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Abstract
Double angle shear connections are commonly found in steel frame buildings because of their ease of design, fabrication and installation. While these connections are normally designed for only vertical shearing force, previous research has proven that these connections can resist an interaction of shear, axial, and moment forces. There exists a need for further research concerning the behavior of these connections due to their abundant use throughout the engineering and construction industries.
The purpose of this thesis was to observe and quantitatively measure the interaction of forces in double angle connections. Results from this research illustrate the behavior of these connections during an unanticipated loading event: the compromising and collapse of the center support in a steel frame building. In this study, robustness, redundancy and structural integrity of the connection were considered. Test results were used to establish the level of flexural capacity and presence of catenary action of various double angle connections.
To study and analyze the performance of these connections, physical testing was commenced on nine double angle connections, mounted in a testing frame, consisting of 3-, 4-, and 5-bolt configurations. Data collected during this testing were used to calculate forces, including axial, shear, and moment, at the connection and along the length of a supported beam within the testing frame. Further analysis explored failure modes and overall test assembly performance.
Testing showed that double angle shear connections possess a level of flexural resistance, and catenary action occurred in the test assembly beyond the flexural resistance range of this connection. Every tested double angle connection exhibited high levels of ductility, and aside from angle unfolding, did not pose a risk of brittle failure under the limitations present during testing. Excessive rotation of the member, interaction of shear, axial and moment, combined with the unfolding of the connecting angles and eminent binding of the beam flanges with the column flanges indicates that while double angle connections provide a certain level of robustness, they are incapable of supporting full design loads due to the additional shear and moment introduction.