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Lecture9-Masonry1.pdf

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CSMT 441

Masonry Units

Lecture 9

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Division 4 - Masonry

• Concrete Masonry Unit (CMU)

• Brick

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Concrete Masonry Unit

• Separate masonry according to:

– size of the units

– shape of the units

– colors of the units

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Concrete Masonry Unit

• The standard modular face dimensions of the CM

units are 7 5/8" high and 15 5/8" long.

Thicknesses available are 3, 4, 6, 8, 10, and 12

inches (nominal, actual dimensions are 3/8"less).

• A 3/8" mortar joint provides 8"x16" face

dimension (112.5 units per 100 sf of wall).

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Concrete Masonry Unit

• Thicker face shells are required for a specific fire rating.

• Unit: No of units required (SF of wall x 1.125)

• Deduct all openings in excess of 10 sf.

• Allowance for waste and breakage:

– 5 -10%

• Cutting of the units is expensive and should be anticipated.

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Bricks

• Brick is a solid masonry made of clay.

• Bricks are classified by:

– kind (common or face)

– size

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Bricks

• No. of brick per square foot of wall depends on:

– size of brick (standard size: 2 1/4"x 3 3/4"x 8")

– width of the mortar joint

• For running bond with 3/8" thick mortar joint,

number of standard brick per 100 sf is 675

• Make deduction for all openings

• Waste

– 5 to 10%

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BCN5618 11

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Mortar

• Masonry mortar usually consists of Portland

cement, mortar sand, and hydrated lime.

– Type M - 1:1/4:3 mix by volume - 1 part cement, ¼ part lime 3 parts sand) for heavy loads and below grade

– Type N - 1:1:6 for use above grade

• 3/8" is a common mortar joint thickness, but 1/4"

and 1/2" joints are also used.

• Colored mortars (red, brown, white, and black)

may be used.

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13 Volume of mortar for block (cf) = (Net area x 3.2)/100

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Coping

• Covers the top course

of a wall to protect it

from the weather.

• coping block (no of

units)

• stone (lf, note type,

width, and thickness)

• precast concrete (lf,

note width, thickness,

and finish)

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Sills

• members at the

bottom of window

or door openings

• brick (no. of units)

• stone (lf, note type,

thickness, and

width)

• precast concrete (lf,

size)