| The simply supported girder bridges with link slab have the advantages of simple structure,definite stress and convenient construction,and the link slab creats the jointless bridge deck in the simply supported girder bridge,which can avoid the bridge diseases and high maintenance costs caused by the bridge expansion joints.Therefore,the link slab has been widely used in small and medium span bridges.However,there are still some imperfections in the design of the existed bridge link deck structures,the failure of the link slab is becoming more and more serious,which affects the safety and durability of the bridge structure.To solve the problem that the existed bridge link deck structure is liable to fracture and water seepage,in this paper,the simply supported bridge link slab is taken as an object,the calculation model of the stress of the link slab is put forward,and the failure mechanism of the existed bridge link deck structures is analyzed and discussed by theoretical analysis and the field tests;In this paper,two kinds of steel-concrete composite link slabs are proposed,the deformation and stress characteristics of steel-concrete composite deck are analyzed by theoretical derivation and finite element simulation;The effectiveness of two kinds of steel concrete composite link slab structures to prevent concrete cracking is verified by full-scale model tests and real bridge load tests;the fatigue life and the effect of overload on fatigue life of steel-concrete composite link slabs are investigated by a series of fatigue tests.The steel-concrete composite link slab can effectively prevent the concrete cracking of bridge link slab deck,and the research results in this paper are of theoretical significance and engineering application value for the structural design,maintenance and management of the simply supported girder bridges with link slabs.The main works of the paper are as follows:1.The domestic and international research and the present situation of the bridge deck continuous structure are summarized systematically;2.The calculation models of existed link slabs are established,the deformation and force formula of the link slab structure under the action of vehicle load,temperature gradient and uneven settlement are deduced,which are verified by finite element simulation;3.Through theoretical analysis and finite element simulation,the failure factors of the bridge link slabs are analyzed quantitatively,and the main factors and the improvement measures are proposed;4.The calculation model of the three direction spring constraint is proposed to take into account the constraint effect of the bridge bearing,and the calculation is used to analyze the influence of the bridge support and the continuous stiffness of the bridge deck on the deformation of the simply supported beam bridge;5.On the basis of improving the steel-concrete composite arched link slab,a new type of steel-concrete composite flat link slab is put forward,the mechanics and deformation mechanism of two kinds of steel-concrete composite link.slab are analyzed by theoretical derivation,the design methods and construction steps of two kinds of bridge deck are introduced in detail;6.Through the full scale model test,the force characteristics of the steel-concrete composite arched link slab and flat link slab are studied,and the effectiveness of two kinds of link slab structure to prevent concrete cracking is verified;7.The actual bridge load test and numerical simulation verify the effectiveness of two kinds of steel-concrete composite link slabs in simply supported girder bridges to prevent the damage of the bridge deck and the applicability of steel-concrete composite link slabs in the skew bridge,the hollow slab girder bridge and T girder bridge;8.Based on the full-scale fatigue tests,the fatigue life,ultimate bearing capacity and failure characteristics of arch bridge deck are studied,the reliability of arched link slab under various loading conditions is verified;9.Based on the full-scale fatigue test,the effects of overloading and initial damage on the fatigue life and structural stiffness of the arched link slab are analyzed;10.Summary and outlook. |
PDF Full Text Request