TEK 1-1E 2007 National Concrete Masonry Association (replaces TEK 1-1D)

NCMA TEKNational Concrete Masonry Associationan information series from the national authority on concrete masonry technology

ASTM SPECIFICATIONS FORCONCRETE MASONRY UNITS

TEK 1-1ECodes & Specs (2007)

Keywords: absorption, ASTM specifi cations, calcium silicate brick, compressive strength, concrete brick, dimensions, face shell and web thickness, gross area, net area, specifi cations, testing, water absorption

INTRODUCTION

The most widely-used standards for specifying concrete masonry units in the United States are published by ASTM International. These ASTM standards contain minimum requirements that assure properties necessary for qual-ity performance. These requirements include items such as conformance to specifi ed component materials, compressive strength, permissible variations in dimensions, and fi nish and appearance criteria. Currently, seven ASTM standards apply to units intended primarily for construction of concrete masonry walls, beams, columns or specialty applications (see Table 1). The letter and fi rst number of an ASTM designation is the fi xed designation for that standard. For example, ASTM C 55 is the fi xed designation for concrete building brick. The number immediately following indicates the year of last revision (i.e., ASTM C 55-06 is the version of C 55 published in 2006). ASTM standards are required to be updated or reapproved at least every fi ve years. If the standard is reapproved, the reapproval date is placed in parentheses after the last revision date. Because signifi cant changes can be introduced into sub-sequent editions, the edition referenced by the building code or by a project specifi cation can be an important consideration when determining specifi c requirements. Also note that it may take several years between publication of a new ASTM standard and its subsequent reference by a building code. For this reason, Table 1 includes the editions referenced in the

2003 and 2006 editions of the International Building Code (IBC) (refs. 1, 2), as well as the most current ASTM edition. Code offi cials will commonly accept more current editions of ASTM standards than that referenced in the code, as they represent more state-of-the-art requirements for a specifi c material or system.

LOADBEARING CONCRETE MASONRY UNITS ASTM C 90

As the most widely-referenced of the ASTM standards for concrete masonry units, ASTM C 90 is under continuous review and revision. The bulk of these revisions are essentially editorial, although two recent major changes are discussed here. In 2006, the minimum face shell thickness requirements were modifi ed for units 10-in. (254-mm) and wider. Prior to ASTM C 90-06 (ref. 2), two minimum face shell thicknesses for these units were listed: a standard thickness, 13/8 in. for 10-in. units, 11/2 in. for 12-in. and greater (35 mm for 254-mm units and 38 mm for 305-mm and greater), and a reduced thickness that can be used when the allowable loads in empirical design are correspondingly reduced. Similarly, in the engineered design methods (allowable stress design and strength design), capacity is automatically reduced as the section properties are reduced. With the introduction of ASTM C 90-06, the two sets of face shell thicknesses were replaced with one minimum thickness requirement (see Table 2). In 2000, a prior change was made to ASTM C 90, removing the Type I (moisture-controlled) and Type II (non moisture-controlled) unit designations which is refl ected in the ASTM C 90 editions adopted by the 2003 and 2006 editions of the

Table 1ASTM Specifi cations for Concrete Masonry Units

ASTM Edition referenced in Type of unit: Designation: the 2003 IBC: the 2006 IBC: Most current edition: Concrete Building Brick C 55 C 55-01a C 55-03 C 55-06 Calcium Silicate Brick C 73 C 73-99a C 73-99a C 73-05 Loadbearing Concrete Masonry Units C 90 C 90-01a C 90-03 C 90-06b Nonloadbearing Concrete Masonry Units C 129 C 129-99aA C 129-01A C 129-06 Catch Basin and Manhole Units C 139 N/AB N/AB C 139-05 Prefaced Concrete Units C 744 C 744-99 C 744-99 C 744-05 Concrete Facing Brick C 1634 N/AB N/AB C 1634-06 A Although not directly referenced in the IBC, C 129 is referenced in Specifi cation for Masonry Structures (refs. 17, 18) B This standard is not referenced in the IBC.

1

IBC. The designations were withdrawn because they were diffi cult to effectively use and enforce, and because of newly developed concrete masonry crack control provisions. The new crack control guidelines are based on anticipated total volume changes, rather than on the specifi ed moisture contents that formed the basis for Type I requirements. Because the Type designations no longer infl uenced recommended control joint spacing or other crack control strategies, Type designations were removed. Control joint criteria can be found in RRefer-ences 5 and 6.

Physical Requirements Physical requirements prescribed by ASTM C 90 include dimensional tolerances, minimum face shell and web thick-nesses for hollow units, minimum strength and maximum absorption requirements, and maximum linear shrinkage. Overall unit dimensions (width, height and length) can vary by no more than 1/8 in. (3.2 mm) from the standard specifi ed dimension. Exceptions are faces of split-face units and faces of slump units which are intended to provide a random surface texture. In these cases, consult local suppliers to determine achievable tolerances. Molded features such as ribs, scores, hex-shapes and patterns must be within 1/16 in. (1.6 mm) of the specifi ed standard dimension and within 1/16 in. (1.6 mm) of the specifi ed placement on the mold. For dry-stack masonry units, the physical tolerances are typically limited to 1/16 in. (1.6 mm), which precludes the need for mortaring, grinding of face shell surfaces or shimming to even out courses during construction (ref. 7). Minimum face shell and web thicknesses are those deemed necessary to obtain satisfactory structural and nonstructural performance. Note that although there are some unique face shell thickness requirements for split-faced units (see Table 2

footnote B), ground-face units (i.e., those ground after manufac-ture) must meet the face shell thickness requirements contained in the body of Table 2. In addition to minimum permissible web thicknesses for individual webs, the specifi cation also requires a minimum total thickness of webs per foot of block length. When evaluating this equivalent web thickness, the portion of a unit to be fi lled with grout is exempted from the minimum requirement. This provision avoids excluding units intentionally manufactured with reduced webs, including bond beam units and open-end block, where grout fulfi lls the structural role of the web. For a unit to be considered a solid unit, the net cross-sec-tional area in every plane parallel to the bearing surface must be at least 75% of the gross cross-sectional area measured in the same plane. Minimum face shell and web thicknesses are not prescribed for solid units. The net area used to determine compressive strength is the average net area of the block, calculated from the unit net volume based on water displacement tests described in ASTM C 140 (ref. 8). For cored units having straight-tapered face shells and webs, average net area approximately equals the net cross-sectional area at the block mid-height. Gross and net areas of a concrete masonry unit are shown in Figure 1. Net area compressive strength is used for engineered masonry design, taking into account the mortar bedded and grouted areas. Compressive strength based on gross area is still used for masonry designed by the empirical provisions of IBC Section 2109. Maximum permissible water absorption is shown in Table 3. Absorption is a measure of the total water required to fi ll all voids within the net volume of concrete. It is determined from the weight-per-unit-volume difference between saturated and oven-dry concrete masonry units. Because absorption measures the water required to fi ll voids, aggregates with relatively large pores, such as some lightweight aggregate, would have a greater absorption than dense, nonporous aggregates, given the same compaction. As a result, lightweight units are permitted higher absorption values than medium or normal weight units. Because concrete masonry units tend to contract as they dry, ASTM C 90 limits their potential drying shrinkage to 0.065%, measured using ASTM C 426, Standard Test Method for Linear Standard Test Method for Linear Drying Shrinkage of Concrete Masonry UnitsDrying Shrinkage of Concrete Masonry Units (ref. 9) (ref. 9).

Finish and Appearance Finish and appearance provisions prohibit defects that would impair the strength or permanence of the construction,

Table 2ASTM C 90 Minimum Thickness of Face Shells and Webs for Hollow Units (ref. 3)

Web thickness Nominal Face shell Equivalent width thicknessB, C, web thickness, of units, minimum, WebsB, C, D in./linear ftE in. (mm) in. (mm) in. (mm) (mm/linear m)3 (76.2) & 4 (102) 3/4 (19) 3/4 (19) 15/8 (136) 6 (152) 1 (25)D 1 (25) 21/4 (188) 8 (203) 11/4 (32)D 1 (25) 21/4 (188)10 (254) and greater 11/4 (32) 11/8 (29) 21/2 (209) A Average of measurements on a minimum of 3 units when measured as described in Test Methods C 140. B When this standard is used for units having split surfaces, a maximum of 10% of the split surface is permitted to have thickness less than those shown, but not less than 3/4 in. (19.1 mm). When the units are to be solid grouted, the 10% limit does not apply and Footnote C establishes a thickness requirement for the entire face shell.C When the units are to be solid grouted, minimum face shell and web thickness shall be not less than 5/8 in. (16 mm).D The minimum web thickness for units with webs closer than 1 in. (25.4 mm) apart shall be 3/4 in. (19.1 mm).E Equivalent web thickness does not apply to the portion of the unit to be fi lled with grout. The length of that portion shall be deducted from the overall length of the unit for the calculation of the equivalent web thickness. Figure 1Gross and Net Areas

Gross area* (shaded) = width (actual) x length (actual)

Net area* (shaded) = net volume (actual)height (actual)

= (% solid) x (gross area)

* For design calculations, a masonry element's section properties are based upon minimum specified dimensions instead of actual dimensions.

2

but permit minor cracks incidental to usual manufacturing methods. For units to be used in exposed walls, the presence of objectionable imperfections is based on viewing the unit face or faces from a distance of at least 20 ft (6.1 m) under diffused lighting. Five percent of a shipment may contain chips not larger than 1 in. (25.4 mm) in any dimension, or cracks not wider than 0.02 in. (0.5 mm) and not longer than 25% of the nominal unit height. Similarly, the specifi cation requires that color and texture be specifi ed by the purchaser. An approved sample of at least four units, representing the range of color and texture permitted, is used to determine conformance.

