04 20 00 Unit Masonry.docx

08-01-17

SECTION 04 20 00

UNIT MASONRY

GENERAL

SUMMARY

Section Includes: Concrete masonry unit (CMU) assemblies for:

Exterior walls.

RELATED REQUIREMENTS

Sealants and Sealant Installation: Section 07 92 00, JOINT SEALANTS.

APPLICABLE PUBLICATIONS

Comply with references to extent specified in this section.

American Concrete Institute (ACI):

315‑99 - Details and Detailing of Concrete Reinforcement.

530.1/ASCE 6/TMS 602‑13 - Specification for Masonry Structures.

ASTM International (ASTM):

A615/A615M‑15ae1 - Deformed and Plain Carbon‑Steel Bars for Concrete Reinforcement.

A951/A951M‑14 - Steel Wire for Masonry Joint Reinforcement.

A1064/A1064M‑15 - Carbon‑Steel Wire and Welded Wire Reinforcement, Plain and Deformed, for Concrete.

C67‑14 - Sampling and Testing Brick and Structural Clay Tile.

C90‑14 - Load‑Bearing Concrete Masonry Units.

C216‑15 - Facing Brick (Solid Masonry Units Made From Clay or Shale).

D1056‑14 - Flexible Cellular Materials - Sponge or Expanded Rubber.

D2240‑05(2010) - Rubber Property‑Durometer Hardness.

American Welding Society (AWS):

D1.4/D1.4M‑11 - Structural Welding Code - Reinforcing Steel.

Brick Industry Association (BIA):

TN 11B‑88 - Guide Specifications for Brick Masonry, Part 3.

Federal Specifications (Fed. Spec.):

FF‑S‑107C(2) - Screws, Tapping and Drive.

SUBMITTALS

Submittal Procedures: Section 01 33 23, SHOP DRAWINGS, PRODUCT DATA, AND SAMPLES.

Submittal Drawings:

Fabrication, bending, and placement of reinforcing bars. Comply with ACI 315. Show bar schedules, diagrams of bent bars, stirrup spacing, lateral ties and other arrangements and assemblies.

Special masonry shapes, profiles, and placement.

Manufacturer's Literature and Data:

Description of each product.

Installation instructions.

Samples:

Face brick: Sample panel, 200 mm by 400 mm (8 inches by 16 inches,) showing full color range and texture of bricks, bond, and proposed mortar joints.

Concrete masonry units, when exposed in finish work.

Anchors and Ties: Each type.

Joint Reinforcing: 1200 mm (48 inches) long each type.

Certificates: Certify products comply with specifications.

Face brick.

Solid and load‑bearing concrete masonry units, including fire‑resistant rated units.

Delegated Design Drawings and Calculations: Signed and sealed by responsible design professional.

QUALITY ASSURANCE

Welders and Welding Procedures Qualifications: AWS D1.4/D1.4M.

Mockups:

Before starting masonry, build a mockup panel minimum 1800 mm by 1800 mm (6 feet by 6 feet) with 600 mm (24 inch) 90 degree return for outside corner.

Use masonry units from random cubes of units delivered on site.

Include structural backup, reinforcing, ties, and anchors.

Mockup panel approved by Contracting Officer's Representative set workmanship and aesthetic quality for masonry work.

Clean sample panel to test cleaning methods.

Remove mockup panel when directed by Contracting Officer's Representative.

DELIVERY

Deliver products in manufacturer's original sealed packaging.

Mark packaging, legibly. Indicate manufacturer's name or brand, type, color, production run number, and manufacture date.

Before installation, return or dispose of products within distorted, damaged, or opened packaging.

STORAGE AND HANDLING

Store products above grade, protected from contamination.

Protect products from damage during handling and construction operations.

FIELD CONDITIONS

Hot and Cold Weather Requirements: Comply with ACI 530.1/ASCE 6/TMS 602.

WARRANTY

Construction Warranty: FAR clause 52.246‑21, "Warranty of Construction."

PRODUCTS

PRODUCTS - GENERAL

Provide each product from one manufacturer and from one production r.

UNIT MASONRY PRODUCTS

Brick:

Face Brick:

ASTM C216, Grade SW, Type FBS.

Brick when tested according to ASTM C67: Classified slightly efflorescent or better.

Size:

Modular.

Building Brick: ASTM C62, Grade MW for backup and interior work; Grade SW where in contact with earth.

One Face Exposed: Grade S, Type I.

