Code of Massachusetts Regulations › 780 CMR - STATE BOARD OF BUILDING REGULATIONS AND STANDARDS › Chapter 18 - Soils and Foundations › Section 1807 - FOUNDATION WALLS, RETAINING WALLS AND EMBEDDED POSTS AND POLES › Subsection 1807.1 - Foundation walls

Current through Register 1525, July 5, 2024
Foundation walls shall be designed and constructed in
				  accordance with Sections 1807.1.1 through 1807.1.6. Foundation walls shall be
				  supported by foundations designed in accordance with Section 1808.
1807.1.1
Design lateral soil loads.
Foundation walls shall be designed for the lateral soil loads set forth
				in Section 1610.
1807.1.2
Unbalanced backfill height.
Unbalanced backfill height is the difference
				in height between the exterior finish ground level and the lower of the top of
				the concrete footing that supports the foundation wall or the interior finish
				ground level. Where an interior concrete slab on grade is provided and is in
				contact with the interior surface of the foundation wall, the unbalanced
				backfill height shall be permitted to be measured from the exterior finish
				ground level to the top of the interior concrete slab.
1807.1.3
Rubble stone foundation
				walls.
Foundation walls of rough or random rubble stone shall not be
				less than 16 inches (406 mm) thick. Rubble stone shall not be used for
				foundation walls of structures assigned to
Seismic Design
				Category
C, D, E or F.
1807.1.4
Permanent wood foundation
				systems.
Permanent wood foundation systems shall be designed and
				installed in accordance with AF & PA PWF. Lumber and plywood shall be
				treated in accordance with AWPA U1 (Commodity Specification A, Use Category 4B
				and Section 5.2) and shall be identified in accordance with Section
				2303.1.8.1.
1807.1.5
Concrete and masonry foundation walls.
Concrete and masonry foundation
				walls shall be designed in accordance with Chapter 19 or 21, as applicable.
Exception:
Concrete and masonry foundation walls
				  shall be permitted to be designed and constructed in accordance with Section
				  1807.1.6.
1807.1.6
Prescriptive design of concrete and masonry foundation walls.
Concrete
				and masonry foundation walls that are laterally supported at the top and bottom
				shall be permitted to be designed and constructed in accordance with this
				section.
1807.1.6.1
Foundation wall
				thickness.
The thickness of prescriptively designed foundation walls
				shall not be less than the thickness of the wall supported, except that
				foundation walls of at least 8-inch (203 mm) nominal width shall be permitted
				to support brick-veneered frame walls and 10-inch-wide (254 mm) cavity walls
				provided the requirements of Section 1807.1.6.2 or 1807.1.6.3 are
				met.
1807.1.6.2
Concrete
				foundation walls.
Concrete foundation walls shall comply with the
				following:
1. The thickness shall comply with
				the requirements of Table 1807.1.6.2.
2. The size and spacing of vertical
				reinforcement shown in Table 1807.1.6.2 is based on the use of reinforcement
				with a minimum yield strength of 60,000 pounds per square inch (psi) (414 MPa).
				Vertical reinforcement with a minimum yield strength of 40,000 psi (276 MPa) or
				50,000 psi (345 MPa) shall be permitted, provided the same size bar is used and
				the spacing shown in the table is reduced by multiplying the spacing by 0.67 or
				0.83, respectively.
3. Vertical
				reinforcement, when required, shall be placed nearest the inside face of the
				wall a distance,
d
, from the outside face (soil face) of the
				wall. The distance,
d
, is equal to the wall thickness,
t
, minus 1.25 inches (32 mm) plus one-half the bar diameter,
d
b, [
d
=
t
- (1.25 +
d
b / 2) ].
				The reinforcement shall be placed within a tolerance of ±
											3/8 inch (9.5 mm) where
d
is less than or equal to 8 inches (203 mm) or ±
											1/2 inch (12.7 mm) where
d
is greater than 8 inches (203 mm).