CONCRETE BUILDING BRICKASTM C 55

ASTM C 55-03 (ref. 10) included two grades of concrete brick: Grade N for veneer and facing applications and Grade S for general use. In 2006, however, the grades were removed from C 55 and requirements for concrete brick used in veneer and facing applications were moved into a new standard: C 1634 (see below). ASTM C 55-06 (ref. 11) now applies to concrete building brick only, defi ned as concrete masonry units with: a maximum width of 4 in. (102 mm); a weight that will typically permit it to be lifted and placed using one hand; and an intended use in nonfacing, utilitarian applications. Requirements for C 55-06 building brick include: 2,500 psi (17.2 MPa) minimum compressive strength (aver-

age of three units), 0.065% maximum linear drying shrinkage, 75% minimum percent solid, and maximum average absorption requirements of 13 pcf for

normal weight brick, 15 pcf for medium weight brick and 18 pcf for lightweight brick (208, 240 and 288 kg/m3).

The fi nish and appearance section of C 55-06 only ad-dresses defects which might affect placement or permanence of the resulting construction.

CONCRETE FACING BRICKASTM C 1634

The introduction of this new standard in 2006 refl ects the rise in popularity of concrete brick used in architectural facing applications. A facing brick (C 1634) is distinguished

from a building brick (C 55) primarily by its intended use. ASTM C 1634 (ref. 12) defi nes a concrete facing brick as a concrete masonry unit with: a maximum width of 4 in. (102 mm); a weight that will typically permit it to be lifted and placed using one hand; and an intended application where one or more faces of the unit will be exposed. Compression and absorption requirements are listed in Table 4. Linear drying shrinkage, dimensional tolerances and fi nish and appearance requirements are similar to those in C 90, with the exception that chip size is limited to + 1/2 in. (13 mm). The minimum permissible distance between any core holes in the brick and the edge of the brick is 3/4 in. (19 mm), as it is in C 55. Both C 1634 and C 55 refer to C 140 for com-pression testing, which requires compression test specimens to have a height that is 60% + 10% of its least lateral dimension, to minimize the potential impact of specimen aspect ratio on tested compressive strengths.

NONLOADBEARING CONCRETE MASONRY UNITSASTM C 129

ASTM C 129 (ref. 13) covers hollow and solid nonloadbear-ing units, intended for use in nonloadbearing partitions. These units are not suitable for exterior walls subjected to freezing cycles unless effectively protected from the weather. ASTM C 129 requires that these units be clearly marked to preclude their use as loadbearing units. Minimum net area compressive strength requirements are 500 psi (3.45 MPa) for an individual unit and 600 psi (4.14 MPa) average for three units.

CALCIUM SILICATE FACE BRICKASTM C 73

ASTM C 73 (ref. 14) covers brick made from sand and lime. Two grades are included: Grade SWBrick intended for use where exposed to

temperatures below freezing in the presence of moisture. Minimum compressive strength requirements are 4,500 psi (31 MPa) for an individual unit and 5,500 psi (37.9 MPa) for an average of three units, based on average gross area. The maximum water absorption is 15 lb/ft3 (240 kg/m3).

Grade MWBrick intended for exposure to temperatures

Table 3Strength and Absorption Requirements for Concrete Masonry Units, ASTM C 90 (ref. 3)A

Oven-dry density Maximum water Minimum net area Weight of concrete, lb/ft3 (kg/m3) absorption, lb/ft3 (kg/m3) compressive strength, psi (MPa) classifi cation Average of 3 units Average of 3 units Individual units Average of 3 units Individual units Lightweight Less than 105 (1,680) 18 (288) 20 (320) 1,900 (13.1) 1,700 (11.7) Medium weight 105 to less than 125 (1,680 - 2,000) 15 (240) 17 (272) 1,900 (13.1) 1,700 (11.7) Normal weight 125 (2,000) or more 13 (208) 15 (240) 1,900 (13.1) 1,700 (11.7)

A Note that ASTM C 90-01a does not include requirements for maximum water absorption of individual units. Otherwise, the requirements are identical between C 90-03 and C 90-06b.

Table 4Strength and Absorption Requirements for Concrete Facing Brick, ASTM C 1634 (ref. 12) Oven-dry Minimum net area Maximum water absorption, density of concrete, compressive strength, psi (MPa) lb/ft (kg/m) Density lb/ft (kg/m) Average of Individual Average of Individual classifi cation Average of 3 units 3 units units 3 units units Lightweight less than 105 (1,680) 3,500 (24.1) 3,000 (20.7) 15 (240) 17 (272) Medium weight 105 (1,680) to less than 125 (2,000) 3,500 (24.1) 3,000 (20.7) 13 (208) 15 (240) Normal weight 125 (2,000) or more 3,500 (24.1) 3,000 (20.7) 10 (160) 12 (192)

3

REFERENCES1. 1. International Building Code 2003. International Code Council, 2003.2. International Building Code 2006. International Code Council, 2006.3. 3. Standard Specifi cation for Loadbearing Concrete Masonry UnitsStandard Specifi cation for Loadbearing Concrete Masonry Units, ASTM C 90-06b. ASTM International, 2006., ASTM C 90-06b. ASTM International, 2006.4. . Standard Specifi cation for Loadbearing Concrete Masonry UnitsStandard Specifi cation for Loadbearing Concrete Masonry Units, ASTM C 90-03. ASTM International, 2003., ASTM C 90-03. ASTM International, 2003.55. Control Joints for Concrete Masonry Walls. Control Joints for Concrete Masonry WallsEmpirical MethodEmpirical Method, TEK 10-2B. National Concrete Masonry Association, 2005., TEK 10-2B. National Concrete Masonry Association, 2005.66. Control Joints for Concrete Masonry Walls. Control Joints for Concrete Masonry WallsAlternative Engineered Method. Alternative Engineered Method. TEK 10-3. National Concrete Masonry As-TEK 10-3. National Concrete Masonry As-

sociation, 2003.sociation, 2003.7. 7. Design and Construction of Dry-Stack Masonry WallsDesign and Construction of Dry-Stack Masonry Walls, TEK 14-22. National Concrete Masonry Association, 2003., TEK 14-22. National Concrete Masonry Association, 2003.8. 8. Standard Test Methods for Sampling and Testing Concrete Masonry Units and Related UnitsStandard Test Methods for Sampling and Testing Concrete Masonry Units and Related Units, ASTM C 140-03. ASTM , ASTM C 140-03. ASTM

International, 2003.International, 2003.9. 9. Standard Test Method for Linear Drying Shrinkage of Concrete Masonry UnitsStandard Test Method for Linear Drying Shrinkage of Concrete Masonry Units, ASTM C 426-06. ASTM International, 2006., ASTM C 426-06. ASTM International, 2006.10. 10. Standard Specifi cation for Concrete BrickStandard Specifi cation for Concrete Brick, ASTM C 55-03. ASTM International, 2003., ASTM C 55-03. ASTM International, 2003.11. 11. Standard Specifi cation for Concrete Building BrickStandard Specifi cation for Concrete Building Brick, ASTM C 55-06. ASTM International, 2006., ASTM C 55-06. ASTM International, 2006.12. 12. Standard Specifi cation for Concrete Facing BrickStandard Specifi cation for Concrete Facing Brick, ASTM C 1634-06. ASTM International, 2006., ASTM C 1634-06. ASTM International, 2006.13. 13. Standard Specifi cation for Nonloadbearing Concrete Masonry UnitsStandard Specifi cation for Nonloadbearing Concrete Masonry Units, ASTM C 129-06. ASTM International, 2006., ASTM C 129-06. ASTM International, 2006.14. 14. Standard Specifi cation for Calcium Silicate Brick (Sand-Lime Brick)Standard Specifi cation for Calcium Silicate Brick (Sand-Lime Brick), ASTM C 73-99a. ASTM International, 1999., ASTM C 73-99a. ASTM International, 1999.15. 15. Standard Specifi cation for Prefaced Concrete and Calcium Silicate Masonry UnitsStandard Specifi cation for Prefaced Concrete and Calcium Silicate Masonry Units, ASTM C 744-99. ASTM International, 1999., ASTM C 744-99. ASTM International, 1999.16. 16. Standard Specifi cation for Concrete Masonry Units for Construction of Catch Basins and ManholesStandard Specifi cation for Concrete Masonry Units for Construction of Catch Basins and Manholes, ASTM C 139-05. , ASTM C 139-05.

ASTM International, 2005.ASTM International, 2005.17. 17. Specifi cation for Masonry StructuresSpecifi cation for Masonry Structures, , ACI 530.1-02/ASCE 6-02/TMS 602-02. Reported by the Masonry Standards Joint Committee, 2002.18. Specifi cation for Masonry StructuresSpecifi cation for Masonry Structures, , ACI 530.1-05/ASCE 6-05/TMS 602-05. Reported by the Masonry Standards Joint Committee, 2005.

NATIONAL CONCRETE MASONRY ASSOCIATION To order a complete TEK Manual or TEK Index, 13750 Sunrise Valley Drive, Herndon, Virginia 20171 contact NCMA Publications (703) 713-1900www.ncma.org

NCMA and the companies disseminating this technical information disclaim any and all responsibility and liability for the ac-curacy and the application of the information contained in this publication.

below freezing, but unlikely to be saturated with water. Minimum compressive strength requirements are 3,000 psi (20.7 MPa) for an individual unit and 3,500 psi (24.1 MPa) for an average of three units, based on average gross area. The maximum water absorption is 18 lb/ft3 (288 kg/m3).

PREFACED CONCRETE AND CALCIUM SILICATE MASONRY UNITSASTM C 744

ASTM C 744 (ref. 15) for prefaced units establishes requirements for the facing materials applied to masonry unit surfaces. For the concrete masonry units onto which the surface is molded, C 744 requires compliance with the requirements contained in ASTM C 55, C 90 or C 129, as appropriate. Facing requirements in C 744 include: resistance to crazing,

surface burning characteristics, adhesion, color permanence, chemical resistance, cleansability, abrasion, and dimensional tolerances.