Two Faces Exposed: Grade S, Type II.

Concrete Masonry Units (CMU):

Hollow and Solid Load‑Bearing Concrete Masonry Units: ASTM C90.

Unit Weight: Normal weight.

Sizes: Modular, 200 mm by 400 mm (8 inches by 16 inches) nominal face dimension; thickness as indicated on drawings.

ANCHORS, TIES, AND REINFORCEMENT

Steel Reinforcing Bars: ASTM A615/A615M; Grade 60, deformed bars.

Joint Reinforcement:

Form from wire complying with ASTM A951/A951M.

Hot dipped galvanized after fabrication.

Width of joint reinforcement 40 mm (1.6 inches) less than nominal thickness of masonry wall or partition.

Cross wires welded to longitudinal wires.

Joint reinforcement minimum 3000 mm (10 feet) long, factory cut.

Joint reinforcement with crimp formed drip is not acceptable.

Maximum spacing of cross wires 400 mm (16 inch) to longitudinal wires.

Ladder Design:

Longitudinal wires deformed 5 mm (0.20 inch) diameter wire.

Cross wires 4 mm (0.16 inch) diameter.

Trussed Design:

Longitudinal and cross wires minimum 4 mm (0.16 inch nominal) diameter.

Longitudinal wires deformed.

Multiple Wythes and Cavity Wall Ties:

Longitudinal wires 4 mm (0.16 inch), two in each wythe with ladder truss wires 4 mm (0.16 inch) overlay, welded to each longitudinal wire.

Longitudinal wires 4 mm (0.16 inch) with U shape 4 mm (0.16 inch) rectangular ties extending into other wythe minimum 75 mm (3 inches) spaced 400 mm on center (16 inches). Adjustable type with U shape tie designed to receive 4 mm (0.16 inch) pintle projecting into other wythe 75 mm (3 inches min.).

Individual Ties:

Rectangular ties: Form from 5 mm (3/16 inch) diameter galvanized steel rod to rectangular shape minimum 50 mm (2 inches) wide by sufficient length for ends of ties to extend within 25 mm (1 inch) of each face of wall. Ties that are crimped to form drip are not acceptable.

Wall Ties, (Mesh or Wire):

Mesh wall ties formed of ASTM A1064/A1064M, W0.5, 2 mm, (0.08 inch) galvanized steel wire 13 mm by 13 mm (1/2 inch by 1/2 inch) mesh, 75 mm (3 inches) wide by 200 mm (8 inches) long.

Rectangular wire wall ties formed of W1.4, 3 mm, (0.12 inch) galvanized steel wire 50 mm (2 inches) wide by 200 mm (8 inches) long.

Corrugated Wall Tie:

Form from 1.5 mm (0.06 inch) thick corrugated, galvanized steel 30 mm (1‑1/4 inches) wide by lengths to extend minimum 100 mm (4 inches) into joints of masonry plus 38 mm (1‑1/2 inch) turn‑up.

Provide 5 mm (3/16 inch) hole in turn‑up for fastener attachment.

ACCESSORIES

Preformed Compressible Joint Filler:

Thickness and depth to fill joint.

Closed Cell Neoprene: ASTM D1056, Type 2, Class A, Grade 1, B2F1.

Non‑Combustible Type: ASTM C612, Type 5, Max. Temp.1800 degrees F.

Masonry Cleaner:

Detergent type cleaner selected for each type masonry.

Acid cleaners are not acceptable.

Use soapless type specially prepared for cleaning brick or concrete masonry as appropriate.

EXECUTION

INSTALLATION - GENERAL

Install products according to manufacturer's instructions and approved submittal drawings.

When manufacturer's instructions deviate from specifications, submit proposed resolution for Contracting Officer's Representative consideration.

Keep finish work free from mortar smears or spatters, and leave neat and clean.

Tooling Joints:

Do not tool until mortar has stiffened enough to retain thumb print when thumb is pressed against mortar.

Tool while mortar is soft enough to be compressed into joints and not raked out.

Finish joints in exterior face masonry work with jointing tool, and provide smooth, water‑tight concave joint unless specified otherwise.

Tool Exposed interior joints in finish work concave unless specified otherwise.

Wetting and Wetting Test:

Test and wet brick and clay tile according to BIA TN 11B.

Do not wet concrete masonry units or glazed structural facing tile before laying.

Temporary Formwork: Provide formwork and shores as required for temporary support of reinforced masonry elements.

