The existing foundations of a bridge can sometimes be reused. This may occur when a completely new bridge is built but also in bridge or superstructure widening projects. Reuse of existing foundations not only eliminates the costs associated with demolishing and disposing of old foundations, but also reduces the costs of the design and construction of new foundation elements. However, several challenges exist, including assessing the structural integrity, estimating the current capacity, estimating the remaining service life, and considering current design codes and specifications of the existing foundations, and clear guidelines for foundation reuse. The absence of foundation reuse guidelines by INDOT hinders the reuse of bridge foundations and prevents design consultants from designing new structures using existing foundations. In this project, comprehensive foundation reuse guidelines were developed in the form of flow charts based on a literature review on bridge foundation reuse design—including technical publications and existing standards and codes—and a set of analyses. The proposed guidelines include detailed guidance on inspection of the structural integrity of existing foundations, determination of as-built geometry of existing foundations, capacity estimation of existing foundations, minimum requirements for foundation reuse, and selection of foundation reuse solutions. The proposed guidelines for foundation reuse design were tested in an ongoing INDOT project. From the implementation project, we found that a complete site investigation that produces reliable estimation of soil profile and properties, is essential to determine whether there is reserve capacity in existing foundations. Additional site investigation is generally worth doing, not only to account for any strengthening of the soil that may have occurred over time, but also because of the greater accuracy in interpretation and analysis that results. We also found that use of the most current, cutting-edge methods can be useful in estimating the reserve capacity of existing foundations, and that design checks using different design codes can produce contrasting results.

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foundation reuse, foundation reuse design guidelines, inspection of existing foundations, capacity estimation of existing foundations, selection of foundation reuse solutions, pile cap contribution, group efficiencies

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Performing Organization

Joint Transportation Research Program

Publisher Place

West Lafayette

Date of this Version