CONCRETE MASONRY UNITS FOR CATCH BASINS AND MANHOLESASTM C 139

ASTM C 139 (ref. 16) covers solid precast segmental concrete masonry units intended for use in catch basins and manholes. Units are required to be at least 5 in. (127 mm) thick, with a minimum gross area compressive strength of 2,500 psi (17 MPa) (average of 3 units) or 2,000 psi (13 MPa) for an individual unit, and a maximum water absorption of 10 pcf (16 kg/m) (average of 3 units). The overall unit dimensions must be within 3% of the specifi ed dimensions.

Provided by:

4

NCMA TEK 1-2C 1

A n i n f o r m a t i o n s e r i e s f r o m t h e n a t i o n a l a u t h o r i t y o n c o n c r e t e m a s o n r y t e c h n o l o g y

SPECIFICATION FOR MASONRY STRUCTURES

TEK 1-2CCodes & Specs (2010)

INTRODUCTION

Specifi cation for Masonry Structures (MSJC Specifi -cation) (ref. 1) is a national consensus standard intended to be incorporated by reference into the contract documents of masonry construction projects. Compliance with this Specifi cation is mandatory for structures designed in ac-cordance with Building Code Requirements for Masonry Structures (MSJC Code) (ref. 2). The masonry design and construction provisions in Chapter 21 of the International Building Code (IBC) (ref. 3) are based primarily on the MSJC Code and Specifi ca-tion. When adopting the MSJC Code and Specifi cation, the IBC typically amends or modifi es some provisions. Because signifi cant changes can be introduced into subsequent editions of both the MSJC and the IBC, the edition referenced by the local building code can be an important consideration when determining the specifi c requirements to be met. Note that building offi cials will often accept design and construction standards which are more current than those referenced in the applicable code, as they represent more state-of-the art requirements for the specifi c material or system. This TEK provides a broad overview of the MSJC Specifi cation's content, references other NCMA TEK which describe the various provisions in greater detail, outlines updates incorporated into the 2008 edition of the MSJC Specifi cation, and notes differences between the 2008 MSJC Specifi cation and the 2009 IBC.

THE MSJC SPECIFICATION

The MSJC Specifi cation covers material requirements, storage and handling of materials, construction, and clean-

ing, as well as provisions for quality assurance, testing and inspection. Construction includes requirements for masonry placement, bonding and anchorage, and the placement of grout, reinforcement and prestressing ten-dons. The document is formatted to allow the designer to modify those provisions which include a choice of alternatives. Thus, the MSJC Specifi cation may be tailored to meet the specifi c needs of a project. Modifi cations are considered to be a supplemental specifi cation to the MSJC Specifi cation. The advantages of a standard specifi cation include consistency, coordination and understanding among all parties involved. A Commentary, which accompanies the MSJC Specifi cation, explains the mandatory requirements and further clarifi es the Specifi cation's intent. The document is written in the three-part section format of the Construction Specifi cations Institute. Each of the three parts (General, Products and Execution) is described in the following sections. In addition to these three parts, checklists are included at the end of the MSJC Specifi cation to help the designer prepare the contract documents. The checklists identify the decisions that must be made when preparing any supplemental specifi cations. They are not a mandatory part of the Specifi cation. Several articles of the MSJC Specifi cation are prefaced with the phrase "when required..." These articles do not become a part of the contract documents unless action is taken by the designer to include a requirement in the supple-mental specifi cations. Other articles are prefaced with the phrase "unless otherwise required..." These articles are a part of the contract documents unless the designer takes

Related TEK:1-3C

Keywords: building codes, construction, quality assurance, specifi cations

5

that the minimum compressive strength of units could be less than the 1,900 psi (13.1 MPa) required by ASTM C90, Standard Specifi cation for Loadbearing Concrete Masonry Units (ref 8). To avoid potential confusion, Table 2 was revised to refl ect a minimum unit compressive strength of 1,900 psi (13.1 MPa).

IBC Inspection Requirements The International Building Code inspection require-ments are almost identical to the MSJC requirements but are organized a little differently. MSJC Level A require-ments correspond to the basic inspection requirements performed by the building offi cial as required in Section 110.3 of the IBC. The special inspection requirements of IBC for masonry are found in Section 1704.5 of that code. MSJC Level B corresponds to IBC Level 1 and MSJC Level C corresponds to IBC Level 2. IBC Section 2105 addresses quality assurance of ma-sonry. These provisions are essentially the same as those in the MSJC Specifi cation, with the exception that the IBC addresses testing prisms from constructed masonry. Such prisms are addressed only to a minor extent within the MSJC Specifi cation, via one of the referenced standards, ASTM C1314-07, Standard Test Method for Compressive Strength of Masonry Prisms (ref.9).

PART 2PRODUCTS

Part 2 of the MSJC Specifi cation covers: required material properties for masonry units, mor-

tar, grout, reinforcement, prestressing tendons, metal accessories and other accessories such as movement joint materials. These material properties are primarily references to applicable ASTM standards. See TEKs 1-1E, ASTM Specifi cations for Concrete Masonry Units (ref. 10), and 12-4D, Steel Reinforcement for Concrete Masonry (ref. 11), for further information.

mortar and grout mixing requirements, found within Article 2.1 A via ASTM C270, Standard Specifi ca-tion for Mortar for Unit Masonry (ref. 12), and also within Article 2.6A (see TEK 3-8A, Concrete Masonry Construction (ref. 13), for more detailed information), and

reinforcement fabrication requirements.

Updates to 2008 MSJC Specifi cation The Part 2 provisions were not greatly modifi ed be-tween the 2005 and 2008 editions of the MSJC Specifi ca-tion. The reinforcement used for stirrups and lateral ties that are terminated with a standard hook is now limited to a maximum reinforcing bar size of No. 5 (M# 16), because of the diffi culty of bending, placing and developing larger diameter bars in typical masonry construction.

specifi c action to modify the article in the supplemental specifi cations.

PART 1GENERAL

Part 1 of the MSJC Specifi cation covers: defi nitions, referenced standards, system description, which includes: 1. compressive strength requirements, 2. compressive strength determination (choice of two

methods). See TEK 18-1A, Compressive Strength Evalu-ation of Concrete Masonry (ref. 4), for more detailed information.

3. adhered veneer requirements (choice of two methods to determine adhesion),

submittals, which includes a minimum list of required submittals. If the designer wishes to specify a higher level of quality assurance, additional submittals may be required.

quality assurance, which includes quality control mea-sures as well as testing and inspection. The services and duties of the testing agency, inspection agency and contractor are included here (see TEK 18-3B, Concrete Masonry Inspection (ref. 5), for more detailed informa-tion),

delivery, storage and handling requirements, and cold weather and hot weather construction require-

ments (see TEK 3-1C, All-Weather Concrete Masonry Construction (ref. 6)).

Updates to 2008 MSJC Specifi cation From the 2005 edition of the MSJC Specifi cation to the 2008 edition, Tables 3, 4 and 5 which defi ne Level A Quality Assurance, Level B Quality Assurance and Level C Quality Assurance, respectively, were revised. Columns were added to the tables to defi ne the frequency of inspection for the various items. New inspection tasks in the tables are: verifi cation of the grade, type and size of anchor bolts

prior to grouting for Levels B and C quality assurance, and

verifi cation of the grade and size of prestressing tendons and anchorages for Level B quality assurance.

Part 1 also includes new provisions addressing the addition of self-consolidating grout to the MSJC speci-fi cation. See TEK 9-2B, Self-Consolidating Grout for Concrete Masonry (ref. 7) for further information. The 2008 Specifi cation includes minor modifi cations to the provisions for verifying compliance with the speci-fi ed compressive strength of masonry, f'm, using the unit strength method. In prior editions of the MSJC Specifi ca-tion, the unit strength table for concrete masonry implied

2 NCMA TEK 1-2C

6

As in Part 1, Part 2 also includes new provisions addressing the addition of self-consolidating grout to the MSJC Specifi cation. See TEK 9-2B, Self-Consolidating Grout for Concrete Masonry (ref. 7) for further infor-mation.

IBC Masonry Material Requirements IBC Section 2103 addresses masonry construction materials, and the requirements are essentially the same as in the corresponding MSJC Specifi cation. The IBC does include a provision for surface bonding mortar however, which is not addressed in the MSJC Specifi cation.

PART 3EXECUTION

Part 3, Execution, covers: inspection prior to the start of masonry construction, preparation of reinforcement and masonry prior to

grouting (see TEK 3-2A, Grouting Concrete Masonry Walls (ref. 14)),

masonry erection, including site tolerances (see TEK 3-8A, Concrete Masonry Construction (ref. 13)),

bracing, which simply requires bracing to be designed and installed to assure stability (see TEK 3-4B, Brac-ing Masonry Walls During Construction (ref. 15) for detailed guidance),

placement of reinforcement, ties and anchors (see TEK 12-1A, Anchors and Ties for Masonry (ref. 16)),

grout placement (see TEK 3-2A, Grouting Concrete Masonry Walls (ref. 14)),

procedures for prestressing tendon installation and stressing (see TEK 3-14, Post-Tensioned Concrete Masonry Wall Construction (ref. 17)),

fi eld quality control requirements, and cleaning (see TEK 8-4A, Cleaning Concrete Masonry

(ref. 18)).

Updates to 2008 MSJC Specifi cation In addition to changes addressing self-consolidating grout, several changes have been incorporated into the Part 3 provisions, dealing with foundation dowels and with grouting procedures. MSJC Specifi cation Article 3.4 B.8(d) is a new pro-vision, allowing foundation dowels that interfere with masonry unit webs to be bent up to 1 in. (25 mm) hori-zontally for each 6 in. (152 mm) of vertical height. This provision is similar to that used in reinforced concrete construction. Article 3.5A of the MSJC Specifi cation requires that grout be placed within 11/2 hours from the introduction of water into the mix. The 2008 edition exempts transit-mixed grout from this requirement, as long as the grout meets the specifi ed slump.