Construct formwork to conform to shape, line and dimensions indicated on drawings. Make sufficiently tight to prevent mortar, grout, or concrete leakage. Brace, tie and support formwork as required to maintain position and shape during construction and curing of reinforced masonry.

Do not remove forms and shores until reinforced masonry members have hardened sufficiently to carry their own weight and other reasonable temporary construction loads.

Minimum Curing Times Before Removing Shores and Forms:

Girders and Beams: 10 days.

INSTALLATION - REINFORCEMENT

Joint Reinforcement:

Install joint reinforcement in CMU wythe of combination brick and CMU, cavity walls, and single wythe concrete masonry unit walls or partitions.

Reinforcing is acceptable in lieu of individual ties for anchoring brick facing to CMU backup in exterior masonry walls.

Locate joint reinforcement in mortar joints at 400 mm (16 inch) maximum vertical intervals.

Steel Reinforcing Bars:

Install reinforcing bars in cells of hollow masonry units where required for vertical reinforcement and in bond beam units for horizontal reinforcement. Install in wall cavities of reinforced masonry walls where indicated on drawings.

Bond Beams:

Form Bond beams of load‑bearing concrete masonry units filled with grout and reinforced with two No. 15m (No. 5) reinforcing bars unless shown otherwise. Do not cut reinforcement.

Brake bond beams only at expansion joints and at control joints, if shown.

Stack Bond:

Locate additional joint reinforcement in vertical and horizontal joints as indicated on drawings.

Anchor vertical reinforcement into foundation or wall or bond beam below.

Provide temporary bracing for walls over 8 feet tall until permanent horizontal bracing is completed.

INSTALLATION - BRICK EXPANSION AND CMU CONTROL JOINTS

Provide brick expansion joint (EJ) and CMU control joints (CJ) where indicated on drawings.

Keep joint free of mortar and other debris.

Joints Occur In Masonry Walls:

Install preformed compressible joint filler in brick wythe.

Install cross shaped shear keys in concrete masonry unit wythe with preformed compressible joint filler on both sides of shear key.

Use standard notched concrete masonry units (sash blocks) made in full and half‑length units where shear keys are used to create a continuous vertical joint.

Interrupt joint reinforcement at expansion and control joints.

Fill opening in exposed face of expansion and control joints with sealant as specified in Section 07 92 00, JOINT SEALANTS.

INSTALLATION - BRICKWORK

Lay clay brick according to BIA TN 11B.

Laying:

Lay brick in one‑half running bond with bonded corners, unless indicated otherwise.

Maintain bond pattern throughout.

Do not use brick smaller than half‑brick at any angle, corner, break, and jamb.

Where length of cut brick is greater than one half length, maintain vertical joint location.

Lay exposed brickwork joints symmetrical about center lines of openings.

Do not structurally bond multi‑wythe brick walls, unless indicated on drawings.

Before starting work, lay facing brick on foundation wall and adjust bond to openings, angles, and corners.

Lay brick for sills with wash and drip.

Build solid brickwork as required for anchorage of items.

Joints:

Exterior And Interior Joint Widths: Lay for three equal joints in 200 mm (8 inches) vertically, unless shown otherwise.

Rake joints for pointing with colored mortar when colored mortar is not full depth.

Solid Exterior Walls:

Build with 100 mm (4 inches) of nominal thick facing brick, backed up with concrete masonry units cast‑in‑place concrete 100 mm (4 inches) nominal thick face brick.

Parging:

For solid masonry walls, lay backup to height of six brick courses, parge backup with 13 mm (1/2 inch) of mortar troweled smooth; then lay exterior wythe to height of backup.

Make parging continuous over backup, and extend 150 mm (6 inches) onto adjacent concrete or masonry.

Parge ends and backs for recesses in exterior walls to thickness of 13 mm (1/2 inch).

INSTALLATION - CONCRETE MASONRY UNITS

Types and Uses:

Provide special concrete masonry shapes as required, including lintel and bond beam units, sash units, and corner units. Provide solid concrete masonry units, where full units cannot be installed, or where needed for anchorage of accessories.

Provide solid load‑bearing concrete masonry units or grout cell of hollow units at jambs of openings in walls, where structural members impose loads directly on concrete masonry, and where shown.

Do not install brick jambs in exposed finish work.

Install concrete building brick only as filler in backup material where not exposed.

