Code of Massachusetts Regulations › 780 CMR - STATE BOARD OF BUILDING REGULATIONS AND STANDARDS › Chapter 21 - Masonry › Section 2102 - DEFINITIONS AND NOTATIONS › Subsection 2102.1 - General

Current through Register 1525, July 5, 2024
The following words and terms shall, for the purposes of
				  this chapter and as used elsewhere in this code, have the meanings shown
				  herein.
AAC MASONRY.
Masonry made of autoclaved aerated
				  concrete (AAC) units, manufactured without internal reinforcement and bonded
				  together using thin- or thick-bed mortar.
ADOBE CONSTRUCTION.
Construction in which the
				  exterior
load-bearing
and nonload-bearing walls and partitions
				  are of unfired clay masonry units, and floors, roofs and interior framing are
				  wholly or partly of wood or other
approved
materials.
Adobe, stabilized.
Unfired clay masonry units to
				  which admixtures, such as emulsified asphalt, are added during the
				  manufacturing process to limit the units' water absorption so as to increase
				  their durability.
Adobe, unstabilized.
Unfired clay masonry units
				  that do not meet the definition of "Adobe, stabilized."
ANCHOR.
Metal rod, wire or strap that secures
				  masonry to its structural support.
ARCHITECTURAL TERRA COTTA.
Plain or ornamental
				  hard-burned modified clay units, larger in size than brick, with glazed or
				  unglazed ceramic finish.
AREA.
Bedded.
The area of the surface of a masonry
				  unit that is in contact with mortar in the plane of the joint.
Gross cross-sectional.
The area delineated by
				  the out- to-out specified dimensions of masonry in the plane under
				  consideration.
Net cross-sectional.
The area of masonry units,
				  grout and mortar crossed by the plane under consideration based on out-to-out
				  specified dimensions.
AUTOCLAVED AERATED CONCRETE (AAC).
Low- density
				  cementitious product of calcium silicate hydrates, whose material
				  specifications are defined in ASTM C 1386.
BED JOINT.
The horizontal layer of mortar on
				  which a masonry unit is laid.
BOND BEAM.
A horizontal grouted element within
				  masonry in which reinforcement is embedded.
BRICK.
Calcium silicate (sand lime brick).
A masonry
				  unit made of sand and lime.
Clay or shale.
A masonry unit made of clay or
				  shale, usually formed into a rectangular prism while in the plastic state and
				  burned or fired in a kiln.
Concrete.
A masonry unit having the approximate
				  shape of a rectangular prism and composed of inert aggregate particles embedded
				  in a hardened cementitious matrix.
CAST STONE.
A building stone manufactured from
				  portland cement concrete precast and used as a
trim
, veneer or
				  facing on or in buildings or structures.
CELL.
A void space having a gross
				  cross-sectional area greater than
				  11/2 square inches (967
				  mm2).
CHIMNEY.
A primarily vertical enclosure
				  containing one or more passageways for conveying flue gases to the outside
				  atmosphere.
CHIMNEY TYPES.
High-heat appliance type.
An
approved
chimney for removing the products of combustion from
				  fuel-burning, high-heat appliances producing combustion gases in excess of
				  2,000°F (1093°C) measured at the appliance flue outlet (see Section
				  2113.11.3).
Low-heat appliance type.
An
approved
chimney for removing the products of combustion from
				  fuel-burning, low-heat appliances producing combustion gases not in excess of
				  1,000°F (538°C) under normal operating conditions, but capable of
				  producing combustion gases of 1,400°F (760°C) during intermittent
				  forces firing for periods up to 1 hour. Temperatures shall be measured at the
				  appliance flue outlet.
Masonry type.
A field-constructed chimney of
				  solid masonry units or stones.
Medium-heat appliance type.
An
approved
chimney for removing the products of combustion from
				  fuel-burning, medium-heat appliances producing combustion gases not exceeding
				  2,000°F (1093°C) measured at the appliance flue outlet (see Section
				  2113.11.2).
CLEANOUT.
An opening to the bottom of a grout
				  space of sufficient size and spacing to allow the removal of debris.
COLLAR JOINT.
Vertical longitudinal joint
				  between wythes of masonry or between masonry and backup construction that is
				  permitted to be filled with mortar or grout.
COMPRESSIVE STRENGTH OF MASONRY.
Maximum
				  compressive force resisted per unit of net cross-sectional area of masonry,
				  determined by the testing of masonry prisms or a function of individual masonry
				  units, mortar and grout.
CONNECTOR.
A mechanical device for securing two
				  or more pieces, parts or members together, including anchors, wall ties and
				  fasteners.
COVER.
Distance between surface of reinforcing
				  bar and edge of member.
DIMENSIONS.
Actual.
The measured dimension of a masonry unit
				  or element.
Nominal.
The specified dimension plus an
				  allowance for the joints with which the units are to be laid. Thickness is
				  given first, followed by height and then length.
Specified.
The dimensions specified for the
				  manufacture or construction of masonry, masonry units, joints or any other
				  component of a structure.
FIREPLACE.
A hearth and fire chamber or similar
				  prepared place in which a fire may be made and which is built in conjunction
				  with a chimney.
