Development and evaluation of mechanical anchorage rebar for joints between precast concrete slabs

The increasing deterioration of ageing reinforced concrete road bridge slabs in Japan has necessitated their replacement to ensure user safety. Currently, various rationalized joints using mechanical anchorage rebars have been developed, but most rely on rebar with post-installed anchorage, with few utilizing integrally formed anchorage zones for higher fatigue durability. In this study, a mechanical anchorage rebar with an anchorage zone integrally formed by high-frequency induction heating was developed. To verify its applicability to the joints between precast concrete slabs, the mechanical anchorage rebar underwent rebar tensile, static bending, wheel-load running, and water leakage tests. The results confirmed the developed rebar fractured at the base material. In addition, a static bending test of the joint confirmed that the load-carrying capacity of the slab joint using the rebar was maintained even after the member yielded. The wheel load running test using a full-scale specimen showed no failure under loading conditions. No water leakage from the underside of the slab was observed in the water leakage test on the upper surface of the slab. Furthermore, no punching shear failure occurred after accelerated fatigue loading, confirming that the slab joints with the developed mechanical anchorage rebars exhibited high fatigue durability.