Study on the flexural performance of dry joint between plates connected by bolted grout sleeve
[Objective]Joints of bridge panels have been a hot research topic as the weak part of the bridge.They are mainly categorized as dry and wet connections.Wet joint is the main method used in the existing assembled composite beams.However,the wet joint cast-in-place operation often takes a long time to assemble,and it adversely affects the integrity of the bridge panel because of its age difference from the postcast concrete.Particularly in the negative moment zone,initial cracks of the bridge panel often appear in the location of the postcasting slot.Although the performance of dry connection bridge panels is lower than that of wet connection ones,their construction speed is fast and the assembly efficiency high,more in agreement with the concept of green and efficient construction.[Methods]To improve the assembly efficiency of steel-mixed composite beams,achieve green construction,and maintain remarkable structural performance,a prefabricated plate dry joint structure with grouting sleeves and high-strength bolted steel plates is proposed based on the literature.To reveal the influence of the proposed dry connection mode on the performance of the prefabricated composite beam,A flexural performance test and finite element refinement analysis of this type of composite beam are conducted,and the results are compared with those of a composite beam assembled using the traditional cast-in-place and cemented joints.[Results]The results demonstrate the following:1)The bolted grouting sleeve connection structure and the rapid connection structure between the bridge panel and steel beam with high-strength bolts can effectively control the construction quality of the precast bridge panel,expedite the construction speed,eliminate a large number of wet pouring operations during bridge site construction,increase the crack resistance and bending resistance of joints in the precast bridge panel to be similar to the cast-in-place bridge panel and enhance the integrity of the composite beam.2)Crack distribution of the test beam is compared with those in the literature,and it is observed to be considerably more uniform than that of the cemented joint composite beam and tends to be more uniform than that of the integral cast-in-place panel.This is because the restoration of the bearing capacity of the reinforcement results in a more uniform crack distribution in the bridge panel.The mid-span joint of the sleeve connection has little effect on the load-bearing capacity of the specimen,and the crack resistance of the specimen is not considerably different from that of the cast-in-place monolithic plate.3)The finite element refinement results demonstrate that the ultimate bearing capacity of the test beam is 13.3%higher than that of the cemented composite beam and is only 4.5%lower than that of the monoblong composite beam.Compared with composite beams with adhesive joints,the slip distribution and concrete damage are more similar to those for monolithic cast-in-place beams.[Conclusions]The research results confirm the construction feasibility and stress reliability of the new connection mode,which provides a reference for practical bridge engineering design and construction.
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