Modified Meyerhof Empirical Equation for Pile Capacity

The empirical equation linking the pile ultimate geotechnical capacity and standard penetration test number proposed by Meyerhof has been used extensively in Singapore for pile design. However, based on their experience, many experienced practicing engineers are of the view that the equation is too conservative and uneconomical for pile design. In fact, the local approving authority permits the use of a modified version of the Meyerhof equation, which gives higher ultimate geotechnical capacities for piles even though no systematic study has been undertaken and published to substantiate the validity of the this equation. The results of 113 pile load tests comprising 54 driven piles of reinforced concrete piles, steel H and spun piles, and 59 bored piles is analyzed in detail with the aim of establishing whether the Meyerhof equation for ultimate pile capacity is too conservative for the soil conditions studied. A modified Meyerhof equation for ultimate geotechnical capacity of piles is proposed based on back calculations of pile load test results not tested to failure.