4. In lieu of the reinforcement shown in
				Table 1807.1.6.2, smaller reinforcing bar sizes with closer spacings that
				provide an equivalent cross-sectional area of reinforcement per unit length
				shall be permitted.
5. Concrete
				cover for reinforcement measured from the inside face of the wall shall not be
				less than 3/4 inch (19.1 mm).
				Concrete cover for reinforcement measured from the outside face of the wall
				shall not be less than 11/2
				inches (38 mm) for No. 5 bars and smaller, and not less than 2 inches (51 mm)
				for larger bars.
6. Concrete shall
				have a specified compressive strength,
f
c, of not less than 2,500 psi (17.2
				MPa).
7. The unfactored axial load
				per linear foot of wall shall not exceed 1.2
t f
c where
t
is the specified
				wall thickness in inches.
TABLE 1807.1.6.2 CONCRETE FOUNDATION
				  WALLSb, c
MAXIMUM WALL HEIGHT
							 (feet)
MAXIMUM UNBALANCED BACKFILL
							 HEIGHTe (feet)
MINIMUM VERTICAL REINFORCEMENT-BAR
							 SIZE AND SPACING (inches)
Design lateral soil
							 loada(psf per foot of depth)
30d
45d
60
Minimum wall thickness
							 (inches)
7.5
9.5
11.5
7.5
9.5
11.5
7.5
9.5
11.5
5
4
5
PC
PC
PC
PC
PC
PC
PC
PC
PC
PC
PC
PC
PC
PC
PC
PC
PC
PC
6
4
5
6
PC
PC
PC
PC
PC
PC
PC
PC
PC
PC
PC
PC
PC
PC
PC
PC
PC
PC
PC
PC
PC
PC
PC
PC
PC
PC
PC
7
4
5
6
7
PC
PC
PC
PC
PC
PC
PC
PC
PC
PC
PC
PC
PC
PC
PC
#5 at
							 46
PC
PC
PC
PC
PC
PC
PC
PC
PC
PC
#5 at 48
#6
							 at 48
PC
PC
PC
PC
PC
PC
PC
PC
8
4
5
6
7
8
PC
PC
PC
PC
#5 at 47
PC
PC
PC
PC
PC
PC
PC
PC
PC
PC
PC
PC
PC
#5 at
							 41
#6 at 43
PC
PC
PC
PC
PC
PC
PC
PC
PC
PC
PC
PC
#5 at 43
#6
							 at 43
#6 at 32
PC
PC
PC
PC
#6 at 44
PC
PC
PC
PC
PC
9
4
5
6
7
8
9d
PC
PC
PC
PC
#5 at 41
#6 at 46
PC
PC
PC
PC
PC
PC
PC
PC
PC
PC
PC
PC
PC
PC
PC
#5 at
							 37
#6 at 38
#7 at 41
PC
PC
PC
PC
#5 at 37
#6 at 41
PC
PC
PC
PC
PC
PC
PC
PC
#5 at 39
#6
							 at 38
#7 at 39
#7 at 31
PC
PC
PC
#5 at
							 37
#6 at 39
#7 at 41
PC
PC
PC
PC
#4 at 48
#6 at 39
10
4
5
6
7
8
9d
10d
PC
PC
PC
PC
#5 at 38
#6 at 41
#7 at 45
PC
PC
PC
PC
PC
#4 at 48
#6 at 45
PC
PC
PC
PC
PC
PC
PC
PC
PC
PC
#6 at
							 48
#7 at 47
#7 at 37
#7 at 31
PC
PC
PC
PC
#6 at 47
#7 at 48
#7 at 40
PC
PC
PC
PC
PC
#4 at 48
#6 at 38
PC
PC
#5 at 37
#6
							 at 35
#7 at 35
#6 at 22
#6 at 22
PC
PC
PC
#6 at
							 48
#7 at 47
#7 at 37
#7 at 30
PC
PC
PC
PC
#6 at 45
#7 at 47
#7 at 38
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound
							 per square foot per foot = 0.157 kPa/m.
a. For design lateral soil
							 loads, see Section 1610.
b. Provisions for this table are based on
							 design and construction requirements specified in Section 1807.1.6.2.
c. "PC" means plain concrete.
d. Where unbalanced
							 backfill height exceeds 8 feet and design lateral soil loads from Table 1610.1
							 are used, the requirements for 30 and 45 psf per foot of depth are not
							 applicable (see Section 1610).
e. For height of unbalanced
							 backfill, see Section 1807.1.2.
