Limit State Method

The working stress method gives satisfactory performance at working load but no attention is given to the conditions that arise at the time of collapse of the structure. This method does not give exact margin of safety. This drawback was taken into account in the ultimate load or load factor method of design. But load factor method leads to excessive deflection and cracking. A more rational approach is given by limit state method of design which is a balanced combination of working stress and ultimate load design method. The limit state method of design is discussed in Section 5 of IS code 456:2000.
The object of limit state design is based on the concept of achieving an acceptable probability that a structure will not become unserviceable in its lifetime for the use for which it is intended. It should be able to withstand safety all the loads that are going to act on it throughout its life alongwith satisfying the serviceability requirements. To ensure proper degree of safety and serviceability, the design must include all relevant limit states.

Singly reinforced Beam

Design of singly reinforced rectangular section for flexure

Learn : Design of singly reinforced rectangular section for flexure, factored moment, ultimate moment of resistance, limiting moment of resistance factor, fixing dimension of the section, Area of tension steel.   Design of singly reinforced rectangular section for flexure The design problem is generally of determining dimensions (cross-sectional) of a beam (b X D) and …

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Beam Design

Basic rules for design of beams

Learn About design of beams, effective span, effective depth, reinforcement, nominal cover to reinforcement, curtailment of tension reinforcement  BASIC RULES FOR DESIGN OF BEAMS While designing R.C.C. beams, following important rules must be kept in mind: Effective Span (CI. 22.2, IS 456) The effective span of the beams are taken as follows : (a) Simply …

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Stress Strain relationship for concrete, Stress Strain relationship for steel,Design Strength Values for Steel Design Stresses at Specified Strains.

Stress Strain relationship for concrete and Stress Strain relationship for steel

Learn : Stress Strain relationship for concrete, Stress Strain relationship for steel,Design Strength Values for Steel Design Stresses at Specified Strains. fe 415 and fe 500 Stress Strain relationship for concrete and Stress Strain relationship for steel Stress Strain relationship for concrete Stress Strain relationship for concrete : The experimental or actual stress strain curve for …

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Assumptions in limit state of collapse in flexure (Bending)

Learn Assumptions in limit state of collapse in flexure (Bending),relationship between the stress strain distribution in concrete,stresses in the reinforcement are taken from the stress-strain curve Assumptions in limit state of collapse in flexure (Bending) (REFER CL. 38, IS 456) The design of reinforced concrete sections for limit state of collapse in bending, is based …

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Design Strength of Materials,Partial Safety Factors for Materials,Design Loads,Values of Partial Safety Factor for Loads (Refer Clause 36,IS Code)

Design Strength of Materials and Design Loads(Refer Clause 36, IS Code)

Design Strength of Materials :  Partial Safety Factors for Materials (rm), and Design Loads : Values of Partial Safety Factor (rf) for Loads(Refer Clause 36, IS Code)  DESIGN VALUES (REFER CLAUSE 36, IS CODE) Design Strength of Materials The strength of any material obtained in a structure is always less than the characteristic strength of the …

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Vertical Stirrups

Types of shear reinforcement

Types of shear reinforcement : Vertical stirrups, Bent up bars along with stirrups, Inclined stirrups, contribution of bent up bars TYPES OF SHEAR REINFORCEMENT The following three types of shear reinforcement are used : Vertical stirrups. Bent up bars along with stirrups. Inclined stirrups. Vertical Stirrups These are the steel bars vertically placed around the tensile reinforcement at suitable …

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Effects of Shear  Diagonal Tension, maximum bending tensile stress, tensile stress (σ) as well as shear stress (τ),

Effects of Shear Diagonal Tension

Learn : Effects of Shear  Diagonal Tension, maximum bending tensile stress, tensile stress (σ) as well as shear stress (τ),crack pattern for a simply supported beam,  The maximum bending moment in this beam will be at midspan and the maximum shear force, at the supports. EFFECTS OF SHEAR  DIAGONAL TENSION Consider a beam AB subjected …

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Shear Stresses in R.C.C. beams

Shear Stresses in R.C.C. beam (Reinforced cement concrete beam), Stress Based Approach (Elastic Theory), IS Code Approach SHEAR STRESSES IN R.C.C. BEAMS Stress Based Approach (Elastic Theory) R.C.C. is a composite materials so the exact shear distribution as per elastic theory is very complex. It is shown in Fig. 5.2(b) by the hatched portion of the curve.It …

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Characteristic Strength of Materials

Characteristic Strength of Materials Characteristic Load or ultimate load

Learn : Characteristic Strength of Materials :Characteristic Strength of Concrete, Characteristic Strength of Steel. and Characteristic Load or ultimate load CHARACTERISTIC VALUES  (REFER CLAUSE 36, IS CODE) Characteristic Strength of Materials The characteristic strength is based on the statistical analysis of the test results because there are variations in the strength of the material used. In …

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comparison of working stress method and limit state method

Learn : comparison of working stress method and limit state method, working stress method,Drawbacks of the working stress method, Limit state method :  Limit state of collapse, Limit state of serviceability. COMPARISON OF WORKING STRESS METHOD AND LIMIT STATE METHOD Working Stress method and Drawbacks of the working stress method Working Stress method This method of design …

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