Laying:

Lay concrete masonry units with 9 mm (3/8 inch) joints, with a bond overlap of minimum 1/4 of unit length, except where stack bond is indicated on drawings.

Do not wet concrete masonry units before laying.

Bond external corners of partitions by overlapping alternate courses.

Lay first course in a full mortar bed.

Set anchorage items as work progress.

Where ends of anchors, bolts, and other embedded items, project into voids of units, completely fill voids with mortar or grout.

Lay concrete masonry units with full face shell mortar beds and fill head joint beds for depth equivalent to face shell thickness.

Lay concrete masonry units so cores of units, that are to be filled with grout, are vertically continuous with joints of cross webs of such cores completely filled with mortar. Unobstructed core openings minimum 50 mm (2 inches) by 75 mm (3 inches).

Do not wedge masonry against steel reinforcing. Minimum 13 mm (1/2 inch) clear distance between reinforcing and masonry units.

Install deformed reinforcing bars of sizes indicated on drawings.

At time of placement, ensure steel reinforcement is free of loose rust, mud, oil, and other contamination capable of affecting bond.

Place steel reinforcement at spacing indicated on drawings before grouting.

Minimum clear distance between parallel bars: One bar diameter.

Hold vertical steel reinforcement in place vertically by centering clips, caging devices, tie wire, or other approved methods.

Support vertical bars near each end and at maximum 192 bar diameter on center.

Splice reinforcement or attach reinforcement to dowels by placing in contact and securing with wire ties.

Stagger splices in adjacent horizontal reinforcing bars. Lap reinforcing bars at splices a minimum of 40 bar diameters.

Grout cells of concrete masonry units, containing reinforcing bars, solid as specified.

Install cavity and joint reinforcement as masonry work progresses.

Rake joints 6 to 10 mm (1/4 to 3/8 inch) deep for pointing with colored mortar when colored mortar is not full depth.

Waterproofing Parging:

Parge earth side of concrete masonry unit basement walls with mortar applied in two coats, each coat 6 mm (1/4 inch) thick.

Clean wall surfaces to receive parging of dirt, oil, or grease, and moisten before application of first coat.

Roughen first coat when partially set, permit to hardened for 24 hours, and moisten before application of second coat.

Keep second coat damp for minimum 48 hours.

Thicken parging and round to form a cove at the junction of outside wall face and footing.

POINTING

Fill joints with pointing mortar using rubber float trowel to apply mortar solidly into raked joints.

Wipe off excess mortar from joints of glazed masonry units with dry cloth.

Tool exposed joints to smooth concave joint.

At joints with existing work, match existing joint.

GROUTING

Preparation:

Clean grout space of mortar droppings before placing grout.

Close cleanouts.

Install vertical solid masonry dams across grout space for full height of wall at intervals of maximum 9000 mm (30 feet). Do not bond dam units into wythes as masonry headers.

Verify reinforcing bars are installed as indicated on drawings.

Placing:

Place grout in grout space in lifts as specified.

Consolidate each grout lift after free water has disappeared but before plasticity is lost.

Do not slush with mortar or use mortar with grout.

Interruptions:

When grouting must be stopped for more than an hour, top off grout 40 mm (1‑1/2 inches) below top of last masonry course.

Grout from dam to dam on high lift method.

Longitudinal run of masonry may be stopped off only by raking back one‑half masonry unit length in each course and stopping grout 100 mm (4 inches) back of rake on low lift method.

Puddling Method:

Consolidate by puddling with grout stick during and immediately after placing.

Grout cores of concrete masonry units containing reinforcing bars solid as masonry work progresses.

Low Lift Method:

Construct masonry to 1.5 m (5 feet) maximum height before grouting.

Grout in one continuous operation and consolidate grout by mechanical vibration and reconsolidate after initial water loss and settlement has occurred.

High Lift Method:

Do not pour grout until masonry wall has cured minimum of 4 hours.

Place grout in 1.5 m (5 feet) maximum lifts.

Exception:

Where following conditions are met, place grout in 3.86 m (12.67 feet) maximum lifts.

Masonry has cured minimum of 4 hours.

Grout slump is maintained between 250 and 275 mm (10 and 11 inches).

No intermediate reinforced bond beams are placed between top and bottom of grout lift.

When vibrating succeeding lifts, extend vibrator 300 to 450 mm (12 to 18 inches) into preceding lift.

