local force refinement analysis of the concrete in-place paving joints between slabs and girders to verify the safety performance of the designed rigid joint configuration,the results show that when the designed paving joints are 0.12 m thick,the main tensile stress value under the most adverse load does not exceed the design value of tensile strength of C50 concrete and meets the design requirements;(3)The existing configuration of the hollow core slab is changed,and numerical simulations are used to analyze the cross-sectional dimensions of the slab and beam,and the optimal solution for the design of the new cross-sectional wide hollow core slab without hinge joints is obtained with 19 cm cantilever length and 10 cm transverse paving joint width,and all the force analyses meet the design requirements;(4)The three-dimensional solid nonlinear finite element analysis of the main beam of the 1.38-m wide hollow slab without hinge joints proposed in this paper reveals that the force process of the wide hollow slab without hinge joints can be clearly divided into five stages: upper arch,concrete cracking,yielding of common reinforcement,yielding of prestressing tendons and numerical simulation of structural failure;the maximum deflection in the span can reach 1/101 of the calculated span diameter;the ultimate flexural damage of the slab beam is At this time,the prestressing tendons have yielded and the strain exceeds 0.01,but have not yet reached their ultimate strength,while the concrete strain in the compression zone is much smaller than the ultimate compressive strain of concrete;during the loading process,longitudinal cracks will appear at the lower edge of the top plate near the loading point,and when the load approaches the ultimate load,the cracks developed upward at the lower edge of the bottom plate have not extended into the top plate,but the web and bottom plate of the plate and beam in the pure bending zone are basically During the loading process,the neutral axis of the beam cross-section keeps moving upward,and the speed of its upward movement will experience two sudden changes when the concrete cracks and the common reinforcement yields,until the final damage of the plate and beam,the neutral axis has not entered the range of the top plate of the plate and beam. |
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