| Self-locking connector can be used into Steel-concrete Composite Bridge.It can can improve the disadvantages of stud reserved pockets or wet joints between decks.There is no concrete casting process during construction.The efficiency of assembly construction can be increased.It can promote the progress of composite bridge construction technology in China.According to structural characteristics of self-locking connector,experiment and theoretical studies are carried out.The main work and research results are as follows:(1)Self-locking connector push-out test is carried out to study the relationship of load-slip,uplift-slip,separation-slip and the change law of concrete slab's transverse tensile stress were obtained.Interface force mechanism is analyzed.The shear performance of self-locking connector is studied through influence of grouting material and structure.Then it is compared with stud connector.The result of experiment shows that the shear stiffness of self-locking connector is large and the slip is very small when break.The interface will bulge during the cutting process.The connector has obvious anti-pulling effect.The shear stiffness and bearing capacity of self-locking joints with some round holes in the rib are greatly improved.The pin formed between the grout and the holes in the rib is effective.The addition of steel fibers to the grout can not only increase the strength of the grout,but also significantly increase the interfacial adhesion and stiffness.It can further improve the performance of the connector.(2)Full-scale model grouting process test is carried out to compare the constructability and effectiveness of grouting from beam end or top side and determine parameters such as fluidity,fiber amount and size,arrangement of slurry port and vent.The test shows that grouting from the top of beam has better performance and effect.The expansion degree of high-performance grouting materials is recommended between 300 ~ 350 mm.(3)Composite beam test with self-locking connector is carried out to studied static and fatigue performance of beams and the reliability of self-locking connector.The test shows that when the connector break down,the steel beam is subjected to tensile yield,which indicates that the self-locking connector is reliable in force.With the increase of load,the distribution of slip along the longitudinal direction of the steel-concrete interface shows significant uneven distribution.The maximum slip is 0.5mm when the connector is broken.Fatigue loading has no significant effect on the stiffness and bearing capacity of the specimens.It indicates that the fatigue performance of the self-locking connector composite beam is good.(4)a finite element model that can consider interface effects is established to simulate the push-out test.The load-slip law obtained from the finite element calculation is consistent with the test result.There is a large tensile stress area in the upper part of the channel and the concrete will crack in this place.A design method for shearcapacity of self-locking connectors considering various influencing factors was proposed through experimental research and finite element analysis.(5)The shear-slip relationship obtained from the calculation method of self-locking connector shear capacity was used to perform the finite element simulation on the composite beam test.It shows that the finite element simulation results are in good agreement with the test.It shows that the self-locking connector shear capacity calculation method meets the actual accuracy requirements.(6)A simple steel-concrete composite girder bridge was designed including self-locking connector and prefabricated deck.The calculation method mentioned above is used for structural verification.The quality of interface processing,deck panel prefabrication and grouting technology is studied.At the same time,the technical and economic factors of the new connector and stud are compared for application. |
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