Delaware Department of Transportation is planning a $13 million project to completely rehabilitate a bridge on Route 1 in Milton.

The bridge, located between Lockerman and Paynter roads, was built in 1965. DelDOT officials say it has a host of structural problems: the beams and concrete supports are rotting, and the southbound roadway is deteriorating, as is the substructure.

DelDOT is proposing a new bridge in two phases. Phase 1, October to December 2020, will be on the southbound lanes of the bridge. During construction, traffic will be two ways going across the northbound span. Phase 2, January to March 2021, will cover the northbound lane, with traffic diverted to the newly constructed southbound span.

At a Nov. 20 public workshop at Mispillion Elementary School in Milford, DelDOT engineer Bryce Baker said the department plans to use deck modules for construction - precast concrete sections that fit like a jigsaw puzzle and do not require certain weather conditions to be installed, as opposed to pouring concrete, although concrete will be used to bind the sections together.

Baker said using precast sections will also accelerate construction to reduce the traffic impact. Baker said DelDOT will not do a full substructure replacement, but the bridge itself will be widened from 33 feet to 36 feet across.

Baker said DelDOT inspects its bridges every two years, which revealed the bridge was structurally deficient. In order to extend the life of the bridge, Baker said DelDOT decided to replace the deck and portions of the substructure at the same time.

Because the bridge is too narrow to build one lane at a time, Baker said DelDOT decided to replace the northbound and southbound spans in phases.

DelDOT engineer Jason Hastings said the department plans to solicit bids in February, and award the bid by late spring. He said officials hope to find a contractor early so they can begin working on the precast sections. Hastings said DelDOT will begin building lane crossovers in spring 2020 so the lanes are in place for the contractor to begin work in the fall.