Missouri DOT Selects Steel for 45 Foot Span Bridge in Scott County

If you’re a highway bridge owner, engineer, or designer and cost efficiency is what drives your materials decisions, it’s time to take a new look at using steel for bridge structures with lengths of up to 140 feet.

A common misconception is that steel is more costly than other materials for short span bridges—but that’s typically not true.

A case in point is the Scott County Bridge in southeast Missouri. The bridge, MoDOT Bridge No. A8682, is located on Route W over Drainage Ditch #289 between the towns of Sikeston and Cape Girardeau. The replacement bridge was designed as a single 45’-0” span x 26’-8” width structure; wider than the original structure to accommodate two 12-foot lanes; and longer for improved hydraulics.

Bids were accepted for both a prestressed concrete I-beam and rolled steel beam alternate, both four-beam lines. The concrete I-girders were 2’-8” deep, while the galvanized steel rolled beams were 2’-6″, saving 2 inches in bridge depth.

The project was bid by eight general contractors. Half of them bid steel, and the other half bid concrete. For both the bridge and the overall project, which included all of the roadway items, steel came in low. For bridge items only, the galvanized rolled steel beam was still the lower-cost option, beating out concrete by 2.5 percent.*

The contract was let on December 14, 2018 and awarded in early January 2019 to Delong’s, Inc. Steel was delivered during the week of April 1, 2019. The structure was completed and opened to traffic during the week of May 19, 2019.

For bridge items only, the galvanized rolled steel beam for the Scott County Bridge project was still the lower-cost option, beating out concrete by 2.5 percent. Photo by Gary Wisch.

Short span steel bridges deliver significant cost savings because of steel’s light weight, the allowance of smaller abutments, rapid installation, and the use of lighter equipment and local crews. Steel also delivers durability with an expected service life of more than 100 years for many bridges, considerable life cycle advantages, and minimal maintenance requirements over the service life of the structure.

You can design a structure like the Scott County Bridge for free using web-based design tool eSPAN140. The tool offers customized steel solutions for bridges up to 140 feet in length, with results delivered in less than five minutes. eSPAN140 can be accessed at https://www.espan140.com/.

*Bid Tab Results: Missouri Department of Transportation Bid Tabulations.