content_image/508421.jpg content_image/508422.jpg
resistance. Instead a partial factor on the ultimate characteristic pile resistance, Rcc may be taken as the  ts values given in the table above. 

## Ultimate Bearing Resistance from Pile Driving Formulas 

If pile formulae are used to assess the ultimate bearing resistance of individual compression piles in a foundation, the validity of the formulae shall have been demonstrated by previous experimental evi- dence of good performance or static load tests on the same type of pile, of similar length and cross- section, and in similar ground conditions. 

Pile driving formulae shall only be used if the stratification of the ground has been determined. 

In the design, the number of piles to be redriven shall be specified. If redriving gives lower results, these shall be used as basis for ultimate bearing resistance assessment. If redriving gives higher re- sults, these may be taken into consideration. 

Redriving should usually be carried out in silty soils, unless local comparable experience has shown this to be unnecessary. 

## Ultimate Bearing Resistance from Dynamic Load Tests 

Dynamic load tests and their evaluation can be used to assess pile bearing resistance of individual compression piles. The validity of the evaluation shall have been demonstrated by previous evidence of acceptable performance or static load tests on the same pile type of similar length and cross-section and in similar soil conditions. The input energy level during the dynamic load testing shall be high enough to allow for an appropriate interpretation of the pile capacity at a correspondingly high enough strain level. 

When deriving the ultimate characteristic bearing resistance Rcc from values Rcmd measured in two or several dynamic pile load tests, an allowance shall be made for the variability of the ground and the variability of the effect of pile installations a minimum, both conditions (a) and (b) of the table below shall be satisfied using the equation: 

• Rcc = Rcmd /  nd 

Factors  nd to Derive Rcc 

<img src='content_image/508421.jpg'>

In order to derive the ultimate design bearing resistance, the characteristic value Rcc should be divided into components of base resistance Rcbc and shaft resistance Rcsc such that 

• Rcc= Rcbc + Rcsc 

The design bearing resistance Rcd shall be derived from 

• Rcd = Rcbc/  bd + Rcsc/  sd 

where  bd and  sd are taken from the table below 

## Values of  bd,  sd and  td 

<img src='content_image/508422.jpg'>

