Masonry

• Terms– F 15-1 -> 15-5– Go thru all figures– Joints between brick = ¼ inch

Brick

• F 15-6– Go thru sizes for brick– Compressive strength range 2500psi –

22,000psi – T 15-1 shows mortar strength– Brisk wall only as strong as weakest part

Brick

• Pattern bonds– How bricks are laid

• Running bond – only stretcher courses with head joints centered over stretchers

• Common bond – header course repeated at regular intervals – usually 5th,6th or 7th course

• Flemish – bond – alternates stretchers and headers in each course headers are centered over stretchers

• English bond - alternate courses of headers and stretchers• Stack – no interlocking – architectural effect

– F 15-7

Hollow Masonry Walls

• Masonry Cavity Walls • Two masonry wythes separated by a 2” minimum

airspace and held together with metal ties• Advantages over single masonry wall: greater

resistance to moisture penetration, better thermal and acoustical insulation, excellent fire resistance

– Utility wall – made from utility brick, two walls with brick used to bond walls together

Hollow Masonry Walls

• Reinforced Brick Masonry Walls • Hollow walls are filled with grout and rebar to

provide strength• Can be precast• Provides a strong wall with exterior finish – uses

less concrete

Bond Beams and Lintels

• Bond Beam – Continually reinforced horizontal beam of

concrete or masonry designed to provide additional strength and prevent cracking

• Frequently placed in foundations and at roof levels

– Lintel – short beam of wood, steel, or reinforced brick masonry to span opening in masonry wall

– Masonry arch– F15-11

Control Joints

• Expansion Joints • Used to permit differential movement due to

movement of floor slabs, foundation• Separate walls into sections with vertical

expansion joints

Joints at doors and windows, columns, pilasters, wall offsets, cross walls, under shelf anglesin multistory buildings

– Control Joint – cut into masonry wall to control shrinkage cracking

Control Joints

• Structural bonding• Flexible ties extending across joint or interlocking

construction• F 15-12

– Flashing – layers of impervious material• Used above vertical joints, roof and wall junctions,

window sills, other projections, chimneys• F15-13

Concrete Masonry

• Concrete Block

• Concrete Tile

• Solid load bearing concrete block– Over 75% concrete

• Hollow load bearing concrete block

• Hollow non- load bearing concrete block– Hollow block = at least 25% of core area is

empty

Concrete Masonry

• Either heavy weight or light weight concrete blocks– Blocks can either be laid using mortar or laid

dry– If dry use parging to join block together– F 15-14

Reinforced Concrete Masonry

• Provides additional strength and prevents cracking

• F15-15, 15-16 -> 18

Pattern Bond

• Running bond most common

• F 15-20

Estimating Quantity

• Bricks– 1. Calculate net surface area of wall– 2. calculate surface area of 1 brick including

mortar– 3. divide wall area by brick area– 4. multiply by number of wythes in wall– 5. add an amount for waste

Estimating Quantity

• Mortar– Volume per brick =(t)(W)(L+H+t)– t = mortar thickness– W = brick width/depth inches– L = length of bricj inches– H = height of brick inches– Add 25% waste– For double wall must add in for mortar in

space

Wind load on Fresh Masonry

• Need to brace fresh wall until mortar has cured– F 15-24– Safe unbraced height = (Wt of wall / unit of

surface x wall thickness)/wind force– T 15-3

• Mortar– Must be well mixed– Must have correct mix of fines and coarse

material– Must not be used more than 2.5 hours after

initial mixing

• Placing Masonry and Reinforcing– CMU and brick absorb water– Should be stored dry– Should be wetted before use and allowed to

surface dry– Joints must be tooled for watertight joints