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
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.
db = Diameter of reinforcement, inches (mm).
Fs = Allowable tensile or compressive stress in reinforcement, psi (MPa).
fr = 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 db, inches (mm).
Ls = Distance between supports, inches (mm).
ld= Required development length or lap length of reinforcement, inches (mm).
P = The applied load at failure, pounds (N).
St = Thickness of the test specimen measured parallel to the direction of load, inches (mm).
Sw = Width of the test specimen measured parallel to the loading cylinder, inches (mm).
