Transcript No Slide Title

Masonry
Design
MASONRY WALLS
CONSTRUCTION TYPE
• Single Wythe
• Cavity
• Prefabricated
• Barrier
• Masonry Veneer
• Masonry Bonded Hollow Wall
2
MASONRY WALLS
STRUCTURAL FUNCTION
• Veneer
• Nonloadbearing
• Loadbearing
• Shear
3
TYPES OF LOADING
External Loads
• Gravity
• Wind
• Earthquake
• Earth pressure
4
ACCUMULATION OF AXIAL LOAD
WITH HEIGHT BEARING – WALL
BUILDING
5
ACCUMULATION OF AXIAL LOAD
WITH HEIGHT BEARING – WALL
BUILDING
6
AXIAL STRESSES IN BEARING WALL
WITH UNIFORMLY DISTRIBUTED
AXIAL LOAD
7
AXIAL STRESSES IN BEARING WALL
WITH CONCENTRATED AXIAL LOAD
8
ARCHING ACTION BETWEEN
MULTIPLE OPENINGS
9
FREE-BODY DIAGRAM OF A LINTEL
ACTING AS A BEAM
10
FREE-BODY DIAGRAM OF A LINTEL
ACTING AS AN ARCH
11
SHEAR WALL LOAD FROM ROOF OR
FLOOR DIAPHRAGM
12
ACTION OF HORIZONTAL AND
VERTICAL STRIPS ASSUMED FOR
DESIGN
13
SPAN-TO-WIDTH RATIOS FOR FLOOR
DIAPHRAGMS
14
STRUCTURAL ACTIONS ON SHEAR
WALLS
15
16
ASTM Standard Reinforcing Bars
Diameter (inches)
Nominal Cross
Section Area
Bar Size
(in2)
Designation
Decimal
Weight
lb/ft
Nominal
Perimeter
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
Bar Size
Designation
Fraction
#3
17
Required Lap Length of Bars in Inches*
2005 MSJC
2005
Allowable
MSJC
Stress Design Strength
Bar Diameter
Size
(d, in.)
8"
CMU
12"
CMU
8" CMU
MBC 2006
Allowable
Stress
Design
(48d, in.)**
MBC 2006
Strength
Design
8"
12"
CMU 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
* 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.
60.4
18