1807.1.6.2.1
Seismic requirements.
Based on the
seismic design category
assigned to the
				structure in accordance with Section 1613, concrete foundation walls designed
				using Table 1807.1.6.2 shall be subject to the following limitations:
1.
Seismic Design Categories
A and B. No additional seismic requirements, except provide reinforcement
				around openings in accordance with Section 1909.6.3.
2.
Seismic Design Categories
C, D, E and F. Tables shall not be used except as allowed for plain concrete
				members in Section 1908.1.8.
1807.1.6.3
Masonry foundation
				walls.
Masonry foundation walls shall comply with the following:
1. The thickness shall comply with the
				requirements of Table 1807.1.6.3(1) for plain masonry walls or Table
				1807.1.6.3(2), 1807.1.6.3(3) or 1807.1.6.3(4) for masonry walls with
				reinforcement.
2. Vertical
				reinforcement shall have a minimum yield strength of 60,000 psi (414
				MPa).
3. The specified location of
				the reinforcement shall equal or exceed the effective depth distance,
d
, noted in Tables 1807.1.6.3(2), 1807.1.6.3(3) and
				1807.1.6.3(4) and shall be measured from the face of the exterior (soil) side
				of the wall to the center of the vertical reinforcement. The reinforcement
				shall be placed within the tolerances specified in TMS 602/ACI 530.1/ASCE 6,
				Article 3.4.B.8 of the specified location.
4. Grout shall comply with Section
				2103.12.
5. Concrete masonry units
				shall comply with ASTM C 90.
6.
				Clay masonry units shall comply with ASTM C 652 for hollow brick, except
				compliance with ASTM C 62 or ASTM C 216 shall be permitted where solid masonry
				units are installed in accordance with Table 1807.1.6.3(1) for plain
				masonry.
7. Masonry units shall be
				laid in running bond and installed with Type M or S mortar in accordance with
				Section 2103.8.
8. The unfactored
				axial load per linear foot of wall shall not exceed 1.2
t f
				m
where
t
is the specified
				wall thickness in inches and
f m
is the
				specified compressive strength of masonry in pounds per square inch.
9. At least 4 inches (102 mm) of solid
				masonry shall be provided at girder supports at the top of hollow masonry unit
				foundation walls.
10. Corbeling of
				masonry shall be in accordance with Section 2104.2. Where an 8-inch (203 mm)
				wall is corbeled, the top corbel shall not extend higher than the bottom of the
				floor framing and shall be a full course of headers at least 6 inches (152 mm)
				in length or the top course bed joint shall be tied to the vertical wall
				projection. The tie shall be W2.8 (4.8 mm) and spaced at a maximum horizontal
				distance of 36 inches (914 mm). The hollow space behind the corbelled masonry
				shall be filled with mortar or grout.
TABLE 1807.1.6.3(1) PLAIN MASONRY FOUNDATION
				  WALLSa, b, c
MAXIMUM WALL HEIGHT
							 (feet)
MAXIMUM UNBALANCED BACKFILL
							 HEIGHTe (feet)
MINIMUM NOMINAL WALL THICKNESS
							 (inches)
Design lateral soil
							 loada (psf per foot of depth)
30f
45f
60
7
4 (or less)
5
6
7
8
8
10
12
8
10
12
10
							 (solidc)
8
10
10
							 (solidc)
10
							 (solidc)
8
4 (or less)
5
6
7
8
8
8
10
12
10 (solidc)
8
10
12
12
							 (solidc)
12
							 (solidc)
8
12
12
							 (solidc)
Note d
Note d
9
4 (or less)
5
6
7
8
9f
8
8
12
12
							 (solidc)
12
							 (solidc)
Note d
8
10
12
12
							 (solidc)
Note d
Note d
8
12
12
							 (solidc)
Note d
Note
							 d
Note d
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound
							 per square foot per foot = 0.157 kPa/m.
