Load-Bearing Capacity of Piles

Abstract

SYNOPSISThe Paper presents an approach to the prediction of the bearing capacity of piles in advance of piling operations by the use of static cone penetration tests.The study was carried out on cast-in-situ driven concrete piles. The distribution of skin friction and point resistance at various loads was determined during the tests by measuring strains with wire resistance strain gauges.The values of total skin friction and point bearing were also determined independently at different loads by adopting a cyclic load test technique.Pull-out tests were made to determine the frictional resistance under pulling, and the values obtained were found to be less than those obtained under pushing during the load test. The coefficients of earth pressure were also determined from the friction values obtained during the load tests and were found to decrease from a value equivalent to the passive earth pressure state at the top to a lower value at the bottom.A compilation of data already available on the frictional resistance of piles was also made. It revealed that in soils of average stiffness (cone penetration values of IO-100 kg/sq. cm) the value of unit skin friction of a pile was roughly 2% of the average cone penetration resistance along the pile length.

The Behaviour Of Axially Loaded End-Bearing Piles

“…Comparisons have been made between the theoretical behaviour of end-bearing piles and the observed behaviour of piles in full-scale tests reported by Mansur andKaufman (1956), D'Appolonia andRomualdi (1963) and Mohan, Jain and Kumar (1963).…”

Comportamento de estacas escavadas em solos colapsíveis

“…Nos estágios iniciais de carregamento a carga aplicada no topo da estaca é inteiramente absorvida por atrito, sendo que as camadas superiores recebem o máximo (MOHAN et al, 1963). À medida em que o carregamento prossegue, uma parte começa a ser transferida para a ponta e, em determinado estágio, quando a estaca cisalha o solo, uma parcela de carga é transferida para a ponta.…”