10 131130044745-phpapp02

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

211/25/2013

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

Figure:

DEFINITION OF SLAB

311/25/2013

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.

4

DEFINITION OF ONE WAY SLAB

11/25/2013

PICTURE OF ONE WAY SLAB

6

PICTURE OF ONE WAY SLAB

11/25/2013

7

PICTURE OF ONE WAY SLAB

11/25/2013

8

DEFLECTION

11/25/2013

9

DEFLECTION

11/25/2013

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

10

DESIGN CONCEPT

11/25/2013

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

10

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)

11/25/2013

11

LOAD ASSIGNED OF SLAB

11/25/2013

12

LOAD ASSIGNED OF SLAB

11/25/2013

13

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″

14

TEMPERATURE AND SHRINKAGE

REINFORCEMENT

11/25/2013

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

15

TEMPERATURE AND SHRINKAGE

REINFORCEMENT RATIO

11/25/2013

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.

16

DESIGN PROCEDURE

11/25/2013

17

REINFORCEMENT DETAILING

18

REINFORCEMENT DETAILING

11/18/2013

19

THANK YOU

11/25/2013