Experimental and numerical investigation of the bending behavior in nontraditional steel beam-to-beam tip connections

Abstract

This study aimed to conduct combined experimental testing and numerical studies on the static performance of tip beam-to-beam flush endplate moment connections. The research parameters considered were bolt layout, diameters, and end plate thickness. Three specimens consisting of two IPE 300 beams connected to a beam of section HEA 300 using two end plates were designed and assembled with different bolt configurations. The grade of the steel elements was S235, while that of the bolts was 8.8. A monotonic load was applied to the specimen during testing, revealing failure modes such as fractures in bolts, end plate bending, and necking loosening of bolts. The study presented and discussed the moment rotation relationship, rotation capacity, and initial stiffness for the three specimens. A finite element (FE) model was constructed based on the moment-rotation curves of the tested connections, and the numerical and experimental results showed good agreement. An extensive parametric study was conducted to investigate the effect of different end plate thicknesses and bolts of various diameters and configurations on the connection's behavior. The study revealed that increasing the bolts' row number in tension rather than increasing the number of bolts in a row significantly affects the ultimate capacity and ductility of the connection. A thick end plate increases the connection's rotation capacity but decreases its ductility. The study also introduced a simple approach based on virtual work to predict the connections' bending stiffness using load and deflection results.