International Building Code Section 1802


International Building Code 1802.1

General. Foundation and soils investigations shall be
conducted in conformance with Sections 1802.2 through
1802.6. Where required by the building official, the classification
and investigation of the soil shall be made by a registered
design professional.

International Building Code 1802.2

Where required. The owner or applicant shall submit a
foundation and soils investigation to the building official where
required in Sections 1802.2.1 through 1802.2.7.
Exception: The building official need not require a foundation
or soils investigation where satisfactory data from adjacent
areas is available that demonstrates an investigation is
not necessary for any of the conditions in Sections 1802.2.1
through 1802.2.6.

Questionable soil. Where the classification,
strength or compressibility of the soil are in doubt or where
a load-bearing value superior to that specified in this code is
claimed, the building official shall require that the necessary
investigation be made. Such investigation shall comply with
the provisions of Sections 1802.4 through 1802.6.

Expansive soils. In areas likely to have expansive
soil, the building official shall require soil tests to determine
where such soils do exist.

Ground-water table.Asubsurface soil investigation
shall be performed to determine whether the existing
ground-water table is above or within 5 feet (1524 mm)
below the elevation of the lowest floor level where such
floor is located below the finished ground level adjacent to
the foundation.
Exception: A subsurface soil investigation shall not be
required where waterproofing is provided in accordance
with Section 1807.

Pile and pier foundations. Pile and pier foundations
shall be designed and installed on the basis of a foundation
investigation and report as specified in Sections
1802.4 through 1802.6 and Section 1808.2.2.

Rock strata. Where subsurface explorations at the
project site indicate variations or doubtful characteristics in
the structure of the rock upon which foundations are to be
constructed, a sufficient number of borings shall be made to
a depth of not less than 10 feet (3048 mm) belowthe level of
the foundations to provide assurance of the soundness of the
foundation bed and its load-bearing capacity.

Seismic Design Category C. Where a structure is
determined to be in Seismic Design Category C in accordance
with Section 1613, an investigation shall be conducted
and shall include an evaluation of the following
potential hazards resulting from earthquake motions: slope
instability, liquefaction and surface rupture due to faulting
or lateral spreading.

Seismic Design Category D, E or F. Where the
structure is determined to be in Seismic Design Category D,
E or F, in accordance with Section 1613, the soils investigation
requirements for Seismic Design Category C, given in
Section 1802.2.6, shall be met, in addition to the following.
The investigation shall include:
1. A determination of lateral pressures on basement and
retaining walls due to earthquake motions.
2. An assessment of potential consequences of any liquefaction
and soil strength loss, including estimation
of differential settlement, lateral movement or reduction
in foundation soil-bearing capacity, and shall
address mitigation measures. Such measures shall be
given consideration in the design of the structure and
can include but are not limited to ground stabilization,
selection of appropriate foundation type and depths,
selection of appropriate structural systems to accommodate
anticipated displacements or any combination
of these measures. The potential for liquefaction
and soil strength loss shall be evaluated for site peak
ground acceleration magnitudes and source characteristics
consistent with the design earthquake ground
motions. Peak ground acceleration shall be determined
from a site-specific study taking into account
soil amplification effects, as specified in Chapter 21
of ASCE 7.
Exception: A site-specific study need not be performed,
provided that peak ground acceleration
2006 INTERNATIONAL BUILDING CODE 343
equal to SDS/2.5 is used, where SDS is determined in
accordance with Section 21.2.1 of ASCE 7.

International Building Code 1802.2.1

Questionable soil. Where the classification,
strength or compressibility of the soil are in doubt or where
a load-bearing value superior to that specified in this code is
claimed, the building official shall require that the necessary
investigation be made. Such investigation shall comply with
the provisions of Sections 1802.4 through 1802.6.

International Building Code 1802.2.2

Expansive soils. In areas likely to have expansive
soil, the building official shall require soil tests to determine
where such soils do exist.

International Building Code 1802.2.3

Ground-water table.Asubsurface soil investigation
shall be performed to determine whether the existing
ground-water table is above or within 5 feet (1524 mm)
below the elevation of the lowest floor level where such
floor is located below the finished ground level adjacent to
the foundation.
Exception: A subsurface soil investigation shall not be
required where waterproofing is provided in accordance
with Section 1807.

International Building Code 1802.2.4

Pile and pier foundations. Pile and pier foundations
shall be designed and installed on the basis of a foundation
investigation and report as specified in Sections
1802.4 through 1802.6 and Section 1808.2.2.

International Building Code 1802.2.5

Rock strata. Where subsurface explorations at the
project site indicate variations or doubtful characteristics in
the structure of the rock upon which foundations are to be
constructed, a sufficient number of borings shall be made to
a depth of not less than 10 feet (3048 mm) belowthe level of
the foundations to provide assurance of the soundness of the
foundation bed and its load-bearing capacity.

International Building Code 1802.2.6

Seismic Design Category C. Where a structure is
determined to be in Seismic Design Category C in accordance
with Section 1613, an investigation shall be conducted
and shall include an evaluation of the following
potential hazards resulting from earthquake motions: slope
instability, liquefaction and surface rupture due to faulting
or lateral spreading.

