International Building Code Section 1809


International Building Code 1809.1

Timber piles. Timber piles shall be designed in accordance
with the AFPA NDS.

Materials. Round timber piles shall conform to
ASTM D 25. Sawn timber piles shall conform to DOC
PS-20.

Preservative treatment. Timber piles used to
support permanent structures shall be treated in accordance
with this section unless it is established that the tops of the
untreated timber piles will be below the lowest
ground-water level assumed to exist during the life of the
structure. Preservative and minimum final retention shall be
in accordance withAWPAU1 (Commodity Specification E,
Use Category 4C) for round timber piles and AWPA U1
(Commodity Specification A, Use Category 4B) for sawn
timber piles. Preservative-treated timber piles shall be subject
to a quality control program administered by an
approved agency. Pile cutoffs shall be treated in accordance
with AWPA M4.

Defective piles. Any substantial sudden increase
in rate of penetration of a timber pile shall be investigated
for possible damage. If the sudden increase in rate of penetration
cannot be correlated to soil strata, the pile shall be
removed for inspection or rejected.

Allowable stresses. The allowable stresses shall
be in accordance with the AF&PA NDS.

International Building Code 1809.1.1

Materials. Round timber piles shall conform to
ASTM D 25. Sawn timber piles shall conform to DOC
PS-20.

International Building Code 1809.1.2

Preservative treatment. Timber piles used to
support permanent structures shall be treated in accordance
with this section unless it is established that the tops of the
untreated timber piles will be below the lowest
ground-water level assumed to exist during the life of the
structure. Preservative and minimum final retention shall be
in accordance withAWPAU1 (Commodity Specification E,
Use Category 4C) for round timber piles and AWPA U1
(Commodity Specification A, Use Category 4B) for sawn
timber piles. Preservative-treated timber piles shall be subject
to a quality control program administered by an
approved agency. Pile cutoffs shall be treated in accordance
with AWPA M4.

International Building Code 1809.1.3

Defective piles. Any substantial sudden increase
in rate of penetration of a timber pile shall be investigated
for possible damage. If the sudden increase in rate of penetration
cannot be correlated to soil strata, the pile shall be
removed for inspection or rejected.

International Building Code 1809.1.4

Allowable stresses. The allowable stresses shall
be in accordance with the AF&PA NDS.

International Building Code 1809.2

Precast concrete piles.

General. The materials, reinforcement and installation
of precast concrete piles shall conform to Sections
1809.2.1.1 through 1809.2.1.4.

Design and manufacture. Piles shall be
designed and manufactured in accordance with accepted
engineering practice to resist all stresses induced by handling,
driving and service loads.

Minimum dimension. The minimum lateral
dimension shall be 8 inches (203 mm). Corners of square
piles shall be chamfered.

Reinforcement. Longitudinal steel shall be
arranged in a symmetrical pattern and be laterally tied
with steel ties or wire spiral spaced not more than 4
inches (102 mm) apart, center to center, for a distance of
2 feet (610 mm) from the ends of the pile; and not more
than 6 inches (152 mm) elsewhere except that at the ends
of each pile, the first five ties or spirals shall be spaced 1
inch (25 mm) center to center. The gage of ties and spirals
shall be as follows:
For piles having a diameter of 16 inches (406 mm) or
less, wire shall not be smaller than 0.22 inch (5.6 mm)
(No. 5 gage).
For piles having a diameter of more than 16 inches
(406 mm) and less than 20 inches (508 mm), wire shall
not be smaller than 0.238 inch (6 mm) (No. 4 gage).
For piles having a diameter of 20 inches (508 mm) and
larger, wire shall not be smaller than 0.25 inch (6.4 mm)
round or 0.259 inch (6.6 mm) (No. 3 gage).

Installation. Piles shall be handled and
driven so as not to cause injury or overstressing, which
affects durability or strength.

Precast nonprestressed piles. Precast
nonprestressed concrete piles shall conform to Sections
1809.2.2.1 through 1809.2.2.5.

Materials. Concrete shall have a 28-day
specified compressive strength (f c) of not less than
3,000 psi (20.68 MPa).

Minimum reinforcement. The minimum
amount of longitudinal reinforcement shall be 0.8 percent
of the concrete section and shall consist of at least
four bars.

Seismic reinforcement in Seismic
Design Category C. Where a structure is assigned to
Seismic Design Category C in accordance with Section
1613, the following shall apply. Longitudinal
reinforcement with a minimum steel ratio of 0.01
2006 INTERNATIONAL BUILDING CODE 363
SOILS AND FOUNDATIONS
shall be provided throughout the length of precast
concrete piles.Within three pile diameters of the bottom
of the pile cap, the longitudinal reinforcement
shall be confined with closed ties or spirals of a minimum
3/8 inch (9.5 mm) diameter. Ties or spirals shall
be provided at a maximum spacing of eight times the
diameter of the smallest longitudinal bar, not to
exceed 6 inches (152 mm). Throughout the remainder
of the pile, the closed ties or spirals shall have a maximumspacing
of 16 times the smallest longitudinal bar
diameter not to exceed 8 inches (203 mm).

