Current Practices and Guidelines for the Reuse of Bridge Foundations

Reusing bridge foundations for bridge replacement and rehabilitation efforts can result in time and cost savings as well as reduced mobility impacts and environmental benefits. However, foundation reuse presents significant challenges, including uncertainties in existing foundation condition, remaining service life, and capacity. This synthesis documents current practices and guidelines used by transportation agencies for the reuse of bridge foundations. Information was gathered through a literature review, a survey of state and provincial transportation agencies, and case examples from selected agencies with significant foundation reuse experience. The findings indicate that compared with a new foundation project, the scope of site investigation for a foundation reuse project is fundamentally different, equally important, and in many ways more challenging. For a new foundation project, the primary objective of the site investigation is to identify and characterize subsurface materials. For a reuse project, the site investigation seeks not only subsurface material information but also information about the existing foundation, including the type, geometry, condition, and load capacity. Practices for investigating existing foundations vary widely among agencies and within agencies by project, which is likely related to the finding that only three agencies have detailed policies regarding foundation reuse. It is possible the lack of foundation reuse guidance prevents reuse of some foundations that would be strong candidates for reuse, and also contributes to the uncertain standard of care for consultants designing reuse projects. On the other hand, the variable nature of reuse projects suggests that guidance that is overly restrictive would likely discourage reuse. In documented project examples as well as in agency policies regarding foundation reuse, agencies generally appear more concerned with load capacity of existing foundations than with condition assessment. The emphasis on capacity is perhaps attributable to agency practices that are driven by codes focused on capacity; however, it is also likely that the difficulty of condition assessment impedes consideration of remaining service life. The need to evaluate above- and below-ground portions of the substructure concurrently calls for close collaboration among many agency personnel. In addition, many of the technical concepts associated with foundation reuse require external consultation from foundation and bridge contractors, material scientists, and geophysicists. For many agencies, such broad collaboration is likely another challenge for successful implementation of foundation reuse.

Language

  • English

Media Info

  • Media Type: Print
  • Features: Appendices; Figures; Glossary; Photos; References; Tables;
  • Pagination: 117p
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 01632216
  • Record Type: Publication
  • ISBN: 9780309389921
  • Report/Paper Numbers: Project 20-05, Topic 47-03
  • Files: TRIS, TRB, ATRI
  • Created Date: Apr 7 2017 10:08AM