At I-35W, Engineers Develop Bridge-Collapse Scenario
In an Oct. 23 update, NTSB says it is still “in the midst of a complete and thorough analysis.” But forensic engineers working on the probe already have some ideas of what caused the 40-year-old bridge to suddenly collapse. Several sources suggest they are looking at the stress that seized bearings, construction loads, truss corrosion and hot summer weather placed on gusset plates that were underdesigned from the beginning.
The federal team includes Northbrook, Ill.-based Wiss, Janney, Elstner Associates Inc. It was hired as the state’s investigator under a $2-million contract but quickly took on a coordinating role. In August, The New York Times reported that WJE’s team discovered problems with gussets after reviewing the 40-year-old bridge’s design drawings.