The steel fabricator for the third-floor tapered, built-up plate girders at the troubled Salesforce Transit Center in San Francisco is calling for a girder-hanger connection design review as part of the probe into the causes of brittle fractures in bottom flanges of twin 80-ft-long members that bridge Fremont Street. The facility was closed in late September.
At the midspan, each 8-ft-deep girder web is thickened by a vertical hanger plate to support the second-floor bus deck below. The hanger plate is welded to the web and slots through the girder’s bottom flange.
“I believe the hanger detail is the largest contributing factor to the problem,” says Robert Hazleton, president of fabricator The Herrick Corp. “We have been assured that a thorough review of the hanger design is part of the investigation.”