Reinforced Concrete Closed Spandrel Deck Arch Bridges

No-longer-extant three-span Oconaluftee Bridge over Oconaluftee River, Cherokee, Swain County: constructed by Luten Bridge Company in 1921 (source: Library of Congress, Prints & Photographs Division, HAER, Reproduction number HAER NC-40-2) No-longer-extant three-span Oconaluftee Bridge over Oconaluftee River, Cherokee, Swain County: constructed by Luten Bridge Company in 1921 (source: Library of Congress, Prints & Photographs Division, HAER, Reproduction number HAER NC-40-2)

In the late 1880s and 1890s, the earliest reinforced concrete bridges built in the United States were closed spandrel deck arches where a solid, or closed, arch supported vertical sidewalls, or spandrels, and the roadway ran on a deck atop the arch. (At a rainbow or through arch, none of which were recorded in the North Carolina inventory, the roadway passes through rather than over the arch.) The most famous and prolific of the engineers who promoted such arches was Daniel B. Luten. He was one of the nation’s most influential bridge engineers of the early 20th century, a tireless promoter of reinforced concrete, and a shrewd entrepreneur who established a nationwide business of affiliated contracting companies specializing in his patented reinforced concrete bridges.

The company associated with all of the known Luten arch bridges in North Carolina was the Luten Bridge Company of Knoxville, Tennessee, which helped to popularize reinforced concrete arch technology throughout the South. It marketed primarily to county and municipal governments, but was not successful with the State Highway Department, which questioned the propriety of some of Luten’s patents. At least two examples of Luten arch bridges contracted by county engineers stand in Yancey County, Bridge 59 built in 1922 and Bridge 171 built the following year. Yancey County Bridge 59 is particularly long and imposing. Its three Luten arch spans carry Old NC 80 a total of 212 feet over the North Toe River near Micaville.

The State Highway Department also erected reinforced concrete closed spandrel deck arch bridges that did not utilize Luten’s patents. Of particularly high aesthetic quality are three it built in 1925 at Lake Lure in the mountains, Rutherford County Bridges 7, 34, and 52. In an uncharacteristic departure from its reliance on standard designs, the Department custom-designed the three, which carry US 64 on a meandering lakeside route, to complement the landscape plan of famous designer Earle Sumner Draper for the exclusive Lake Lure resort development.

[June 2013]