PLACING REINFORCEMENT

General: Clean reinforcement of loose rust, mill scale, earth, ice or other materials which will reduce bond to mortar or grout. Do not use reinforcement bars with kinks or bends not shown on drawings or approved submittal drawings, or bars with reduced cross‑section due to excessive rusting or other causes.

Position reinforcement accurately at spacing indicated on drawings. Support and secure vertical bars against displacement. Install horizontal reinforcement as masonry work progresses. Where vertical bars are shown in close proximity, provide clear distance between bars of minimum one bar diameter or 25 mm (1 inch), whichever is greater.

For columns, piers and pilasters, maintain clear distance between vertical bars as indicated on drawings, minimum 1.5 bar diameters or 38 mm (1‑1/2 inches), whichever is greater. Provide lateral ties as indicated on drawings.

Splice reinforcement bars only where indicated on drawings, unless approved by Contracting Officer's Representative. Provide lapped splices. In splicing vertical bars or attaching to dowels, lap ends, place in contact and wire tie.

Provide minimum lap as indicated on approved submittal drawings, or if not indicated, minimum 48 bar diameters.

Weld splices where indicated on drawings according to AWS D1.4/D1.4M.

Embed metal ties in mortar joints as work progresses, with minimum mortar cover of 15 mm (5/8 inch) on exterior face of walls and 13 mm (1/2 inch) at other locations.

Embed prefabricated horizontal joint reinforcement as work progresses, with minimum cover of 15 mm (5/8 inch) on exterior face of walls and 13 mm (1/2 inch) at other locations. Lap joint reinforcement minimum 150 mm (6 inches) at ends. Use prefabricated “L” and “T” sections to provide continuity at corners and intersections. Cut and bend joint reinforcement for continuity at returns, offsets, column fireproofing, pipe enclosures and other special conditions.

Anchoring: Anchor reinforced masonry work to supporting structure as indicated on drawings.

INSTALLATION OF REINFORCED BRICK MASONRY

Mortar Jointing and Bedding:

Pattern Bond: Lay exterior wythes in pattern bond shown, or if not shown, lay in 1/2 running bond with vertical joints in each course centered on units in courses above and below. Lay inner wythes (if any) with units in each wythe bonded by lapping minimum 50 mm (2 inches). Bond and interlock each course of each wythe at corners and intersections. Do not use units with less than 100 mm (4 inch) nominal horizontal face dimension at corners or jambs.

Lay exterior wythes with bed (horizontal) and head (vertical) joints between units completely filled with mortar. Top of bed joint mortar may be sloped toward center of walls. Butter ends of units with sufficient mortar to completely fill head joints and shove into place. Do not furrow bed joints or slush head joints. Remove any mortar fins which protrude into grout space.

Maintain joint widths shown for head and bed joints, except for minor variations required to maintain pattern bond. If not shown, lay with 9 mm (3/8 inch) head and bed joints.

Multi‑Wythe Wall Construction: Where walls of three or more wythes are indicated, lay exterior wythes as specified. Maintain space between wythes as required to allow for laying of number of wythes of unit width shown with minimum grout space between wythes. Allow for minimum 19 mm (3/4 inch) grout between wythes if non‑reinforced; if reinforced, allow for grout space minimum 13 mm (1/2 inch) wider than sum of vertical and horizontal reinforcement bars indicated in grout space. Place or float interior wythe units in grout poured between exterior wythes as work progresses. Position units to allow minimum 19 mm (3/4 inch) grout between ends and sides of adjacent units.

Limit extent of masonry construction to sections which do not exceed maximum grouting requirements. Provide temporary dams or barriers to control horizontal flow of grout at ends of wall sections. Build dams full height of grout pour. If masonry units are used, do not bond into permanent masonry wythes. Remove temporary dams after completion of grout pour.

Low‑Lift Grouting:

Use Low‑Lift grouting technique with fine grout for the following:

Multi‑wythe walls.

At Contractor’s option, low‑lift grouting technique is acceptable for reinforced masonry construction with grout spaces wider than 50 mm (2 inches), except use coarse grout and place in lifts maximum 200 mm (8 inches) in height.

Construct low‑lift masonry by placing reinforcement, laying masonry units and pouring grout as work progresses.

Place vertical reinforcement bars and supports before laying of masonry units. Extend above elevation of maximum pour height as required to allow for splicing. Horizontal reinforcement bars may be placed progressively with laying of masonry units.