Seismic reinforcement in Seismic
Design Category D, E or F. Where a structure is
assigned to Seismic Design Category D, E or F in
accordance with Section 1613, the requirements for
Seismic Design Category C in Section 1809.2.2.2.1
shall apply except as modified by this section. Transverse
confinement reinforcement consisting of closed
ties or equivalent spirals shall be provided in accordance
with Sections 21.4.4.1, 21.4.4.2 and 21.4.4.3 of
ACI 318 within three pile diameters of the bottom of
the pile cap. For other than Site Class E or F, or
liquefiable sites and where spirals are used as the
transverse reinforcement, a volumetric ratio of spiral
reinforcement of not less than one-half that required
by Section 21.4.4.1(a) ofACI 318 shall be permitted.

Allowable stresses. The allowable compressive
stress in the concrete shall not exceed 33 percent of
the 28-day specified compressive strength (f c) applied to
the gross cross-sectional area of the pile. The allowable
compressive stress in the reinforcing steel shall not
exceed 40 percent of the yield strength of the steel (fy) or a
maximum of 30,000 psi (207 MPa). The allowable tensile
stress in the reinforcing steel shall not exceed 50 percent
of the yield strength of the steel (fy) or a maximum of
24,000 psi (165 MPa).

Installation.Aprecast concrete pile shall not
be driven before the concrete has attained a compressive
strength of at least 75 percent of the 28-day specified
compressive strength (f c), but not less than the strength
sufficient to withstand handling and driving forces.

Concrete cover. Reinforcement for piles that
are not manufactured under plant conditions shall have a
concrete cover of not less than 2 inches (51 mm).
Reinforcement for piles manufactured under plant
control conditions shall have a concrete cover of not less
than 1.25 inches (32 mm) for No. 5 bars and smaller, and
not less than 1.5 inches (38 mm) for No. 6 through No. 11
bars except that longitudinal bars spaced less than 1.5
inches (38 mm) clear distance apart shall be considered
bundled bars for which the minimum concrete cover
shall be equal to that for the equivalent diameter of the
bundled bars.
Reinforcement for piles exposed to seawater shall
have a concrete cover of not less than 3 inches (76 mm).

Precast prestressed piles. Precast prestressed
concrete piles shall conform to the requirements of Sections
1809.2.3.1 through 1809.2.3.5.

Materials. Prestressing steel shall conform
to ASTM A 416. Concrete shall have a 28-day specified
compressive strength (f c) of not less than 5,000 psi
(34.48 MPa).

Design. Precast prestressed piles shall be
designed to resist stresses induced by handling and driving
as well as by loads. The effective prestress in the pile
shall not be less than 400 psi (2.76MPa) for piles up to 30
feet (9144 mm) in length, 550 psi (3.79 MPa) for piles up
to 50 feet (15 240 mm) in length and 700 psi (4.83 MPa)
for piles greater than 50 feet (15 240 mm) in length.
Effective prestress shall be based on an assumed loss
of 30,000 psi (207 MPa) in the prestressing steel. The
tensile stress in the prestressing steel shall not exceed the
values specified in ACI 318.

Design in Seismic Design Category C.
Where a structure is assigned to Seismic Design Category
C in accordance with Section 1613, the following
shall apply. The minimum volumetric ratio of
spiral reinforcement shall not be less than 0.007 or the
amount required by the following formula for the
upper 20 feet (6096 mm) of the pile.
At least one-half the volumetric ratio required by
Equation 18-4 shall be provided below the upper 20
feet (6096 mm) of the pile.
The pile cap connection by means of dowels as
indicated in Section 1808.2.23.1 is permitted. Pile cap
connection by means of developing pile reinforcing
strand is permitted provided that the pile reinforcing
strand results in a ductile connection.

