04 20 00 - UNIT MASONRY.pdf

MINISTRY OF HOUSING Western Sector Projects Sitework & Infrastructure OMRANIA and ASSOCIATES Project Specification

UNIT MASONRY SECTION 04 20 00 - 1

SECTION 04 20 00

UNIT MASONRY PART 1: GENERAL

1.01 SECTION INCLUDES

A. Unit Masonry including, but not limited to the following:

1. Concrete masonry units.

2. Fair face blockwork.

3. CMU internal partitions.

4. Autoclaved Aerated Concrete (AAC) internal partitions.

5. Reinforcement, anchorage and accessories.

1.02 RELATED SECTIONS

A. Section 01 45 23 Testing Services.

B. Section 01 77 00 Contract Closeout.

C. Section 04 05 03 Mortar and Masonry Grout.

D. Section 07 14 00 Fluid Applied Waterproofing.

E. Section 07 21 13 Board Insulation.

F. Section 07 21 16 Blanket Insulation.

G. Section 07 84 00 Firestopping.

H. Section 07 62 00 Sheet Metal Flashing & Trim.

I. Section 07 92 00 Joint Sealers.

J. Section 09 91 00 Painting.

1.03 REFERENCES

A. ACI 530 Building Code Requirements for Masonry Structures.

B. ACI 530.1 Specifications for Masonry Structures.

C. ASTM A 82 Standard Specification for Steel Wire, Plain, for Concrete Reinforcement.

D. ASTM A 123 Standard Specification for Zinc (Hot-Dip Galvanized) Coatings on Iron and Steel Products.

E. ASTM A 641 Standard Specification for Zinc-Coated (Galvanized) Carbon Steel Wire.

F. ASTM A653 M Standard Specification for Steel Sheet, Zinc-Coated (Galvanized) or Zinc-Iron Alloy-Coated (Galvannealed) by the Hot-Dip Process.



G. ASTM B 370 Standard Specification for Copper Sheet and Strip for Building Construction.

H. ASTM C 90 Standard Specification for Loadbearing Concrete Masonry Units.

I. ASTM C 129 Standard Specification for Nonloadbearing Concrete Masonry Units.

J. ASTM C 1386 Standard Specification for Autoclaved Aerated Concrete Wall Construction Units.

K. ASTM C1691-11 Standard Specification for Unreinforced Autoclaved Aerated Concrete (AAC) Masonry Units.

L. ASTM C1693 Specification for Autoclaved Aerated Concrete.

M. BS EN 771-4:2001 Specification for Masonry Units. Autoclaved Aerated Concrete Masonry Units.

N. C90-97 Specification for Load-Bearing Concrete Masonry Units.

O. C140-96b Method of Sampling & Testing Concrete Masonry Units.

P. C150-97 Specification for Portland Cement.

Q. IMIAC International Masonry Industry All-Weather Council: Recommended Practices and Guide Specification for Hot Weather Masonry Construction.

R. Fire Resistance Directory.

S. E119 Method for Fire Tests of Building Construction & Materials.

1.04 SUBMITTALS

A. Comply with Section 01 33 00.

B. Manufacturer's certificate: Certify that products meet or exceed specific requirements.

C. Product Data: Submit product data for each different concrete masonry unit, accessory and other manufactured product, for incorporation in the works.

D. Shop drawings for fabrication, bending & placement of concrete masonry reinforcing bars.

E. Certification of asbestos-free & lead-free status of all masonry materials & accessories.

F. Material certificates, signed by the manufacturer & contractor, certifying that each of the following materials complies with the requirements of this contract, Saudi Arabian law & industry best practice:

a. Each different cement product required for mortar & grout, including name of manufacturer, brand and type.

b. Each material & grade of reinforcing bars.

c. Each type & size of joint reinforcement.

d. Each type & size of anchor, ties & metal accessoroes.

e. Each masonry unit type.



1.05 QUALITY ASSURANCE

A. Perform work in accordance with ACI 530 and ACI 530.1.

B. Where indicated on drawings, provide materials & construction identical to those of assemblies for which fire resistance has been determined per ASTM E119 by Underwriters Laboratories.

C. Obtain concrete masonry units of uniform texture and colour, within ranges acceptable to the engineer for these characteristics, from one manufacturer for each different product required.

D. Obtain mortar materials of uniform quality from one manufacturer for each cementitious component and from one quarry & producer for each aggregate.