a. For design lateral soil
							 loads, see Section 1610.
b. Provisions for this table are based on
							 design and construction requirements specified in Section 1807.1.6.3.
c. Solid grouted hollow units or solid masonry units.
d. A design in compliance with Chapter 21 or reinforcement in accordance with
							 Table 1807.1.6.3(2) is required.
e. For height of unbalanced
							 backfill, see Section 1807.1.2.
f. Where unbalanced backfill
							 height exceeds 8 feet and design lateral soil loads from Table 1610.1 are used,
							 the requirements for 30 and 45 psf per foot of depth are not applicable (see
							 Section 1610).
TABLE 1807.1.6.3(2) 8-INCH MASONRY FOUNDATION WALLS
				  WITH REINFORCEMENT WHERE d >= 5 INCHESa, b,
				  c
MAXIMUM WALL HEIGHT
							 (feet)
MAXIMUM UNBALANCED BACKFILL
							 HEIGHTe (feet)
MINIMUM VERTICAL REINFORCEMENT-BAR
							 SIZE AND SPACING (inches)
Design lateral soil
							 loada (psf per foot of depth)
30e
45e
60
7-4
4-0 (or less)
5-0
6-0
7-4
#4 at 48
#4 at 48
#4 at
							 48
#5 at 48
#4 at 48
#4 at 48
#5 at
							 48
#6 at 48
#4 at 48
#4 at 48
#5 at
							 48
#7 at 48
8-0
4-0 (or less)
5-0
6-0
7-0
8-0
#4 at 48
#4 at 48
#4 at
							 48
#5 at 48
#5 at 48
#4 at 48
#4 at 48
#5 at
							 48
#6 at 48
#6 at 48
#4 at 48
#4 at 48
#5 at
							 48
#7 at 48
#7 at 48
8-8
4-0 (or less)
5-0
6-0
7-0
8-8e
#4 at 48
#4 at 48
#4 at
							 48
#5 at 48
#6 at 48
#4 at 48
#4 at 48
#5 at
							 48
#6 at 48
#7 at 48
#4 at 48
#5 at 48
#6 at
							 48
#7 at 48
#8 at 48
9-4
4-0 (or less)
5-0
6-0
7-0
8-0
9-4e
#4 at 48
#4 at 48
#4 at
							 48
#5 at 48
#6 at 48
#7 at 48
#4 at 48
#4 at 48
#5 at
							 48
#6 at 48
#7 at 48
#8 at 48
#4 at 48
#5 at 48
#6 at
							 48
#7 at 48
#8 at 48
#9 at 48
10-0
4-0 (or less)
5-0
6-0
7-0
8-0
9-0e
10-0e
#4 at 48
#4 at 48
#4 at
							 48
#5 at 48
#6 at 48
#7 at 48
#7 at 48
#4 at 48
#4 at 48
#5 at
							 48
#6 at 48
#7 at 48
#8 at 48
#9 at 48
#4 at 48
#5 at 48
#6 at
							 48
#7 at 48
#8 at 48
#9 at 48
#9 at 48
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound
							 per square foot per foot = 0.157 kPa/m.
a. For design lateral soil
							 loads, see Section 1610.
b. Provisions for this table are based on
							 design and construction requirements specified in Section 1807.1.6.3.
c. For alternative reinforcement, see Section 1807.1.6.3.1.
d. For height of unbalanced backfill, see Section 1807.1.2.
e. Where unbalanced backfill height exceeds 8 feet and design
							 lateral soil loads from Table 1610.1 are used, the requirements for 30 and 45
							 psf per foot of depth are not applicable. See Section 1610.
