| Based on existing research on connector,this thesis proposes a web-embedded composite connector.This connector directly uses T-section steel with holes in the web to replace the original H-section steel and welded perforated steel plates.The concrete bridge deck is supported and connected through the joint action of concrete dowels,through reinforcement,and studs,forming a composite structure.This structure saves material and labor costs,and is a more economical and reasonable connector that can meet the design concept of high efficiency and lightweight.To study the shear performance of web-embedded composite connector,this thesis designed and manufactured 6 types push-out specimens,and conducted push-out tests on them.The focus was on analyzing the failure mode,load slip curve,and load strain curve of the tests.Fine numerical simulation was conducted on the push-out specimens using ABAQUS finite element software,and expanded parameter analysis was conducted.On this basis,a calculation method for the shear bearing capacity of web-embedded composite connector was proposed.The main research content and conclusions of this thesis are as follows:(1)The mechanical properties of the web-embedded composite connectors were studied through experiments.The results showed that compared to traditional PBL connectors,the stiffness of the connector was higher,and the connector exhibited good ductility after reaching the ultimate load.(2)The failure mode of the web-embedded composite connector is local crushing of the concrete tenon and splitting of the outer concrete.The crack development mechanism is as follows: the damage starts at the steel concrete contact interface and the inner side of the concrete,and as the load increases,observable vertical cracks appear on the outer side of the concrete.The final concrete front crack is connected to the top crack,or to the inner crack,causing the entire inner wall of the concrete to split and fall off,leading to concrete failure.(3)The web-embedded composite connector undergoes bending and shear deformation of the reinforcing steel bars and bolts inside,but they are not cut off.Each component is fully utilized,and the force transmission mechanism is as follows: the penetrating steel bars gradually participate in shear resistance after the failure of the concrete tenon.Due to the load being transmitted from top to bottom,the upper row of steel bars yield earlier than the lower row of steel bars and enter the strengthening stage.The bolt is driven downward by the steel plate,causing a reaction force on the concrete below the root,and the head is constrained by the concrete,resulting in significant bending and shear deformation at the root of the bolt.(4)Parameter analysis was conducted through experiments and finite element simulations,and the results showed that different shear members had different proportions of ultimate bearing capacity,with the highest proportion being through steel bars;As the diameter of the reinforcing steel increases,the ultimate bearing capacity shows a nonlinear growth;The increase in thickness of perforated steel plates has a small impact on the ultimate shear bearing capacity,but a decrease in thickness may result in buckling deformation;The larger the aperture,the more significant the improvement effect on the ultimate bearing capacity;The ultimate bearing capacity increases with the increase of stud diameter.After experiencing repeated loading,the ultimate bearing capacity of the specimen decreases,the ultimate slip increases,and the ductility of the specimen shows a decreasing trend.(5)Referring to existing calculation formulas and combining with the experimental data of this study,an applicable formula for calculating shear bearing capacity was derived.The correlation analysis between the calculated values,experimental values,and simulated values showed a correlation coefficient of 0.93,indicating that the calculation method is more accurate and has certain reference value. |
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