01578Olson Walker As iates Architects
April 11, 1980•
page 4
ME
drying soils will be only possible during extended dry weather, which
would be anticipated from June to September.
We recommended that the sequence of development from stripping
through site grading be accomplished so that surface drainage is
progressively developed. Drainage should be provided, so that if
precipitation falls during the site development, there will be
adequate gradations and ditching to dispose of standing water.
7.2. FOUNDATION TYPE
Since the bearing stratum is located at relatively shallow depths
'ranging from 2.to 3.0 feet based on the test pit examination, shallow
foundations (strip and square footing) are believed to be the most
economical for the proposed development. Therefore, the design
parameters pertinent to the shallow foundation will be the only ones
presented.
7.3. SHALLOW SPREAD FOOTING DESIGN PARAMETERS
a) Allowable bearing capacity on the medium dense sand will be
much more than required for the antici-pated building load. The
minimum footing width recommended in this report will give
sufficient bearing support for the buildings. However, an allowable
bearing capacity of 3000 pounds per.square foot may be used
for the design of strip and square footings, in order to support
the dead and live load.
b) Spread footings should be founded at minimum depths of 18
inches below final grade to limit the affect of weathering.
All footings should be founded on undisturbed inorganic sand
existing 2.0'to 3.0 feet below the present grade.
c) The spread footings should be set back at least 10 feet at a
horizontal distance from the slope face near the creek. The.,
slope face should not'be steeper than 2H:1V slope.
d) Minimum footing widths of 1.5 and 2.0 feet are recommended
for strip and isolated square footings, respectively.
e) Footing excavation should be excavated in a neat condition.
It is recommended that the trench be excavated so that water
can be drained in case of possible seepage and precipitation.
f) No loose, disturbed, remoulded, or slough material should
be allowed to remain in open footing excavations. Hand shovel
cutting must be undertaken if an acceptable surface cannot be
prepared by mechanical equipment.