Design in Seismic Design Category D,
E or F. Where a structure is assigned to Seismic
Design Category D, E or F in accordance with Section
1613, the requirements for Seismic Design Category
C in Section 1809.2.3.2.1 shall be met, in addition to
the following:
1. Requirements in ACI 318, Chapter 21, need not
apply, unless specifically referenced.
2. Where the total pile length in the soil is 35 feet
(10 668 mm) or less, the lateral transverse reinforcement
in the ductile region shall occur
through the length of the pile. Where the pile
364 2006 INTERNATIONAL BUILDING CODE
SOILS AND FOUNDATIONS
length exceeds 35 feet (10 668 mm), the ductile
pile region shall be taken as the greater of 35
feet (10 668 mm) or the distance from the
underside of the pile cap to the point of zero curvature
plus three times the least pile dimension.
3. In the ductile region, the center-to-center spacing
of the spirals or hoop reinforcement shall
not exceed one-fifth of the least pile dimension,
six times the diameter of the longtitudinal
strand, or 8 inches (203 mm), whichever is
smaller.
4. Circular spiral reinforcement shall be spliced
by lapping one full turn and bending the end of
the spiral to a 90-degree hook or by use of a
mechanical or welded splice complying with
Sec. 12.14.3 of ACI 318.
5. Where the transverse reinforcement consists of
circular spirals, the volumetric ratio of spiral
transverse reinforcement in the ductile region
shall comply with the following:
6. When transverse reinforcement consists of
rectangular hoops and cross ties, the total
cross-sectional area of lateral transverse reinforcement
in the ductile region with spacings,
and perpendicular to dimension, hc, shall conform
to:
The hoops and cross ties shall be equivalent to
deformed bars not less than No. 3 in size. Rectangular
hoop ends shall terminate at a corner with seismic
hooks.
Outside of the length of the pile requiring transverse
confinement reinforcing, the spiral or hoop
reinforcing with a volumetric ratio not less than
one-half of that required for transverse confinement
reinforcing shall be provided.

Allowable stresses. The allowable design
compressive stress, fc, in concrete shall be determined as
follows:

Installation. A prestressed pile shall not be
driven before the concrete has attained a compressive
strength of at least 75 percent of the 28-day specified
compressive strength (f c), but not less than the strength
sufficient to withstand handling and driving forces.

Concrete cover. Prestressing steel and pile
reinforcement shall have a concrete cover of not less than
11/4 inches (32 mm) for square piles of 12 inches (305
mm) or smaller size and 11/2 inches (38 mm) for larger
piles, except that for piles exposed to seawater, the minimum
protective concrete cover shall not be less than 21/2
inches (64 mm).
2006 INTERNATIONAL BUILDING CODE 365
SOILS AND FOUNDATIONS

International Building Code 1809.2.1

General. The materials, reinforcement and installation
of precast concrete piles shall conform to Sections
1809.2.1.1 through 1809.2.1.4.

Design and manufacture. Piles shall be
designed and manufactured in accordance with accepted
engineering practice to resist all stresses induced by handling,
driving and service loads.

Minimum dimension. The minimum lateral
dimension shall be 8 inches (203 mm). Corners of square
piles shall be chamfered.

Reinforcement. Longitudinal steel shall be
arranged in a symmetrical pattern and be laterally tied
with steel ties or wire spiral spaced not more than 4
inches (102 mm) apart, center to center, for a distance of
2 feet (610 mm) from the ends of the pile; and not more
than 6 inches (152 mm) elsewhere except that at the ends
of each pile, the first five ties or spirals shall be spaced 1
inch (25 mm) center to center. The gage of ties and spirals
shall be as follows:
For piles having a diameter of 16 inches (406 mm) or
less, wire shall not be smaller than 0.22 inch (5.6 mm)
(No. 5 gage).
For piles having a diameter of more than 16 inches
(406 mm) and less than 20 inches (508 mm), wire shall
not be smaller than 0.238 inch (6 mm) (No. 4 gage).
For piles having a diameter of 20 inches (508 mm) and
larger, wire shall not be smaller than 0.25 inch (6.4 mm)
round or 0.259 inch (6.6 mm) (No. 3 gage).

Installation. Piles shall be handled and
driven so as not to cause injury or overstressing, which
affects durability or strength.

International Building Code 1809.2.1.1

Design and manufacture. Piles shall be
designed and manufactured in accordance with accepted
engineering practice to resist all stresses induced by handling,
driving and service loads.

International Building Code 1809.2.1.2

Minimum dimension. The minimum lateral
dimension shall be 8 inches (203 mm). Corners of square
piles shall be chamfered.

International Building Code 1809.2.1.3

Reinforcement. Longitudinal steel shall be
arranged in a symmetrical pattern and be laterally tied
with steel ties or wire spiral spaced not more than 4
inches (102 mm) apart, center to center, for a distance of
2 feet (610 mm) from the ends of the pile; and not more
than 6 inches (152 mm) elsewhere except that at the ends
of each pile, the first five ties or spirals shall be spaced 1
inch (25 mm) center to center. The gage of ties and spirals
shall be as follows:
For piles having a diameter of 16 inches (406 mm) or
less, wire shall not be smaller than 0.22 inch (5.6 mm)
(No. 5 gage).
For piles having a diameter of more than 16 inches
(406 mm) and less than 20 inches (508 mm), wire shall
not be smaller than 0.238 inch (6 mm) (No. 4 gage).
For piles having a diameter of 20 inches (508 mm) and
larger, wire shall not be smaller than 0.25 inch (6.4 mm)
round or 0.259 inch (6.6 mm) (No. 3 gage).

