Bridges

Standard design techniques for corrugated steel culverts take advantage of the flexibility and ductility of the steel liners to transfer soil loads mainly through axial compression, with very small bending moments, relative to the size of the structure. When these systems require repair or strengthening with a reinforced concrete liner the use of traditional simplified design methods results in a much less efficient design, requiring a comparatively thick concrete section with heavy reinforcement.

In this paper the use of finite element analysis methods, taking account of soil-structure interaction, is compared with simplified methods such as those specified in the codes “Design for installation of buried concrete pipes” (AS 3725 (1)), and “Precast reinforced concrete box culverts” (AS 1597 (2)). These code procedures were developed for comparatively small pipe structures, and rectangular structures, where soil-structure interaction and arching effects are less significant. The paper reviews the analysis and design of reinforced concrete liners to two multi-cell steel culverts subject to rail loading in West Australia. The analysis allows for placement of the concrete liners, followed by total corrosion of the original steel structures, so that all loads are transferred to the new concrete structures.

The paper compares the critical design actions resulting from the alternative analysis techniques, and provides recommendations for appropriate and efficient analysis procedures for structures of this type.