National Center for Wood Transportation Structures

About the research

Concrete encasements are utilized to protect bridge piles from corrosion and environmental stressors. However, the contributions of concrete encasements in pile capacity are not considered in the design procedure. On the other hand, rating engineers need to have realistic evaluations of the piles to estimate the capacity of the foundation for scour-critical bridges. For this reason, a rapid assessment tool was developed in the Phase I research to calculate the capacity of concrete encased piles.

This rapid pile assessment tool was developed and verified using theoretical modeling approaches. However, experimental data to validate the tool’s results were not available or included as part of that work. The goal of this research project was to validate the previously developed rapid pile assessment tool’s findings to ensure accurate pile capacity determination, both for bare piles and those encased in concrete.

To achieve this goal, four specimens with various pile lengths and concrete encasement lengths and ratios were constructed and tested using axial loads in the laboratory. The results from the experimental test were compared with the predictions from the assessment tool. The results indicated that the pile assessment tool provides conservative estimation of the axial capacity of the piles. The prediction results were about 8% to 24% lower than those from the experimental results. Even more important is the fact that considering the encasement in capacity calculations can result in significantly higher available capacities.