Aviation | Transportation

I35 Bridge Collapse

Minneapolis, Minnesota

The I35W freeway bridge that spans over the Mississippi River suddenly collapsed, killing 13 motorists during the evening rush hour. At the time of the collapse, four lanes of the eight-lane 1,900-foot-long bridge were closed to traffic with staged construction materials and equipmment in preparation to began paving the overlay concrete on the deck top surface that was removed.  Investigation by The National Transportation Safety Board (NTSB) began immediately and RRJ was retained by the deck resurfacing contractor's legal counsel to investigate the cause including whether the contractor's resurfacing operations played any role in the collapse. RRJ gathered physical evidence at the bridge site and off site including information shared by NTSB. RRJ conducted structural analysis computational modeling of the bridge structure to evaluate the original design, the design as subsequently modified, the as-constructed structure including the deformations reported in several steel gusset plates, and comparison of required highway design live loading to the traffic and construction loads present on the bridge at the time of collapse. RRJ and NTSB both determined the probable cause of the collapse to be a gross inadequacy in the original bridge design which had escaped discovery for over 40 years.

Indianapolis International Airport | Terminal Building

Indianapolis, Indiana

A roof truss shifted downward off the temporary roof shoring/jacking system during the jacking of the terminal buildinrg roof structure causing a construction shutdown for several months. RRJ investigated the cause of the shift in the roof shoring / jacking system and developed a procedure to lift and restore the roof structure to planned design elevations without damaging the structure and the unfinished and partially completed truss connections.

MIA Mover | Full-Scale Load Testing

Miami International Airport, Florida

Full-scale load testing of the prestressed concrete beams which are supported on concrete piers to demonstrate the expected in-service behavoir for this automated people mover elevated guideway transportation system.  During the testing, new cracks originating at the re-entrant corner of the dapped end of the beams were discovered, resulting in  analysis that these re-entrant corner cracks did not pose a significant structural concern.  When cracks began developing near the dapped ends of the beams in the casting yard, shortly after release of the prestressing strands, RRJ was retained by the Contractor to evaluate the cracks and make recommendations to mitigate possible structural capacity or long-term durability concerns.  RRJ conducted additional in-service monitoring of the beams after erection during active guideway traffic that  revealed consistent behavior and little in-service movement of the cracks. RRJ provided remedial recommendations for coating the cracked areas to enhance the long-term durability of the beams.