Building Design and Construction

Masonry Definitions

Following are some of the terms most commonly encountered in masonry construction:
Architectural Terra Cotta. (See Ceramic Veneer.)
Ashlar Masonry. Masonry composed of rectangular units usually larger in size than brick and properly bonded, having sawed, dressed, or squared beds. It is laid in mortar.
Bearing Walls. (See Load-Bearing Wall.)
Bonder. (See Header.)
Brick. A rectangular masonry building unit, not less than 75% solid, made from burned clay, shale, or a mixture of these materials.
Buttress. A bonded masonry column built as an integral part of a wall and decreasing in thickness from base to top, though never thinner than the wall. It is used to provide lateral stability to the wall.
Ceramic Veneer. Hard-burned, non-load-bearing, clay building units, glazed or unglazed, plain or ornamental.
Chase. A continuous recess in a wall to receive pipes, ducts, conduits.
Column. A compression member with width not exceeding 4 times the thickness, and with height more than 3 times the least lateral dimension.
Concrete Block. A machine-formed masonry building unit composed of portland cement, aggregates, and water.
Coping. A cap or finish on top of a wall, pier, chimney, or pilaster to prevent penetration of water to masonry below.
Corbel. Successive course of masonry projecting from the face of a wall to increase its thickness or to form a shelf or ledge (Fig. 11.3ƒ).

Course. A continuous horizontal layer of masonry units bonded together (Fig. 11.3).
Cross-Sectional Area. Net cross-sectional area of a masonry unit is the gross cross-sectional area minus the area of cores or cellular spaces. Gross crosssectional area of scored units is determined to the outside of the scoring, but the cross-sectional area of the grooves is not deducted to obtain the net area.
Eccentricity. The normal distance between the centroidal axis of a member and the component of resultant load parallel to that axis.
Effective Height. The height of a member to be assumed for calculating the slenderness ratio.
Effective Thickness. The thickness of a member to be assumed for calculating the slenderness ratio.
Grout. A mixture of cementitious material, fine aggregate, and sufficient water to produce pouring consistency without segregation of the constituents.
Grouted Masonry. Masonry in which the interior joints are filled by pouring grout into them as the work progresses.
Header (Bonder). A brick or other masonry unit laid flat across a wall with end surface exposed, to bond two wythes (Fig. 11.1b).
Height of Wall. Vertical distance from top of wall to foundation wall or other intermediate support.
Hollow Masonry Unit. Masonry with net cross-sectional area in any plane parallel to the bearing surface less than 75% of its gross cross-sectional area measured in the same plane.
Lateral Support. Members such as cross walls, columns, pilasters, buttresses, floors, roofs, or spandrel beams that have sufficient strength and stability to resist horizontal forces transmitted to them may be considered lateral supports.
Load-Bearing Wall. A wall that supports any vertical load in addition to its own weight.
Masonry. A built-up construction or combination of masonry units bonded together with mortar or other cementitious material.
Mortar. A plastic mixture of cementitious materials, fine aggregates, and water.
Partition. An interior non-bearing wall one story or less in height.
Pier. An isolated column of masonry. A bearing wall not bonded at the sides into associated masonry is considered a pier when its horizontal dimension measured at right angles to the thickness does not exceed 4 times its thickness.
Pilaster. A bonded or keyed column of masonry built as part of a wall, but thicker than the wall, and of uniform thickness throughout its height. It serves as a vertical beam, column, or both.
Prism. An assemblage of brick and mortar for the purpose of laboratory testing for design strength, quality control of materials, and workmanship. Minimum height for prisms is 12 in, and the slenderness ratio should lie between 2 and 5.
Coursed Rubble. Masonry composed of roughly shaped stones fitting approximately on level beds, well bonded, and brought at vertical intervals to continuous level beds or courses.

Random Rubble. Masonry composed of roughly shaped stones, well bonded and brought at irregular vertical intervals to discontinuous but approximately level beds or courses.
Rough or Ordinary Rubble. Masonry composed of nonshaped field stones laid without regularity of coursing, but well bonded.
Slenderness Ratio. Ratio of the effective height of a member to its effective thickness.
Solid Masonry Unit. A masonry unit with net cross-sectional area in every plane parallel to the bearing surface 75% or more of its gross cross-sectional area measured in the same plane.
Solid Masonry Wall. A wall built of solid masonry units laid contiguously, with joints between units filled with mortar or grout.

Stretcher. A masonry unit laid with length horizontal and parallel with the wall face (Fig. 12.3).
Veneer. A wythe securely attached to a wall but not considered as sharing load or adding strength to it (Fig. 11.1a).
Virtual Eccentricity. The eccentricity of resultant axial loads required to produce axial and bending stresses equivalent to those produced by applied axial and transverse loads.
Wall. Vertical or near-vertical construction, with length exceeding three times the thickness, for enclosing space or retaining earth or stored materials.
Bearing Wall. A wall that supports any vertical load in addition to its own weight.
Cavity Wall. (See Hollow Wall below.)
Curtain Wall. A non-load-bearing exterior wall.
Faced Wall. A wall in which the masonry facing and the backing are of different materials and are so bonded as to exert a common reaction under load.
Hollow Wall. A wall of masonry so arranged as to provide an air space within the wall between the inner and outer wythes (Fig. 11.1b, c, and d). A cavity wall is built of masonry units or plain concrete, or of a combination of these materials, so arranged as to provide an airspace within the wall, which may be filled with insulation, and in which inner and outer wythes are tied together with metal ties (Fig. 11.1d).
Nonbearing Wall. A wall that supports no vertical load other than its own weight.
Party Wall. A wall on an interior lot line used or adapted for joint service between two buildings.
Shear Wall. A wall that resists horizontal forces applied in the plane of the wall.
Spandrel Wall. An exterior curtain wall at the level of the outside floor beams in multistory buildings. It may extend from the head of the window below the floor to the sill of the window above.
Veneered Wall. A wall having a facing of masonry or other material securely attached to a backing, but not so bonded as to exert a common reaction under load (Fig. 11.1a).
Wythe. Each continuous vertical section of a wall one masonry unit in thickness (Fig. 11.1).


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