This paper describes the development of an approximate approach for the analysis and design of piles subjected to axial and lateral loading and also to vertical and horizontal ground movements. The analysis involves a number of simpli"cations in order to make it feasible to implement. For example, it considers the behaviour of a &representative' pile in a group to characterize the behaviour of all piles in the group, and adopts approximations to derive free-"eld interaction factors from the conventional interaction factors for direct loading. The analysis has been implemented via a computer program called EMbankment PIle Group (EMPIG) and has the ability to incorporate the following features:
- single piles or pile groups, 2. applied vertical, lateral and moment loading on the pile cap, 3. the e!ects of axial and lateral soil movements caused by embankment construction, 4. a layered soil pro"le, 5. non-linear axial and lateral response of the piles.
Comparisons between solutions from EMPIG and other independent programs suggest that it is capable of providing results of adequate accuracy for practical design purposes.
The analysis has been used to investigate the e!ects of pile rake on a typical bridge abutment group. The presence of raked piles can have a detrimental e!ect on group behaviour, especially in the presence of ground movements. Large lateral de#ections can be generated and axial forces and moments in the piles are increased. Comparisons are also made with the results of centrifuge model tests on abutment pile groups.