E. All masonry units used shall be sound, free of cracks or other defects that may interfere with proper placing of the unit or impair strength of construction.

F. Finished fairfaced masonry shall not show chips cracks or imperfections when viewed from a distance of 6.1m.

G. Use of damaged items is prohibited except by specific authorization of the engineer on a case-by case basis.

H. The following testing of masonry shall be conducted at contractor expense, by a qualified independent testing laboratory:

a. Frequency per each 5000 sq.ft. (465 sq.m.) of wall area, or as directed by the engineer. b. Strength, absorption & moisture content per ASTM C140, for each masonry unit type. c. Masonry prism tests per ASTM E447, Method B, at 7 days & 28 days.

I. Maintain one copy of each document on site.

1.06 QUALIFICATIONS

A. Manufacturers: Company specializing in manufacturing the products specified in this section with minimum 5 years experience.

1.07 DELIVERY, STORAGE AND HANDLING


B. Deliver masonry to site in undamaged condition.

C. Store & handle masonry units & cementitious materials off the ground, under cover, in a dry location & prevent deterioration or damage due to moisture, temperature changes, contaminants, corrosion or other causes. If masonry units become wet, do not place until in an air-dried condition.

D. Blocks delivered to site shall be carefully unloaded and handled so as to prevent chipping and breakage. Tipping shall not be allowed. The blocks shall be stacked on a level area in an orderly manner on planks or other suitable supports to ensure that they are free from contact with the ground.

E. Store aggregates in a manner such that grading & other required characteristics can be maintained & contamination avoided. Store different aggregates separately.

F. Store masonry accessories including metal items, off the ground, in a manner which will prevent corrosion, accumulation of dirt & oil or permanent corrosion.



G. Each block manufactured from sulfate resisting cement shall be color coded with a green identifying mark and shall be stored separately.

PART 2: PRODUCTS 2.01 ACCEPTABLE MANUFACTURERS

Not used.

2.02 CONCRETE MASONRY UNITS

A. Extent of each type of masonry work shall be as shown on the Drawings and the provisions of this Section.

B. Hollow and solid load bearing concrete units shall comply with ASTM C 90, Type 1, normal.

C. Masonry unit sizes:

1. Module 92 mm x 203 mm x 406 mm. Units 92 mm x 194 mm x 397 mm.

2. Module 142 mm thick x 203 mm high x 406 mm long. Units 142 mm x 194 mm x 397 mm.

3. Module 194 mm thick x 203 mm high x 406 mm long. Units 194 mm x 194 mm x 397 mm.

D. Blocks up to 92mm thick shall be solid, & blocks of greater thickness hollow, unless otherwise approved by the Engineer.

E. The minimum compressive strength of blocks shall be as following unless shown otherwise on drawings:

1. Blocks up to 92 mm thick - 5.5 N/mm²

2. Blocks over 92 mm thick - 8.6 N/mm²

2.03 MATERIALS FOR CONCRETE BLOCKS

A. Cement shall conform to the requirements of Section 03 30 00.

B. Coarse aggregates shall conform to ACI 530 and ACI 530-1 for grading and to the requirements of this Section with maximum 10 mm nominal size.

C. Sand shall conform to ACI 530 and ACI 530-1, Table 5 Zones C and M.

D. Coarse aggregate and sand shall meet the same requirements for chlorides and sulphates as the sand for mortar as specified in Section 04 05 13.13.

2.04 MANUFACTURE OF CONCRETE BLOCKS

A. Blocks shall be manufactured by the use of vibration machinery and shall be cast on removable pallets. They shall be left on pallets to cure for ten days during which time they shall be kept damp and shall be protected from direct sunlight, drying winds, heavy rain and frost. No blocks shall be used in the works until they have attained an age of twenty-eight days.

B. Blocks shall be made with Ordinary Portland Cement unless used below ground, in which case sulphate resisting cement shall be used.



C. The thickness of the webs and walls shall not be less than 30 mm and the volume of the cavities in the block shall not exceed 50% of the gross volume of the block.

D. All surfaces shall be flat and rectangular and adjacent surfaces shall be at right angles to one another with clearly defined undamaged arises. Unless otherwise specified, all block faces shall provide a satisfactory bond for mortar, plastering or rendering.

