Strength of Bolted Aluminum Alloy Tension Members

Aluminum alloy tension members are incorporated in structural and mechanical systems, examples of which include bracing in railcars, members in roof trusses, and transmission towers. In practice, it is difficult to connect all elements of a complex cross section. Procedures used to estimate the net section rupture strength of a tension member through a bolted end connection must account for the accompanying reduction in efficiency. Current provisions within the Aluminum Design Manual fail to adequately address situations other than single or double angle tension members attached by a single leg. During the course of this investigation, 72 aluminum alloy tension members consisting of angles, channels, and structural T’s were fabricated and tested to failure. Variables considered during the course of the study included bolt pattern, connection length, cross-section profile and area, connection eccentricity, and alloy. Experimental results were accompanied by finite-element analysis of several of the test specimens. A design rule is proposed and compared to the experimental data as well as several other methods for calculation of the net section rupture strength.