M. Jahanandish - Department of Civil Engineering, Shiraz University, Shiraz, Iran.
A. Eslami Haghighat - Department of Civil Engineering, Shiraz University, Shiraz, Iran.

The essential elements of the zero extension line method in analyzing the load-deflection behavior of strip footings have been presented. The model has been shown to provide a simple analytical tool for the analysis of such problems. Strain and strength resulted from different modes of footing movement can well be predicted by the model. The steps in computation of strain and stress fields have been explained. Strip footings resting on a typical clay and sand have been analyzed in different modes of failure namely,rotation and translation. In contrast to the limit analysis, the outward mechanism has been considered for rotational mode. This is because experimental observations indicate that it develops first and before the leeward one in this mode of failure. Loaddeflection behavior of footings have also been established by the model. Results of he analysis indicate larger ultimate load in rotational failure compared to that of translation, which is consistent with experimental results obtained before.

Zero extension line, load-deflection, outward / leeward mechanisms