2.05 SPECIAL CONCRETE BLOCKS

A. Where vertical reinforcement is to be used special hollow blocks and half blocks of the same quality as standard blocks shall be provided, having slots in the ends or sides to allow them to be fitted round the vertical reinforcement. Samples shall be submitted to the Engineer.

2.06 REINFORCEMENT AND ANCHORAGE

A. Horizontal reinforcement for single wythe joint: Ladder type design with a minimum 5 mm (7 gage) deformed side wires and welded 2.8 mm (12 gage) or larger cross wires, factory fabricated from steel wire conforming to ASTM A 82. Wires shall have zinc coating conforming to ASTM A 641 Class 3 after fabrication. Reinforcement shall have one longitudinal wire in mortar bed of each face for hollow units and one wire for solid units. Joint reinforcement shall be placed a minimum of 16 mm cover from either face. The distance between cross wires shall not exceed 400 mm. Joint reinforcement for straight runs shall be furnished in flat sections not less than 3 m long. Joint reinforcement shall be provided with factory formed corners and intersections.

B. Vertical reinforcing steel: ASTM A 615 grade 60, deformed billet bars, uncoated finish.

C. Metal anchorages for connecting or tying blockwork:

1. Anchorage to Concrete: Anchorage of masonry to the face of concrete columns, beams, or walls shall be with dovetail anchors spaced not over 400 mm on centers vertically and 600 mm on center horizontally.

2. Anchorage to Structural Steel: Masonry shall be anchored to vertical structural steel framing with adjustable steel wire anchors spaced not over 400 mm on centers vertically, and where applicable, not over 600 mm on centers horizontally.

2.07 MORTAR AND GROUT

A. Mortar and grout: As specified in Section 04 05 13.13.

2.08 TIES & ANCHORS

A. Galvanized Carbon Steel Wire: ASTM A82, hot-dip galvanized after fabrication to comply with ASTM A153, Class B2. Wire diameter 0.1875 inch (4.76 mm), unless otherwise indicated.

B. Galvanized Steel Sheet: ASTM A366 (commercial quality) cold-rolled carbon steel sheet hot-dip galvanized after fabrication to comply with ASTM A525, for sheet metal ties and anchors. Minimum thickness 0.0598 inch (16 gage) (1.52 mm), unless otherwise indicated.

C. Steel Plates and Bars: ASTM A36, hot-dip galvanized to comply with ASTM A123 or ASTM A153, Class B3, as applicable to size and form indicated.

D. Bent Wire Ties: Individual units prefabricated from bent wire to comply with requirements indicated below:



1. Tie Shape for Hollow Masonry Units Laid with Cells Vertical: Rectangular with closed ends and not less than 4 inches (102 mm) wide.

2. Tie Shape for Solid Masonry Unit Construction: Z-shaped ties with ends bent 90 degrees to provide hooks not less than 2 inches (51 mm) long.

E. Adjustable Anchors for Connecting Masonry to Structural Framework: Provide two-piece

assemblies as described below allowing vertical or horizontal differential movement between wall and framework parallel to plane of wall, but resisting tension and compression forces perpendicular to it.

1. For anchorage to concrete framework, provide manufacturer's standard with dovetail anchor section formed from sheet metal and triangular-shaped wire tie section sized to extend within 1 inch (25 mm) of masonry face. Wire diameter 0.1875 inch ( 4.76 mm).

2. For anchorage to steel framework provide manufacturer's standard anchors with crimped 1/4-inch (6.35 mm) diameter wire anchor section for welding to steel and triangular- shaped wire tie section sized to extend within 1 inch (25 mm) of masonry face. Wire diameter 0.1875 inch (4.76 mm).

F. Rigid Anchors: Provide straps of form and length indicated, fabricated from metal strips of following width and thickness.

1. 1-1/2 inches (38.1 mm) wide by 1/4 inch (6.35 mm) thick, unless otherwise indicated.

G. Miscellaneous Anchors

1. Unit Type Masonry Inserts in Concrete: Cast iron or malleable iron inserts of type and size indicated.

2. Dovetail Slots: Furnish dovetail slots, with filler strips, of slot size indicated, fabricated from 0.0336-inch (22-gage) (0.8534 mm) sheet metal.

3. Anchor Bolts: Steel bolts complying with A307, Grade A; with ASTM A563 hex nuts and, where indicated, flat washers; hot-dip galvanized to comply with ASTM A153, Class C; of diameter, length and type indicated on the drawings.

