What are the assumptions made in elastic analysis?

Fundamental assumptions of elastic theory of bending The concrete and steel reinforcement are perfectly bonded.It means that the tensile strain in steel reinforcement is equal to the tensile strain in concrete surrounding the steel. All tensile stresses are taken up by steel and none by concrete.

What does it mean by plane sections remain plane?

In the Euler–Bernoulli theory of slender beams, a major assumption is that ‘plane sections remain plane’. In other words, any deformation due to shear across the section is not accounted for (no shear deformation).

What are the assumptions of Limit State method of design with stress-strain diagram?

Assumption in Limit State of Collapse: In concrete, the relationship between the stress-strain distribution is assumed to be parabolic. The tensile strength of concrete is ignored. The maximum compressive load of the structure takes by the concrete.

Do plane sections remain plane?

Consequently, as the beam bends, plane sections remain plane but rotate relative to each other as shown in the figure below. As illustrated in the figure above, the top surface of the beam is shortened due to compression, and the bottom surface is elongated due to tension – both as a result of bending moment M.

What are the assumptions made in the limit state method of design?

What are the various assumptions made in the theory of Limit State of Collapse (flexure) in case of RC members? Plane sections normal to the axis remain plane after bending. The maximum strain in concrete at the outermost compression fibre is 0.0035 in bending. Tensile strength of concrete is ignored.

What are the basic assumptions made for design of flexure for RCC structure?

The design of reinforced concrete sections for limit state of collapse in bending, is based on the following assumptions : (a) Plane sections normal to the axis remain plane after bending. It means that the strain at any point in the cross-section is proportional to the distance from the neutral axis.

What is the primary assumption for deriving the equation for elastic beam theory?

The two primary assumptions made by the Bernoulli-Euler beam theory are that ‘plane sections remain plane’ and that deformed beam angles (slopes) are small. The plane sections remain plane assumption is illustrated in Figure 5.1.

Which of the following is an assumption in classical beam theory?

Under this theory, the following assumptions are made: The beam is initially straight and has a constant cross-section. The beam is made of homogenous material and the beam has longitudinal plane of symmetry. Resultant of the applied loads lie in the plane of symmetry.

What are the assumptions for the beam element?

The main assumption related to beam, is that beam cross section remains straight during deformation. However, we do not enforce that a surface normal to the beam neutral axis remains normal during the deformation (as in classical Bernoulli beam). In other words, the beam detailed in this article is a Timoshenko beam.

What are the assumption of limit state method of design as per IS 456 2000?

As per IS:456-2000, all columns shall be designed for minimum eccentricity, equal to the unsupported length of column/ 500 plus lateral dimensions/30, subject to a minimum of 20 mm. 1. The maximum compressive strain in concrete in axial compression is taken as 0.002.

What are the basic assumptions made in RCC design by LSM?

Tensile strength of concrete is ignored. Maximum strain in the tension reinforcement in the section at failure shall not be less. There is a perfect bond between steel and concrete. The stresses in the reinforcement are derived from stress strain curve for the type of steel used.

What are the assumptions made on analysis and design of RCC members in working stress method?

The basic assumptions in WSM are: Plane Section before bending will remain plane after bending. The stress-strain relationship will follow Hooke’s law. The tensile stress is taken by steel only.

What are the fundamental assumptions of elastic theory of bending?

The fundamental assumptions of elastic theory of bending are explained below: A section which is plane before bending remains plane after bending.

What is the design bending moment capacity for elastic design?

For elastic design, each of the members in the structure must have a design bending moment capacity (ϕMs) greater than the design moment ( M*) obtained from an elastic analysis.

What do you mean by elastic analysis?

Analysis of structures that is based on the following assumptions is called the elastic analysis. 1. Material of the structure is continuous and absolutely elastic. 2. Relationship between stress and strain is linear. 3. Deformations of a structure, caused by applied loads, are small and do not change original design diagram.

Which section is plane before and after bending?

A section which is plane before bending remains plane after bending. This assumption implies that the strain above and below the neutral axis are proportional to the distance from the neutral axis i.e. the strain distribution is triangular, linearly varying from zero at the neutral axis to maximum value at the extreme fibre.