ORIGINAL PAPER A New Method for the Evaluation of the Ultimate Load of Piles by Tests not Carried to Failure Giovanni Dalerci • Rossella Bovolenta Received: 29 June 2012 / Accepted: 22 June 2013 Ó Springer Science+Business Media Dordrecht 2013 Abstract A new method for the evaluation of the ultimate load of piles by tests not carried to failure is proposed. It allows, by a proper use of the experi- mental results, a complete analysis of a pile behavior. In fact, the total, shaft and base load-settlement curves can be evaluated. It can be applied when shaft friction is fully mobilized during the test. Keywords Foundations  Piles  Loading tests  Geotechnics 1 Introduction Few methods have been proposed in order to deduce the shaft and base performance of a single pile by load tests. One of the most famous methods for single pile settlement prediction and analysis is the one proposed by Fleming (1992) and (1997). It is based on the use of hyperbolic functions to describe individual shaft and base load-head settlement performance. Besides, the method provides useful indications about soil Young’s modulus at low strains. The method is quite simple but it introduces many parameters and it does not provide a unique solution. The calculated values of ultimate shaft and base loads and the low strain modulus can vary in wide ranges (see Passalacqua et al. 1999). Potential errors in the total ultimate load determination by the Fleming method are rather moderate if the maximum axial load applied during the test is close to the failure one. In this case the recourse to the approach proposed by Chin (1970) and (1972) is to be preferred because of its simplicity. Dalerci (1991) formulated a method able to provide the ultimate shaft load and the soil Young’s modulus. These values are deduced by representing the settle- ment/load values as a function of the 1/load (i.e. s/Q vs. 1/Q) and interpolating the data where a linear plot is obtained. The application of this method together with the Chin’s one provides complete information about the pile performance (see Passalacqua et al. 1999). Dalerci and Bovolenta (2009) proposed a new method in order to estimate the ultimate shaft load and the soil Young’s modulus. This approach allows a simple interpretation of full-scale pile tests. It can be applied when shaft friction is fully mobilized. In the present work a new procedure is described for the evaluation of the ultimate load by tests not carried to failure. The curves representing the shaft load versus the shaft settlement (in the middle of the pile) and the base load versus the base settlement are assumed hyperbolic. The calculated shaft and base load values represented as functions of the pile head G. Dalerci  R. Bovolenta (&) Department of Civil, Environmental, Architectural Engineering, University of Genova (Italy), Via Montallegro, 16145 Genoa, Italy e-mail: Bovolenta@dicat.unige.it 123 Geotech Geol Eng DOI 10.1007/s10706-013-9673-z