2.09 PRECAST CONCRETE ITEMS

1. Trim, lintels, copings and doorsills shall be factory-made units from a plant regularly engaged in producing precast concrete units. Concrete members weighing over 35 kg shall have built-in loops of galvanized wire or other approved provisions for lifting and anchoring.

2. Unless otherwise indicated, concrete shall be 30 MPa at 28 days minimum conforming to Section 03 30 00. Provide the minimum reinforcement required for handling of the units with clearance of 20 mm maintained between reinforcement and faces of units.

3. Precast lintels: Provide over openings and unless otherwise shown, shall be of a thickness equal to the wall and reinforced with two No. 4 bars for the full length. Lintels shall be labeled or clearly marked to show location in the structure.

4. Sills and Copings: Sills and copings shall be cast with washes. Sills for windows having mullions shall be cast in sections with head joints at mullions and a 6 mm allowance for mortar joints. The ends of sills, except a 20 mm wide margin at exposed surfaces, shall be roughened for bond. Treads of doorsills shall have rounded nosings.

2.10 AERATED AUTOCLAVED CONCRETE MASONRY



A. Internal partitions between air conditioned & non-air conditioned spaces are to be of Aerated Autoclaved Concrete masonry construction, per wall type indications on the architectural drawings.

B. AAC masonry units shall comply with ASTM 1386 & ASTM C1691-11.

C. AAC masonry unit sizes: 200 mm width x 200 mm height x 600 mm length.

D. AAC strength class to engineers approval.

E. AAC masonry reinforcement & structural design is to be per structural engineering drawings.

PART 3: EXECUTION 3.01 SAMPLES AND TESTING

A. Samples of each type of block manufactured on the site or delivered to the site shall be submitted to and approved by the Engineer before use. All subsequent blocks shall be up to the standard of the approved samples.

B. Initially 12 blocks shall be selected by the Engineer from the first batch of blocks manufactured or delivered, and shall be marked for future identification as instructed by the Engineer. The blocks shall be delivered by the Contractor to an approved independent testing laboratory.

C. Samples shall be accompanied by the following written information:

1. Name of Manufacturer.

2. Type of block making machine.

3. Capacity of plant and present stocks available.

4. Type of block.

5. Means of identification of block.

6. Authoritative evidence that the blocks are suitable for the purposes for which they are to be used.

D. Further samples shall be selected and tested as directed by the Engineer or if the supplier is changed. The Contractor will not be permitted to change his source of supply without the permission of the Engineer.

3.02 SAMPLE PANELS OF CONCRETE BLOCKWORK

A. Two sample panels 1.6 m long x 2.0 m high shall be constructed for the Engineer's approval, including a corner and a junction, with mortar pointing as specified, as an example of the standard to be achieved and no permanent work shall commence until such approval is given.

3.03 EXAMINATION

A. Verify that field conditions are acceptable and are ready to receive work.

B. Verify items provided by other sections of work are properly sized and located.

C. Verify that built-in items are in proper location, and ready for roughing into masonry work.

3.04 PROJECT CONDITIONS



A. Protection of Masonry: During erection, cover tops of walls, projections, and sills with waterproof sheeting at end of each day's work. Cover partially completed masonry when construction is not in progress. Extend cover a minimum of 24 inches (610 mm) down both sides and hold cover securely in place.

B. Do not apply uniform floor or roof loads for at least 12 hours and concentrated loads for at least 3 days after building masonry walls or columns.

C. Stain Prevention: Prevent grout, mortar, and soil from staining the face of masonry to be left exposed or painted. Remove immediately any grout, mortar, and soil that come in contact with such masonry.

1. Protect base of walls from rain-splashed mud and mortar splatter by means of coverings spread on ground and over wall surface.

2. Protect sills, ledges, and projections from mortar droppings.

3. Protect surfaces of windows and door frames, as well as similar products with painted and integral finishes from mortar droppings.

D. Cold-Weather Construction: Comply with the following when ambient temperature falls below 40o F (4.4o C).

1. General: Remove masonry damaged by freezing conditions. Do not lay masonry units having temperature below 20o F (-6.7o C). Remove visible ice on masonry units before the unit is laid.