FIREPLACE THROAT.
The opening between the top of
				  the firebox and the smoke chamber.
FOUNDATION PIER.
An isolated vertical foundation
				  member whose horizontal dimension measured at right angles to its thickness
				  does not exceed three times its thickness and whose height is equal to or less
				  than four times its thickness.
GROUTED MASONRY.
Grouted hollow-unit masonry.
That form of
				  grouted masonry construction in which certain designated cells of hollow units
				  are continuously filled with grout.
Grouted multiwythe masonry.
That form of grouted
				  masonry construction in which the space between the wythes is solidly or
				  periodically filled with grout.
HEAD JOINT.
Vertical mortar joint placed between
				  masonry units within the wythe at the time the masonry units are laid.
HEIGHT, WALLS.
The vertical distance from the
				  foundation wall or other immediate support of such wall to the top of the
				  wall.
MASONRY.
A built-up construction or combination
				  of building units or materials of clay, shale, concrete, glass, gypsum, stone
				  or other
approved
units bonded together with or without mortar
				  or grout or other accepted methods of joining.
Ashlar masonry.
Masonry composed of
				  various-sized rectangular units having sawed, dressed or squared bed surfaces,
				  properly bonded and laid in mortar.
Coursed ashlar.
Ashlar masonry laid in courses
				  of stone of equal height for each course, although different courses shall be
				  permitted to be of varying height.
Glass unit masonry.
Masonry composed of glass
				  units bonded by mortar.
Plain masonry.
Masonry in which the tensile
				  resistance of the masonry is taken into consideration and the effects of
				  stresses in reinforcement are neglected.
Random ashlar.
Ashlar masonry laid in courses of
				  stone set without continuous joints and laid up without drawn patterns. When
				  composed of material cut into modular heights, discontinuous but aligned
				  horizontal joints are discernible.
Reinforced masonry.
Masonry construction in
				  which reinforcement acting in conjunction with the masonry is used to resist
				  forces.
Solid masonry.
Masonry consisting of solid
				  masonry units laid contiguously with the joints between the units filled with
				  mortar.
Unreinforced (plain) masonry.
Masonry in which
				  the tensile resistance of masonry is taken into consideration and the
				  resistance of the reinforcing steel, if present, is neglected.
MASONRY UNIT.
Brick, tile, stone, glass block or
				  concrete block conforming to the requirements specified in Section 2103.
Clay.
A building unit larger in size than a
				  brick, composed of burned clay, shale, fired clay or mixtures thereof.
Concrete.
A building unit or block larger in
				  size than 12 inches by 4 inches by 4 inches (305 mm by 102 mm by 102 mm) made
				  of cement and suitable aggregates.
Hollow.
A masonry unit whose net cross-sectional
				  area in any plane parallel to the load-bearing surface is less than 75 percent
				  of its gross cross-sectional area measured in the same plane.
Solid.
A masonry unit whose net cross-sectional
				  area in every plane parallel to the load-bearing surface is 75 percent or more
				  of its gross cross-sectional area measured in the same plane.
MORTAR.
A plastic mixture of
approved
cementitious materials, fine aggregates and water
				  used to bond masonry or other structural units.
MORTAR, SURFACE-BONDING.
A mixture to bond
				  concrete masonry units that contains hydraulic cement, glass fiber
				  reinforcement with or without inorganic fillers or organic modifiers and
				  water.
PRESTRESSED MASONRY.
Masonry in which internal
				  stresses have been introduced to counteract potential tensile stresses in
				  masonry resulting from applied loads.
PRISM.
An assemblage of masonry units and mortar
				  with or without grout used as a test specimen for determining properties of the
				  masonry.
RUBBLE MASONRY.
Masonry composed of roughly
				  shaped stones.
Coursed rubble.
Masonry composed of roughly
				  shaped stones fitting approximately on level beds and well bonded.
Random rubble.
Masonry composed of roughly
				  shaped stones laid without regularity of coursing but well bonded and fitted
				  together to form well-divided joints.
Rough or ordinary rubble.
Masonry composed of
				  unsquared field stones laid without regularity of coursing but well
				  bonded.
RUNNING BOND.
The placement of masonry units
				  such that head joints in successive courses are horizontally offset at least
				  one-quarter the unit length.
SHEAR WALL.
Detailed plain masonry shear wall.
A masonry
				  shear wall designed to resist lateral forces neglecting stresses in
				  reinforcement, and designed in accordance with Section 2106.1.
Intermediate prestressed masonry shear wall.
A
				  prestressed masonry shear wall designed to resist lateral forces considering
				  stresses in reinforcement, and designed in accordance with Section
				  2106.1.
Intermediate reinforced masonry shear wall.
A
				  masonry shear wall designed to resist lateral forces considering stresses in
				  reinforcement, and designed in accordance with Section 2106.1.
Ordinary plain masonry shear wall.
A masonry
				  shear wall designed to resist lateral forces neglecting stresses in
				  reinforcement, and designed in accordance with Section 2106.1.
Ordinary plain prestressed masonry shear wall.
