Concrete Structures
Prof Awad S. Hanna
Units of Measure
Concrete: Cubic Yard
Steel:
Lb or tons
Formwork:
area
Square feet per contact
Prof Awad S. Hanna
Types of Concrete
construction
1.
Foundations
2.
Columns
3.
Slabs and beams
Prof Awad S. Hanna
Foundat ions
Isolat ed
foot ing
Combined
foot ing
Shallow
Deep
St rap
foot ing
Wall
foot ing
Prof Awad S. Hanna
Raft
foundat ion
Shallow Foundation
Isolate
d
Footin
g
Strap
Footin
g
Combined
Footing
Raft
Foundatio
n
Prof Awad S. Hanna
Continuous
Wall
Footing
Deep Foundation
Caissons
Piles
Prof Awad S. Hanna
Columns
 Shapes
Square - Rectangle - Circular
Others
 Reinforcement
Ordinary - Spiral
Prof Awad S. Hanna
Slabs and Beams: One-Way slabs
One-Way Slab, Beam, and Girde
One-Way Slab,
Supported by Beams
or Walls
One-Way Joist Slab
Prof Awad S. Hanna
Slabs and Beams: Two-Way Slabs
Flat Plate
Waffle Slab
Flat Slab
Two-Way Slab
Supported by Beams
Prof Awad S. Hanna
Estimating Issues
1.Formwork is the largest cost item that
represent 40% to 60% of concrete
structure cost.
Distribution of costs for cast-in-place concrete slab wall:
Slab
Concret e
21%
Reinforcing
28%
Concret e
Placing
3%
Wall
Concret e
Mat erials
30%
formwork
Mat erials
10%
Formwork
Labor
38%
Formwork
Labor
52%
Prof Awad S. Hanna
Concret e
Labor
7%
Formwork
Mat erials
11%
2.Waste allowance from 2% to 10%
should be added for concrete and
concrete formwork.
Prof Awad S. Hanna
1. Center Line Method
30’10”
30’
Building size: 30’ x 40’
40’0”
40’10”
Calculations:
1. Length = 30’10” - 1’6”
= 29’4”
2. Width = 40’10” - 1’6”
= 39’4”
3. Perimeter = 29’4” + 29’4” + 39’4” +39’4”
= 137”4”
4. Volume of concrete = 137.33’ x 1’ x 1.5’
Prof Awad S. Hanna
= 206 ft3
2. Sectional Method
Calculations:
1.Length
= 10.833’+40.833’
2.Width = 27.833’+27.833’
= 81.67’
= 55.67’
3.Perimeter
= 81.67’+55.67’= 137.34 Total Linear ft
4.Volume
feet
= 137.34’x1’x1.5’
30’10”
27’10”
5.volume in CY = 206/27
40’10”
Prof Awad S. Hanna
= 206 Cubic
= 7.6 Cubic Yards
COST OF OTHER COMPONENTS
OF CONCRETE WORK
1.Reinforcement Steel
2.Forms
3.Concrete Mix
4.Finishing
5.Curing
Prof Awad S. Hanna
Table 1.
DIMENSIONS & WEIGHT OF WELDED WIRE FABRIC
SPACING
WIRE GAUGE
POUNDS/100 SF
4" X12"
NO. 6 XNO. 6
41.6
4" X12"
NO. 8 XNO. 8
29.6
6" X12"
NO. 4 XNO. 4
43.8
6" X12"
NO. 6 XNO. 6
31.8
6~ X6"
NO. 6 XNO. 6
42.8
6" X6"
NO. 8 XNO. 8
30.0
6" X6"
NO. 9 XNO. 9
25.8
6" X6"
NO. 10 XNO. 10
20.7
4" X4"
NO. 6 XNO. 6
61.9
4" X4"
NO. 8 XNO. 8
44.1
Prof Awad S. Hanna
Table 2
SIZES & WEIGHTS OF REINFORCING BAR
BAR NUMBER
SIZE (IN.)
WEIGHT (LB./FT.)
2
3
4
1/4 ROUND
3/8 ROUND
1/2 ROUND
0.167
0.367
0.668
5
6
7
8
5/8 ROUND
3/4 ROUND
7/8 ROUND
1ROUND
1.043
1.502
2.044
2.670
9
10
11
1SQUARE
1- 1/8 SQUARE
1- 1/4 SQUARE
3.400
4.303
5.313
Prof Awad S. Hanna
EXAMPLE:
How many pounds of rebar are required for
the concrete floor area below?
6” Concrete slab with #4
rebar 15” on center each
way
30’
Prof Awad S. Hanna
40’
20’
60’
Step #1: Calculate the total SF of area involved.
20'0" X 30'0"
= 600 SF
30'0" X 40'0"
= 1 200 SF
Total
= 1,800 SF floor area
Step #2: Calculate the pounds of rebar per SF of floor based on the
unit spacing of the rebar at any point of intersection.
Unit area:
15" X 15"
= 1.25' X 1.25'
= 1.56 SF
Unit rebar length: 1.25' + 1.25'
= 2.5 LF
Lbs. of rebar/unit:= 2.5 LF X .668 lbs/ LF
= 1.67 lbs
 It is now known that there are 1. 67 lbs of rebar per 1.56 SQ FT
of floor area.
1.67 / 1.56
= 1.07 lbs/SF of floor area.
SO: 1.07 lbs/ SF X 1,800 SF
= 1,926 lbs of #4 rebar required.
Prof Awad S. Hanna