What are the assumptions in the limit state design method?

Assumption in Limit State of Collapse: The tensile strength of concrete is ignored. The maximum compressive load of the structure takes by the concrete. The steel takes the maximum tensile load of the structure and takes a little bit of compressive load. There should have a perfect bond between steel and concrete.

What is the maximum strain in steel at failure?

(vi) The maximum strain in tension reinforcement in the section at failure is to be not less than 0.002 + (fy /1.15 Es). For limit state of collapse in compression, in addition to the above six assumptions, two additional assumptions are also stated in the code Clause 39.1.

What are the assumptions made in limit state of collapse in flexure?

Assumptions in limit state of collapse in flexure (Bending) It means that the strain at any point in the cross-section is proportional to the distance from the neutral axis. (b) The maximum strain in concrete at the outermost compression fibre is taken as 0.0035 in bending.

What is the design strength of steel in limit state method?

5. Clause 36.4. 2 of IS 456 states that γm for concrete and steel should be taken as 1.5 and 1.15, respectively when assessing the strength of the structures or structural members employing limit state of collapse.

Why do we need minimum shear reinforcement?

The minimum shear reinforcement is provided for the following: (i) Any sudden failure of beams is prevented if concrete cover bursts and the bond to the tension steel is lost. (ii) Brittle shear failure is arrested which would have occurred without shear reinforcement.

Why steel is used as reinforcement?

Steel is commonly used as good reinforcing material because of the following reasons: Steel is highly ductile material. It can deform without losing its toughness. Young’s Modulus of elasticity of steel is equal in both tension and compression.

What will be the maximum strain of concrete and steel for limit state of collapse for flexure?

39.1 of IS 456:2000, the maximum compressive strain in concrete in axial compression is taken as 0.002.