Experimental Study of Bolted HSS Flange-Plate Connections in Axial Tension

Abstract

Bolted flange-plate connections represent a practical and inexpensive solution for splicing axially loaded steel members. Research on bolted hollow section splices has hitherto been mainly focused on flange-plate connections for circular hollow sections or connections for rectangular hollow sections with bolts only on two sides of the connection. This paper presents the results of a study on connections for square hollow sections with bolts symmetrically placed on all four sides of the tube and the hollow section loaded in axial tension. As with earlier studies, the prying forces were of major interest. Strain gaged bolts as well as an ultrasonic bolt gage monitored the bolt forces during the tests to reveal any prying action. A total of 16 specimens varying in the number of bolts, bolt layout, and flange-plate thickness were tested. Different existing design methods and analytical models are presented and their corresponding connection strength predictions are compared to the results of the tests, as well as 10 further tests done previously by others. It was found that a slightly adjusted version of the design procedure provided by the AISC HSS Connections Manual (1997) gave the best predictions.