International Building Code 1809.2.1.4

Installation. Piles shall be handled and
driven so as not to cause injury or overstressing, which
affects durability or strength.

International Building Code 1809.2.2

Precast nonprestressed piles. Precast
nonprestressed concrete piles shall conform to Sections
1809.2.2.1 through 1809.2.2.5.

Materials. Concrete shall have a 28-day
specified compressive strength (f c) of not less than
3,000 psi (20.68 MPa).

Minimum reinforcement. The minimum
amount of longitudinal reinforcement shall be 0.8 percent
of the concrete section and shall consist of at least
four bars.

Seismic reinforcement in Seismic
Design Category C. Where a structure is assigned to
Seismic Design Category C in accordance with Section
1613, the following shall apply. Longitudinal
reinforcement with a minimum steel ratio of 0.01
2006 INTERNATIONAL BUILDING CODE 363
SOILS AND FOUNDATIONS
shall be provided throughout the length of precast
concrete piles.Within three pile diameters of the bottom
of the pile cap, the longitudinal reinforcement
shall be confined with closed ties or spirals of a minimum
3/8 inch (9.5 mm) diameter. Ties or spirals shall
be provided at a maximum spacing of eight times the
diameter of the smallest longitudinal bar, not to
exceed 6 inches (152 mm). Throughout the remainder
of the pile, the closed ties or spirals shall have a maximumspacing
of 16 times the smallest longitudinal bar
diameter not to exceed 8 inches (203 mm).

Seismic reinforcement in Seismic
Design Category D, E or F. Where a structure is
assigned to Seismic Design Category D, E or F in
accordance with Section 1613, the requirements for
Seismic Design Category C in Section 1809.2.2.2.1
shall apply except as modified by this section. Transverse
confinement reinforcement consisting of closed
ties or equivalent spirals shall be provided in accordance
with Sections 21.4.4.1, 21.4.4.2 and 21.4.4.3 of
ACI 318 within three pile diameters of the bottom of
the pile cap. For other than Site Class E or F, or
liquefiable sites and where spirals are used as the
transverse reinforcement, a volumetric ratio of spiral
reinforcement of not less than one-half that required
by Section 21.4.4.1(a) ofACI 318 shall be permitted.

Allowable stresses. The allowable compressive
stress in the concrete shall not exceed 33 percent of
the 28-day specified compressive strength (f c) applied to
the gross cross-sectional area of the pile. The allowable
compressive stress in the reinforcing steel shall not
exceed 40 percent of the yield strength of the steel (fy) or a
maximum of 30,000 psi (207 MPa). The allowable tensile
stress in the reinforcing steel shall not exceed 50 percent
of the yield strength of the steel (fy) or a maximum of
24,000 psi (165 MPa).

Installation.Aprecast concrete pile shall not
be driven before the concrete has attained a compressive
strength of at least 75 percent of the 28-day specified
compressive strength (f c), but not less than the strength
sufficient to withstand handling and driving forces.

Concrete cover. Reinforcement for piles that
are not manufactured under plant conditions shall have a
concrete cover of not less than 2 inches (51 mm).
Reinforcement for piles manufactured under plant
control conditions shall have a concrete cover of not less
than 1.25 inches (32 mm) for No. 5 bars and smaller, and
not less than 1.5 inches (38 mm) for No. 6 through No. 11
bars except that longitudinal bars spaced less than 1.5
inches (38 mm) clear distance apart shall be considered
bundled bars for which the minimum concrete cover
shall be equal to that for the equivalent diameter of the
bundled bars.
Reinforcement for piles exposed to seawater shall
have a concrete cover of not less than 3 inches (76 mm).

International Building Code 1809.2.2.1

Materials. Concrete shall have a 28-day
specified compressive strength (f c) of not less than
3,000 psi (20.68 MPa).

International Building Code 1809.2.2.2

Minimum reinforcement. The minimum
amount of longitudinal reinforcement shall be 0.8 percent
of the concrete section and shall consist of at least
four bars.

Seismic reinforcement in Seismic
Design Category C. Where a structure is assigned to
Seismic Design Category C in accordance with Section
1613, the following shall apply. Longitudinal
reinforcement with a minimum steel ratio of 0.01
2006 INTERNATIONAL BUILDING CODE 363
SOILS AND FOUNDATIONS
shall be provided throughout the length of precast
concrete piles.Within three pile diameters of the bottom
of the pile cap, the longitudinal reinforcement
shall be confined with closed ties or spirals of a minimum
3/8 inch (9.5 mm) diameter. Ties or spirals shall
be provided at a maximum spacing of eight times the
diameter of the smallest longitudinal bar, not to
exceed 6 inches (152 mm). Throughout the remainder
of the pile, the closed ties or spirals shall have a maximumspacing
of 16 times the smallest longitudinal bar
diameter not to exceed 8 inches (203 mm).

