Comparison of direct SPT method for calculating axial capacity of piles in Jakarta Area

Abstract

Estimating axial capacity of piles using Direct Method are still considered as challenges these days. Estimation mainly achieved after construction is done and field method such as static load test or PDA are used for calculating axial capacity of piles in real field cosnditions. This paper discussed estimation from 8 building project cases from Jakarta and Depok that have complete standard penetration test data and field calculations (static load test & PDA). The main objectives are to observe and correlate the results between every Direct Methods and field methods and to obtain which Direct Method is the most efficient to use for estimating axial capacity of piles in Jakarta area. Direct Methods that are used are Meyerhoff, Shariatmadari, Decourt, Aoki, and Robert. Calculation results showed that the most efficient standard penetration test method is that proposed by Decourt with average result of comparison between estimated axial capacity of piles and field calculation is roughly 1.03. The most underpredicted between every standard penetration test method is the one proposed by Aoki de Alencar with roughly 92% underprediction ratios and the largest overpredicted method is proposed by Shariatmadari with roughly ratios of 56%.