Alternative Title

Steel research for construction


A survey of light poles, water-tank stanchions, orthotropic deck bridges, marine tubular catwalks, davits and welded steel columns strongly suggests, contrary to some beliefs, that interior surfaces of closed steel sections rust but little in the atmosphere, even when not fully sealed. Only light rusting occurs because amounts of oxy'gen and water in entrapped air are limited and condensation necessary for rusting is infrequent. Computations based on the oxidation reaction taking into account inside surface, volume of entrapped air, relative humidity and air changes show that the loss of iron thickness due to such rusting is negligible. Use of closed steel sections for structural members in bridges and buildings is therefore feasible with the knowledge that no strength loss will occur from inside oxidation. The concept applies whether the closed steel section is, for example, of relatively small tubular configuration or of large box shape. The fact that interior surfaces of closed steel sections need not be painted to prevent oxidation will result in substantial reduction of maintenance costs and eliminate the need for manholes with removable covers where this has been the practice. Schwendeman estimated potential savings in maintenance costs up to 45% where use of closed box sections in bridges eliminate need for painting section interiors.


Civil, Architectural and Environmental Engineering

Research Center/Laboratory(s)

Wei-Wen Yu Center for Cold-Formed Steel Structures


American Iron and Steel Institute
Committee of Steel Plate Producers


American Iron and Steel Institute

Publication Date


Document Version

Final Version


© American Iron and Steel Institute

Document Type

Report - Technical

File Type