Seismic reinforcement in Seismic
Design Category D, E or F. Where a structure is
assigned to Seismic Design Category D, E or F in
accordance with Section 1613, the requirements for
Seismic Design Category C in Section 1809.2.2.2.1
shall apply except as modified by this section. Transverse
confinement reinforcement consisting of closed
ties or equivalent spirals shall be provided in accordance
with Sections 21.4.4.1, 21.4.4.2 and 21.4.4.3 of
ACI 318 within three pile diameters of the bottom of
the pile cap. For other than Site Class E or F, or
liquefiable sites and where spirals are used as the
transverse reinforcement, a volumetric ratio of spiral
reinforcement of not less than one-half that required
by Section 21.4.4.1(a) ofACI 318 shall be permitted.

International Building Code 1809.2.2.2.1

Seismic reinforcement in Seismic
Design Category C. Where a structure is assigned to
Seismic Design Category C in accordance with Section
1613, the following shall apply. Longitudinal
reinforcement with a minimum steel ratio of 0.01
2006 INTERNATIONAL BUILDING CODE 363
SOILS AND FOUNDATIONS
shall be provided throughout the length of precast
concrete piles.Within three pile diameters of the bottom
of the pile cap, the longitudinal reinforcement
shall be confined with closed ties or spirals of a minimum
3/8 inch (9.5 mm) diameter. Ties or spirals shall
be provided at a maximum spacing of eight times the
diameter of the smallest longitudinal bar, not to
exceed 6 inches (152 mm). Throughout the remainder
of the pile, the closed ties or spirals shall have a maximumspacing
of 16 times the smallest longitudinal bar
diameter not to exceed 8 inches (203 mm).

International Building Code 1809.2.2.2.2

Seismic reinforcement in Seismic
Design Category D, E or F. Where a structure is
assigned to Seismic Design Category D, E or F in
accordance with Section 1613, the requirements for
Seismic Design Category C in Section 1809.2.2.2.1
shall apply except as modified by this section. Transverse
confinement reinforcement consisting of closed
ties or equivalent spirals shall be provided in accordance
with Sections 21.4.4.1, 21.4.4.2 and 21.4.4.3 of
ACI 318 within three pile diameters of the bottom of
the pile cap. For other than Site Class E or F, or
liquefiable sites and where spirals are used as the
transverse reinforcement, a volumetric ratio of spiral
reinforcement of not less than one-half that required
by Section 21.4.4.1(a) ofACI 318 shall be permitted.

International Building Code 1809.2.2.3

Allowable stresses. The allowable compressive
stress in the concrete shall not exceed 33 percent of
the 28-day specified compressive strength (f c) applied to
the gross cross-sectional area of the pile. The allowable
compressive stress in the reinforcing steel shall not
exceed 40 percent of the yield strength of the steel (fy) or a
maximum of 30,000 psi (207 MPa). The allowable tensile
stress in the reinforcing steel shall not exceed 50 percent
of the yield strength of the steel (fy) or a maximum of
24,000 psi (165 MPa).

International Building Code 1809.2.2.4

Installation.Aprecast concrete pile shall not
be driven before the concrete has attained a compressive
strength of at least 75 percent of the 28-day specified
compressive strength (f c), but not less than the strength
sufficient to withstand handling and driving forces.

International Building Code 1809.2.2.5

Concrete cover. Reinforcement for piles that
are not manufactured under plant conditions shall have a
concrete cover of not less than 2 inches (51 mm).
Reinforcement for piles manufactured under plant
control conditions shall have a concrete cover of not less
than 1.25 inches (32 mm) for No. 5 bars and smaller, and
not less than 1.5 inches (38 mm) for No. 6 through No. 11
bars except that longitudinal bars spaced less than 1.5
inches (38 mm) clear distance apart shall be considered
bundled bars for which the minimum concrete cover
shall be equal to that for the equivalent diameter of the
bundled bars.
Reinforcement for piles exposed to seawater shall
have a concrete cover of not less than 3 inches (76 mm).

International Building Code 1809.2.3

Precast prestressed piles. Precast prestressed
concrete piles shall conform to the requirements of Sections
1809.2.3.1 through 1809.2.3.5.

Materials. Prestressing steel shall conform
to ASTM A 416. Concrete shall have a 28-day specified
compressive strength (f c) of not less than 5,000 psi
(34.48 MPa).

