# Prof Awad S. Hanna Concrete Structures Concrete Structures.

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Prof Awad S. Hanna Concrete Structures Concrete Structures

Prof Awad S. Hanna Units of Measure Concrete:Cubic Yard Steel:Lb or tons Formwork:Square feet per contact area

Prof Awad S. Hanna Types of Concrete construction 1.Foundations 2.Columns 3.Slabs and beams

Shallow Foundation Isolate d Footing Combined Footing Continuous Wall Footing Strap Footing Raft Foundatio n

Prof Awad S. Hanna 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 Girder One-Way Slab, Supported by Beams or Walls One-Way Joist Slab

Prof Awad S. Hanna Slabs and Beams: Two-Way Slabs Flat Plate Two-Way Slab Supported by Beams Flat Slab Waffle Slab

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:

Prof Awad S. Hanna 2.Waste allowance from 2% to 10% should be added for concrete and concrete formwork.

Prof Awad S. Hanna 1. Center Line Method 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 ft 3 30’10” 30’ 40’0” 40’10” Building size: 30’ x 40’

Prof Awad S. Hanna 2. Sectional Method 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 ft 4.Volume = 137.34’x1’x1.5’= 206 Cubic feet 5.volume in CY = 206/27= 7.6 Cubic Yards 30’10” 27’10” 40’10”

Prof Awad S. Hanna 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

Prof Awad S. Hanna Table 2 SIZES & WEIGHTS OF REINFORCING BAR

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 20’ 60’ 40’ 30’

Prof Awad S. Hanna 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.