NCMA TEK 1-2C 3

To help ensure structural continuity between subse-quent grout pours, Article 3.5F now requires a 11/2-in. (38-mm) grout key (i.e., terminating the grout at least 11/2-in. (38-mm) below a mortar joint) when the previous grout lift has set before the next lift is poured. Grout keys may not be formed within masonry bond beams or lintels.

IBC Construction Requirements IBC Section 2104 addresses masonry construction procedures, which essentially references the MSJC Speci-fi cation without modifi cation. In the 2006 IBC, many of the provisions of the 2005 MSJC requirements were reiterated in the IBC. In the 2009 IBC however, most of the text of these requirements was removed from the IBC and a simple reference was made to the 2008 MSJC.

FINISH AND APPEARANCE

The MSJC Specifi cation addresses structural re-quirements only and not fi nish or appearance, though several Articles, such as 1.6 D Sample Panels and 3.3 F Site Tolerances certainly may affect such. Addition-ally, several MSJC reference standards, such as ASTM C90, Standard Specifi cation for Loadbearing Concrete Masonry Units, specifi cally address this topic. Further guidance may be found by including reference to state standards such as Arizona Masonry Guild Standard 107, Levels of Quality (ref. 19), as well as to NCMA TEK 1-1E ASTM Specifi cations for Concrete Masonry Units and TEK 8-4A Cleaning Concrete Masonry.

7

REFERENCES1. Specifi cation for Masonry Structures, TMS 602/ACI 530.1/ASCE 6. Reported by the Masonry Standards Joint Com-

mittee, 2005 and 2008.2. Building Code Requirements for Masonry Structures. TMS 402/ACI 530/ASCE 5. Reported by the Masonry Standards

Joint Committee, 2005 and 2008.3. International Building Code. International Code Council, 2006 and 2009.4. Compressive Strength Evaluation of Concrete Masonry, TEK 18-1A. National Concrete Masonry Association, 2004.5. Concrete Masonry Inspection, TEK 18-3B. National Concrete Masonry Association, 2006.6. All-Weather Concrete Masonry Construction, TEK 3-1C. National Concrete Masonry Association, 2002.7. Self-Consolidating Grout for Concrete Masonry, TEK 9-2B. National Concrete Masonry Association, 2007.8. Standard Specifi cation for Loadbearing Concrete Masonry Units, ASTM C90-09. ASTM International, 2009.9. Standard Test Method for Compressive Strength of Masonry Prisms, ASTM C1314-07. ASTM International, 2007.10. ASTM Specifi cations for Concrete Masonry Units, TEK 1-1E. National Concrete Masonry Association, 2007.11. Steel Reinforcement for Concrete Masonry, 12-4D. National Concrete Masonry Association, 2007.12. Standard Specifi cation for Mortar for Unit Masonry, ASTM C270-07a. ASTM International, 2007.13. Concrete Masonry Construction, TEK 3-8A. National Concrete Masonry Association, 2001.14. Grouting Concrete Masonry Walls, TEK 3-2A. National Concrete Masonry Association, 2005.15. Bracing Masonry Walls During Construction, TEK 3-4B. National Concrete Masonry Association, 2005.16. Anchors and Ties for Masonry, TEK 12-1A. National Concrete Masonry Association, 2001.17. Post-Tensioned Concrete Masonry Wall Construction, TEK 3-14. National Concrete Masonry Association, 2002.18. Cleaning Concrete Masonry, TEK 8-4A. National Concrete Masonry Association, 2005.19. Levels of Quality, Standard AMG 107-98. Arizona Masonry Guild, 1998.

4 NCMA TEK 1-2C

NCMA and the companies disseminating this technical information disclaim any and all responsibility and liability for the accuracy and the application of the information contained in this publication.

NATIONAL CONCRETE MASONRY ASSOCIATION13750 Sunrise Valley Drive, Herndon, Virginia 20171

www.ncma.org

To order a complete TEK Manual or TEK Index, contact NCMA Publications (703) 713-1900

Provided by:

8

TEK 1-3C 2007 National Concrete Masonry Association (replaces TEK 1-3B)

NCMA TEKNational Concrete Masonry Associationan information series from the national authority on concrete masonry technology

BUILDING CODE REQUIREMENTS FOR CONCRETE MASONRY

TEK 1-3CCodes & Specs (2007)

Keywords: building codes, construction, masonry design, quality assurance, specifi cations

INTRODUCTION

The majority of jurisdictions in the United States adopt a national model code, most commonly the International Building Code (IBC) (refs. 1, 2), as the basis of their building code. The intent of the IBC is to reference and coordinate other standardized documents, rather than to develop design and construction provisions from scratch. With this in mind, the IBC masonry design and construction provisions are based primarily on Building Code Requirements for Masonry Structures (MSJC code) (refs. 3, 4) and Specifi cation for Masonry Structures (MSJC specifi cation) (refs. 5, 6). The code adoption process is shown schematically in Figure 1. In adopting the MSJC code and specifi cation, the IBC typically amends or modifi es some provisions. Similarly, depending on state laws, modifi cations can be made to the IBC at the state or local level to better suit local building practices or design traditions. However, most state codes require that any modifi cations to the IBC be more stringent than the corresponding requirement in the IBC. Because signifi cant changes can be introduced into subsequent editions of both the MSJC and IBC, the edition referenced by the local building code can be an important consideration when determining the specifi c requirements to be met. Note that code offi cials will often accept more current design and construction standards than those referenced in the code, as they represent more state-of-the-art requirements for a specifi c material or system. To help determine which code provisions apply and high-light changes of note, this TEK outlines the major modifi cations to the MSJC code and specifi cation made in the 2003 and 2006 IBC, as well as the principal changes made between the 2002 and 2005 editions of the MSJC code and specifi cation. Note that the scope of the MSJC code and specifi cation cov-ers structural design and construction. Hence, requirements for items such as fi re resistance, sound insulation and energy effi ciency are not addressed in the MSJC documents.

2003 INTERNATIONAL BUILDING CODE

The 2003 International Building Code (ref. 1) adopts by reference the 2002 editions of the MSJC code and MSJC specifi cation (refs. 3, 5). The MSJC code covers the design of concrete masonry, clay masonry, glass unit masonry, stone masonry, as well as masonry veneer. The MSJC code requires compliance with the MSJC specifi cation, which governs masonry construction requirements and quality assurance provisions (see also TEK 1-2B, ref. 7).

Figure 1Masonry Structural Code Development Process

Consensus process

MSJC Code and Specifi cation

International Building Code

State or Local Building Code

adoption with modifi cationsand additions

adoption, possibly with modifi cations

National process

State/local

process

9

The 2002 MSJC Code and Specifi cation Compared to earlier editions of the MSJC code and specifi cation, updates included in the 2002 edition are sum-marized below.

Masonry Design Changes to masonry design provisions included: for the design of masonry structures, the 2002 MSJC code

included new strength design provisions (see TEK 14-4A, ref. 8), offering a design method in addition to allowable stress design and empirical design,

revised seismic design requirements, including prescriptive shear wall reinforcement (see TEK 14-18A, ref. 9) and transition from Seismic Performance Categories to Seismic Design Categories (SDCs) (see TEK 14-18A, ref. 9),

for allowable stress design, revised allowable fl exural tension values for unreinforced grouted masonry elements when subjected to fl exural tension perpendicular to the bed joints,

new prohibition on the use of wall ties with drips (bends intended to inhibit moisture migration from one masonry wythe to the other),

for empirical design, revised wind speed threshold from a design wind pressure of 25 psf (1,197 MPa) to a wind speed of 110 mph (145 km/h) three-second gust,

for empirical design, revised shear wall spacing require-ments (see TEK 14-8A, ref. 10), and

revisions to the types of masonry veneer permitted to be supported by wood construction (see TEK 3-6B, ref. 11).

Construction and Quality Assurance Specifi cation revisions included: new corrosion protection requirements for joint reinforce-

ment, anchors and ties depending on their intended use or exposure conditions (see TEK 12-4D, ref. 12),

new prestressed masonry quality assurance provisions for Level 2 (moderate) and Level 3 (rigorous) programs (see TEK 18-3B, ref. 13),

the addition of grout demonstration panels as a means of meeting grout pour requirements (see TEK 3-2A, ref. 14),

revised cold weather construction requirements, including new protection procedures for grouted masonry (see TEK 3-1C, ref. 15),

new veneer anchor placement requirements (see TEK 3-6B, ref. 11), and

updating of ASTM C 270 (ref. 16) mortar specifi cation tables to include mortar cement.

Differences Between the 2003 IBC and the 2002 MSJC The 2002 editions of the MSJC code and specifi cation are included in their entirety (by reference) in the 2003 IBC. The IBC modifi es several areas of the MSJC code and specifi ca-tion applicable to concrete masonry. The most signifi cant of these are summarized below. In addition, quality assurance provisions are close, but not identical between the IBC and MSJC.

Seismic Design Requirements The IBC bases loads on ASCE 7-02 (ref. 17), rather than

the 1998 edition (ref. 18) referenced by the MSJC, the IBC includes prescriptive seismic requirements for post-

tensioned masonry shear walls, which are not included in the MSJC, and

the IBC has some more stringent seismic requirements than the MSJC, applicable to SDCs B, C, D, E and F.