Design. Precast prestressed piles shall be
designed to resist stresses induced by handling and driving
as well as by loads. The effective prestress in the pile
shall not be less than 400 psi (2.76MPa) for piles up to 30
feet (9144 mm) in length, 550 psi (3.79 MPa) for piles up
to 50 feet (15 240 mm) in length and 700 psi (4.83 MPa)
for piles greater than 50 feet (15 240 mm) in length.
Effective prestress shall be based on an assumed loss
of 30,000 psi (207 MPa) in the prestressing steel. The
tensile stress in the prestressing steel shall not exceed the
values specified in ACI 318.

Design in Seismic Design Category C.
Where a structure is assigned to Seismic Design Category
C in accordance with Section 1613, the following
shall apply. The minimum volumetric ratio of
spiral reinforcement shall not be less than 0.007 or the
amount required by the following formula for the
upper 20 feet (6096 mm) of the pile.
At least one-half the volumetric ratio required by
Equation 18-4 shall be provided below the upper 20
feet (6096 mm) of the pile.
The pile cap connection by means of dowels as
indicated in Section 1808.2.23.1 is permitted. Pile cap
connection by means of developing pile reinforcing
strand is permitted provided that the pile reinforcing
strand results in a ductile connection.

Design in Seismic Design Category D,
E or F. Where a structure is assigned to Seismic
Design Category D, E or F in accordance with Section
1613, the requirements for Seismic Design Category
C in Section 1809.2.3.2.1 shall be met, in addition to
the following:
1. Requirements in ACI 318, Chapter 21, need not
apply, unless specifically referenced.
2. Where the total pile length in the soil is 35 feet
(10 668 mm) or less, the lateral transverse reinforcement
in the ductile region shall occur
through the length of the pile. Where the pile
364 2006 INTERNATIONAL BUILDING CODE
SOILS AND FOUNDATIONS
length exceeds 35 feet (10 668 mm), the ductile
pile region shall be taken as the greater of 35
feet (10 668 mm) or the distance from the
underside of the pile cap to the point of zero curvature
plus three times the least pile dimension.
3. In the ductile region, the center-to-center spacing
of the spirals or hoop reinforcement shall
not exceed one-fifth of the least pile dimension,
six times the diameter of the longtitudinal
strand, or 8 inches (203 mm), whichever is
smaller.
4. Circular spiral reinforcement shall be spliced
by lapping one full turn and bending the end of
the spiral to a 90-degree hook or by use of a
mechanical or welded splice complying with
Sec. 12.14.3 of ACI 318.
5. Where the transverse reinforcement consists of
circular spirals, the volumetric ratio of spiral
transverse reinforcement in the ductile region
shall comply with the following:
6. When transverse reinforcement consists of
rectangular hoops and cross ties, the total
cross-sectional area of lateral transverse reinforcement
in the ductile region with spacings,
and perpendicular to dimension, hc, shall conform
to:
The hoops and cross ties shall be equivalent to
deformed bars not less than No. 3 in size. Rectangular
hoop ends shall terminate at a corner with seismic
hooks.
Outside of the length of the pile requiring transverse
confinement reinforcing, the spiral or hoop
reinforcing with a volumetric ratio not less than
one-half of that required for transverse confinement
reinforcing shall be provided.

Allowable stresses. The allowable design
compressive stress, fc, in concrete shall be determined as
follows:

Installation. A prestressed pile shall not be
driven before the concrete has attained a compressive
strength of at least 75 percent of the 28-day specified
compressive strength (f c), but not less than the strength
sufficient to withstand handling and driving forces.

Concrete cover. Prestressing steel and pile
reinforcement shall have a concrete cover of not less than
11/4 inches (32 mm) for square piles of 12 inches (305
mm) or smaller size and 11/2 inches (38 mm) for larger
piles, except that for piles exposed to seawater, the minimum
protective concrete cover shall not be less than 21/2
inches (64 mm).
2006 INTERNATIONAL BUILDING CODE 365
SOILS AND FOUNDATIONS

International Building Code 1809.2.3.1

Materials. Prestressing steel shall conform
to ASTM A 416. Concrete shall have a 28-day specified
compressive strength (f c) of not less than 5,000 psi
(34.48 MPa).

International Building Code 1809.2.3.2

Design. Precast prestressed piles shall be
designed to resist stresses induced by handling and driving
as well as by loads. The effective prestress in the pile
shall not be less than 400 psi (2.76MPa) for piles up to 30
feet (9144 mm) in length, 550 psi (3.79 MPa) for piles up
to 50 feet (15 240 mm) in length and 700 psi (4.83 MPa)
for piles greater than 50 feet (15 240 mm) in length.
Effective prestress shall be based on an assumed loss
of 30,000 psi (207 MPa) in the prestressing steel. The
tensile stress in the prestressing steel shall not exceed the
values specified in ACI 318.

