experimental and numerical analyses of two instrumented large diameter drilled shafts under bidirectional static loading test

This article presents the results of bidirectional static loading test carried out on two drilled shafts of 1.6 m in diameter, which were instrumented along the depth for analysis of the mechanical behavior (final lengths of 48.4 m and 48.8 m). the tests were carried out up to the load of 18,400 and 13,200 kn, respectively. due to the longer delay between drilling and concreting in the first case, results of the instrumentations indicated that no tip resistance was mobilized, mobilizing its side resistance of the upper segment up to 90 kpa, while in the second case, this value was around 60 kpa and 150 kpa for its tip resistance. the stabilizing polymer used for drilling affected the shaft resistance of both piles. in addition, in the last case studied, the total loss of contact at the pile–soil interface between the load application point and the instrumented level just above allowed the evaluation of the possible existence of residual loads along the shaft. load-transfer curves were approximated in hyperbolic functions, and a load-transfer model was implemented for data validation and equivalent load–displacement curve estimating, showing good agreement between load tests and simulations. this model indicated that the upper segment load–displacement curve of the second case was displaced by 1150 kn due to the possible residual load, and the ultimate bearing capacity for both piles under conventional loading was 23,000 and 26,600 kn, respectively. © the author(s), under exclusive licence to the iran university of science and technology 2023.