Allowable Stress Design For masonry designed using allowable stress design procedures, the IBC: modifi es load combinations to be based on IBC section

1605, rather than those in MSJC code section 2.1.2.1, modifi es minimum inspections required during construc-

tion, includes separate design requirements for columns used

only to support light-frame roofs of carports, porches, sheds or similar structures with a maximum area of 450 ft2 (41.8 m2) and assigned to Seismic Design category A, B or C,

modifi es the minimum required lap splice length for reinforc-ing bars (Note that development length and corresponding lap splice length requirements have changed frequently in recent years. NCMA recommends using the lap splice requirements published in the 2006 IBC. See TEK 12-4D (ref. 12) for more detailed information.),

sets a maximum reinforcing bar size based on the size of the cell or collar joint where the reinforcement is placed (see ref. 12), and

sets a limit on the amount of reinforcement permitted in the in-plane direction for special reinforced masonry shear walls.

Strength Design For masonry designed using strength design procedures, the IBC: sets a maximum width for the equivalent stress block of six

times the nominal thickness of the masonry wall or spacing between reinforcement (whichever is less), or six times the thickness of the fl ange for in-plane bending of fl ange walls,

modifi es welded and mechanical splice requirements (see ref. 12), and

adds maximum reinforcement percentage for special post-tensioned masonry shear walls.

Empirical Design The IBC includes empirical design procedures within the body of the code and references the MSJC code as an alternate means of compliance. However, the IBC and MSJC empirical requirements are essentially the same, except that the IBC also includes: an exception allowing shear walls of one-story buildings

to be a minimum of 6 in. (152 mm) thick, rather than 8 in. (203 mm),

provisions for empirically-designed surface-bonded masonry walls, and

10

additional parapet wall requirements, covering fl ashing and copings.

2006 INTERNATIONAL BUILDING CODE

The 2006 International Building Code (ref. 2) adopts by reference the 2005 editions of the MSJC code and MSJC specifi cation (refs. 4, 6). The fi rst section below highlights the major changes between the 2002 and 2005 MSJC code and specifi cation. The following section summarizes important changes between the 2005 MSJC and the 2006 IBC.

The 2005 MSJC Code and Specifi cation Compared to the 2002 edition of the MSJC code and specifi cation, the 2005 edition includes the following changes and additions.

Allowable Stress Design For masonry designed using allowable stress design procedures: the use of the one-third increase in allowable stresses has

been tied to specifi c load combinations, the minimum required lap splice and development lengths

for reinforcing bars are the same for allowable stress design and strength design (Note that development length and cor-responding lap splice length requirements have changed frequently in recent years. NCMA recommends using the lap splice requirements published in the 2006 IBC. See TEK 12-4D (ref. 12) for more detailed information.), and

in-plane allowable fl exural tension has been changed from zero to be the same value as for out-of-plane fl exural ten-sion.

Strength Design For masonry designed using strength design proce-dures: the 2005 MSJC code includes explicit bearing strength

provisions, the modulus of rupture for in-plane bending is now the same

as that for out-of-plane bending, the maximum reinforcement limits have been modifi ed,

based on less restrictive assumptions that are related directly to the expected seismic ductility demand,

new provisions for noncontact splices have been added, the minimum required lap splice and development lengths

for reinforcing bars are the same for allowable stress design and strength design (Note that development length and cor-responding lap splice length requirements have changed frequently in recent years. NCMA recommends using the lap splice requirements published in the 2006 IBC. See TEK 12-4D (ref. 12) for more detailed information.), and

provisions for computing effective compression width have been added, using the same requirements historically employed for allowable stress design.

Other Revisions The post-tensioned masonry design provisions have been updated. The most signifi cant change is that design is now based on strength design with serviceability checks, rather than on allowable stress design with strength checks, making the design procedures easier to use for those accustomed to strength design of prestressed concrete. For grouted masonry, the maximum grout lift height has been increased from 5 ft to 12 ft-8 in (1.5 to 3.9 m) under con-trolled conditions, such as a consistent grout slump between 10 and 11 in. (254 and 279 mm), the absence of reinforced bond beams between the top and bottom of the grout pour, and a minimum masonry curing time of 4 hours prior to grouting. See TEK 3-2A (ref. 14) for further information. Empirical design includes several revisions to the limita-tions that defi ne where empirical design can be used. In the 2002 MSJC documents, the three levels of quality assurance were designated Levels 1, 2 and 3, which were re-placed by Levels A, B and C, respectively in the 2005 edition. This change in nomenclature is wholly editorial and does not affect the requirements specifi ed for each level. For masonry veneers, prescriptive seismic requirements have been modifi ed (several requirements that previously ap-plied in SDC D and higher now apply in SDC E and higher), and new prescriptive requirements have been introduced for areas with high winds (wind speeds between 110 and 130 mph (177 and 209 km/hr)). Prescriptive requirements for corbelled masonry have been moved from the empirical design chapter to Chapter 1, making the corbel requirements independent of the design procedure used. In addition, design and construction provisions for au-toclaved aerated concrete (AAC) appear in the MSJC for the fi rst time.

Differences Between the 2006 IBC and the 2005 MSJC The 2005 editions of the MSJC code and specifi cation are included in their entirety (by reference) in the 2006 IBC. In addition to the modifi cations listed under the 2003 IBC (which are also included in the 2006 IBC unless noted be-low), the 2006 IBC modifi es several areas of the MSJC code and specifi cation applicable to concrete masonry. The most signifi cant of these are summarized below. Development length and minimum lap splice length for

reinforcing bars has been updated to 48 bar diameters for Grade 60 steel, with some exceptions. See TEK 12-4D (ref. 12) for more detailed information.

Design loads and load combinations are based on ASCE 7-05 (ref. 19), rather than ASCE 7-02.

For grouted masonry, the IBC requires a "grout key" between grout pours, i.e. a horizontal construction joint formed by stopping the grout pour 11/2 in. (38 mm) below a mortar joint.

For certain special reinforced masonry shear walls, the IBC prescribes a maximum reinforcement percentage, applicable in the in-plane direction.

11

REFERENCES1. International Building Code 2003. International Code Council, 2003.2. International Building Code 2006. International Code Council, 2006.3. Building Code Requirements for Masonry Structures, ACI 530-02/ASCE 5-02/TMS 402-02. Reported by the Masonry Stan-

dards Joint Committee, 2002.4. Building Code Requirements for Masonry Structures, ACI 530-05/ASCE 5-05/TMS 402-05. Reported by the Masonry Stan-

dards Joint Committee, 2005.5. Specifi cation for Masonry Structures, ACI 530.1-02/ASCE 6-02/TMS 602-02. Reported by the Masonry Standards Joint

Committee, 2002.6. Specifi cation for Masonry Structures, ACI 530.1-05/ASCE 6-05/TMS 602-05. Reported by the Masonry Standards Joint

Committee, 2005.7. Specifi cation for Masonry Structures, TEK 1-2B. National Concrete Masonry Association, 2004.8. Strength Design of Concrete Masonry, TEK 14-4A. National Concrete Masonry Association, 2002.9. Prescriptive Seismic Reinforcement Requirements for Masonry Structures, TEK 14-18A. National Concrete Masonry As-

sociation, 2003.10. Empirical Design of Concrete Masonry Walls, TEK 14-8A. National Concrete Masonry Association, 2001.11. Concrete Masonry Veneers, TEK 3-6B. National Concrete Masonry Association, 2005.12. Steel Reinforcement for Concrete Masonry, TEK 12-4D. National Concrete Masonry Association, 2006.13. Concrete Masonry Inspection, TEK 18-3B. National Concrete Masonry Association, 2006.14. Grouting Concrete Masonry Walls, TEK 3-2A. National Concrete Masonry Association, 2005.15. All-Weather Concrete Masonry Construction, TEK 3-1C. National Concrete Masonry Association, 2002.16. Standard Specifi cation for Mortar for Unit Masonry, ASTM C 270-99b. ASTM International, Inc., 1999.17. Minimum Design Loads for Buildings and Other Structures, ASCE 7-02. American Society of Civil Engineers, 2002.18. Minimum Design Loads for Buildings and Other Structures, ASCE 7-98. American Society of Civil Engineers, 1998.19. Minimum Design Loads for Buildings and Other Structures, ASCE 7-05. American Society of Civil Engineers, 2005.

NATIONAL CONCRETE MASONRY ASSOCIATION To order a complete TEK Manual or TEK Index, 13750 Sunrise Valley Drive, Herndon, Virginia 20171 contact NCMA Publications (703) 713-1900www.ncma.org

NCMA and the companies disseminating this technical information disclaim any and all responsibility and liability for the ac-curacy and the application of the information contained in this publication.

Provided by:

12

TEK 1-4 2004 National Concrete Masonry Association

NCMA TEKNational Concrete Masonry Associationan information series from the national authority on concrete masonry technology

GLOSSARY OFCONCRETE MASONRY TERMS

TEK 1-4 Codes & Specs (2004)

Keywords: definitions, glossary, terminology

A block: Hollow masonry unit with one end closed by across web and the opposite end open or lacking an end crossweb. (See Open end block.)

Absorption: The difference in the amount of water containedwithin a concrete masonry unit between saturated and oven-dry conditions, expressed as weight of water per cubic footof concrete. [4]

Accelerator: A liquid or powder admixture added to acementitious paste to speed hydration and promote earlystrength development. An example of an accelerator materialis calcium nitrite.

Adhesive anchor : An anchoring device that is placed in apredrilled hole and secured using a chemical compound.

Admixture: Substance other than prescribed materials ofwater, aggregate and cementitious materials added toconcrete, mortar or grout to improve one or more chemicalor physical properties. [3]

Aggregate: An inert granular or powdered material such asnatural sand, manufactured sand, gravel, crushed stone, slag,fines and lightweight aggregate, which, when bound togetherby a cementitious matrix forms concrete, grout or mortar. [3]

Air entraining: The capability of a material or process todevelop a system of uniformly distributed microscopic airbubbles in a cementitious paste to increase the workabilityor durability of the resulting product. Some admixtures actas air entraining agents.

