concrete structures
DESCRIPTION
Concrete StructureTRANSCRIPT
Prof Awad S. Hanna
Prof Awad S. Hanna
Concrete: Cubic YardSteel: Lb or tonsFormwork:Square feet per
contact area
Prof Awad S. Hanna
1. Foundations2. Columns3. Slabs and beams
Prof Awad S. Hanna
Is olat edfoot ing
Combinedfoot ing
S t rapfoot ing
Wallfoot ing
Raftfoundat ion
S hallow Deep
F oundat ions
Prof Awad S. Hanna
Isolated
Footing
CombinedFooting
Continuous
Wall Footing
StrapFootin
g
RaftFoundati
on
Prof Awad S. Hanna
Caissons Piles
Prof Awad S. Hanna
ShapesSquare - Rectangle - CircularOthers
ReinforcementOrdinary - Spiral
Prof Awad S. Hanna
One-Way Slab, Beam, and Girder
One-Way Slab, Supported by Beams or Walls
One-Way Joist Slab
Prof Awad S. Hanna
Flat Plate
Two-Way SlabSupported by Beams
Flat Slab
Waffle Slab
Prof Awad S. Hanna
1. Formwork is the largest cost item that represent 40% to 60% of concrete structure cost.
Slab
Concrete Placing
3%
Reinforcing28%
Concrete21%
formwork Materials
10%
Formwork Labor38%
Wall
Formwork Labor52%
Concrete Materials
30%
Formwork Materials
11%Concrete Labor7%
Distribution of costs for cast-in-place concrete slab wall:
Prof Awad S. Hanna
2.Waste allowance from 2% to 10% should be added for concrete and concrete formwork.
Prof Awad S. Hanna
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’ = 206 ft3
30’1
0”30
’
40’0”40’10”
Building size: 30’ x 40’
Prof Awad S. Hanna
Calculations:1.Length = 10.833’+40.833’ = 81.67’2.Width = 27.833’+27.833’ = 55.67’3.Perimeter = 81.67’+55.67’ = 137.34 Total Linear ft4.Volume = 137.34’x1’x1.5’ = 206 Cubic feet5.volume in CY = 206/27 = 7.6 Cubic Yards30
’10”
27’1
0”
40’10”
Prof Awad S. Hanna
1. Reinforcement Steel2. Forms3. Concrete Mix4. Finishing5. Curing
Prof Awad S. Hanna
SPACING WIRE GAUGE POUNDS/100 SF4" X 12" NO. 6 X NO. 6 41.64" X 12" NO. 8 X NO. 8 29.66" X 12" NO. 4 X NO. 4 43.86" X 12" NO. 6 X NO. 6 31.8 6~ X 6" NO. 6 X NO. 6 42.86" X 6" NO. 8 X NO. 8 30.06" X 6" NO. 9 X NO. 9 25.8 6" X 6" NO. 10 X NO. 10 20.74" X 4" NO. 6 X NO. 6 61.94" X 4" NO. 8 X NO. 8 44.1
Prof Awad S. Hanna
BAR NUMBER SIZE (IN.) WEIGHT (LB./FT.)2 1/4 ROUND 0.1673 3/8 ROUND 0.3674 1/2 ROUND 0.6685 5/8 ROUND 1.0436 3/4 ROUND 1.5027 7/8 ROUND 2.0448 1 ROUND 2.6709 1 SQUARE 3.40010 1 - 1/8 SQUARE 4.30311 1 - 1/4 SQUARE 5.313
Prof Awad S. Hanna
How many pounds of rebar are required for the concrete floor area below?
6” Concrete slab with #4 rebar 15” on center each way
20’
60’
40’
30’
Prof Awad S. Hanna
Step #1: Calculate the total SF of area involved.20'0" X 30'0" = 600 SF30'0" 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 SFUnit rebar length: 1.25' + 1.25' = 2.5 LFLbs. 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.