PCI removed the old 80^th Street overpass bridge and constructed two new bridge structures while maintaining US 30 traffic. PCI performed the grading and demolition work for this project prior to bridge construction.  Permission was secured from IDOT to use heavy haul units to cross the old 80^th Street overpass bridge.  The removal of this bridge was a critical first activity on the project schedule.  It was decided to delay the early removal of the overpass bridge and to accelerate the hauling of embankment material across the bridge.  This decision did not cause a delay in the project schedule and saved the cost of hauling embankment material in smaller highway legal haul trucks with several added miles in the haul, having to travel to the nearest highway interchange to cross US 30 traffic.  Iowa State University took advantage of this situation and placed strain gauges on the old bridge structure for their studies on bridge design and loading.

The project documents also required that the contractor provide embankment material that is needed for the construction of the interchange.  Approximately 325,000 cubic yards of suitable embankment material was required. 

PCI submitted a value-engineered (VE) proposal for this project to change plan staging requirements and to save the placement and removal of temporary pavements for the maintenance of traffic on 80^th Street during staged construction.  A total of $115,000 was saved for the project with this VE proposal.

The contract documents required maintaining US 30 traffic through the project, allowing only short duration closures at night.   Close coordination was required with IDOT Maintenance forces and local Law Enforcement for the short duration nighttime closures and detour of traffic.  Traffic must be returned to US 30 by 6:00 AM each morning. 

All structural concrete was monitored and tested by certified plant inspection with onsite acceptance testing provided by the Iowa Department of Transportation.  In addition to typical IDOT Specifications, Developmental Specifications also applied to this project.  DS-15044 for High Performance Concrete for Structures applied to the concrete placed in the bridge decks.  DS-15032 for Mass Concrete and Control of Heat of Hydration applied to the foundation pours with larger width or height dimensions on the bridge structure. 

DOT Specifications provided incentives for smoothness on bridge decks and pavements.  Incentives also applied for Portland cement concrete pavement thickness compliance.  DOT Specifications required the contractor to provide quality control procedures for the embankment building and grading activities. Compaction with moisture control and compaction with moisture and density control were requirements on this project.

The contract period consisted of a firm completion date along with an intermediate completion date for the construction of two bridge berms.  The completion of the two bridge berms was critical for the scheduling of another bridge contractor to start their work.  The contract documents required detailed scheduling to be submitted for this project thru their developmental specification DS-15005 for Construction Progress Schedule.  Work on the 80^th Street overpass bridge during the winter months of 2016-2017 was critical in maintaining the project schedule.