Limit grout pours as required to prevent displacement of masonry by grout pressures (blowout), but do not exceed 1200 mm (4 feet) pour height.

Lay masonry units before each grout pour, but do not construct more than 300 mm (12 inches) above maximum grout pour height in exterior wythe and 100 mm (4 inches) above in other exterior wythe. Provide metal wall ties if required to prevent blowouts.

Consolidate immediately by rodding or puddling; do not use trowels. Place grout continuously; do not interrupt pouring of grout for more than one hour. If poured in lifts, place from center‑to‑center of masonry courses. Terminate pour 38 mm (1 1/2 inches) below top of highest course in pour.

INSTALLATION OF REINFORCED CONCRETE UNIT MASONRY

Do not wet concrete masonry units (CMU).

Lay CMU units with full‑face shell mortar beds. Fill vertical head joints (end joints between units) solidly with mortar from face of unit to distance behind face equal to thickness of longitudinal face shells. Solidly bed cross‑webs of starting courses in mortar. Maintain head and bed 9 mm (3/8 inch) joint widths.

Where solid CMU units are shown, lay with full mortar head and bed joints.

Walls:

Pattern Bond: Lay CMU wall units in 1/2‑running bond with vertical joints in each course centered on units in courses above and below, unless otherwise indicated. Bond and interlock each course at corners and intersections. Use special‑shaped units where shown, and as required for corners, jambs, sash, control joints, lintels, bond beams and other special conditions.

Maintain vertical continuity of core or cell cavities, which are to be reinforced and grouted, to provide minimum clear dimension indicated and to provide minimum clearance and grout coverage for vertical reinforcement bars. Keep cavities free of mortar. Solidly bed webs in mortar where adjacent to reinforced cores or cells.

Where horizontally reinforced beams (bond beams) are indicated on drawings, use special units or modify regular units to allow for placement of continuous horizontal reinforcement bars. Place small mesh expanded metal lath or wire screening in mortar joints under bond beam courses over cores or cells of non‑reinforced vertical cells, or provide units with solid bottoms.

Columns, Piers and Pilasters:

Use CMU units of size, shape and number of vertical core spaces shown. If not shown, use units which provide minimum clearances and grout coverage for number and size of vertical reinforcement bars shown.

Provide pattern bond shown, or if not shown, alternate head joints in vertical alignment.

Where bonded pilaster construction is shown, lay wall and pilaster units together to maximum grout pour height specified.

Grouting:

Use fine grout for filling spaces less than 100 mm (4 inches) in one or both horizontal directions.

Use coarse grout for filling 100 mm (4 inch) spaces or larger in both horizontal directions.

Grouting Technique: At Contractor’s option, use either low‑lift or high‑lift grouting techniques.

Low‑Lift Grouting:

Provide minimum clear dimension of 50 mm (2 inches) and clear area of 5160 sq. mm (8 sq. inches) in vertical cores to be grouted.

Place vertical reinforcement before grouting of CMU. Extend above elevation of maximum pour height as required for splicing. Support in position at vertical intervals not exceeding 192 bar diameters nor 3 m (10 feet).

Lay CMU to maximum pour height. Do not exceed 1.5 m (5 feet) height, or if bond beam occurs below 1.5 m (5 feet) height, stop pour 38 mm (1‑1/2 inches) below top of bond beam.

Rod or vibrate grout during placing. Place grout continuously; do not interrupt pouring of grout for more than one hour. Terminate grout pours 38 mm (1‑1/2 inches) below top course of pour.

Bond Beams: Stop grout in vertical cells 38 mm (1‑1/2 inches) below bond beam course. Place horizontal reinforcement in bond beams; lap at corners and intersections as indicated on drawings. Place grout in bond beam course before filling vertical cores above bond beam.

Limit grout lifts to maximum height of 1.5 m (5 feet) and grout pour to maximum height of 7.3 m (24 feet), for single wythe hollow concrete masonry walls, unless otherwise indicated.

Place vertical reinforcement before grouting. Place before or after laying masonry units, to suit application. Tie vertical reinforcement to dowels at base of masonry where shown and thread CMU over or around reinforcement. Support vertical reinforcement at intervals not exceeding 192 bar diameters nor 3 m (10 feet).

Where individual bars are placed after laying masonry, place wire loops extending into cells as masonry is laid and loosen before mortar sets. After insertion of reinforcement bar, pull loops and bar to proper position and tie free ends.

