Static and Dynamic Testing of Precast Concrete Joint Piles Installed with Pre-drilling

Abstract

This paper presents the results of static and dynamic load tests, along with driveability analysis, of precast concrete joint piles with a 400 × 400 mm cross-section and total lengths up to 28 m. These piles were installed as part of foundation systems in the North Caspian region of Kazakhstan. Three static load tests were performed to assess the axial bearing capacity and settlement behavior of the pile–soil system. In all cases, the applied load reached 3278 kN, with final settlements ranging from 20 to 34.26 mm and residual displacements from 8.24 to 22.35 mm, confirming a transition from elastic to plastic deformation and the achievement of an ultimate limit state. The Davisson Offset Method was used to estimate allowable working loads, which were found to lie between 2450 and 2480 kN. Dynamic load tests demonstrated even higher bearing capacities—up to 6842 kN—while showing comparable settlement behavior and confirming pile integrity. Driveability analysis using Pile Driving Analyzer equipment and wave equation modeling revealed severe installation difficulties, particularly for a pile located adjacent to a sheet pile wall, where excessive blow counts and overstressing were observed. Pre-augering was studied as a mitigation approach. While it facilitated pile penetration in dense soils, it also reduced shaft resistance by up to 40% due to a decrease in cone resistance. The findings emphasize the necessity of adapting pile length and reinforcement to site-specific conditions and underline the value of combining field testing, numerical modeling, and geotechnical profiling to ensure safe and efficient foundation performance in complex soil conditions.