International Building Code 1802.2.7

Seismic Design Category D, E or F. Where the
structure is determined to be in Seismic Design Category D,
E or F, in accordance with Section 1613, the soils investigation
requirements for Seismic Design Category C, given in
Section 1802.2.6, shall be met, in addition to the following.
The investigation shall include:
1. A determination of lateral pressures on basement and
retaining walls due to earthquake motions.
2. An assessment of potential consequences of any liquefaction
and soil strength loss, including estimation
of differential settlement, lateral movement or reduction
in foundation soil-bearing capacity, and shall
address mitigation measures. Such measures shall be
given consideration in the design of the structure and
can include but are not limited to ground stabilization,
selection of appropriate foundation type and depths,
selection of appropriate structural systems to accommodate
anticipated displacements or any combination
of these measures. The potential for liquefaction
and soil strength loss shall be evaluated for site peak
ground acceleration magnitudes and source characteristics
consistent with the design earthquake ground
motions. Peak ground acceleration shall be determined
from a site-specific study taking into account
soil amplification effects, as specified in Chapter 21
of ASCE 7.
Exception: A site-specific study need not be performed,
provided that peak ground acceleration
2006 INTERNATIONAL BUILDING CODE 343
equal to SDS/2.5 is used, where SDS is determined in
accordance with Section 21.2.1 of ASCE 7.

International Building Code 1802.3

Soil classification. Where required, soils shall be classified
in accordance with Section 1802.3.1 or 1802.3.2.

General. For the purposes of this chapter, the definition
and classification of soil materials for use in Table
1804.2 shall be in accordance with ASTM D 2487.

Expansive soils. Soils meeting all four of the following
provisions shall be considered expansive, except
that tests to show compliance with Items 1, 2 and 3 shall not
be required if the test prescribed in Item 4 is conducted:
1. Plasticity index (PI) of 15 or greater, determined in
accordance with ASTM D 4318.
2. More than 10 percent of the soil particles pass a No.
200 sieve (75 ?m), determined in accordance with
ASTM D 422.
3. More than 10 percent of the soil particles are less than
5 micrometers in size, determined in accordance with
ASTM D 422.
4. Expansion index greater than 20, determined in
accordance with ASTM D 4829.

International Building Code 1802.3.1

General. For the purposes of this chapter, the definition
and classification of soil materials for use in Table
1804.2 shall be in accordance with ASTM D 2487.

International Building Code 1802.3.2

Expansive soils. Soils meeting all four of the following
provisions shall be considered expansive, except
that tests to show compliance with Items 1, 2 and 3 shall not
be required if the test prescribed in Item 4 is conducted:
1. Plasticity index (PI) of 15 or greater, determined in
accordance with ASTM D 4318.
2. More than 10 percent of the soil particles pass a No.
200 sieve (75 ?m), determined in accordance with
ASTM D 422.
3. More than 10 percent of the soil particles are less than
5 micrometers in size, determined in accordance with
ASTM D 422.
4. Expansion index greater than 20, determined in
accordance with ASTM D 4829.

International Building Code 1802.4

Investigation. Soil classification shall be based on
observation and any necessary tests of the materials disclosed
by borings, test pits or other subsurface exploration made in
appropriate locations. Additional studies shall be made as necessary
to evaluate slope stability, soil strength, position and
adequacy of load-bearing soils, the effect of moisture variation
on soil-bearing capacity, compressibility, liquefaction and
expansiveness.

Exploratory boring. The scope of the soil investigation
including the number and types of borings or
soundings, the equipment used to drill and sample, the
in-situ testing equipment and the laboratory testing program
shall be determined by a registered design professional.

International Building Code 1802.4.1

Exploratory boring. The scope of the soil investigation
including the number and types of borings or
soundings, the equipment used to drill and sample, the
in-situ testing equipment and the laboratory testing program
shall be determined by a registered design professional.

International Building Code 1802.5

Soil boring and sampling. The soil boring and sampling
procedure and apparatus shall be in accordance with generally
accepted engineering practice. The registered design
professional shall have a fully qualified representative on the
site during all boring and sampling operations.

International Building Code 1802.6

Reports. The soil classification and design load-bearing
capacity shall be shown on the construction document.
Where required by the building official, a written report of the
investigation shall be submitted that includes, but need not be
limited to, the following information:
1. A plot showing the location of test borings and/or excavations.
2. A complete record of the soil samples.
3. A record of the soil profile.
4. Elevation of the water table, if encountered.
5. Recommendations for foundation type and design criteria,
including but not limited to: bearing capacity of natural
or compacted soil; provisions to mitigate the effects
of expansive soils; mitigation of the effects of liquefaction,
differential settlement and varying soil strength;
and the effects of adjacent loads.
6. Expected total and differential settlement.
7. Pile and pier foundation information in accordance with
Section 1808.2.2.
8. Special design and construction provisions for footings
or foundations founded on expansive soils, as necessary.
9. Compacted fill material properties and testing in accordance
with Section 1803.5.