The slope of cut or fill surfaces shall be no
steeper than two horizontal to one vertical or shall be no steeper
than is safe for the soil and intended use, whichever is more restrictive.
A bench not less than three feet wide and with a maximum slope of
ten percent shall be provided adjacent to all structures at the top
of slopes steeper than three to one. The need for slopes steeper than
allowed above shall be avoided by the installation for approved retaining
walls or approved equivalent stabilization procedures. Cut slopes
to be revegetated shall be no steeper than three horizontal to one
vertical. Any requests for exception shall be accompanied by engineering
data which indicates that a steeper slope can be constructed in accordance
with sound engineering practices, and includes details of treatment
to prevent surface erosion and provide adequate structural stability.
The ground surface shall be prepared to receive
fill by removing vegetation, noncomplying fill, topsoil, and other
unsuitable materials. The ground shall be scarified to provide a bond
with the new fill. Where slopes are steeper than five to one, and
the height is greater than five feet, the slope shall be benched into
sound bedrock or other competent material as determined by the civil
or soils engineer. The bench under the toe of a fill on slopes steeper
than five to one shall be at least ten feet wide. The area beyond
the toe of fill shall be sloped for sheet overflow or a paved drain
shall be provided. Where fill is to be placed over a cut, the bench
under the toe of fill shall be at least ten feet wide, but the cut
must be made before placing fill and approved by the soils engineer
or engineering geologist as a suitable foundation for fill. Unsuitable
soil is soil which, in the opinion of the City engineer, the civil
engineer, the soils engineer, or the engineering geologist, is not
competent to support other soil or fill, to support structures, or
to satisfactorily perform the other functions for which the soil is
intended.
All retaining walls shall be designed in accordance
with the Uniform Building Code and with good engineering practices.
Walls higher than four feet shall be designed by a licensed engineer
and plans submitted to the City for approval before construction.
Any wood used in retaining walls shall be pressure treated in accordance
with the Uniform Building Code, stamped or certified by an approved
testing agency at the factory. Where the drainage flow is over the
top of retaining walls, adequate protection shall be provided to prevent
erosion of the soil on both sides of the wall.
All fills which support foundations and slabs
on grade, including but not limited to floors, patios, porches, driveways,
sidewalks, and fills for utility trenches shall be compacted to a
minimum of ninety-five percent of maximum density as determined in
accordance with ASTM D-698 or its approved equivalent. It is not the
intent of this Part 6 to control compaction of backfill around foundation,
but rather to make it the responsibility of the builder to correct
substantial subsidence which occurs within one year of the date of
the issuance of the final certificate of occupancy or City acceptance.
When substantial subsidence occurs within this year, it shall be the
responsibility of the owner of the property to notify the builder
and to temporarily prevent any further damage in the subsided area.
The builder shall correct the subsidence within thirty days of written
notice by the owner.
Rough and/or fine grading within major drainage
ways or subdivisions shall be per an approved set of construction
plans and per the approved grading plan. This grading work shall also
be per the approved final drainage plan required by the City storm
water runoff control ordinance.
These regulations shall be and are hereby declared
to be in full force and effect upon the date of passage.