portation priorities, he says. 



Enough clamor from the public can 

 go a long way toward getting a trans- 

 portation project placed on the board's 

 seven-year schedule for completion, he 

 indicated. 



"Usually when there is a lot of out- 

 cry from an area for a bridge or a road 

 that is an indication there is a certain 

 amount of need," Caddell says. But, he 

 adds, careful studies are made of all 

 projects to determine their social, 

 economic and environmental benefits 

 before funds are earmarked. 



No bridge, however, can be built 

 over navigable waters without the con- 

 sent of the U.S. Coast Guard. 



Once a bridge is completed, trans- 

 portation officials say the lifespan of 

 that bridge is 40 to 50 years in the 

 coastal environment. "After that 

 amount of time, bridge supports begin 

 to deteriorate and usually the bridge is 

 posted for less than legal loads until it 

 can be replaced, says Jimmy Lee, head 

 of the transportation department's 

 bridge maintenance unit. 



How fast a bridge is replaced de- 

 pends on such factors as its general 

 location, the alternate routes available 

 and the number of school buses that 

 use the bridge, Caddell says. 



"All bridges in the state are inspec- 

 ted every two years and none of them 

 are unsafe," Caddell says. "We do 

 have some that are posted, but these 

 are not unsafe as long as people observe 

 the posted limits." 



Few bridges are posted for weight 

 limits along major routes and none of 

 these restrict commercial traffic, Cad- 

 dell adds. 



While officials must decide when and 

 where to build a bridge, they also must 

 decide what type of bridge is most 

 suitable for the waterway being span- 

 ned. 



Lee says the drawbridge is one type 

 of bridge that allows road traffic and 

 water traffic to alternately cross the 

 same waterway. 



Four types of drawbridges are 

 currently being used by the depart- 

 ment of transportation in coastal 

 North Carolina. 



One of these is the outdated pontoon 

 bridge that connects Sunset Beach 

 with Brunswick County. The opening 

 section of this one-lane bridge floats on 

 pontoons. It is opened by a cable which 

 pulls the bridge to the bank. 



Lee says this bridge, slated for 

 replacement, is opened more than any 



other state-operated drawbridge 

 because it does not allow any water 

 traffic to pass beneath it. Other types 

 of drawbridges — swing, bascula and 

 vertical lift — allow smaller craft to 

 pass beneath their movable spans. 



Swing bridges, such as the one that 

 crosses Bogue Sound from Morehead 

 City to Atlantic Beach, open by 

 rotating 90° on a center support. 

 Bascula bridges divide in the middle 

 with each side rising to a vertical posi- 

 tion. 



The fourth type of bridge, the ver- 

 tical lift, can be seen in Wilmington 

 where U.S. 17 crosses the Cape Fear 

 River. Lee says this bridge, built to ac- 

 commodate the passage of large ocean- 

 going vessels, rises between two towers. 



There are 22 drawbridges in full- 



Photo by Mary Day Mordecai 



time operation by the state, Lee says. 

 Four drawbridges are on call and water 

 traffic must give the state 24 hours 

 notice for a tender to be present to 

 open these bridges. 



The U.S. Army Corps of Engineers 

 also operates several of its own draw- 

 bridges in the state. 



It is usually more expensive to build, 

 maintain and operate a drawbridge 

 than a span bridge, but span bridges 

 cannot be built everywhere, Lee says. 

 There is not always enough un- 

 developed land available on each side 

 of the river or waterway to allow 

 engineers the proper slope necessary to 

 build such high-level bridges. 



The coast is known to be unstable 

 and the clash between shifting sands 

 and permanent structures can result in 



Howard Holden opens pontoon bridge at Sunset Beach 



