Analysis of bored pile foundation bearing capacity based on N-SPT data: (a case study of At-Taqwa Mosque Tower Construction Project, Paciran, Lamongan, East Java)

Abstract

Purpose: The foundation serves as the structural base of a building and is typically located beneath the surface. In this study, the selected foundation type is a bored pile, commonly used in soft soils with low bearing capacity. The choice of bored pile foundations in this project was due to the densely populated surrounding area, making alternative foundation types less feasible. The objective of this research is to evaluate the bearing capacity of bored pile foundations at depths that do not reach the original design plan and to determine the required number of additional bored piles on certain pile caps.

Methods/Design: This study employs a data collection approach, gathering both primary and secondary data. These include soil investigation results (N-SPT data) and bored pile foundation design drawings.

Findings: The data were analyzed to assess the bearing capacity of the bored pile foundation using three methods: Reese & Wright (1977), O'Neil & Reese (1989), and Converse-Labarre (as cited in A'yun, 2022). The analysis revealed the need to increase the number of bored piles from 38 to 45 in order to enhance the total bearing capacity from 2402.33 kN to 3437.81 kN.

Practical Implications: Based on the results of the analysis, the efficiency of the bored pile foundation bearing capacity was found to vary across the three methods: (1) Reese & Wright (1977) yielded 500.28 kN, (2) O'Neil & Reese (1989) yielded 2424.87 kN, and (3) Converse-Labarre (A’yun, 2022) yielded 1778.23 kN. The addition of seven bored piles across the pile caps is considered sufficient in terms of meeting the desired bearing capacity.