Aviation | Transportation

Chicago Transit  Authority | Elevated Train Structures Testing

Chicago, Illinois

As a part of a comprehensive study to assess the condition of Chicago Transit Authority's elevated train structures, RRJ conducted full-scale diagnostic load tests of four lines to evaluate their structural behavior under actual train loadings. The test program, specifically tailored for each train line, evaluated end connection continuity, load distribution, critical stresses, impact loading, fatigue, and longitudinal forces caused by train braking. The test data and engineering and cost analysis led to a decision to rehabilitate the four train lines saving $3.7 billion in replacement costs.

I35 Bridge Collapse

Minneapolis, Minnesota

The I35W freeway bridge suddenly collapsed, killing 13 motorists during the evening rush hour. At the time of the collapse, the concrete deck top surface was being removed and replaced on the eight-lane 1,900-foot-long bridge that spanned across the Mississippi River. Four lanes were closed to traffic as the contractor had staged materials and equipment on the bridge in preparation to begin paving the overlay concrete that evening. 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.