WilTel Technology Curtain Wall Framing Failure Investigation

The WilTel Technology Center was a recently constructed 15-story building in Tulsa, Oklahoma. The structure had many green aspects and LEED certifications. One key feature was the solar well acted as the plenum for the entire building. Along the entire east elevation, the plenum was created by a glass curtain wall system supported by vertical steel trusses. During a windstorm on June 2, 2004, approximately 20% of the curtain wall structure buckled outward away from the building, releasing over 70 panes of glass upon the adjacent sidewalk and roadway. Subsequent forensic investigation revealed numerous fabrication and construction defects during construction that led to the failure. A tubular truss and strut frame provided the main wind force resisting system for the solar well structure. The joint design between components relied upon clevis and pin connections secured by snap rings. While the design intent was achieved as presented in the architectural drawings in the overall structural design and fabrication details, the design, fabrication and construction of the joints did not provide an acceptable structural system. Review of the construction documents revealed significant and unapproved changes in the fabrication of these joint components including dimensional and material selection changes. The failure investigation included the expertise of meteorologists, structural engineers, mechanical engineers, and metallurgists providing an all-encompassing investigation into the facade failure. The investigation findings illustrate the requisite review process that must be adhered to between the architect, structural engineer, and fabricator. The following presents the findings regarding the structural engineering aspects of the investigation.