Anchor: Metal rod, tie, bolt or strap used to secure masonryto other elements. May be cast, adhered, expanded orfastened into masonry. [1]

Angle: A structural steel section that has two legs joined at 90degrees to one another. Used as a lintel to support masonryover openings such as doors or windows in lieu of a masonryarch or reinforced masonry lintel. Also used as a shelf tovertically support masonry veneer. Sometimes referred toas a relieving angle.

Arch: A vertically curved compressive structural memberspanning openings or recesses. May also be built flat byusing special masonry shapes or specially placed units.

Area, gross cross-sectional: The area delineated by the out-to-out dimensions of masonry in the plane under consideration.This includes the total area of a section perpendicular to the

direction of the load, including areas within cells and voids. [1]Area, net cross-sectional: The area of masonry units, grout

and mortar crossed by the plane under consideration, basedon out-to-out dimensions and neglecting the area of all voidssuch as ungrouted cores, open spaces, or any other areadevoid of masonry. [1]

Axial load: The load exerted on a wall or other structuralelement and acting parallel to the elements axis. Axial loadstypically act in a vertical direction, but may be otherwisedepending on the type and orientation of the element.

Backing: The wall or surface to which veneer is secured. Thebacking material may be concrete, masonry, steel framing orwood framing. [1]

Beam: A structural member, typically horizontal, designed toprimarily resist flexure.

Burnished block: (See Ground face block.)Bedded area: The surface area of a masonry unit that is in

contact with mortar in the plane of the mortar joint.Blast furnace slag cement: A blended cement which

incorporates blast furnace slag.Blended cement: Portland cement or air-entrained portland

cement combined through blending with such materials asblast furnace slag or pozzolan, which is usually fly ash. Maybe used as an alternative to portland cement in mortar.

Block: A solid or hollow unit larger than brick-sized units. (Seealso Concrete block, concrete masonry unit, masonry unit)

Block machine: Equipment used to mold, consolidate andcompact shapes when manufacturing concrete masonry units.

Bond: (1) The arrangement of units to provide strength, stabilityor a unique visual effect created by laying units in a prescribedpattern. See reference 6 for illustrations and descriptions ofcommon masonry bond patterns. (2) The physical adhesive ormechanical binding between masonry units, mortar, grout andreinforcement. (3) To connect wythes or masonry units.

Bond beam: (1) The grouted course or courses of masonryunits reinforced with longitudinal bars and designed to takethe longitudinal flexural and tensile forces that may beinduced in a masonry wall. (2) A horizontal grouted elementwithin masonry in which reinforcement is embedded.

Bond beam block: A hollow unit with depressed webs or with"knock-out" webs (which are removed prior to placement)to accommodate horizontal reinforcement and grout.

Bond breaker: A material used to prevent adhesion betweentwo surfaces.

13

Bond, running: The placement of masonry units such that headjoints in successive courses are horizontally offset at least one-quarter the unit length. [1] Centering head joints over the unitbelow, called center or half bond, is the most common form ofrunning bond. A horizontal offset between head joints insuccessive courses of one-third and one-quarter the unit lengthis called third bond and quarter bond, respectively.

Bond, stack: For structural design purposes, Building CodeRequirements for Masonry Structures considers all masonry notlaid in running bond as stack bond. [1] In common use, stack bondtypically refers to masonry laid so head joints in successive coursesare vertically aligned. Also called plumb joint bond, straight stack,jack bond, jack-on-jack and checkerboard bond.

Bond strength: The resistance to separation of mortar frommasonry units and of mortar and grout from reinforcing steeland other materials with which it is in contact.

Brick: A solid or hollow manufactured masonry unit of eitherconcrete, clay or stone.

Cantilever: A member structurally supported at only one endthrough a fixed connection. The opposite end has no structuralsupport.

Cap block: A solid slab used as a coping unit. May containridges, bevels or slopes to facilitate drainage. (See alsoCoping block.)

Cavity: A continuous air space between wythes of masonry orbetween masonry and its backup system. Typically greaterthan 2 in. (51 mm) in thickness. (See Collar joint.)

Cell: The hollow space within a concrete masonry unit formedby the face shells and webs. Also called core.

Cementitious material: A generic term for any inorganic materialincluding cement, pozzolanic or other finely divided mineraladmixtures or other reactive admixtures, or a mixture of suchmaterials that sets and develops strength by chemical reaction withwater. In general, the following are considered cementitiousmaterials: portland cement, hydraulic cements, lime putty, hydratedlime, pozzolans and ground granulated blast furnace slag. [3]

Cleanout/cleanout hole: An opening of sufficient size andspacing so as to allow removal of debris from the bottom ofthe grout space. Typically located in the first course ofmasonry. [2]

Cold weather construction: Procedures used to constructmasonry when ambient air temperature or masonry unittemperature is below 40F (4.4C).

Collar joint: A vertical longitudinal space between wythes ofmasonry or between masonry wythe and backup construction,sometimes filled with mortar or grout. Typically less than 2in. (51 mm) in thickness. [1] (See also Cavity.)

Color (pigment): A compatible, color fast, chemically stableadmixture that gives a cementitious matrix its coloring.

Column: (1) In structures, a relatively long, slender structuralcompression member such as a post, pillar, or strut. Usuallyvertical, a column supports loads that act primarily in thedirection of its longitudinal axis. (2) For the purposes of design,an isolated vertical member whose horizontal dimension measuredat right angles to the thickness does not exceed 3 times its thicknessand whose height is greater than 4 times it thickness. [1]

Composite action: Transfer of stress between components ofa member designed so that in resisting loads, the combinedcomponents act together as a single member. [1]

Compressive strength: The maximum compressive load thata specimen will support divided by the net cross-sectionalarea of the specimen.

Compressive strength of masonry: Maximum compressiveforce resisted per unit of net cross-sectional area of masonry,determined by testing masonry prisms or as a function ofindividual masonry units, mortar and grout in accordancewith ref. 2. [2] (See also Specified compressive strength ofmasonry.)

Concrete: A composite material that consists of a water reactivebinding medium, water and aggregate (usually a combinationof fine aggregate and coarse aggregate) with or withoutadmixtures. In portland cement concrete, the binder is amixture of portland cement, water and may contain admixtures.

Concrete block: A hollow or solid concrete masonry unit.Larger in size than a concrete brick.

Concrete brick: A concrete hollow or solid unit smaller insize than a concrete block.

Concrete masonry unit: Hollow or solid masonry unit,manufactured using low frequency, high amplitude vibrationto consolidate concrete of stiff or extremely dry consistency.

Connector: A mechanical device for securing two or morepieces, parts or members together; includes anchors, wall tiesand fasteners. May be either structural or nonstructural. [1]

Connector, tie: A metal device used to join wythes of masonryin a multiwythe wall or to attach a masonry veneer to itsbacking. [1] (See also Anchor.)

Control joint: A continuous unbonded masonry joint that isformed, sawed or tooled in a masonry structure to regulatethe location and amount of cracking and separation resultingfrom dimensional changes of different parts of the structure,thereby avoiding the development of high stresses.

Coping: The materials or masonry units used to form thefinished top of a wall, pier, chimney or pilaster to protect themasonry below from water penetration.

Coping block: A solid concrete masonry unit intended for useas the top finished course in wall construction.

Corbel: A projection of successive courses from the face ofmasonry. [1]

Core: (See Cell.)Corrosion resistant: A material that is treated or coated to

retard corrosive action. An example is steel that is galvanizedafter fabrication.

Course: A horizontal layer of masonry units in a wall or, muchless commonly, curved over an arch.

Crack control: Methods used to control the extent, size andlocation of cracking in masonry including reinforcing steel,control joints and dimensional stability of masonry materials.

Cull: A masonry unit that does not meet the standards orspecifications and therefore has been rejected.

Curing: (1) The maintenance of proper conditions of moistureand temperature during initial set to develop a requiredstrength and reduce shrinkage in products containing portlandcement. (2) The initial time period during which cementitiousmaterials gain strength.

Damp-proofing: The treatment of masonry to retard thepassage or absorption of water or water vapor, either byapplication of a suitable coating or membrane to exposedsurfaces or by use of a suitable admixture or treated cement.

Damp check: An impervious horizontal layer to preventvertical penetration of water in a wall or other masonryelement. A damp check consists of either a course of solidmasonry, metal or a thin layer of asphaltic or bituminousmaterial. It is generally placed near grade to prevent upwardmigration of moisture by capillary action.

14

Diaphragm: A roof or floor system designed to transmitlateral forces to shear walls or other lateral load resistingelements. [1]

Dimension, actual: The measured size of a concrete masonryunit or assemblage.

Dimension, nominal: The specified dimension plus anallowance for mortar joints, typically 3/8 in. (9.5 mm).Nominal dimensions are usually stated in whole numbers.Width (thickness) is given first, followed by height and thenlength. [1]

Dimension, specified: The dimensions specified for themanufacture or construction of a unit, joint or element.Unless otherwise stated, all calculations are based onspecified dimensions. Actual dimensions may vary fromspecified dimensions by permissible variations. [1]

Dowel: A metal reinforcing bar used to connect masonry tomasonry or to concrete.

Drip: A groove or slot cut beneath and slightly behind theforward edge of a projecting unit or element, such as a sill,lintel or coping, to cause rainwater to drip off and prevent itfrom penetrating the wall.

Drying shrinkage: The change in linear dimension of aconcrete masonry wall or unit due to drying.

Dry stack: Masonry work laid without mortar.Eccentricity: The distance between the resultant of an applied

load and the centroidal axis of the masonry element underload.

Effective height: Clear height of a braced member betweenlateral supports and used for calculating the slendernessratio of the member. [1]

Effective thickness: The assumed thickness of a member usedto calculate the slenderness ratio.

Efflorescence: A deposit or encrustation of soluble salts (generallywhite), that may form on the surface of stone, brick, concreteor mortar when moisture moves through the masonry materialsand evaporates on the surface. In new construction, sometimesreferred to as new building bloom. Once the structure dries, thebloom normally disappears or is removed with water.

