Answer :
Flat slabs and concrete slabs are two different types of structural systems used in construction, particularly in building floors and roofs. While concrete slabs refer to a general category of slab systems, flat slabs are a specific type of concrete slab construction.
1. Flat Slabs: Flat slabs are slabs that lack beams between columns and support the weight of the floor by flat slab columns. They're constructed of concrete and are sometimes utilized in multi-story buildings since they're simple to construct and provide more efficient, open space.
2. Calculation of design load: Given values, Dimensions of slab, Length(L) = 6.4 m Width(B) = 5.2 m. Effective depth (d) = slab thickness - cover - (diameter/2) of bar = (180 - 20 - (12/2)) mm = 143 mm Unit weight of concrete = 25 kN/m3 Grade of concrete = C25 Characteristic live load = 7.5 kN/m2 Finishing load = 1 kN/m2 Grade of steel = S420 Partial safety factor for concrete = 1.5Partial safety factor for steel = 1.15 Dead load of the slab, G = thickness x unit weight of concrete = 180 x 25 = 4500 N/m2 Finishing load = 1 kN/m2 Dead load of the slab with finishing = 4500 + 1000 = 5500 N/m2 Factored load = 1.4 x dead load + 1.6 x live load = (1.4 x 5500) + (1.6 x 7.5) = 7930 N/m2. Therefore, the design load (factored design load) is 7930 N/m2.3.
One-way slab design procedure: Step 1: Calculation of the load. Step 2: Selection of slab thickness and its reinforcement. Step 3: Determination of effective span. Step 4: Calculation of moment of resistance (M.R.). Step 5: Calculation of bar bending schedule. Two-way slab design procedure: Step 1: Calculation of the load. Step 2: Selection of slab thickness and its reinforcement. Step 3: Calculation of the effective span of the slab. Step 4: Calculation of moment of resistance (M.R.). Step 5: Calculation of bar bending schedule.
For further information on concrete slabs visit:
https://brainly.com/question/31948917
#SPJ11
1) The factored design load is 19,400 kN/m².
2) The design level of reinforcement are Ast₁ is 152.02 mm² and Ast₂ is 138.21 mm².
3) The area of steel for each reinforcement bar type are A₁=80.11 mm² and A₂=71.67 mm².
One Way Slab Design:
1. Calculate the design loads:
Calculate the dead load (G) by multiplying the slab thickness (in this example it is 180 mm) by the unit weight of concrete (25 kN/m³)
G = 180×25 = 4500 kN/m²
Calculate the live load Q = 7.5 kN/m²
Calculate the finishing load [tex]P_d[/tex]= 1 kN/m².
Determine the factored design load
Pd = 1.4G + 1.6Q + 1.6 [tex]P_d[/tex]
= 1.4×4500 + 1.6×7500 + 1.6×1000
= 19,400 kN/m².
2. Calculate the necessary reinforcement:
Calculate the moment of resistance of the slab (M) by using the bending and sheer equation.
M = ((1/250)[(M/fc) + (M/fy)]) x bd₂
= (1/250)[(3200/25)+ (2260/420)]×5.22×1802 = 78750 kN.m
Calculate the design moments M₁ and M₂:
M₁ = 0.036×19,400×16.22 = 106.25 kN.m
M₂= 0.012×19,400×(5.22+6.42) = 99.34 kN.m
Calculate the design level of reinforcement (Ast₁ and Ast₂) using the formula:
Ast₁ = M₁/fy.bd = 106.25/420 ×522×180 = 152.02 mm²
Ast₂= M₂/fy.bd = 99.34/420 ×522×180 = 138.21 mm²
3. Calculate the required area of steel:
Calculate the area of steel for each reinforcement bar type:
A₁ = (Ast₁/ (π/4)) 0.78= ( 152.02/(π/4) )0.78= 80.11 mm²
A₂= (Ast₂/ (π/4)) 0.78= ( 138.21/(π/4) )0.78= 71.67 mm²
4. Complete the design by calculating the minimum number of reinforcement bars:
Calculate the minimum number of reinforcement bars:
N₁= ( 80.11/A₁)=( 80.11/80.11)=1
N₂= ( 71.67/A₂)=( 71.67/71.67)=1
Two-Way Slab Design:
1. Calculate the design loads:
- Calculate the dead load (G) by multiplying the slab thickness (in this example it is 180 mm) by the unit weight of concrete (25 kN/m³)
G = 180×25 = 4500 kN/m²
Calculate the live load Q = 7.5 kN/m²
Calculate the finishing load [tex]P_d[/tex] = 1 kN/m².
Determine the factored design load [tex]P_d[/tex] = 1.4G + 1.6Q + 1.6[tex]P_d[/tex]
= 1.4× 4500+1.6×7500+1.6×1000 =19,400 kN/m².
2. Calculate the necessary reinforcement:
- Calculate the moment of resistance of the slab (M) by using the bending and sheer equation.
M = ((1/250)[(M/fc) + (M/fy)])×bd₂
= (1/250)[(3200/25)+ (2260/420)]×5.22×1802
= 78750 kN.m
Calculate the design moments M₁ and M₂:
M₁= 0.08×19,400×32.42 = 619.04 kN.m
M₂= 0.028×19,400×(5.22+6.42) = 271.98 kN.m
Calculate the design level of reinforcement (Ast₁ and Ast₂) using the formula:
Ast₁= M₁/fy.bd = 619.04/420 ×522×180 = 1189.56 mm²
Ast₂= M₂/fy.bd = 271.98/420 ×522×180 = 528.3 mm²
3. Calculate the required area of steel:
- Calculate the area of steel for each reinforcement bar type:
A₁= ( Ast₁/(π/4))0.78= (1189.56/(π/4)) 0.78 = 643.71 mm²
A₂= ( Ast₂/(π/4))0.78= (528.3/(π/4)) 0.78 = 287.98 mm²
4. Complete the design by calculating the minimum number of reinforcement bars:
Calculate the minimum number of reinforcement bars:
N₁= ( 643.71/A₁) = ( 643.71/643.71) =1
N₂= ( 287.98/A₂) = ( 287.98/287.98) = 1
Therefore,
1) The factored design load is 19,400 kN/m².
2) The design level of reinforcement are Ast₁ is 152.02 mm² and Ast₂ is 138.21 mm².
3) The area of steel for each reinforcement bar type are A₁=80.11 mm² and A₂=71.67 mm².
Learn more about the reinforcement here:
https://brainly.com/question/32262917.
#SPJ4