Design in Seismic Design Category C.
Where a structure is assigned to Seismic Design Category
C in accordance with Section 1613, the following
shall apply. The minimum volumetric ratio of
spiral reinforcement shall not be less than 0.007 or the
amount required by the following formula for the
upper 20 feet (6096 mm) of the pile.
At least one-half the volumetric ratio required by
Equation 18-4 shall be provided below the upper 20
feet (6096 mm) of the pile.
The pile cap connection by means of dowels as
indicated in Section 1808.2.23.1 is permitted. Pile cap
connection by means of developing pile reinforcing
strand is permitted provided that the pile reinforcing
strand results in a ductile connection.

Design in Seismic Design Category D,
E or F. Where a structure is assigned to Seismic
Design Category D, E or F in accordance with Section
1613, the requirements for Seismic Design Category
C in Section 1809.2.3.2.1 shall be met, in addition to
the following:
1. Requirements in ACI 318, Chapter 21, need not
apply, unless specifically referenced.
2. Where the total pile length in the soil is 35 feet
(10 668 mm) or less, the lateral transverse reinforcement
in the ductile region shall occur
through the length of the pile. Where the pile
364 2006 INTERNATIONAL BUILDING CODE
SOILS AND FOUNDATIONS
length exceeds 35 feet (10 668 mm), the ductile
pile region shall be taken as the greater of 35
feet (10 668 mm) or the distance from the
underside of the pile cap to the point of zero curvature
plus three times the least pile dimension.
3. In the ductile region, the center-to-center spacing
of the spirals or hoop reinforcement shall
not exceed one-fifth of the least pile dimension,
six times the diameter of the longtitudinal
strand, or 8 inches (203 mm), whichever is
smaller.
4. Circular spiral reinforcement shall be spliced
by lapping one full turn and bending the end of
the spiral to a 90-degree hook or by use of a
mechanical or welded splice complying with
Sec. 12.14.3 of ACI 318.
5. Where the transverse reinforcement consists of
circular spirals, the volumetric ratio of spiral
transverse reinforcement in the ductile region
shall comply with the following:
6. When transverse reinforcement consists of
rectangular hoops and cross ties, the total
cross-sectional area of lateral transverse reinforcement
in the ductile region with spacings,
and perpendicular to dimension, hc, shall conform
to:
The hoops and cross ties shall be equivalent to
deformed bars not less than No. 3 in size. Rectangular
hoop ends shall terminate at a corner with seismic
hooks.
Outside of the length of the pile requiring transverse
confinement reinforcing, the spiral or hoop
reinforcing with a volumetric ratio not less than
one-half of that required for transverse confinement
reinforcing shall be provided.

International Building Code 1809.2.3.2.1

Design in Seismic Design Category C.
Where a structure is assigned to Seismic Design Category
C in accordance with Section 1613, the following
shall apply. The minimum volumetric ratio of
spiral reinforcement shall not be less than 0.007 or the
amount required by the following formula for the
upper 20 feet (6096 mm) of the pile.
At least one-half the volumetric ratio required by
Equation 18-4 shall be provided below the upper 20
feet (6096 mm) of the pile.
The pile cap connection by means of dowels as
indicated in Section 1808.2.23.1 is permitted. Pile cap
connection by means of developing pile reinforcing
strand is permitted provided that the pile reinforcing
strand results in a ductile connection.

International Building Code 1809.2.3.2.2

Design in Seismic Design Category D,
E or F. Where a structure is assigned to Seismic
Design Category D, E or F in accordance with Section
1613, the requirements for Seismic Design Category
C in Section 1809.2.3.2.1 shall be met, in addition to
the following:
1. Requirements in ACI 318, Chapter 21, need not
apply, unless specifically referenced.
2. Where the total pile length in the soil is 35 feet
(10 668 mm) or less, the lateral transverse reinforcement
in the ductile region shall occur
through the length of the pile. Where the pile
364 2006 INTERNATIONAL BUILDING CODE
SOILS AND FOUNDATIONS
length exceeds 35 feet (10 668 mm), the ductile
pile region shall be taken as the greater of 35
feet (10 668 mm) or the distance from the
underside of the pile cap to the point of zero curvature
plus three times the least pile dimension.
3. In the ductile region, the center-to-center spacing
of the spirals or hoop reinforcement shall
not exceed one-fifth of the least pile dimension,
six times the diameter of the longtitudinal
strand, or 8 inches (203 mm), whichever is
smaller.
4. Circular spiral reinforcement shall be spliced
by lapping one full turn and bending the end of
the spiral to a 90-degree hook or by use of a
mechanical or welded splice complying with
Sec. 12.14.3 of ACI 318.
5. Where the transverse reinforcement consists of
circular spirals, the volumetric ratio of spiral
transverse reinforcement in the ductile region
shall comply with the following:
6. When transverse reinforcement consists of
rectangular hoops and cross ties, the total
cross-sectional area of lateral transverse reinforcement
in the ductile region with spacings,
and perpendicular to dimension, hc, shall conform
to:
The hoops and cross ties shall be equivalent to
deformed bars not less than No. 3 in size. Rectangular
hoop ends shall terminate at a corner with seismic
hooks.
Outside of the length of the pile requiring transverse
confinement reinforcing, the spiral or hoop
reinforcing with a volumetric ratio not less than
one-half of that required for transverse confinement
reinforcing shall be provided.