Equivalent thickness: The solid thickness to which a hollowunit would be reduced if the material in the unit were recastinto a unit with the same face dimensions (height and length)but without voids. The equivalent thickness of a 100% solidunit is equal to the actual thickness. Used primarily todetermine masonry fire resistance ratings.

Expansion anchor: An anchoring device (based on a frictiongrip) in which an expandable socket expands, causing awedge action, as a bolt is tightened into it.

Face: (1) The surface of a wall or masonry unit. (2) Thesurface of a unit designed to be exposed in the finishedmasonry.

Face shell: The outer wall of a hollow concrete masonry unit. [5]Face shell mortar bedding: Hollow masonry unit construction

where mortar is applied only to the horizontal surface of theunit face shells and the head joints to a depth equal to thethickness of the face shell. No mortar is applied to the unitcross webs. (See also Full mortar bedding.)

Facing: Any material forming a part of a wall and used as afinished surface.

Fastener: A device used to attach components to masonry,typically nonstructural in nature.

Fire resistance: A rating assigned to walls indicating thelength of time a wall performs as a barrier to the passage of

flame, hot gases and heat when subjected to a standardizedfire and hose stream test. For masonry, fire resistance is mostoften determined based on the masonrys equivalent thicknessand aggregate type.

Flashing: A thin impervious material placed in mortar jointsand through air spaces in masonry to prevent water penetrationand to facilitate water drainage.

Fly ash: The finely divided residue resulting from thecombustion of ground or powdered coal.

Footing: A structural element that transmits loads directly tothe soil.

Freeze-thaw durability: The ability to resist damage fromthe cyclic freezing and thawing of moisture in materials andthe resultant expansion and contraction.

Full mortar bedding: Masonry construction where mortar isapplied to the entire horizontal surface of the masonry unitand the head joints to a depth equal to the thickness of theface shell. (See also Face shell mortar bedding.)

Glass unit masonry: Masonry composed of glass unitsbonded by mortar. [1]

Glazed block: A concrete masonry unit with a permanentsmooth resinous tile facing applied during manufacture.Also called prefaced block.

Ground face block: A concrete masonry unit in which thesurface is ground to a smooth finish exposing the internalmatrix and aggregate of the unit. Also called burnished orhoned block.

Grout: (1) A plastic mixture of cementitious materials,aggregates, water, with or without admixtures initiallyproduced to pouring consistency without segregation of theconstituents during placement. [3] (2) The hardenedequivalent of such mixtures.

Grout, prestressing: A cementitious mixture used toencapsulate bonded prestressing tendons. [2]

Grout, self-consolidating: Highly fluid and stable grout usedin high lift and low lift grouting that does not requireconsolidation or reconsolidation.

Grout lift: An increment of grout height within a total groutpour. A grout pour consists of one or more grout lifts. [2]

Grout pour: The total height of masonry to be grouted priorto erection of additional masonry. A grout pour consists ofone or more grout lifts. [2]

Grouted masonry: (1) Masonry construction of hollow unitswhere hollow cells are filled with grout, or multiwytheconstruction in which the space between wythes is solidlyfilled with grout. (2) Masonry construction using solidmasonry units where the interior joints and voids are filledwith grout.

Grouting, high lift: The technique of grouting masonry in liftsfor the full height of the wall.

Grouting, low lift: The technique of grouting as the wall isconstructed, usually to scaffold or bond beam height, but notgreater than 4 to 6 ft (1,219 to 1,829 mm), depending on codelimitations.

H block: Hollow masonry unit lacking cross webs at bothends forming an H in cross section. Used with reinforcedmasonry construction. (See also Open end block.)

Header: A masonry unit that connects two or more adjacentwythes of masonry. Also called a bonder. [1]

Height of wall: (1) The vertical distance from the foundationwall or other similar intermediate support to the top of thewall. (2) The vertical distance between intermediate supports.

15

Height-to-thickness ratio: The height of a masonry walldivided by its nominal thickness. The thickness of cavitywalls is taken as the overall thickness minus the width of thecavity.

High lift grouting: (See Grouting, high lift.)Hollow masonry unit: A unit whose net cross-sectional area

in any plane parallel to the bearing surface is less than 75 %of its gross cross-sectional area measured in the same plane.[4]

Honed block: (See Ground face block.)Hot weather construction: Procedures used to construct

masonry when ambient air temperature exceeds 100F(37.8C) or temperature exceeds 90F (32.2C) with a windspeed greater than 8 mph (13 km/h).

Inspection: The observations to verify that the masonryconstruction meets the requirements of the applicable designstandards and contract documents.

Jamb block: A block specially formed for the jamb of windowsor doors, generally with a vertical slot to receive windowframes, etc. Also called sash block.

Joint: The surface at which two members join or abut. If theyare held together by mortar, the mortar-filled volume is thejoint.

Joint reinforcement: Steel wires placed in mortar bed joints(over the face shells in hollow masonry). Multi-wire jointreinforcement assemblies have cross wires welded betweenthe longitudinal wires at regular intervals.

Lap: (1) The distance two bars overlap when forming a splice.(2) The distance one masonry unit extends over another.

Lap splice: The connection between reinforcing steel generatedby overlapping the ends of the reinforcement.

Lateral support: The means of bracing structural members inthe horizontal span by columns, buttresses, pilasters or crosswalls, or in the vertical span by beams, floors, foundations,or roofs.

Lightweight aggregate: Natural or manufactured aggregateof low density, such as expanded or sintered clay, shale,slate, diatomaceous shale, perlite, vermiculite, slag, naturalpumice, volcanic cinders, diatomite, sintered fly ash orindustrial cinders.

Lightweight concrete masonry unit: A unit whose oven-drydensity is less than 105 lb/ft3 (1,680 kg/m3). [4]

Lime: Calcium oxide (CaO), a general term for the variouschemical and physical forms of quicklime, hydrated limeand hydraulic hydrated lime.

Lintel: A beam placed or constructed over a wall opening tocarry the superimposed load.

Lintel block: A U-shaped masonry unit, placed with the openside up to accommodate horizontal reinforcement and groutto form a continuous beam. Also called channel block.

Loadbearing: (See Wall, loadbearing.)Low lift grouting: (See Grouting, low lift.)Manufactured masonry unit: A man-made noncombustible

building product intended to be laid by hand and joined bymortar, grout or other methods. [5]

Masonry: An assemblage of masonry units, joined withmortar, grout or other accepted methods. [5]

Masonry cement: (1) A mill-mixed cementitious material towhich sand and water is added to make mortar. (2) Hydrauliccement produced for use in mortars for masonry construction.

Medium weight concrete masonry unit: A unit whose oven-dry density is at least 105 lb/ft3 (1,680 kg/m3) but less than

125 lb/ft3 (2,000 kg/m3). [4]Metric: The Systeme Internationale (SI), the standard

international system of measurement. Hard metric refers toproducts or materials manufactured to metric specifieddimensions. Soft metric refers to products or materialsmanufactured to English specified dimensions, thenconverted into metric dimensions.

Mix design: The proportions of materials used to producemortar, grout or concrete.

Modular coordination: The designation of masonry units,door and window frames, and other construction componentsthat fit together during construction without customization.

Modular design: Construction with standardized units ordimensions for flexibility and variety in use.

Moisture content: The amount of water contained within aunit at the time of sampling expressed as a percentage of thetotal amount of water in the unit when saturated. [4]

Mortar: (1) A mixture of cementitious materials, fine aggregatewater, with or without admixtures, used to construct unitmasonry assemblages. [3] (2) The hardened equivalent ofsuch mixtures.

Mortar bed: A horizontal layer of mortar used to seat amasonry unit.

Mortar bond: (See Bond.)Mortar joint, bed: The horizontal layer of mortar between

masonry units. [1]Mortar joint, head: The vertical mortar joint placed between

masonry units within the wythe. [1]Mortar joint profile: The finished shape of the exposed

portion of the mortar joint. Common profiles include:Concave: Produced with a rounded jointer, this is the standardmortar joint unless otherwise specified. Recommended forexterior walls because it easily sheds water.Raked: A joint where 1/4 to 1/2 in. (6.4 to 13 mm) is removedfrom the outside of the joint.Struck: An approximately flush joint. See also Strike.

Net section: The minimum cross section of the member underconsideration.

Nonloadbearing: (See Wall, nonloadbearing.)Normal weight concrete masonry unit: A unit whose oven-

dry density is 125 lb/ft3 (2000 kg/m3) or greater. [4]Open end block: A hollow unit, with one or both ends open.

Used primarily with reinforced masonry construction. (SeeA block and H block.)

Parging: (1) A coating of mortar, which may contain damp-proofing ingredients, over a surface. (2) The process ofapplying such a coating.

Pier: An isolated column of masonry or a bearing wall notbonded at the sides to associated masonry. For design, avertical member whose horizontal dimension measured atright angles to its thickness is not less than three times itsthickness nor greater than six times its thickness and whoseheight is less than five times its length. [1]

Pigment: (See Color.)Pilaster: A bonded or keyed column of masonry built as part

of a wall. It may be flush or project from either or both wallsurfaces. It has a uniform cross section throughout its heightand serves as a vertical beam, a column or both.

Pilaster block: Concrete masonry units designed for use in theconstruction of plain or reinforced concrete masonry pilastersand columns.

Plain masonry: (See Unreinforced masonry.)16

Plaster: (See "Stucco.")Plasticizer: An ingredient such as an admixture incorporated

into a cementitious material to increase its workability,flexibility or extensibility.

Post-tensioning: A method of prestressing in whichprestressing tendons are tensioned after the masonry hasbeen placed. [1] See also Wall, prestressed.

Prestressing tendon: Steel element such as wire, bar orstrand, used to impart prestress to masonry. [1]

Prism: A small assemblage made with masonry units and mortarand sometimes grout. Primarily used for quality control purposesto assess the strength of full-scale masonry members.

