Item(s) of Interest: During the 2002 Spring Field review we visited the rehab of NBL under I-4025. Due to major overruns and problems with the NBL, the rehab of the SBL was scrapped and it was decided to replace the structure, which is now underway. The structure bridges over a 2 lane road, a railroad spur and the Yadkin River. A concrete girder superstructure was selected due to the high cost of steel. The replacement bridge superstructure consists of 130 ft. span, 72" bulb-tee girders. 10 ksi. concrete for the girders and a lightweight deck was required to achieve the span lengths.
The site required staged construction with anchored temporary barrier rail. Temporary rails on the lightweight deck were a concern for popouts. A 10" gas main not located during design resulted in relocating a bent. Bents adjacent to the railroad track were placed so that a minimum 25'-0" horizontal clearance was maintained, thus eliminating the need for crashwalls. Replacement bearings for the NBL required widened bent caps. Emergency repairs to the SBL required addition of some crutch bents. 'L' bars in girders were too high.
Observations and Points of Discussion:
Closed drainage system appeared to follow the deck profile instead of being graded to drain.
Drains discharge well away from RR tracks.
Lightweight concrete deck looked very good. No major cracking problems reported or observed, though Construction indicated that the material was difficult to work with.
Approach roadway has been changed from concrete pavement to asphalt, which required some modifications to the approach slabs.
NC DOT
NC DOH
NC GOV
