Analisis perencanaan fondasi tiang pancang dengan variasi diameter pada tower Pegadaian

Abstract

The foundation serves as the crucial support structure for a building, bearing the weight of the structure above. In the construction of the Pegadaian Tower Building on Jalan Kramat Raya, Central Jakarta, drilled pile foundations with a 1.0 m diameter and a length of 39 m were utilized. This study aims to reassess the design of these drilled pile foundations by considering variations in diameter to investigate their impact on loadbearing capacity and settlement. Four diameter variations, namely 0.7 m, 0.8 m, 0.9 m, and 1.0 m, were evaluated, all with a consistent pile length of 39 m. Data from the Detail Engineering Design (DED), Standard Penetration Test (SPT), and existing foundation information were employed for analysis. Structural analysis was conducted using SAP2000 version 14. The support capacity of the drilled pile foundations was assessed using the Skempton and Tomlinson methods, while the Meyerhoff and Tomlinson methods were applied for pile foundations. Reduction calculations for single piles were performed using the Poulus and Davis method, and for pile groups, the Vesic and 2:1 Spread methods were utilized. The analysis identified the 1.0 m diameter option, calculated using the Tomlinson method, as the most suitable. This configuration consisted of five piles within a group, providing a total support capacity (Qg) of 12554.91 kN, exceeding the axial load (P) of 11436.13 kN. Settlement analysis revealed a decrease of 25.57 cm, which, upon recalculating the pile length to 42 m and distance using the formula 2.5D + 0.02L, resulted in a settlement of 13.89 cm—below the permissible limit of 15.17 cm. Thus, the foundation's capacity and settlement meet safety requirements, confirming its viability for use.