SLAB DESIGN - ONE WAY

CE- 416

Pre-stressed Concrete Lab SessionalPresented By:

Md. Abu Raihan

Id No:10.01.03.049

Course teachers:

Munshi Galib Muktadir

Sabreena Nasrin

Department Of Civil Engineering

Ahsanullah University of Science & Technology

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Definition Of Slab Definition Of One-Way Slab Deflection Design Concept Minimum Thickness Of One-Way Slab Load Assigned To Slabs Temperature And Shrinkage Reinforcement Temperature And Shrinkage Reinforcement Ratio Design Procedure

PRESENTATION OUTLINE

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Layer of reinforce-concrete with uniform/variable thickness supported by restraints

Figure:

DEFINITION OF SLAB

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The ratio of the longer to the shorter side (L/B) of the slab is at least equal to 2.0

Support conditions is an important impact. Deflection is another important factorLoad is distributed to the direction perpendicular of the

supporting restraints.

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DEFINITION OF ONE WAY SLAB

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PICTURE OF ONE WAY SLAB

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PICTURE OF ONE WAY SLAB

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PICTURE OF ONE WAY SLAB

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DEFLECTION

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DEFLECTION

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For the purpose of analysis and design, a unit strip of a slab is cut out at right to the supported beams.

The method here is used for rectangular beams. Figure

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DESIGN CONCEPT

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To control deflection, ACI Code 9.5.2.1 specifies minimum thickness values for one-way solid slabs, shown in Table.

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MINIMUM THICKNESS OF SLAB

Element Simply Supported

One-End Continuous

Both-End Continuous

Cantilever

One-way Slab

L/20 L/24 L/28 L/10

L is the span length direction of bending.If Wc ≈ 90 – 120 psf factor will be applied by ( 1.65-0.005Wc)If Fy ≠ 60 ksi factor will be ( 0.4 + Fy/100000)

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LOAD ASSIGNED OF SLAB

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LOAD ASSIGNED OF SLAB

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LOAD ASSIGNED OF SLAB

Concrete gets shrinks and results crackingCracks known as Hairline cracks.provide special reinforcement for shrinkage and

temperature contraction in the direction perpendicular to the main reinforcement.

Maximum lateral spacing 5h or 8″

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TEMPERATURE AND SHRINKAGE

REINFORCEMENT

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Based on the Gross Concrete AreaSlabs with 40 or 50 grade reinforcement-0.002Slabs with 60 grade reinforcement-0.0018Slabs where reinforcement with yield stress exceeding 60 KSI

at 35% yield-(0.0018*60000)/Fy

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TEMPERATURE AND SHRINKAGE

REINFORCEMENT RATIO

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Step-1: From given panel find out the Tmin.

Step-2: Find out the Factored Load.(Wu = 1.2*DL + 1.6*LL)

Step-3: Find out Moments of the panel.

(M = Moment Coefficients*Wu*L²)

Step-4: Find out maximum steel ratio

(ρmax = 0.85*β1*(f´c/fy)*(εu/ εu + 0.004)

Step-5: Find dreq. ( )

Step-6: As and a. (

)

Step-7: Temperature and shrinkage reinforcement

Step-7: Reinforcement Detailing.

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DESIGN PROCEDURE

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REINFORCEMENT DETAILING

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REINFORCEMENT DETAILING

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THANK YOU

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