Tensile behaviour of innovative one-sided bolts in concrete-filled steel tubular connections

This paper investigated the tensile pull-out responses of an innovative one-sided bolt in the application of the concrete-filled tubular (CFT) connection. The one-sided bolt allows a simplified installation process through the ellipse bolt head compared to existing ones. Five anchorage configurations were proposed and examined experimentally to evaluate their contributions to the stiffness and tensile capacity of the one-sided bolt connections in the concrete-filled steel tubes. It was observed that with a properly designed anchorage system, concrete cone could be developed in the concrete infill, resulting in the improved stiffness and tensile capacity of the connection. The optimal anchorage configuration was determined based on three criteria, namely stiffness, tensile capacity and ease of fabrication. Finite element (FE) analyses on the tensile pull-out response of five anchorage configurations achieved a good agreement with the experimental results. Using the validated FE modelling technique, parametric studies were performed using the optimal anchorage configurations with bolt diameters of 12 mm and 16 mm to investigate the effects of concrete grade, embedment depth, bolt grade and tube slenderness. It was observed that the change in parameters significantly influences the overall connection behaviour and strength.