Contents [show]
Download paper, available by permission of the publisher.
Reference: Zekkos, D.P., Bray, J.D., Der Kiureghian, A. (2004), “Reliability of shallow foundation design using the standard penetration test”, 2nd International Conference on Site Characterization Proceedings, 19-22/9/2004, Porto, Portugal, Vol.2, pp. 1575-1582.
Abstract
The sources of uncertainty, variability and bias in the performance of the Standard Penetration Test were identified using an extensive literature review and were classified in a manner that should assist the practice in recognizing and reducing them. These uncertainties and additional uncertainties introduced in the design process are then incorporated in a reliability-based evaluation of the design of shallow foundations. The results of the reliability analyses show that the factor of safety approach can provide an impression of degree of conservatism that is often unrealistic. At times,foundations with smaller factors of safety have smaller probabilities of failure than foundations with higher factors of safety.The reliability-based approach provides rational design criteria,accounting for all key sources of uncertainty in the foundation engineering process, and thus should be the basis of design.
An extensive literature review was made to evaluate sources of uncertainty in the performance of the SPT, based on the previous work of many researchers (Kulhawy and Mayne (1990), Schmertmann (1975), Barton (1990), ASTM D6066-96, Youd et al. (2001), Kulhawy and Trautmann (1996)).
Table 1 summarizes a total of 27 sources of uncertainty and bias, classified in five categories. This classification aims to assist the practicing engineer in taking the necessary measures to minimize the uncertainties in the performance of the test:
Figure: Note that for the same factor of safety you get different Probability of Failures, depending on the type of soil.
Findings-Conclusions
Shallow foundations, often called footings, are situated beneath the lowest part of the structure...
Foundation is the lowest part of a structure which transfers loads from the superstructure to the...
All Engineers can relate to an experience we’ve had where what we designed was not how it turned ou...
Sponsored by the Geo-Institute, the ASCE will be publishing a Geotechnical Special Publication (GSP)...
For any transportation project it’s essential to have a clear view of the subsurface and any proble...
A foundation is considered as shallow when its width is greater than its embedment depth (Df ≤ B)...
Critical Failure Surface As discussed in the previous chapters of the Geoengineer.org series on Slo...
A deep foundation is a type of foundation which is placed at a greater depth below the ground surf...
1 COMMENT
wael Mohamed Ebid*
Jun, 01, 2020 i just downloaded the software, but I am not sure, if the categories mentioned include SPT's in carbonate soil and its correlation as well. will it be a big difference compared to siliceous soils?