Prism strength: Maximum compressive force resisted perunit of net cross-sectional area of masonry, determined bytesting masonry prisms.

Project specifications: The written documents that specifyproject requirements in accordance with the serviceparameters and other specific criteria established by theowner or owners agent.

Quality assurance: The administrative and proceduralrequirements established by the contract documents and bycode to assure that constructed masonry is in compliancewith the contract documents. [1]

Quality control: The planned system of activities used toprovide a level of quality that meets the needs of the usersand the use of such a system. The objective of quality controlis to provide a system that is safe, adequate, dependable andeconomic. The overall program involves integrating factorsincluding: the proper specification; production to meet thefull intent of the specification; inspection to determinewhether the resulting material, product and service is inaccordance with the specifications; and review of usage todetermine any necessary revisions to the specifications.

Reinforced masonry: (1) Masonry containing reinforcementin the mortar joints or grouted cores used to resist stresses.(2) Unit masonry in which reinforcement is embedded insuch a manner that the component materials act together toresist applied forces.

Reinforcing steel: Steel embedded in masonry in such amanner that the two materials act together to resist forces.

Retarding agent: An ingredient or admixture in mortar thatslows setting or hardening, most commonly in the form offinely ground gypsum.

Ribbed block: A block with projecting ribs (with either arectangular or circular profile) on the face for aestheticpurposes. Also called fluted.

Sash block: (See Jamb block.)Scored block: A block with grooves on the face for aesthetic

purposes. For example, the grooves may simulate raked joints.Screen block: An open-faced masonry unit used for decorative

purposes or to partially screen areas from the sun or from view.Shell: (See Face shell.)Shoring and bracing: The props or posts used to temporarily

support members during construction.Shrinkage: The decrease in volume due to moisture loss, decrease

in temperature or carbonation of a cementitious material.Sill: A flat or slightly beveled unit set horizontally at the base

of an opening in a wall.Simply supported: A member structurally supported at top

and bottom or both sides through a pin-type connection,which assumes no moment transfer.

Slenderness ratio: (1) The ratio of a members effective

height to radius of gyration. (2) The ratio of a member'sheight to thickness.

Slump: (1) The drop in the height of a cementitious materialfrom its original shape when in a plastic state. (2) Astandardized measurement of a plastic cementitious materialto determine its flow and workability.

Slump block: A concrete masonry unit produced so that itslumps or sags in irregular fashion before it hardens.

Slushed joint: A mortar joint filled after units are laid bythrowing mortar in with the edge of a trowel.

Solid masonry unit: A unit whose net cross-sectional area inevery plane parallel to the bearing surface is 75 percent or moreof its gross cross-sectional area measured in the same plane. [4]Note that Canadian standards define a solid unit as 100% solid.

Spall: To flake or split away due to internal or external forcessuch as frost action, pressure, dimensional changes afterinstallation, vibration, impact, or some combination.

Specified dimensions: (See Dimension, specified.)Specified compressive strength of masonry, f'

m: Minimum

masonry compressive strength required by contractdocuments, upon which the project design is based (expressedin terms of force per unit of net cross-sectional area). [1]

Split block: A concrete masonry unit with one or more facespurposely fractured to produce a rough texture for aestheticpurposes. Also called a split-faced or rock-faced block.

Stirrup: Shear reinforcement in a flexural member. [1]Strike: To finish a mortar joint with a stroke of the trowel or

special tool, simultaneously removing extruded mortar andsmoothing the surface of the mortar remaining in the joint.

Stucco: A combination of cement and aggregate mixed with asuitable amount of water to form a plastic mixture that willadhere to a surface and preserve the texture imposed on it.

Temper: To moisten and mix mortar to a proper consistency.Thermal movement: Dimension change due to temperature

change.Tie: (See Connector, tie.)Tolerance: The specified allowance in variation from a

specified size, location, or placement.Tooling: Compressing and shaping the face of a mortar joint

with a tool other than a trowel. See "Mortar joint profile" fordefinitions of common joints.

Unreinforced masonry: Masonry in which the tensileresistance of the masonry is taken into consideration and theresistance of reinforcement, if present, is neglected. Alsocalled plain masonry. [1]

Veneer, adhered: Masonry veneer secured to and supportedby the backing through adhesion. [2]

Veneer, anchored: Masonry veneer secured to and supportedlaterally by the backing through anchors and supportedvertically by the foundation or other structural elements.

Veneer, masonry: A masonry wythe that provides the finishof a wall system and transfers out-of-plane loads directly toa backing, but is not considered to add load resistingcapacity to the wall system. [1]

Wall, bonded: A masonry wall in which two or more wythesare bonded to act as a composite structural unit.

Wall, cavity: A multiwythe noncomposite masonry wall witha continuous air space within the wall (with or withoutinsulation), which is tied together with metal ties. [1]

Wall, composite: A multiwythe wall where the individualmasonry wythes act together to resist applied loads. (Seealso Composite action.)

17

NATIONAL CONCRETE MASONRY ASSOCIATION To order a complete TEK Manual or TEK Index,13750 Sunrise Valley Drive, Herndon, Virginia 20171 contact NCMA Publications (703) 713-1900www.ncma.org

Disclaimer: Although care has been taken to ensure the enclosed information is as accurate and complete as possible, NCMAdoes not assume responsibility for errors or omissions resulting from the use of this TEK.

Wall, curtain: (1) A nonloadbearing wall between columns orpiers. (2) A nonloadbearing exterior wall vertically supportedonly at its base, or having bearing support at prescribedvertical intervals. (3) An exterior nonloadbearing wall inskeleton frame construction. Such walls may be anchored tocolumns, spandrel beams or floors, but not

Wall, foundation: A wall below the floor nearest grade servingas a support for a wall, pier, column or other structural part ofa building and in turn supported by a footing.

Wall, loadbearing: Wall that supports vertical load in additionto its own weight. By code, a wall carrying vertical loadsgreater than 200 lb/ft (2.9 kN/m) in addition to its own weight. [1]

Wall, multiwythe: Wall composed of 2 or more masonrywythes.

Wall, nonloadbearing: A wall that supports no vertical loadother than its own weight. By code, a wall carrying verticalloads less than 200 lb/ft (2.9 kN/m) in addition to its ownweight. [1]

Wall, panel: (1) An exterior nonloadbearing wall in skeletonframe construction, wholly supported at each story. (2) Anonloadbearing exterior masonry wall having bearing supportat each story.

Wall, partition: An interior wall without structural function. [2]Wall, prestressed: A masonry wall in which internal

compressive stresses have been introduced to counteractstresses resulting from applied loads. [1]

Wall, reinforced: (1) A masonry wall reinforced with steelembedded so that the two materials act together in resistingforces. (2) A wall containing reinforcement used to resistshear and tensile stresses.

Wall, retaining: A wall designed to prevent the movement ofsoils and structures placed behind the wall.

Wall, screen: A masonry wall constructed with more than25% open area intended for decorative purposes, typicallyto partially screen an area from the sun or from view.

Wall, shear: A wall, bearing or nonbearing, designed to resistlateral forces acting in the plane of the wall. [1]

Wall, single wythe: A wall of one masonry unit thickness.

Wall, solid masonry: A wall either built of solid masonryunits or built of hollow units and grouted solid.

Wall tie: A metal connector that connects wythes of masonry.Wall tie, veneer: A wall tie used to connect a facing veneer to

the backing.Water permeance: The ability of water to penetrate through

a substance such as mortar or brick.Waterproofing: (1) The methods used to prevent moisture

flow through masonry. (2) The materials used to preventmoisture flow through masonry.

Water repellency: The reduction of absorption.Water repellent: Material added to the masonry to increase

resistance to water penetration. Can be a surface treatmentor integral water repellent admixture.

Web: The portion of a hollow concrete masonry unit connectingthe face shells.

Weep hole: An opening left (or cut) in mortar joints ormasonry face shells to allow moisture to exit the wall.Usually located immediately above flashing.

Workability: The ability of mortar or grout to be easily placedand spread.

Wythe: Each continuous vertical section of a wall, one masonryunit in thickness. [1]

REFERENCES1. Building Code Requirements for Masonry Structures, ACI 530-

02/ASCE 5-02/TMS 402-02. Reported by the Masonry StandardsJoint Committee, 2002.

2. Specification for Masonry Structures, ACI 530.1-02/ASCE 6-02/TMS 602-02. Reported by the Masonry Standards Joint Commit-tee, 2002.

3. Standard Terminology of Mortar and Grout for Unit Masonry,ASTM C 1180-03. ASTM International, 2003.

4. Standard Terminology of Concrete Masonry Units and RelatedUnits, ASTM C 1209-01a. ASTM International, 2001.

5. Standard Terminology of Masonry, ASTM C 1232-02. ASTMInternational, 2002.

6. Concrete Masonry Bond Patterns, TEK 14-6. National ConcreteMasonry Association, 1999.

Provided by:

18

TEK 2-1A 2002 National Concrete Masonry Association

NCMA TEKNational Concrete Masonry Associationan information series from the national authority on concrete masonry technology

Figure 1Nominal and Actual Unit Dimensions

Actual Unit Dimensions

Nominal Unit Dimensions

8" (203 mm)

75/8" (194 mm)

16" (406 m

m)

155/8" (397

mm)

8" (203 mm)

75/8" (194 mm)

INTRODUCTION

Concrete masonry is one of the most versatile buildingproducts available because of the wide variety of appearancesthat can be achieved using concrete masonry units. Concretemasonry units are manufactured in different sizes, shapes,colors, and textures to achieve a number of finishes andfunctions. In addition, because of its modular nature, differentconcrete masonry units can be combined within the same wallto achieve variations in texture, pattern, and color.

Certain concrete masonry sizes and shapes are consideredstandard, while others are popular only in certain regions. Localmanufacturers can provid