2. Specific requirements for various temperature ranges are as follows:

a. Aggregates and mixing water shall be heated to produce mortar and grout temperatures between 40o F (4.4o C) and 120o F(48.9o C) at the time of mixing.

b. Maintain mortar temperature on mortar boards above freezing until used on masonry.

c. When ambient temperature is between 20o F (-6.7o C) and 25o F (-3.9o C), provide heat sources on both sides of walls under construction and install wind breaks when wind velocity exceeds 15 miles per hour (24 km per hour).

d. When ambient temperature is below 20o F (-6.7o C), provide enclosures and heat sources to maintain the temperatures above 32o F (0o C) within the enclosure.

3. Protection

a. When mean daily temperature is between 40o F (4.4o C) and 32o F (0o C), protect completed masonry from rain or snow by covering with weather-resistive membrane for 24 hours after construction.

b. When mean daily temperature is between 32o F (0o C) and 25o F (-3.9o C), completely cover completed masonry with weather-resistive membrane for 24 hours after construction.

c. When mean daily temperature is between 25o F (-3.9o C) and 20o F (-6.7o

d. When mean daily temperature is below 20

C), completely cover completed masonry with insulating blankets or equal protection for 24 hours after construction.

o F (-6.7o C), maintain masonry temperature above 32o F (0o C) for 24 hours after construction by enclosure with



supplementary heat, by electric heating blankets, by infrared heat lamps, or by other acceptable methods.

E. Hot-Weather Construction: Protect masonry construction from direct exposure to wind and sun when erected in ambient temperature of 90o F (32o

1. Do not spread mortar beds more than 4 feet (1.2 m) ahead of masonry. Set masonry units within one minute of spreading mortar. Dampen, but do not saturate masonry units immediately before installation.

C) or greater in the shade, with a relative humidity less than 50%.

2. Mortar can be retempered with cool water only once to maintain consistency.

3. Protection: When the mean daily temperature exceeds 100o F (38o C) or exceeds 90o F (32o

3.05 PREPARATION

C) with a wind velocity greater than 8 mph, fog spray all newly constructed masonry until damp, at least three times a day until the masonry is three days old.

A. Direct and coordinate placement of metal anchors supplied to other sections.

B. Clean all reinforcement by removing mud, oil, or other materials that will adversely affect or reduce bond at the time mortar or grout is placed. Reinforcement with rust and/or mill scale will be accepted, provided the dimensions and weights, including heights of deformations, are not less than required by the ASTM specification covering this reinforcement in this Specification.

C. Prior to placing masonry, remove laitance, loose aggregate, and anything else that would prevent mortar from bonding.

D. Provide temporary bracing during installation of masonry work. Maintain in place until building structure provides permanent bracing.

3.06 COURSING

A. Establish lines, levels, and coursing indicated. Protect from displacement.

B. Maintain masonry courses to uniform dimension. Form vertical and horizontal joints of uniform thickness.

C. Concrete Masonry Units:

1. Bond: Running.

2. Coursing: One unit and one mortar joint to equal 200 mm.

3. Mortar Joints: Flush.

3.07 PLACING AND BONDING

A. Lay solid masonry units in full bed of mortar, with full head joints, uniformly jointed with other work.

B. Lay hollow masonry units with face shell bedding on head and bed joints.

C. Buttering corners of joints or excessive furrowing of mortar joints are not permitted.

D. Remove excess mortar as work progresses.



E. Interlock intersections and external corners.

F. Do not shift or tap masonry units after mortar has achieved initial set. Where adjustment must be made, remove and replace.

G. Perform job site cutting of masonry units with proper tools to provide straight, clean, unchipped edges. Prevent broken masonry unit corners or edges.

H. The surface of the blocks shall be wetted before laying in order to prevent too rapid drying out of the mortar. On no account shall blockwork be saturated with water. The tops of walls left off from a previous days work shall be similarly wetted before any new work is commenced.

I. During block laying, an open joint not more than 13 mm wide shall be left between the end of all concrete lintels whether precast or cast in-situ, and the blocks adjacent to those ends. These open joints shall be left as long as possible during construction and not filled in until plastering or other work renders such filling necessary. All such joints shall be properly filled in before the completion of the work. 1200 gauge polythene sheet shall be laid on the blockwork under the concrete lintel bearing.

J. The horizontal 10 mm joints between blockwork internal partitions and soffits of beams or slabs shall be left clear and free from mortar and compressible joint filler shall be packed into the joint. In fairface blockwork the exposed faces of the joint shall be sealed with a suitable non-hardening sealant.

