Experimental and analytical study on shear mechanism of rubber-ring perfobond connector

This paper proposed an easy-installed rubber-ring perfobond connector (RPBL) to mitigate the shear concentration of partial holes in perfobond connector (PBL) groups. Four modified push-out tests with different rubber ring thicknesses were conducted to investigate the shear behavior of RPBLs. The test results showed that specimens experienced four stages, including (i) damage of bond, (ii) shear fractures of concrete dowels, (iii) tension-shear yielding of perforated rebars, and (iv) hardening and fractures of perforated rebars. The rubber rings can significantly improve the slip capacity and drop the shear stiffness of perfobond connectors. Compared with ordinary perfobond connectors, the yield slips of specimens with 2 mm, 4 nun and 6 mm thick rubber rings increase by 304%, 509% and 745%. Further, three-dimensional nonlinear parametric FEA (finite element analysis) models of modified push-out tests were established and verified by the test results. The shear mechanism of each component and the effects of rubber ring thickness on shear behaviors were discussed. Finally, the shear yield load equations and shear capacity equations of PBL and RPBL were proposed based on the collected modified push-out test results. The calculated results agree well with the test results.