Prediction of Pile Capacity

The method used for calculating pile capacity is based on the effective stress approach applying beta and Nt-coefficients to determine the shaft and toe resistances. The capacities of the two driven piles, the pipe pile and the H-pile, are assumed to be about equal and amount to 900 KN (100 tons) on the forthcoming third testing occasion. Residual load is calculated and its influence on the load distribution is shown. Capacities at the first and second loading tests are 80 % and 90 % of that of the third occasion. The capacities of the two bored piles are expected to be about similar to that of the driven piles. INTRODUCTION Prediction of foundation behavior is a daily task of the foundation engineering profession. However, only rarely are the predictions compared with measurements of the actual behavior of the foundations. The academic profession, on the other hand, often gets to measure the behavior of foundation units in laboratory model scale and, sometimes, in half scale test but rarely in full scale field tests. In additional contrast and not very much realized, the academic profession seldom makes predictions, but concentrates on theoretical evaluation of known results. This situation is hidden by the erroneous use of the words "prediction" and "to predict" as synonymous to the words "calculation", "determination", "computation", and to calculate", "to determine", "to compute", etc. On occasions, there have been interesting and worthwhile pile foundation engineering "prediction seminars". More notably, W. Lambe's seminar at MIT in 1973 and, amongst others, the FHWA's seminar in Baltimore in 1986. The first of these seminars provided data that were similar in completeness, or lack thereof, to those of a conventional engineering project. Therefore, the predictions were not very well backed up and, consequently, many predictions were off the mark. The FHWA project was arranged specially for that prediction seminar and much data were provided, but the project suffered from that it had been designed with a