Description: B-4319 - WAYNE -WILSON COUNTIES LOCATION: Bridge #21, on NC 222 over the Great Swamp.
ITEM(S) OF INTEREST: Proposed 3-span, 90-foot long bridge with a 90° skew. The 3-span bridge shall be a top-down construction with an offsite detour. The subsurface consists of high blow count sand. There is an in-water moratorium until June 15th. A single span bridge would be preferred.
Observations and Points of Discussion:
Existing 50 foot, 3-span timber girder bridge over the Great Swamp needs to be replaced.
The current structure recommendation shows a 3-span 90 foot cored Slab Bridge.
The Hydraulics Unit noted that the shallow low flow conditions as well as lack of trees leaning into the flow channel made the site suitable for A-frame bents.
The possibility of spanning the swamp with a 70' box beam structure was discussed.
This option would require raising the grade by approximately 6".
In general it was agreed that the Department should consider alternate designs to eliminate piers.
The FHWA noted that there are many instances where load postings are on bridge, and therefore any vehicle that may exceed the posted load would have no advance notice of the maximum load allowed on the posted bridge.
NC DOT
NC DOH
NC GOV
