Masonry Design

2

MASONRY WALLSCONSTRUCTION TYPE

• Single Wythe

• Cavity

• Prefabricated

• Barrier

• Masonry Veneer

• Masonry Bonded Hollow Wall

3

MASONRY WALLSSTRUCTURAL FUNCTION

• Veneer

• Nonloadbearing

• Loadbearing

• Shear

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TYPES OF LOADING

External Loads

• Gravity

• Wind

• Earthquake

• Earth pressure

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ACCUMULATION OF AXIAL LOAD WITH HEIGHT BEARING – WALL

BUILDING

6

ACCUMULATION OF AXIAL LOAD WITH HEIGHT BEARING – WALL

BUILDING

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AXIAL STRESSES IN BEARING WALL WITH UNIFORMLY DISTRIBUTED

AXIAL LOAD

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AXIAL STRESSES IN BEARING WALL WITH CONCENTRATED AXIAL LOAD

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ARCHING ACTION BETWEEN MULTIPLE OPENINGS

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FREE-BODY DIAGRAM OF A LINTEL ACTING AS A BEAM

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FREE-BODY DIAGRAM OF A LINTEL ACTING AS AN ARCH

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SHEAR WALL LOAD FROM ROOF OR FLOOR DIAPHRAGM

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ACTION OF HORIZONTAL AND VERTICAL STRIPS ASSUMED FOR

DESIGN

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SPAN-TO-WIDTH RATIOS FOR FLOOR DIAPHRAGMS

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STRUCTURAL ACTIONS ON SHEAR WALLS

16

17

Bar Size Designation

Diameter (inches)

Weightlb/ft

Nominal Perimeter

Nominal Cross Section Area

(in2)Bar Size

DesignationFraction Decimal

#3 3/8 0.375 0.376 1.178 0.11 #3

#4 1/2 0.500 0.668 1.571 0.20 #4

#5 5/8 0.625 1.043 1.963 0.31 #5

#6 3/4 0.750 1.502 2.356 0.44 #6

#7 7/8 0.875 2.044 2.749 0.60 #7

#8 1 1.000 2.670 3.142 0.79 #8

#9 1 1/8 1.128 3.400 3.544 1.00 #9

#10 1 1/4 1.270 4.303 3.990 1.27 #10

#11 1 3/8 1.410 5.313 4.430 1.56 #11

#14 1 3/4 1.693 7.650 5.320 2.25 #14

#18 2 1/4 2.257 13.600 7.090 4.00 #18

ASTM Standard Reinforcing Bars

18

Required Lap Length of Bars in Inches*

Bar Size

Diameter (d, in.)

2005 MSJC Allowable

Stress Design

2005 MSJC

Strength

MBC 2006 Allowable

Stress Design (48d, in.)**

MBC 2006 Strength Design

8" CMU

12" CMU 8" CMU

8" CMU

12" CMU

#3 3/8 15.1 15.1 15.1 18 15.1 15.1

#4 4/8 20.1 20.1 20.1 24 20.1 20.1

#5 5/8 25.2 25.2 25.2 30 25.2 25.2

#6 6/8 42.8 39.3 42.8 36 39.3 39.3

#7 7/8 59.4 45.8 59.4 42 45.8 45.8

#8 8/8 91.2 60.4 91.2 48 60.4 60.4

* Assume bar placed in center, Grade 60 steel, 48" o.c. spacing, and f'm=1500psi** Where design tensile stresses are > 80% of Fs, lap length shall be increased not < 50% of the minimum required length.