Probabilistic Considerations for the Design of Deep Foundations Against Excessive Differential Settlement

Current foundation design practice for serviceability limit states involves proportioning the foundation to achieve an acceptably small probability that the foundation settlement exceeds some target maximum total settlement. However, it is usually differential settlement which leads to problems in the supported structure. The design question, then, is how should the target maximum total settlement of an individual foundation be selected so that differential settlement is not excessive? Evidently, if the target maximum total settlement is increased, the differential settlement between foundations will also tend to increase, so that there is a relationship between the two, although not necessarily a simple relationship. This paper investigates how the target maximum total settlement specified in the design of an individual foundation relates to the distribution of the differential settlement between two identical foundation elements, as a function of the ground statistics and the distance between the two foundations. A probabilistic theory is developed, and validated by simulation, which is used to prescribe target maximum settlements employed in the design process to avoid excessive differential settlements to some acceptable probability.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author