Comparative Study of Various Interpretative Methods of Pile Load Test

Abstract

Pile foundation is one of the most commonly used types of deep foundations provided when the required bearing capacity of the soil is not achieved through shallow foundations. Comparatively, the pile foundation is more complex to design and has a greater impact on the economy of a project. Unpredictable and heterogeneous nature of soil demands to verify theoretical pile capacity by performing a full-scale pile load test. Different methods with unique assumptions and limitations are available to interpret ultimate pile capacity based on the results of the pile load test. This study provides an in-depth review of eight commonly used methods and investigates the most suitable and reliable interpretation method to be adopted for cast-in-situ piles. A comparison between these pile capacity interpretation methods is made using a database of 45 pile load tests conducted on the cast in situ (bored) piles as per the procedure specified by ASTM-D1143. Consistency and accuracy of each method are quantified statistically using pile capacity predicted theoretically and pile capacity interpreted based on load test results. The most suitable and reliable pile capacity interpretation method that can be applied to the maximum number of bored piles and does not over or underestimates ultimate pile capacity is recommended to be adopted for field practice. Based on the results obtained and statistical evaluation of different pile load test interpretation methods used, it is found that Debeer’s method and Mazurkiewicz’s method are applicable to all the piles and give consistent results by yielding a pile capacity that is in good agreement with analytical pile capacity.