BBEAKWATER CONSTRUCTION. 163
Limiting Loads. — In all these cases it is uecessary to bear in mind the
limiting resistance to compression of the stratum founded upon. The follow-
ing values may be adopted for use in ordinary cases.
s
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0
I. ----/5i------4
Transverse Section.
U ----------------je'.----------------
En/argement of
Cutting Edge
Fig. 132. —Foundation Caisson for Piers.
Concrète will safely stand from 10 to 15 tons’ compression per square foot
of area; hard rock from 9 to 10 tons; soft rock and stiff clay from 2 to 3
tons; and sand and gravel from 11 to 2 tons.