Where reinforcement is prefabricated into cage units before placing, fabricate units with vertical reinforcement bars and lateral ties of the size and spacing indicated.

Place horizontal beam reinforcement as masonry units are laid.

Embed lateral tie reinforcement in mortar joints where indicated. Place as masonry units are laid, at vertical spacing shown.

Where lateral ties are shown in contact with vertical reinforcement bars, embed additional lateral tie reinforcement in mortar joints. Place as indicated on drawings, or if not shown, provide as required to prevent grout blowout or rupture of CMU face shells, but provide minimum 4.1 mm diameter (0.16 inch) wire ties spaced 400 mm (16 inches) on center for members with 500 mm (20 inches) or less side dimensions, and 200 mm (8 inches) on center for members with side dimensions exceeding 500 mm (20 inches).

Preparation of Grout Spaces: Before grouting, inspect and clean grout spaces. Remove dust, dirt, mortar droppings, loose pieces of masonry and other foreign materials from grout spaces. Clean reinforcement and adjust to proper position. Clean top surface of structural members supporting masonry to ensure bond. After final cleaning and inspection, close cleanout holes and brace closures to resist grout pressures.

Do not place grout until entire height of masonry to be grouted has attained sufficient strength to resist displacement of masonry units and breaking of mortar bond. Install shores and bracing, if required, before starting grouting operations.

Limit grout pours to sections which can be completed in one working day with maximum one hour interruption of pouring operation. Place grout in lifts which do not exceed 1.5 m (5 feet). Allow minimum 30 minutes and maximum one hour between lifts. Mechanically consolidate each lift.

Place grout in lintels or beams over openings in one continuous pour.

Where bond beam occurs more than one course below top of pour, fill bond beam course to within 25 mm (1 inch) of vertically reinforced cavities, during construction of masonry.

When more than one pour is required to complete a given section of masonry, extend reinforcement beyond masonry as required for splicing. Pour grout to within 38 mm (1‑1/2 inches) of top course of first pour. After grouted masonry is cured, lay masonry units and place reinforcement for second pour section before grouting. Repeat sequence if more pours are required.

CONSTRUCTION TOLERANCES

Lay masonry units plumb, level and true to line within tolerances according to ACI 530.1/ASCE 6/TMS 602 and as follows:

Maximum variation from plumb:

In 3000 mm (10 feet) - 6 mm (1/4 inch).

In 6000 mm (20 feet) - 9 mm (3/8 inch).

In 12,000 mm (40 feet) or more - 13 mm (1/2 inch).

Maximum variation from level:

In any bay or up to 6000 mm (20 feet) - 6 mm (1/4 inch).

In 12,000 mm (40 feet) or more - 13 mm (1/2 inch).

Maximum variation from linear building lines:

In any bay or up to 6000 mm (20 feet) - 13 mm (1/2 inch).

In 12,000 mm (40 feet) or more - 19 mm (3/4 inch).

Maximum variation in cross‑sectional dimensions of columns and thickness of walls from dimensions shown:

Minus 6 mm (1/4 inch).

Plus 13 mm (1/2 inch).

Maximum variation in prepared opening dimensions:

Accurate to minus 0 mm (0 inch).

Plus 6 mm (1/4 inch).

CLEANING AND REPAIR

General:

Clean exposed masonry surfaces on completion.

Protect adjoining construction materials and landscaping during cleaning operations.

Cut out defective exposed new joints to depth of approximately 19 mm (3/4 inch) and repoint.

Remove mortar droppings and other foreign substances from wall surfaces.

Brickwork:

First wet surfaces with clean water, then wash down with detergent solution. Do not use muriatic acid.

Brush with stiff fiber brushes while washing, and immediately wash with clean water.

Remove traces of detergent, foreign streaks, or stains of any nature.

Concrete Masonry Units:

Immediately following setting, brush exposed surfaces free of mortar or other foreign matter.

Allow mud to dry before brushing.

FIELD QUALITY CONTROL

Water Penetration Testing:

Seven days before plastering or painting, in presence of Contracting Officer's Representative, test solid exterior masonry walls for water penetration.

Direct water on masonry for a period of one hour when wind velocity is less than five miles per hour.

Should moisture appear on inside of walls tested, make additional tests at other areas as directed by Contracting Officer's Representative.

Correct areas showing moisture on inside of walls, and repeat test at repaired areas, to ensure moisture penetration has been stopped.

Make water test at following locations:

Eight places.

END OF SECTION

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