Analysis of the possible failure modes in CSH bolted sleeve connections

摘要

Steel circular hollowsections (CHS) have good resistance under tension, compression and torsionrnloads, considered isolated or combined. Recent researches have been carried out to evaluate the behavior andrnresistance of these structures. A current use of steel hollow sections is roof trusses, a kind of structure thatrndemands standard procedures and fast assemblage. This work presents an experimental study of a new typernof connection called sleeve, developed to attend the assembly process. The connection consists of two tubesrninternally connected through a third tube with a smaller diameter with passing bolts arranged in line and cross.rnThis connection makes easier the structure assemblage and is aesthetically advantageous if compared to usualrnflanged connection used in hollow sections. An experimental program of the sleeve connection with bolts in linern(along the tube) and crossed at 90◦ was developed. In this work were tested 3 prototypes with staggered bolts torncomplement previous research and 12 prototypes with crossed bolts. The parameters considered in investigationrnwere tube diameter and thickness and number of bolts. Experimental results lead to identification of failurernmode and the resistance of sleeve connection. The analysis of theoretical and experimental data revealed that therndominant failure mode was bending in the bolts, and indicated a reduction in connection resistance that needsrnto be quantified. For the prototypes with staggered bolts, the analysis also let the development of an expressionrnfor the determination of flexural failure in the bolts. The results have demonstrated the viability of this new typernof connection, but indicated that all possible failure modes need to be carefully checked.