This presentation is focused on the development of modular shallow trapezoidal boxes fabricated from  cold-bent structural steel plate using standard mill plate widths and thicknesses. This concept was developed by a technical working group within the Steel Market Development Institute’s (a business unit of the American Iron and Steel Institute) Short Span Steel Bridge Alliance (SSSBA), led by the current authors. This working group consists of all stakeholders in the steel bridge industry, including mills, fabricators, service centers, industry trade organizations, universities, and bridge owners. The goal of this project was to develop an innovative and economical modular solution for the short-span steel bridge market. Presented is the methodology used for the design of this system along with experimental validation of the modular composite girder’s flexural capacity. Using experimentally-verified analytical methods, the applicability of AASHTO specifications in computing the flexural capacity of the proposed system was assessed. Results of this study show that AASHTO specifications are conservative when employed to compute the composite girder’s ultimate capacity. Therefore, a more accurate means of computing the capacity of the proposed system are proposed.

Karl E. Barth, Ph.D. – Jack H. Samples Distinguished Professor at West Virginia University