The Influence of Corrugated Pipe Spacing on the Anchoring Performance of UHPC Grouting

To enhance the connection performance and durability of prefabricated bridge piers, the corrugated duct grouting connection technique using ultra-high-performance concrete (UHPC) has attracted increasing attention as a novel construction approach. However, there is a lack of systematic research on the influence of the clear spacing between ducts on the bond performance at the connection interface. In this study, based on previous rebar pull-out test results, a three-dimensional finite element model of a rebar–UHPC grouted corrugated duct anchorage block was developed using ABAQUS. The model was used to systematically analyze the variation in bond behavior between the corrugated duct and the surrounding normal concrete under different duct spacing conditions. By comparing the failure modes and load–displacement responses obtained from experiments and simulations, the reliability of the developed model and quasi-static analysis method was validated. The results indicate that when the anchorage length is 10 times the rebar diameter, a strong bond between the rebar and UHPC is achieved. However, when the duct spacing is too small (S_n<45 mm), bthe concrete strain between adjacent corrugated ducts is large when the specimen fails, which is likely to cause bond failure between the corrugated ducts and the concrete. When the clear spacing S_n is not less than 45 mm, such interface failure can be effectively avoided, ensuring the overall anchorage reliability. These findings provide a theoretical basis and design reference for optimizing connection configurations and structural design in prefabricated bridge piers.