Study On Combined Effect Of Steel-concrete Composite Beams And Properties Of Shear Connectors

In the practice of modern engineering,the steel concrete composite structure has been widely used.In the field of long span cable stayed bridge,the steel concrete composite beam has been used in a large number of projects for its advantages such as light weight,simple construction,reasonable cost and so on.The steel concrete beams are connected to a whole by the shear bond,which makes them work together,and the shear bond is mainly responsible for the shear force between the two,to prevent the steel beam from slipping between concrete.In this paper,the following two aspects are studied :(1)Shear strength of the shear bond is generally available through the introduction of the test.On the basis of the existing launch test,by selecting proper material constitutive relation,considering material nonlinearity,this paper will establish the model of the test,which based on finite element model,and analysis the test pieces by the stress mechanism and failure process,and comparing the differences between the test value and the calculated value.After the coincident of the value of test and calculation,this paper will conclude the main factors which influence the bearing of shear bond by changing the concrete strength,stud diameter and rod length,and prove in the linear elastic segment,studs and concrete slip is small,the connection is reliable.(2)Based on the engineering background of Guizhou Wujiang super large bridge,the combined effect of the "upper" type steel composite beams is studied.The main span,L/8 and the L/4 section of the bridge were selected as the research object.The finite element model of the whole bridge construction stage was established by MIDAS CIVIL,and the internal force of the unit under the condition of the maximum bending moment of the two phase dead load and live load was extracted.On the basis of this,the boundary conditions,external loads and internal forces of the local model are obtained by establishing the transition model.Finally,the Midas FEA is used to establish the local model of the main span,L/8 and the L/4 section,and analyze the stress mechanism and the shear lag effect of the bridge deck under different load conditions,and calculate the effective distribution width.The effective width coefficient of bridge panel is calculated between 0.586~0.994.