The document provides guidelines for constructing raft foundations and beams. It recommends making the thickness of a raft foundation equal to the number of storeys times 80 to 100 mm. It also suggests sizing beams so that their depth in inches equals the length of the beam in feet, and that typical economical beam spans for special moment frames range from 20 to 30 feet with a minimum strap beam depth of 1'10".

1. ThumbRule
Raft Foundation
Thickness(mm)=nos.of storeyx (80to 100)
Beam
Depthininch=lengthof the beaminfeet
Eg. 10’ lengthneeds10” beam
Typical economical beamspansforspecial momentframesare inthe range of 20 to 30 feet(NEHRP
SeismicDesignTechnical Brief No. 1)
Minimumdepthof Strap Beam 1’10”