Estimation of ultimate pile capacity for press-in piles using measurement of penetration resistance By Ngai Kuan Io Thesis supervisor: Dr. Lok Man Hoi Abstract The press-in piling method has become a common piling method in Macau in the latest few years. In order to have an economical and feasible design, the prediction of ultimate pile capacity for press-in piles is an important task. There are five press-in piles and one hydraulic hammer driven pile chosen from about 600piles from a construction site in this study. The penetration resistance of the press-in piles is measured by the jacking force of the hydraulic system during the press-in process, which was recorded every 2 seconds using a data logger. Then, the relationship between jacking force and pile length can be obtained. However, the maximum pile jacking force may not represent the ultimate pile capacity, due to complex behavior such as excess pore water pressure generated during press-in piling. Therefore, this study focused on the estimation of ultimate pile capacity. There are three methods used to perform ultimate pile capacity estimation, namely empirical method, analytical method and static load test. The comparison of these three methods will be discussed. Generally, static load test result gives the most valuable ultimate pile capacity. However, due to the high cost, static load test can only be performed on selected piles after installation. In order to compare with the jacking force during the press-in process, the ultimate pile capacities were estimated using empirical and analytical method based on the field and laboratory testing results. After the ultimate pile capacity estimations by empirical method, analytical method and static load test were obtained, the relationship between the ratio of ultimate pile capacity by each method and the jacking force versus the pile length is first examined. However, it was found that the relationship between the ratio of ultimate pile capacity and the pile length is not obvious due to change of soil stratum. The relationship between the ultimate pile capacity and the jacking force is then examined. A power law relationship between ultimate pile capacity and jacking force is observed in this study. The relationship is also calibrated using the ultimate pile capacity from the static load tests, and the deviation from the proposed relationship to the results of the static load test is 0-29% with an average of about 12.8%. Therefore, the proposed method for estimation of ultimate pile capacity for press-in pile using measurement of penetration resistance (jacking force) is established and further improvement by field test is suggested.