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
Universal Citation: 780 CMR MA Code of Regs 1807.1
Current through Register 1531, September 27, 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,
db, [ d =
t - (1.25 + db / 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.
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