International Building Code 1809.2.3.3

Allowable stresses. The allowable design
compressive stress, fc, in concrete shall be determined as
follows:

International Building Code 1809.2.3.4

Installation. A prestressed pile shall not be
driven before the concrete has attained a compressive
strength of at least 75 percent of the 28-day specified
compressive strength (f c), but not less than the strength
sufficient to withstand handling and driving forces.

International Building Code 1809.2.3.5

Concrete cover. Prestressing steel and pile
reinforcement shall have a concrete cover of not less than
11/4 inches (32 mm) for square piles of 12 inches (305
mm) or smaller size and 11/2 inches (38 mm) for larger
piles, except that for piles exposed to seawater, the minimum
protective concrete cover shall not be less than 21/2
inches (64 mm).
2006 INTERNATIONAL BUILDING CODE 365
SOILS AND FOUNDATIONS

International Building Code 1809.3

Structural steel piles. Structural steel piles shall conform
to the requirements of Sections 1809.3.1 through
1809.3.4.

Materials. Structural steel piles, steel pipe and
fully welded steel piles fabricated from plates shall conform
toASTMA36, ASTMA252, ASTMA283, ASTMA572,
ASTM A 588, ASTM A 690, ASTM A 913 or ASTM A
992.

Allowable stresses. The allowable axial stresses
shall not exceed 35 percent of the minimum specified yield
strength (Fy).
Exception: Where justified in accordance with Section
1808.2.10, the allowable axial stress is permitted to be
increased above 0.35Fy, but shall not exceed 0.5Fy.

Dimensions of H-piles. Sections of H-piles shall
comply with the following:
1. The flange projections shall not exceed 14 times the
minimum thickness of metal in either the flange or the
web and the flange widths shall not be less than 80
percent of the depth of the section.
2. The nominal depth in the direction of the web shall
not be less than 8 inches (203 mm).
3. Flanges and web shall have a minimum nominal
thickness of 3/8 inch (9.5 mm).

Dimensions of steel pipe piles. Steel pipe piles
driven open ended shall have a nominal outside diameter of
not less than 8 inches (203 mm). The pipe shall have a minimum
cross section of 0.34 square inch (219 mm2) to resist
each 1,000 foot-pounds (1356 N-m) of pile hammer energy,
or shall have the equivalent strength for steels having a yield
strength greater than 35,000 psi (241 Mpa) or the wave
equation analysis shall be permitted to be used to assess
compression stresses induced by driving to evaluate if the
pile section is appropriate for the selected hammer. Where
pipe wall thickness less than 0.179 inch (4.6 mm) is driven
open ended, a suitable cutting shoe shall be provided.

International Building Code 1809.3.1

Materials. Structural steel piles, steel pipe and
fully welded steel piles fabricated from plates shall conform
toASTMA36, ASTMA252, ASTMA283, ASTMA572,
ASTM A 588, ASTM A 690, ASTM A 913 or ASTM A
992.

International Building Code 1809.3.2

Allowable stresses. The allowable axial stresses
shall not exceed 35 percent of the minimum specified yield
strength (Fy).
Exception: Where justified in accordance with Section
1808.2.10, the allowable axial stress is permitted to be
increased above 0.35Fy, but shall not exceed 0.5Fy.

International Building Code 1809.3.3

Dimensions of H-piles. Sections of H-piles shall
comply with the following:
1. The flange projections shall not exceed 14 times the
minimum thickness of metal in either the flange or the
web and the flange widths shall not be less than 80
percent of the depth of the section.
2. The nominal depth in the direction of the web shall
not be less than 8 inches (203 mm).
3. Flanges and web shall have a minimum nominal
thickness of 3/8 inch (9.5 mm).

International Building Code 1809.3.4

Dimensions of steel pipe piles. Steel pipe piles
driven open ended shall have a nominal outside diameter of
not less than 8 inches (203 mm). The pipe shall have a minimum
cross section of 0.34 square inch (219 mm2) to resist
each 1,000 foot-pounds (1356 N-m) of pile hammer energy,
or shall have the equivalent strength for steels having a yield
strength greater than 35,000 psi (241 Mpa) or the wave
equation analysis shall be permitted to be used to assess
compression stresses induced by driving to evaluate if the
pile section is appropriate for the selected hammer. Where
pipe wall thickness less than 0.179 inch (4.6 mm) is driven
open ended, a suitable cutting shoe shall be provided.