Wrightsville Beach Bridge

Information and Findings From North Carolina's Historic Bridge Inventory

Discussion of Bridge

The C. Heide Trask Memorial Bridge is technologically significant as an example of a simple trunnion, double leaf, bascule bridge that used the innovative Hopkins-drive-system as the common base for its operating machinery. The system allowed for the pre-assembly of high-speed components in the shop and simplified erection and alignment in the field, important advances for a movable bridge type that required precise operations. The Trask Memorial Bridge and the contemporary Graydon Paul Bridge (Carteret County Bridge 29) are the only pre-1961, Hopkins-drive. bascule bridges in North Carolina.

The span at the heart of this 15-span, 731-long-bridge is the 171-foot-long bascule. Concrete counterweights, necessary to the teeter-totter-like movement of the bridge, are framed into the heel ends of its bascule leaves. The bascule retains its original mechanical systems including motors, gear sets, and Hopkins-drive. The 14 approach spans, which give the bridge its extensive total length, are 41-foot-long, tee beam spans finished with state-standard-design, concrete balustrades.

The Trask Memorial Bridge carries US 74/US 76 over the Intracoastal Waterway between Wilmington and Wrightsville Beach. It was built to replace a much shorter bascule span located just to its south. (That span's old approach roadways are still visible.) The erection of the bridge in 1957-1958 was prompted by the efforts of local State Highway Commission member C. Heide Trask (1902-1957), for whom it was named. The State Highway Commission designed the bridge with the assistance of consulting engineer L.O. Hopkins of Nashville, Tennessee, the developer and namesake of the bridge's drive-system.

Bascule technology saw its greatest period of development and innovation between 1890 and 1910 in the United States. In a variety of ways during the period, engineers solved the complex problems of designing a bridge that shifted out of the way of vessels in an efficient and reliable manner. Post-1910 bascule bridges often incorporated later refinements that improved safety and speed of operation, and lowered erection or maintenance costs, but did not substantially change the principles of operation. Hopkins' drive-system was one of these advances. The Trask Memorial Bridge is a simple trunnion design, also known as a Chicago-type bascule, for the city where the design became so popular. In a simple trunnion design, the bascule leaves pivot in a vertical plane (up and down), with the center of rotation fixed at the pivot point or trunnion. Over the long term, the simple trunnion proved more economical and simpler to construct, operate, and maintain than several of the earlier bascule designs, including the rolling lift type represented in North Carolina at the Smith Mills Bridge (Camden County Bridge 14).

Bridge Considered Historic By Survey: Yes