The Experimental Research On New And Old Concrete Interfacial Shear

Enlarge section reinforcement method is the most widely used section bearing capacity reinforcement,In the engineering sector, almost everyone knows.But the most critical aspect is that the old and new concrete interface shear bearing capacity.And the shear capacity of section has important engineering significance.Member whether flexural, shear, torsion bearing capacity reinforcement will produce shear stress at the interface.Only when the interface with sufficient and reliable shear strength,new cross-section can collaboratively work with the matrix concrete,and achieve reinforcement goals.but the handling of the interface and the interface steel connections has a great impact on the performance of old and new concrete shear.But now the engineering and specifications generally respected the way is concrete interface chiseling and interface uses new steel U-shaped stirrups and welding original stirrup While the current specification of the interface with the provisions of chiseling.However, in sub-acceptance the extent of chiseling is hard to define,,at the same welding U-stirrups is inconvenient in construction and creating damage to the original concrete structure,in addition the post-repaired chiseling section of concrete is also a problem.Therefore, this paper proposes a new concrete interface treatment of clearing the original concrete surface,depth controling in 5-6mm (Referred peeling).At the same time the interface is also used planting steel bar connections.This topic through interfacial shear experimental comparison the interface shear behavior of interface chiseling and peeling, welding steel and planting steel bar.By the completion of 12 groups 36 member interfacial shear experiments, the main contents are as follows:① By comparing concrete interface chiseling and peeling interface shear capacity, stiffness, crack development to research on shear performance.② By comparing welding steel and planting steel bar nterface shear capacity, stiffness, crack development to research on shear performance.③ Comparing the performance of different planting steel bar rate shear capacity,At the same time through the strain of steel bar to study steel shear stress mechanism at the interface in the process of receiving.④ Compare the shear properties whether brushing the organic epoxy interface agent after the concrete surface peeling.⑤ By studying the results of load - shear displacement and load - crack width curve,obtained its load a simplified model of load - shear displacement and load - crack width curve.The innovationof this article:1) Now the engineering generally respected the interface treatment way is concrete interface chiseling,.However, in sub-acceptance the extent of chiseling is hard to define.Therefore, this experiment give a new concrete interface treatment-peeling, analysising their shear performance through the comparing with interface chiseling.2) While the new and old concrete interfacial shear-related test, interface steel have adopted the planting steel bar,there is no research about the comparing of the shear behavior of planting steel bar and welding U-stirrups in interface shear test.The article is the first time to make a comparison in this regard.3) In this experiment,in order to ensure that new and old concrete interface is pure shear state,to make imposed load equal to the sectional suffered shear,I design a self-balancing interfacial shear test device,This means the device not only installation and removal easy and simple,and we can make the best that the interface in pure shear state,the results more accurately,The experimental results:The shear performance of interface peeling is significantly better than interface chiseling,and the shear capacity of interface welding U-stirrups is better than the interface planting steel bar,But also brushing interface agent after peeling can enhance some extent to the interface shear behavior.