Behaviour of Steel Shear Connections for Assessing Structural Vulnerability to Disproportionate Collapse

• Author / Creator

  Oosterhof, Steven A

• The performance of structures under the effects of extreme loads can be a critical consideration in their design. The potential for disproportionate collapse following localized damage to a column can be mitigated by the provision of sufficient strength and ductility throughout a structural system to allow for the establishment of a stable alternative load path. An understanding of the behaviour of shear connections in steel gravity frames under the unique combinations of moment, shear, and axial force relevant to column removal scenarios is necessary to assess the vulnerability of a structure to disproportionate collapse. However, such an understanding is currently limited by a deficiency of physical test data.
  In order to investigate the inherent robustness of commonly used steel shear connections, an experimental program consisting of 45 full scale physical tests was completed. Specimens included shear tab, welded–bolted single angle, bolted–bolted single angle, bolted–bolted double angle, and seat and top angle connections combined with different types of shear connections at the beam web. A testing procedure was developed that imposes upon a connection the force and deformation demands that are expected following removal of the central column in a symmetric two bay frame. Various geometric arrangements of each connection type were tested, and each arrangement was subjected to a range of loading histories representing different column removal scenarios.
  The physical test results characterize the load development history, deformation mechanisms, and failure modes expected following column removal for each type of connection. Connection stiffness, strength, and ductility limits under the effects of combined loading are quantified.
  An approach to mechanical modelling that predicts connection response following column removal is presented and validated using the test results. The models are used to expand the database of results and study the effects of critical parameters on performance. Design recommendations based on the physical tests and mechanical modelling are presented, including connection detailing considerations and a simplified connection modelling technique that is suitable for whole-building column removal analysis.

• Subjects / Keywords

  • Design recommendations
  • Mechanical model
  • Component model
  • Experimental tests
  • Disproportionate collapse
  • Combined moment, shear, and tension
  • Steel shear connections
  • Progressive collapse
  • Column removal scenario

• Graduation date

  Fall 2013

• Type of Item

  Thesis

• Degree

  Doctor of Philosophy

• DOI

  https://doi.org/10.7939/R3J960M7N

• License

  This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.