Probabilistic design chart for settlements of shallow foundations in granular soils

The current state-of-the-art for predicting settlements of shallow foundations in granular soils is far from adequate. Even the most popular settlement prediction method can over-estimate the settlement significantly. Using a large database of settlement records, a probabilistic design chart was developed for four traditional settlement prediction methods. When the settlement is estimated by any of these four deterministic methods, the proposed design chart enables the designer to obtain the probability that the actual settlement exceeds 25 mm. This design chart, incorporating the uncertainty associated with the different settlement prediction methods, will be a very useful tool in the design of shallow foundations in granular soils. A case study is included to illustrate use of the probabilistic design chart