introduction to rcc.pptx

1. Comparison
of Design
Methods
• Stress Strain Curve
• Load Factor
• Failure criteria
• Performance of structure

2. Stress Strain Curve
• Non- linear stress strain curve
• Elastic region
• Plastic region

3. Stress Strain Curve for concrete

4. Stress Strain for Steel

5. Load factor
Enhancing
working load
Characteristics
strength

6. Failure criteria
Load at
Failure
Strain
criteria
Stress
criteria

7. Performance
of structure
Limit State of
Serviceability
Limit State of
Durability

8. THANK YOU

9. Limit State Design
• Characteristic Strength
• Characteristic Load
• Partial Safety Factor

10. Characteristics Strength
• Characteristic Strength of material is that value of material
strength below which not more than 5% of test result are expected
to Fall
• fck=fm-1.65s

11. Example

12. Characteristics Load
• Characteristic load is that value of load which has a 95 percent
probability of not being exceeded during the life time of the
structure
• Fk=Fm+1.64s

13. Partial Safety Factor
• Two different safety factor one for the load & other for material
strength are used
• Each of the two safety factors contribute partially to safety they
are termed as partial safety factor
• Design Strength = Characteristic Strength / Strength Factor
• Design Load = Characteristic Load X Load Factor

14. Partial Safety Factor
Material Limit
State of
Collapse
Limit State
Of
Serviceability
Concrete
1.5 1
Steel 1.15 1

15. Limit State Method
• Limit State of Collapse
• Limit State of Serviceability
• Limit State of Durability

16. Assumption in Limit State Method IS 456 Pg 69
• Plane sections normal to the axis remain plane after bending

17. Assumption in Limit State Method IS 456 Pg 69
• The maximum strain in concrete at the outermost compression
fibre is taken as 0.0035 in bending.
• The tensile strength of the concrete is ignored.

18. Assumption in Limit State Method IS 456 Pg 69
• The stresses in the reinforcement are derived from representative
stress-strain curve for the type of steel used
• The maximum strain in the tension reinforcement in the section at
failure shall not be less than 0.002 + 0.87Fy/Es

19. Stress Block Parameter

20. Calculation of x1 & X2 for Rectangular &
Parabolic
• From Similar Triangle

21. Tensile & Compressive Force
• Tensile Force T=Design stress in steel x Area of steel
T=0.87fy x Ast
• Compressive Force C=C1+C2
C=0.36fckbxu

22. Stress Block Parameter