On March 15, 2018, a devastating pedestrian bridge that was under construction collapsed onto an open roadway below, killing 1 bridge worker and five motorists, as well as injuring 8 others. As was expected, investigations have been underway since the accident, which are expected to take at least several more months to complete
The National Transportation Safety Board (NTSB) has released preliminary report after the accident and is focused on cracks that formed about 3 weeks prior to the collapse. The group is also evaluating the bridge design, construction materials, and the construction process.
After the collapse happened, it was hard to keep track of what the facts of the incident were and the preliminary report helps to clear up some of the confusion. On the day of the collapse, crews were working on re-tensioning a diagonal member of the bridge after de-tensioning the bridge 5 days prior. A crane was being used to complete the work, so crews shut down 2 of the 3 westbound lanes, but did not close the 5 eastbound lanes.
In the next month, the NTSB stated that they will be conducting some additional forensic examinations of structural components and will also perform destructive testing of core and steel samples.
Once the probable cause of the incident is determined, the NTSB will issue safety recommendations to hopefully prevent something like this from occurring again.