| For multi span simply supported girder bridge,in order to adapt to the temperature change of main girder and concrete shrinkage and cr eep effect,it is generally necessary to set more expansion joints.But the expansion joint is easy to be damaged,which easily leads to rainwater seeping into the bridge structure through the expansion joint,thus reducing the durability of the bridge str ucture.In order to effectively solve this problem,the relevant scholars put forward the use of bridge deck connecting plate instead of expansion joint.The continuous simply supported beam bridge with bridge deck can not only ensure the continuity of bridge structure and ride comfort,but also effectively reduce the number of expansion joints and reduce the cost of bridge maintenance.In addition,the steel-concrete composite simply supported beam has the advantages of standardized prefabrication,convenient construction,light weight,economy,green and so on.If the fabricated steel-concrete composite simply supported beam bridge can be combined with the continuous deck,combined with the rapid construction technology,it will produce huge economic and s ocial benefits.Therefore,it is necessary to study the continuous structure of steel-concrete composite simply supported bridge deck.The research work includes:Firstly,the design theory and method of continuous deck structure of simply supported girder bridge are summarized,Based on the linear elastic analysis,the main beam is simplified as a bar structure.The calculation method of the bridge deck connecting plate under live load and temperature load is summarized and analyzed,and the analytical expressions of the stress and deformation of the bridge deck connecting plate are derived.Combined with the analytical expression of the bridge deck connecting plate,the parameters which have great influence on the force of the bridge deck connecting plate a re analyzed.Secondly,taking the continuous steel-concrete composite simply supported beam bridge as the background,the linear elastic and nonlinear numerical simulation models are established by using the general finite element software ANSYS,and the mechanical characteristics of the bridge deck connecting plate are studied.The mechanical properties of the continuous part of the bridge deck under live load,overall temperature change and temperature gradient change are studied.The main reasons and failure forms of the deck connecting plate of the steel-concrete composite simply supported beam bridge are analyzed.In addition,the whole process failure analysis of bridge deck connecting plate is carried out,and the calculation of cracking moment and ultimate moment of bridge deck connecting plate is discussed.Then it summarizes the differences between the continuous steel-concrete composite simply supported beam bridge and the continuous reinforced concrete simply supported beam bridge in the structural form and stress characteristics,puts forward the improvement measures for the mechanic al performance of the deck connecting plate of the steel-concrete composite simply supported beam bridge,and establishes the refined finite element model to study and analyze the continuous structure of the proposed deck.The results show that when the sh ear studs are optimized and the material of the connecting plate is changed,the mechanical performance of the connecting plate is improved obviously.When the half depth form is used to optimize the material of the bridge deck connecting plate,the layered interface should keep bonding and debonding at the bottom of the whole connecting plate,so that the optimized bridge deck connecting plate has better mechanical performance.Finally,according to the characteristics of steel-concrete composite girder bridge,the layout of shear studs is studied.In addition,the influence of the layer thickness,layer interface debonding length,beam end spacing and support spacing of the deck connecting plate on the force of the deck connecting plate is also analyzed.The results show that the reasonable delamination thickness is beneficial to reduce the stress level of the connecting plate,and the increase of debonding length will increase the deformation capacity of the connecting plate,but the debonding length should not be too long.For the steel-concrete composite girder bridge,the optimization of shear studs can effectively reduce the stress level of the upper edge of the connecting plate,especially the optimization of shear studs on both sides of the flange can significantly improve the stress of the connecting plate.Appropriately increasing the spacing between beam ends is beneficial to increase the free length of bridge deck connecting plate,but too long will increase the stress and deformation of the lower edge of the connecting plate,which will have adverse effects on the bridge deck connecting plate.The change of bearing spacing has little influence on the stress of bridge deck connecting plate. |
