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CHAPTER 18
SOILS AND FOUNDATIONS
SECTION 1801
GENERAL
1801.1.1 Certificate of compliance. Design compliance
with the provisions of this chapter and Chapter 16 shall be
satisfied when certification of an architect or engineer
licensed in Kentucky to that affect is placed on the
drawings submitted to the code official, unless the code
official shall notify the designer that a specific code
violation exists.
SECTION 1803
GEOTECHNICAL INVESTIGATIONS
1803.2 Investigations Required. Geotechnical
investigations shall be conducted, for other than construction
of a minor nature, where a registered design professional
seal is required per Table 122.1 or for special cases where
site soil conditions are determined to be substandard by the
building official. Investigations where required shall be
conducted in accordance with Sections 1803.3 through
1803.5.
Exception: The building official shall be permitted to
waive the requirement for a geotechnical investigation
where satisfactory data from adjacent areas is available
that demonstrates an investigation is not necessary for any
of the conditions in Sections 1803.5.1 through 1803.5.6
and Sections 1803.5.10 and 1803.5.11.
1803.5 Investigated conditions. Geotechnical
investigations shall be conducted as indicated in Sections
1803.5.1 through 1803.5.13.
1803.5.13 Karst Hazards. Risk Category III and IV
buildings and structures, as defined in Table 1604.5 and
located in regions within or near areas designated as being
underlain by bedrock with high potential for karst
development on Kentucky Geological Survey Map and
Chart 33, Series XII, 2001, Karst Occurrence in Kentucky,
shall have geophysical or other approved testing
performed by a qualified registered design professional to
determine if sinkhole or weak cavern conditions exist
under the building or structure. The geophysical report
shall include measures to mitigate any karst hazards found.
The Karst Occurrence in Kentucky Map may be viewed at
www.uky.edu/kgs.
The following counties in Kentucky include areas where
karst potential are known to exist: Adair, Allen, Anderson,
Bath, Barren, Bell, Boyle, Bourbon, Bracken,
Breckinridge, Bullitt, Caldwell, Calloway, Carter, Casey,
Christian, Clark, Clinton, Crittenden, Cumberland,
Edmonson, Elliott, Estill, Fayette, Fleming, Franklin,
Garrard, Grant, Grayson, Green, Greenup, Hardin, Harlan,
Harrison, Hart, Henry, Jackson, Jefferson, Jessamine,
Larue, Lewis, Lincoln, Livingston, Logan, Lee, Letcher,
Lyon, Madison, Marshall, Meade, Mercer, Menifee,
Metcalfe, Monroe, Nelson, Nicholas, Oldham, Owen,
Pike, Powell, Pulaski, Robertson, Rockcastle, Rowan,
Russell, Scott, Simpson, Taylor, Todd, Trigg, Trimble,
Warren, Washington, Wayne, Whitley, Woodford and
Wolfe.
Exceptions:
1. Construction sites where it can be demonstrated by
published geologic mapping that the upper 100 feet
of strata for a site does not include any limestone,
dolomite or other predominantly calcareous rock
exceeding 5 feet in thickness. Geologic maps and
digital mapping can be obtained from the Kentucky
Geologic Survey.
2. Risk Category IV buildings or structures, not
similar in occupancy to Risk Category III, under
5,000 square feet in building area, and not providing
any residential facilities within the structure.
3. Risk Category IV facilities not normally occupied.
SECTION 1807
FOUNDATION WALLS, RETAINING WALLS AND
EMBEDDED POSTS AND POLES
1807.2 Retaining walls. Retaining walls shall be designed in
accordance with Sections 1807.2.1 through 1807.2.4.
1807.2.1 General. Retaining walls shall be designed to
ensure stability against overturning, sliding, excessive
foundation pressure and water uplift. Where a keyway is
extended below the wall base with the intent to engage
passive pressure and enhance sliding stability, lateral soil
pressures on both sides of the keyway shall be considered
in the sliding analysis.
1807.2.2 Design lateral soil loads. Retaining walls shall
be designed for the lateral soil loads set forth in Section
1610.
1807.2.3 Safety factor. Retaining walls shall be designed
to resist the lateral action of soil to produce sliding and
overturning with a minimum safety factor of 1.5 in each
case. The load combinations of Section 1605 shall not
apply to this requirement. Instead, design shall be based on
0.7 times nominal earthquake loads, 1.0 times other nomi-
nal loads, and investigation with one or more of the vari-
able loads set to zero. The safety factor against lateral
sliding shall be taken as the available soil resistance at the