This approach to raft design consists of ﬁve main steps:
(1) Adopt a sensible layout of beam thickenings to avoid stress concentrations and areas of weakness.
(2) Check bearing pressure under concentrated loads on slabs and beam thickenings.
(3) Establish a design span for local depressions, based on the ground conditions and thickness of compacted hardcore ﬁlling.
(4) Design the raft slab areas to span over local depressions and to resist shrinkage cracking.
(5) Design the raft beam thickenings to span over local depressions.
It should be emphasized that, as with all other aspects of foundation design, it is not possible to exhaustively cover every imaginable situation, i.e. in this case every possible combination of loading, raft proﬁle and reinforcement, compacted ﬁll, and ground conditions. Therefore, although the guidance which follows should cover most normal situations, any new design situation should be looked at wearing one’s ‘engineering spectacles’ to spot those situations where rules need adapting, or do not apply.