K. All corners and intersections of blockwork walls are to be bonded or tied at every other course for the full height of the wall, unless movement joints are required.

L. Mortar joints for fairface block unit wall shall be packed joints.

3.08 REINFORCEMENT AND ANCHORAGE - SINGLE WYTHE MASONRY

A. Install horizontal joint reinforcement as shown in the following table:

Reinforcement Spacing

None 400 mm Vertically

400 mm Vertically

200 mm Vertically

Maximum L/H

Maximum L

2

12.25 m

2.5

13.75 m

3

15.25 m

4

18.25 m

B. Place masonry joint reinforcement in first and second horizontal joints above and below openings. Extend minimum 800 mm each side of opening.

C. Place joint reinforcement continuous in first joint below top of walls.

D. Lap joint reinforcement ends minimum 150 mm.

E. At all openings in blockwork walls, two continuous voids of hollow blockwork for the full height of the wall immediately adjacent to the opening shall be completely filled with class C200 concrete, with maximum aggregate size 10 mm. The two filled voids shall be reinforced with one 12 mm diameter mild steel bar per void, lapped 500 mm and secured with galvanized tying wire. The minimum clear distance between the reinforcement and the inner face of the wall of the block shall be 12 mm. Blockwork walls containing reinforcement shall be constructed in 400 mm lifts with the concrete surrounding the reinforcement compacted by hand tamping immediately after placing.



F. Special structural requirements for vertical and horizontal reinforcement shall be as shown on the Drawings.

G. Lateral Support: The ratio of unsupported height or length of a wall to its thickness shall not exceed 20 for a “bearing wall” of solid masonry laid in type M S N or O mortar, nor 12 if laid in type K mortar, and shall not exceed 18 for hollow walls or walls of hollow units.

H. Horizontal Bond Beams: Where horizontal bond beams are required for lateral support, they shall be located at door head height and as directed by the Engineer.

I. Lateral Support for masonry shall be in accordance with ANSI A 41.1, the distance between lateral supports of non bearing partitions shall not exceed 36 times the thickness of the partition including plaster. Horizontal lateral support may be obtained from cross walls or columns. Vertical lateral support may be obtained from floors and soffits.

J. Where blockwork abuts steel columns, concrete columns or concrete walls, it shall be secured to them with L-shaped galvanized steel ties 175 mm long x 25 mm wide x 3 mm thick, with a 75 mm long right angle return at one end. The ties shall be built into the blockwork at every second course vertically and the return pinned to the steelwork or concrete with washered steel pins applied with a cartridge assisted hand tool or by any other method acceptable to the Engineer.

K. Where necessary to limit the distance between lateral supports to within permissible limits, walls shall be restrained at the soffit of slabs and beams by means of 100 x 100 x 3 mm galvanized mild steel angles fixed to the concrete at 2.0 m centres on either side of the blockwork using washered steel pins applied with a cartridge assisted handtool or by means acceptable to the Engineer and the blockwork/concrete joint shall be packed with compressible joint filler. Where the face of the wall is in the same plane as the side of a beam, the angle shall be replaced with a galvanized mild steel flat plate, 150 mm wide by 8 mm thick, to allow fixing to the beam above the level of the main reinforcement.

L. Where wall construction comprises a concrete leaf and blockwork leaf, with or without a cavity between, the blockwork leaf shall be secured to the concrete leaf by galvanized steel L shaped ties 25 mm wide x 3 mm thick, of length to suit the thickness of the blockwork leaf and width of the cavity (if any). The tie shall have a 75 mm long right angle return at one end. The ties shall not extend within 20 mm of the external face of the blockwork leaf. Ties shall be pinned to the concrete leaf with washered steel pins applied with a cartridge assisted hand tool or by any other method acceptable to the Engineer.

3.09 LINTELS, PADSTONES ETC.

A. Lintels, padstones, sills and copings etc. shall be set in a full bed of mortar of the specified quality with faces plumb and true to line and level. Precast lintels shall have a minimum bearing length of 200 mm unless otherwise indicated on the drawings.

B. Design of reinforcement and concrete shall comply with clause 2.06 of this Section such that mortar shall be able to carry all loading without deflection or cracking.