TABLE 1807.1.6.3(3)
10-INCH MASONRY
				  FOUNDATION WALLS WITH REINFORCEMENT WHERE d >= 6.75 INCHES
				  a,b,c
MAXIMUM WALL HEIGHT
(feet-inches)
MAXIMUM UNBALANCED
BACKFILL HEIGHTd
(feet-inches)
MINIMUM VERTICAL REINFORCEMENT-BAR
							 SIZE AND SPACING (inches)
Design lateral soil
							 loada (psf per foot of depth)
30e
45e
60
7-4
4-0 (or less)
5-0
6-0
7-4
#4 at 56
#4 at 56
#4 at
							 56
#4 at 56
#4 at 56
#4 at 56
#4 at
							 56
#5 at 56
#4 at 56
#4 at 56
#5 at
							 56
#6 at 56
8-0
4-0 (or less)
5-0
6-0
7-0
8-0
#4 at 56
#4 at 56
#4 at
							 56
#4 at 56
#5 at 56
#4 at 56
#4 at 56
#4 at
							 56
#5 at 56
#6 at 56
#4 at 56
#4 at 56
#5 at
							 56
#6 at 56
#7 at 56
8-8
4-0 (or less)
5-0
6-0
7-0
8-8e
#4 at 56
#4 at 56
#4 at
							 56
#4 at 56
#5 at 56
#4 at 56
#4 at 56
#4 at
							 56
#5 at 56
#7 at 56
#4 at 56
#4 at 56
#5 at
							 56
#6 at 56
#8 at 56
9-4
4-0 (or less)
5-0
6-0
7-0
8-0
9-4e
#4 at 56
#4 at 56
#4 at
							 56
#4 at 56
#5 at 56
#6 at 56
#4 at 56
#4 at 56
#5 at
							 56
#5 at 56
#6 at 56
#7 at 56
#4 at 56
#4 at 56
#5 at
							 56
#6 at 56
#7 at 56
#7 at 56
10-0
4-0 (or less)
5-0
6-0
7-0
8-0
9-0e
10-0e
#4 at 56
#4 at 56
#4 at
							 56
#5 at 56
#5 at 56
#6 at 56
#7 at 56
#4 at 56
#4 at 56
#5 at
							 56
#6 at 56
#7 at 56
#7 at 56
#8 at 56
#4 at 56
#4 at 56
#5 at
							 56
#7 at 56
#8 at 56
#9 at 56
#9 at 56
For SI: 1 inch = 25.4 mm, 1 foot = 304.8, 1 pound per
							 square foot per foot = 0.157 kPa/m.
a. For design lateral soil loads, see Section
							 1610.
b. Provisions for this table are based on design and
							 construction requirements specified in Section 1807.1.6.3.
c. For alternative reinforcement, see Section
							 1807.1.6.3.1.
d. For height of unbalanced backfill, See Section
							 1807.1.2.
e. Where unbalanced backfill height exceeds 8 feet and
							 design lateral soil loads from Table 1610.1 are used, the requirements for 30
							 and 45 psf per foot of depth are not applicable. See Section 1610.
