Experimental and numerical investigation on structural bolts under compression

Abstract

Structural bolts have been widely used in prefabricated construction to connect one steel column to another steel column due to their construction and structural benefits. In recent years, innovative prefabricated column-to-column (PCC) connections using normal structural bolts have been developed to simplify the construction process of prefabricated concrete-filled steel tubular (CFST) columns and to transfer the upper column load to the bottom column through bolt-coupler connection. The structural bolts used in the PCC connection are under compression. Therefore, there is an essential need to explore the structural behaviour of bolts under compression as their behaviour under compression is different from the tension. In this paper, experimental and numerical studies have been conducted to investigate the behaviour of structural bolts under compression by considering different bolt diameters and grades. It is observed from this research that the failure modes and ultimate load capacity of structural bolts under compression are different compared to the bolts under tension. Finally, a simplified design equation is developed to determine the design capacity of structural bolts under compression, which will be very useful in designing the prefabricated column-to-column connections.