Shear performance and failure mechanism of socket CFST column-beam connection with UHPC grouting.

Prefabrication assembly technology has been widely recognized due to its rapid construction, minimal environmental impact, and superior quality of precast components. The reliability and construction convenience of the connection joints of precast components are particularly important. In this paper, a novel Ultra High-Performance Concrete (UHPC)-filled concrete-filled steel tube (CFST) socket connection (UCSC) was proposed for the column-beam connection. To explore the shear behavior and shear load transfer mechanism of UCSC joints, four direct shear experiments were conducted in terms of different parameters (socket depth, presence of studs). Meanwhile, ABAQUS was used to perform a systematic parametric analysis (socket length, embedded length, outer diameter of CFST, thickness of steel tube). The results indicated that the shear performance of UCSC joints was significantly influenced by both the socket depth and the outer diameter of CFST. The proposed finite element model (FEM) can predict the load-displacement relationships of UCSC joints with a maximum peak load error of 2.3 %. Combining the experimental results and numerical results, a simplified calculation model was formulated to accurately estimate the shear bearing capacity of UCSC joints, and was verified by numerical and experimental results with a maximum error of 8.6 %. The research results have practical implications for the preliminary design of UCSC joints to avoid non-ideal failure mode. • Experimental studies were conducted to evaluate the shear performance of UCSC. • A FEM was established to predict the force-displacement curve and shear failure mode of UCSC. • A simplified calculation model was developed to predict the ultimate shear bear capacity of UCSC. [ABSTRACT FROM AUTHOR]