The SnapLocX Connection: A Novel Approach to Interlocking Steel W-Shape Column Splices

Abstract

Column splices are critical components in steel structures above three stories that ensure the stability and integrity of the building framework. Splices are required when standard column lengths are insufficient for the design height of the structure. Standard erection practice for W-shape column splices begins with lowering an upper column onto a lower column guided by ironworkers, and while one column may arrive pre-welded or bolted with the connecting plates, the connecting column must be bolted and welded onsite. These labor-intensive on-site processes contribute to schedule delays, creating risky conditions that include fall, pinching, and welding hazards.Funded by the American Institute of Steel Construction (AISC), this thesis presents the first part of a multi-phase project to develop and manufacture an industry-ready solution for improving column erection. The SnapLocX Connection utilizes shop-bolted plates connected to the lower column that act as snapping plates, while shop-welded plates are secured to the column above the splice. The designed splice connection allows crane operators and ironworkers to drop the upper column down into the lower column, where the prefabricated SnapLocX Connection would secure the two columns to each other. This process would eliminate additional scheduled time for further assembly compared to traditional assembly, as the temporary erection stage and site welding and bolting are bypassed completely. This thesis developed a design methodology for the SnapLocX Connection. To accomplish this, the necessary loading requirements from building codes are reviewed, and the limit states controlling the connection component design strengths are organized into a coherent design process. A design tool was developed in MatLab to ensure that the components can achieve the snapping assembly behavior with an elastic response. An example SnapLocX Connection was designed and evaluated under the identified limit states. Finally, sets of standardized designs were developed for a wide range of column pairs that could be spliced in practice. The result is a set of tables that act as design aids for practitioners to easily select the necessary connection components for most possible column splice pairings.