TABLE 1807.1.6.3(4) 12-INCH MASONRY FOUNDATION WALLS
				  WITH REINFORCEMENT WHERE d >= 8.75 INCHESa, b,
				  c
MAXIMUM WALL HEIGHT
							 (feet-inches)
MAXIMUM UNBALANCED BACKFILL
							 HEIGHTd
(feet-inches)
MINIMUM VERTICAL REINFORCEMENT-BAR
							 SIZE AND SPACING (inches)
Design lateral soil
							 loada(psf per foot of depth)
30e
45e
60
7-4
4 (or less)
5-0
6-0
7-4
#4 at 72
#4 at 72
#4 at
							 72
#4 at 72
#4 at 72
#4 at 72
#4 at
							 72
#5 at 72
#4 at 72
#4 at 72
#5 at
							 72
#6 at 72
8-0
4 (or less)
5-0
6-0
7-0
8-0
#4 at 72
#4 at 72
#4 at
							 72
#4 at 72
#5 at 72
#4 at 72
#4 at 72
#4 at
							 72
#5 at 72
#6 at 72
#4 at 72
#4 at 72
#5 at
							 72
#6 at 72
#8 at 72
8-8
4 (or less)
5-0
6-0
7-0
8-8e
#4 at 72
#4 at 72
#4 at
							 72
#4 at 72
#5 at 72
#4 at 72
#4 at 72
#4 at
							 72
#5 at 72
#7 at 72
#4 at 72
#4 at 72
#5 at
							 72
#6 at 72
#8 at 72
9-4
4 (or less)
5-0
6-0
7-0
8-0
9-4e
#4 at 72
#4 at 72
#4 at
							 72
#4 at 72
#5 at 72
#6 at 72
#4 at 72
#4 at 72
#5 at
							 72
#5 at 72
#6 at 72
#7 at 72
#4 at 72
#4 at 72
#5 at
							 72
#6 at 72
#7 at 72
#8 at 72
10-0
4 (or less)
5-0
6-0
7-0
8-0
9-0e
10-0e
#4 at 72
#4 at 72
#4 at
							 72
#4 at 72
#5 at 72
#6 at 72
#7 at 72
#4 at 72
#4 at 72
#5 at
							 72
#6 at 72
#6 at 72
#7 at 72
#8 at 72
#4 at 72
#4 at 72
#5 at
							 72
#6 at 72
#7 at 72
#8 at 72
#9 at 72
For SI: 1 inch = 25.4 mm, 1 foot = 304.8 mm, 1 pound
							 per square foot per foot = 0.157 kPa/m.
a. For design lateral soil
							 loads, see Section 1610.
b. Provisions for this table are based on
							 design and construction requirements specified in Section 1807.1.6.3.
c. For alternative reinforcement, see Section 1807.1.6.3.1.
d. For height of unbalanced backfill, see Section 1807.1.2.
e. Where unbalanced backfill height exceeds 8 feet and design
							 lateral soil loads from Table 1610.1 are used, the requirements for 30 and 45
							 psf per foot of depth are not applicable. See Section 1610.
1807.1.6.3.1
Alternative foundation
				wall reinforcement.
In lieu of the reinforcement provisions for masonry
				foundation walls in Table 1807.1.6.3(2), 1807.1.6.3(3) or 1807.1.6.3(4),
				alternative reinforcing bar sizes and spacings having an equivalent
				cross-sectional area of reinforcement per linear foot (mm) of wall shall be
				permitted to be used, provided the spacing of reinforcement does not exceed 72
				inches (1829 mm) and reinforcing bar sizes do not exceed No. 11.
1807.1.6.3.2
Seismic requirements.
Based on the
seismic design category
assigned to the
				structure in accordance with Section 1613, masonry foundation walls designed
				using Tables 1807.1.6.3(1) through 1807.1.6.3(4) shall be subject to the
				following limitations:
1.
Seismic
				Design Categories
A and B. No additional seismic requirements.
2.
Seismic Design Category
C. A design using Tables 1807.1.6.3(1) through 1807.1.6.3(4) is
				subject to the seismic requirements of Section 1.17.4.3 of TMS 402/ACI 530/ASCE
				5.
3.
Seismic Design
				Category
D. A design using Tables 1807.1.6.3(2) through 1807.1.6.3(4)
				is subject to the seismic requirements of Section 1.17.4.4 of TMS 402/ACI
				530/ASCE 5.
4.
Seismic
				Design Categories
E and F. A design using Tables 1807.1.6.3(2) through
				1807.1.6.3(4) is subject to the seismic requirements of Section 1.17.4.5 of TMS
				402/ACI 530/ASCE 5.