Service Load of Short Large‐Diameter Bored Piles

Field loading tests of 10 short nondisplacement piles are analyzed using the writer's method of calculating the service load of long piles. The method is based on the analysis of over 200 field loading tests. A hyperbolic relation is assumed between the specific skin friction $q_s$ or toe pressure $q_t$ and the slenderness $L/D$ (length/diameter) of piles. The assumption is affirmed statistically to be acceptable for long piles (since $q_t\to 0\mathrm{for}L/D\to 0$). Using the method, an expression is deduced relating the skin friction share of the total service load to the pile slenderness. This forms a simple and uniform basis of the calculation of service load of piles of different slenderness and of soils of different consistencies and densities. The calculated service load of short piles was overestimated. This was explained by the toe pressure having been reduced by the heavy disturbance of the soil experienced at the pile toe by boring.