Demolition, site work, paving and new construction of a bridge / tunnel in Rigby, Idaho. Completed plans call for the demolition of a bridge / tunnel; for the construction of a bridge / tunnel; for site work for a bridge / tunnel; and for paving for a bridge / tunnel.

Remove the existing concrete bridge with concrete abutments and replace it with a single span steel girder bridge on spread footings. Bridge Key No. 36100; E 421 N over Lewisville Canal, Jefferson County Existing Bridge Key Number 36100 is in Jefferson County and carries E 421 N over Lewisville Canal. The bridge is owned and maintained by Jefferson County and is located approximately 4.3 miles northeast of Rigby, ID. This proposal is for the contractor to remove the existing concrete bridge with concrete foundations and replace it with a single span steel bridge on spread footings. The bridge will be staged constructed and one lane open for traffic during construction. Additional work includes roadway approach construction and permitted canal alterations including placing riprap. The proposed project will replace the poor condition and/or posted bridge and improve the bridge to current design and flood standards. This proposed configuration allows for two 12-foot lanes with a 3-foot shoulder. The proposed bridge will be a 48-foot prefabricated bridge structure with a 30-foot curb to curb width. The total length of the bridge is determined by the proposed channel, hydraulics, and existing topography. The total length required to span the active waterway is approximately 33.75 feet. It is anticipated the bridge will be paved and crowned at 2% with paved approaches transitioning to match the existing paved roadway. The new structure will be approximately 6-feet wider curb to curb than the existing bridge. The proposed horizontal alignment for the new structure and roadway will mostly match existing alignment. A spread footing foundation will be implemented on the bridge. The existing abutments will be removed and the slopes will be graded to a 2:1 slope with riprapping. Bridge replacement will require removing half of the existing bridge building 2/3 of the prefabricated bridge then removing the rest of the existing bridge. This will require a shift in the existing alignment to build the 2/3 of the prefabricated bridge. It is anticipated that the project would take 30 working days. The project will generally involve the use of excavators, back hoes, bull dozers, dump trucks, and a crane for the roadway construction, existing bridge removal, and proposed bridge construction.