DOT: Temporary trestle needed for bridge project
By Peter Williams
The Perquimans Weekly
Monday, August 12, 2019
HERTFORD — The N.C. Department of Transportation is seeking to modify a water quality permit in order to allow a contractor to build a 200-foot long temporary trestle — some of it over wetlands — to aid construction of the replacement S-Bridge.
The trestle is needed so a barge carrying a crane can access pilings and other materials in a staging yard, according to DOT’s request filed on July 29.
The crane is driving five pilings that will serve as a test to make sure they are the proper length to support the new bridge. Once the test is complete, 190 more pilings will be needed. The contractor, McLean Construction, needs a place to store the pilings on land and then access them with the crane.
Finding an appropriate site has taken time, said Tim Hass, a spokesman for DOT.
“It took the contractor more time than expected to find a suitable staging area for the project, which I’m told will be at the old Davenport Motors site,” Hass said.
DOT looked at four other sites, but ruled the one behind Bear Garden Road as the best.
Two of the sites were located upstream from the S-Bridge. One was the vacant Feed and Seed location on Grubb Street. DOT ruled that out in part because it would introduce a number of large, heavy trucks onto smaller town roads. It would also face the same problem as another site near Winfall Town Hall: Both would require navigating through the existing S-Bridge.
“The use of this site would require frequent opening of the existing swing span bridge,” DOT wrote in its request for the permit change. “In addition to traffic nuisances this would cause, the potential for bridge malfunction increases each time the span is opened.”
Another proposed site was downstream near the foot of the U.S. Highway 17 high-rise bridge on the Winfall site. It was ruled out because the water depth was less than three feet and would have required a significant amount of trestle. It’s also a relatively long distance to the construction site.
The final site seriously considered was the Perquimans County Marine Industrial Park near the Perquimans Recreation Center. It was rejected as being too far away, making concrete delivery “nearly impossible,” DOT said.
DOT said a factor not considered during early selection of an access site was the size of the barge on which the crane sits. When looking at stability data, it was determined that a 50-foot-wide barge was the minimum size needed.
“The published width of the fender system on the swing span is also 50 feet, leaving significant uncertainty if the crane barge would be able to access” either of the sites upriver, DOT said.
So DOT wants to build a 200-foot-long, 30-foot-wide steel trestle extending into the river behind the former car dealership in Winfall. The first 100 feet of the trestle will require clearing a 5-foot-wide swath on either side as under the 30-foot wide trestle. The work will be done by hand.
For the next 65 feet, the swath will need to be 5 feet wide on the east side and 50 feet on the west side. That will allow the crane to unload material from the barge and swing around to load on the trestle. That clearing work will also be done by hand.
The last 35 feet of trestle will be over open water.
Of the 10 support piles eight will be located in wetlands and two will be in surface waters. In all, DOT estimates two-tenths of an acre of the clearing will happen in wetlands. It also estimates less than .01 acres of temporary fill will be required in the wetlands or surface waters.
Once the project is finished in about June 2021, the trestle and piles will be removed.