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St. Vrain Greenway Repair Bridge Replacement

During the September 2013 floods, the existing bridge and trail along St. Vrain Creek were washed away and the bridge significantly damaged, forcing the closure of St. Vrain Regional Trail. Downstream of this location, an additional pedestrian bridge had been stranded during the floods as flood water scoured out the approaching trail and left the bridge intact but inaccessible. Matrix worked closely with the City of Longmont to utilize the existing stranded bridge in the location of the washed away bridge. The re-used bridge was a 28-foot span, prefabricated steel truss pedestrian bridge with a timber deck. Matrix was tasked with designing the new bridge abutments and wingwalls on the North and South banks of the St. Vrain Creek. The abutment and wingwall design have seven H-piles per structure to ensure the stability of the abutments in the event of future flooding.

Matrix worked closely with the contractor while the bridge was moved from the old location to the new abutments. The truss had to be disassembled into two pieces and transported on two trucks to the new bridge site. Once both pieces arrived, new bolts were utilized to join the bridge back together  before being lifted by a crane and set into place. The bridge was moved and reset within a single day. Coordination between the City of Longmont, Matrix, and the contractor allowed for the bridge construction to be completed in just over a month.