Performance of axially loaded small size presstressed concrete piles

Abstract

The thesis deals with the penormanee of small size ( I751I1ITU'( I75mm) prestressed pile. Maintained load test were conducted to investigate the load carrying capacity and settlement of the piles. Four sites within Dhaka City were selected for the. purpose. "111emeasured capacity detennined from pile load tesls was compared with the predicted capacity using static methods & dynamic methods.The measured ultimate capacity of piles driven through Dhaka Clay and resting on Dhaka Clay is in close agreement with the predicted values using A. method.The skin friction of piles driven through Dhaka Clay predicted by IX, method is slightly smaller than the estimated value from pile load test. This method can safely be used for predicting the ultimate skin friction of Dhaka Clay. It is observed that API method grossly underestimate the skin friction of piles in Dhaka Clay. The ultimate capacity of piles driven through Dhaka Clay and resting on medium dense sand can be predicted using the combinations of A. method and Meyerhofs empirical method, A. method and Hansen's method,1Xmethod and Meycrhofs empirical method, IX method and Hansen's method, IX, method and Meyerhof s empirical method, IX, method and Hansen's method. The value of ultimate capacity predicted by API method and Indian Standards method is about half of the measured ultimate pile capacity determined from pile load test. It is also observed that the ultimate capacity predicted by pile driving formulae such as Engineering News Records formula, Janbu formula and Hiley formula, in general, overestimate the measured ultimate capacity. However these formulae underestimate the allowable capacity when used with the recommended factors of safety