A
				  prestressed masonry shear wall designed to resist lateral forces considering
				  stresses in reinforcement, and designed in accordance with Section
				  2106.1.
Ordinary reinforced masonry shear wall.
A
				  masonry shear wall designed to resist lateral forces considering stresses in
				  reinforcement, and designed in accordance with Section 2106.1.
Special prestressed masonry shear wall.
A
				  prestressed masonry shear wall designed to resist lateral forces considering
				  stresses in reinforcement and designed in accordance with Section 2106.1 except
				  that only grouted, laterally restrained tendons are used.
Special reinforced masonry shear wall.
A masonry
				  shear wall designed to resist lateral forces considering stresses in
				  reinforcement, and designed in accordance with Section 2106.1.
SHELL.
The outer portion of a hollow masonry
				  unit as placed in masonry.
SPECIFIED.
Required by
construction
				  documents
.
SPECIFIED COMPRESSIVE STRENGTH OF MASONRY,
f
				  '
m.
Minimum compressive strength,
				  expressed as force per unit of net cross-sectional area, required of the
				  masonry used in construction by the
construction documents
,
				  and upon which the project design is based. Whenever the quantity
f
				  '
m is under the radical sign, the square root
				  of numerical value only is intended and the result has units of pounds per
				  square inch (psi) (MPa).
STACK BOND.
The placement of masonry units in a
				  bond pattern is such that head joints in successive courses are vertically
				  aligned. For the purpose of this code, requirements for stack bond shall apply
				  to masonry laid in other than running bond.
STONE MASONRY.
Masonry composed of field,
				  quarried or cast stone units bonded by mortar.
Ashlar stone masonry.
Stone masonry composed of
				  rectangular units having sawed, dressed or squared bed surfaces and bonded by
				  mortar.
Rubble stone masonry.
Stone masonry composed of
				  irregular-shaped units bonded by mortar.
STRENGTH.
Design strength.
Nominal strength multiplied by
				  a strength reduction factor.
Nominal strength.
Strength of a member or cross
				  section calculated in accordance with these provisions before application of
				  any strength-reduction factors.
Required strength.
Strength of a member or cross
				  section required to resist factored loads.
THIN-BED MORTAR.
Mortar for use in construction
				  of AAC unit masonry with joints 0.06 inch (1.5 mm) or less.
TIE, LATERAL.
Loop of reinforcing bar or wire
				  enclosing longitudinal reinforcement.
TIE, WALL.
A connector that connects wythes of
				  masonry walls together.
TILE.
A ceramic surface unit, usually relatively
				  thin in relation to facial area, made from clay or a mixture of clay or other
				  ceramic materials, called the body of the tile, having either a "glazed" or
				  "unglazed" face and fired above red heat in the course of manufacture to a
				  temperature sufficiently high enough to produce specific physical properties
				  and characteristics.
TILE, STRUCTURAL CLAY.
A hollow masonry unit
				  composed of burned clay, shale, fire clay or mixture thereof, and having
				  parallel cells.
WALL.
A vertical element with a horizontal
				  length-to-thickness ratio greater than three, used to enclose space.
Cavity wall.
A wall built of masonry units or of
				  concrete, or a combination of these materials, arranged to provide an airspace
				  within the wall, and in which the inner and outer parts of the wall are tied
				  together with metal ties.
Composite wall.
A wall built of a combination of
				  two or more masonry units bonded together, one forming the backup and the other
				  forming the facing elements.
Dry-stacked, surface-bonded wall.
A wall built
				  of concrete masonry units where the units are stacked dry, without mortar on
				  the bed or head joints, and where both sides of the wall are coated with a
				  surface-bonding mortar.
Masonry-bonded hollow wall.
A wall built of
				  masonry units so arranged as to provide an airspace within the wall, and in
				  which the facing and backing of the wall are bonded together with masonry
				  units.
Parapet wall.
The part of any wall entirely
				  above the roof line.
WEB.
An interior solid portion of a hollow
				  masonry unit as placed in masonry.
WYTHE.
Each continuous, vertical section of a
				  wall, one masonry unit in thickness.
NOTATIONS.
d
b = Diameter of
				  reinforcement, inches (mm).
F
s = Allowable
				  tensile or compressive stress in reinforcement, psi (MPa).
f
r = Modulus of
				  rupture, psi (MPa).
f'
AAC = Specified
				  compressive strength of AAC masonry, the minimum compressive strength for a
				  class of AAC masonry as specified in ASTM C 1386, psi (MPa).
f'
m = Specified
				  compressive strength of masonry at age of 28 days, psi (MPa).
f'
mi = Specified
				  compressive strength of masonry at the time of prestress transfer, psi
				  (MPa).
K
= The lesser of the masonry cover, clear
				  spacing between adjacent reinforcement, or five times
d
b, inches (mm).
L
s = Distance between
				  supports, inches (mm).
l
d= Required
				  development length or lap length of reinforcement, inches (mm).
P
= The applied load at failure, pounds
				  (N).
S
t = Thickness of the
				  test specimen measured parallel to the direction of load, inches (mm).
S
w = Width of the
				  test specimen measured parallel to the loading cylinder, inches
				  (mm).