Method of Evaluating Axial Load Capacity of Piles

Method of Evaluating Axial Load Capacity of PilesPile Driving Dynamics

Firman Bima A.Putri Maudy KusumahDefinitionPrecast pile which is driven into the soil by a hammer Pile Driving Analyzer systems evaluate shaft integrity, driving stress, and hammer energy to pile driving dynamicPDA test calculates foundation capacityOldest and most frequently used method.Primary objectives are:Safe working load for a pile based on pile driving recordDetermine the driving requirements for a required working load

Pile Driving Analyzer

Pile Driving Formulas

Foundation Capacity (Qv)ult = (Qp) + (Qs) WQu = Ap cu Nc + pi L fsQs = pi L fs , fS = caCu/ca given on the NAVFAC Table

Pile Driving capacity can handle only QsIt doesnt have to reach stratumWave EquationEach hammer-blow produces a stress wave that moves down the length of the pile at the speed of sound, so that the entire length of the pile is not stressed simultaneously.

ExampleMini Franki MF-28 Pile Specifications : K-500 ConcretePile Reinforcement = 3 concrete iron screws 16mm, BJTD 40, spiral bound using plain concrete iron 6mm, distance to center 5 mm, and beveled 45Connection Plate = steel, thickness 10 mm Welding wire = 3,2 mm, low hydrogen caliber AWS E7018

Pile Bearing Capacity for Mini Franki MF-28Using Hileys Formula :

Ru = Ultimate Pile Bearing Capacity = Safety factor x allowable bearing capacity (Q)If Q = 25 tons, Ru = 2.5 x 25 = 62.50 tonsW = weight of hammer = 1.5 tonsh = effective height of drop hammer = 0.8 x 1m = 0.8 m = 31.5 = efficiency of piling = 0.6c = temporary elastic compression = 0.5How long is the (s) penetration per hit (cm) ?

ReferencesPoulus, H.G., Davis, E.H. 1980. Pile Foundation and Analysis Design. University of Sydney