Description: R-2404A - BERTIE COUNTY Location: New bridge on US 17, Windsor Bypass, over the Cashie River.
Item(s) of Interest:
1700' long bridge consisting of 33 - 50' cored slab spans.
Arranged in 3 or 4 continuous span sections.
Armored evazote joints every 3-4 spans.
14 spans have 4" drains at 6' centers.
5 ¾" thick concrete overlay with #3s @ 6" cts., and additional longitudinal reinforcing steel over the continuous bents.
HP14 x 102 piles used over the main channel used, and HP14 x 72 piles elsewhere.
Interior bent piles driven to 75 - 82 tons.
Observations and Points of Discussion:
The bridge deck will require a lot of cleaning before the concrete overlay is placed. The contractor is considering various cleaning options and methods.
There was some discussion on the appropriate superstructure type for this location, and the consensus was a girder bridge with a cast-in-place deck. Future design-build scopes of work will preclude short span bridges of this length.
There was discussion on the clearing and grubbing operations, which left a significant amount of chainsaw cut and mechanized clearing debris accumulated against the natural vegetation line on the downstream side.
The bridge had a 0.3% tangent grade, which is not very efficient for drainage on a long bridge. The Bridge Maintenance Unit suggested requiring vertical curves on long bridges to improve drainage efficiency.
ACTION ITEM(S):
For future projects, the Construction Unit will review the contract language for removal of woody vegetation.
The Roadway and Hydraulics Units will consider 0.5% for the minimum grade, and vertical curves on long structures to facilitate drainage.
NC DOT
NC DOH
NC GOV
