A Case Study to Evaluate the Capacity of H-Pile Reinforced Auger Cast Pile Utilizing Bi-directional Load Testing-Video

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Video Summary

Ahmed Mufti, a geotechnical engineer with 39 years of experience, presents a bidirectional static load test on barrettes for a 365-meter, 105-story building in Dubai. Drawing on projects across seven countries, he compares traditional pile-testing systems with the bidirectional method, which uses hydraulic cells embedded in a pile to load its upper and lower sections simultaneously. He explains how instrumentation and strain-gauge data are used to calculate skin friction, end bearing, pile shortening, and equivalent top-load settlement curves.<br /><br />A major focus is interpreting test results. Because the upper and lower pile sections may move different distances, their load–displacement curves must be aligned, with the upper section extrapolated when necessary. The results also require corrections for elastic shortening. Mufti discusses applying these findings to the project’s barrettes, including soil layering, test locations, load distribution, and numerical modeling.<br /><br />He notes that bidirectional tests can achieve very high loads but do not directly reproduce a pile’s behavior under load applied from the top. He proposes deriving soil-response curves from the corrected top-load curve rather than from measurements at the cell level, while emphasizing that this approach needs further calibration.

Keywords

geotechnical engineering

bidirectional static load test

barrettes

Dubai skyscraper

hydraulic load cell

skin friction

pile settlement analysis