C. Lintels, padstones etc. shall bear on to solid or filled blocks for the full depth of the wall.

D. In-situ cast lintels and padstones etc. shall be poured directly onto the last whole course of blockwork.

3.10 ENGINEERED MASONRY

A. Lay masonry units with core cells vertically aligned clear of mortar and unobstructed.



B. Place mortar in masonry unit bed joints back 6 mm from edge of unit grout spaces, bevel back and upward. Permit mortar to cure 3 days before placing grout.

C. Reinforce masonry unit cores and cavities with reinforcement bars and grout as indicated.

D. Retain vertical reinforcement in position at top and bottom of cells and at intervals not exceeding 190 bar diameters.

E. Wet masonry unit surfaces in contact with grout just prior to grout placement.

3.11 BUILT-IN WORK

A. As work progresses, install built-in metal door and glazed frames, fabricated metal frames, window frames, anchor bolts, plates, and other items to be built-in the work and furnished by other sections.

B. Install built-in items plumb and level.

C. Bed anchors of metal door and glazed frames in adjacent mortar joints. Fill frame voids solid with grout. Fill adjacent masonry cores with grout minimum 300 mm from framed openings.

D. Do not build in organic materials subject to deterioration.

3.12 TOLERANCES

A. Maximum variation from alignment of pilasters: 6 mm.

B. Maximum variation from unit to adjacent unit: 1.6 mm.

C. Maximum variation from plane of wall: 6 mm/3 m and 13 mm/6 m or more.

D. Maximum variation from plumb: 6 mm per story non-cumulative; 13 mm in two stories or more.

E. Maximum variation from level coursing: 3 mm/1 m and 6 mm/3 m; 13 mm/9 m.

F. Maximum variation of joint thickness: 3 mm/m.

G. Maximum variation from cross sectional thickness of walls: 6 mm.

3.13 CUTTING AND FITTING

A. Cut and fit for chases, pipes, conduit, sleeves, Coordinate with other sections of work to provide correct size, shape, and location.

B. Obtain approval prior to cutting or fitting masonry work not indicated or where appearance or strength of masonry work may be impaired.

3.14 FIRE STOPPING

A. Where walls indicated on the Drawings as fire resisting walls abut the underside of concrete floor slabs or beams, the top joint shall be filled with a ceramic fibre blanket made from kaolin or synthetic mixes of alumina and silica or of an equivalent composition satisfying the requirements of UL for two-hour fire resistance and having a density of not less than 96 kg/m3

B. The material shall be fixed in strict accordance with the manufacturer's instructions.

. Movement joints in walls indicated on the Drawings as fire resisting walls shall be similarly filled with a ceramic fibre blanket prior to sealing as specified elsewhere in the Specification.



3.15 CONTROL JOINTS

A. Generally control joints to limit cracking due to drying shrinkage are to be incorporated into the blockwork at centers not exceeding 6 meters. Where this dimension is exceeded, horizontal reinforcement shall be provided. Submit proposals for the location of control joints for the approval of the Engineer.

B. Walls shall be built in the normal stretcher bond with the exception that on alternate courses, purpose made half blocks shall be used to form a straight vertical joint. Control joints so formed are to be carried through all finishes. Plaster finishes shall incorporate plaster stops. Control joints in all fire resisting walls as defined on the drawings shall be formed using a ceramic fiber blanket as specified herein.

3.16 EXPANSION JOINTS

A. Expansion joints in masonry structures shall be formed by means of a closed cell filler board placed between the two adjoining panels of masonry.

B. Ensure that the expansion jointing is not bridged at any point by solid material so that the joint is made ineffective.

C. At exposed faces of expansion joints, the filler shall be cut back 20 mm on completion of the structure and the joint sealed with a joint sealant.

3.17 FIELD QUALITY CONTROL


B. Inspect and test all masonry work.

C. Inspect and test all engineered masonry work.

3.18 CLEANING

A. Clean work under provisions of Section 01 77 00.

B. Remove excess mortar and mortar smears as work progresses.

C. Replace defective mortar. Match adjacent work.

D. Clean soiled surfaces with cleaning solution.

E. Use non-metallic tools in cleaning operations.

3.19 PROTECTION OF FINISHED WORK


B. Without damaging completed work, provide protective boards at exposed external corners which may be damaged by construction activities.

END OF SECTION

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04 20 00 - UNIT MASONRY.pdf