Experimental study on the tensile performance of a large-diameter UHPC grouted sleeve with thread: Fid-Bau Portal

Experimental study on the tensile performance of a large-diameter UHPC grouted sleeve with thread

Huang, Zhen / Yang, Yang / Zhang, Jiabing / Ma, Shaokun / Cao, Chen

Highlights • A large-diameter seamless steel pipe with an UHPC grouted sleeve was designed. • The bonding performance of the designed sleeve was studied. • The working mechanism of the designed sleeve is discussed. • The calculation model for surface stress on the sleeve surface were obtained.

Abstract An ultra-high-performance concrete (UHPC)-grouted sleeve with a large-diameter seamless steel pipe with threads and bolts was designed. To study the mechanical properties of this grouted sleeve, various factors, such as the grouts type, rebar, thread, and bolts, were considered to conduct a uniaxial tensile test on the grouted sleeve specimens. The bonding performance of the grouted sleeve under a combination of various factors was studied, and its working mechanism was discussed. The results showed that the failure modes of the test sleeve specimens included rebar fracture, rebar slip and grouts slip. The G1 (UHPC without basalt fibre) grouted sleeve showed the best bonding performance and bearing capacity. Bolts and inner wall threads of the sleeve improved the grouts–sleeve bond strength. However, the level of improvement was related to the bolt location, thread spacing and depth. The closer the bolt position was to the elastic section of the sleeve port, the more significant the bond performance improved. The thread could provide mechanical bite force. The greater the thread depth were, the greater the mechanical bite force; nevertheless, there was a threshold. Based on the thick-walled cylinder theory, the calculation model for stress on the sleeve surface was obtained; these calculations were used to analyse the stress–strain law on the sleeve surface.