# COMBINED AXIAL AND BENDING

https://www.mesubjects.net/wp-admin/post.php?post=3503&action=edit Q. ANs on bending

https://www.mesubjects.net/wp-admin/post.php?post=3454&action=edit Bending stresses

**COMBINED AXIAL AND**

** BENDING**

## It is applicable for a beam column. A beam

## carries transverse loads (bending loads)

## and a column carries an axial compressive

## load. Examples of beam column are

## chimneys, dams, retaining wall, trees, poles

## and building structures. Axial compressive

## load is due to the self weight and the

## bending is due to the wind affect.

**STRESSES IN A BEAM COLUMN**

#### (i) Axial stresses are compressive stresses of CONSTANT value, σ_{A} =W/A

#### (ii) Bending stresses are both simultaneously tensile and compressive stresses and are of VARYING values

#### σ_{b} = (M/I) y

#### (iii) Maximum compressive stress σ_{max} = σ_{A} + σ_{b}

#### (iv)Maximum tensile stress σ_{max} = σ_{b} – σ_{A} i.e. tensile stress is there only if σ_{b} > σ_{A}.

**There are three possible cases**

### Case 1 Bending stress is greater the axial stress

### σ_{b} > σ_{A}

#### First σ_{max} = σ_{A} + σ_{b Compressive}

#### Second σ_{max} = σ_{b} – σ_{A Tensile}

**Neutral axis will not coincide with the centroid axis. Neutral axis is towards compressive fibers.**

**Case 2 Bending stress is equal to the axial stress**

** σ**_{b} = σ_{A}

_{b}= σ

_{A}

#### First σ_{max} = σ_{A} + σ_{b Compressive}

#### Second σ_{max} = σ_{b} – σ_{A = 0 }

_{Neutral axis will coincide with the centroid axis. }

**Case 3 Bending stress is lesser than the axial stress**

**σ**_{b} < σ_{A}

_{b}< σ

_{A}

#### First σ_{max} = σ_{A} + σ_{b Compressive}

#### Second σ_{max} = σ_{b} – σ_{A Compressive}

**Neutral axis will not coincide with the centroid axis. Neutral axis will be towards tensile fibers.**

#### In each case, for safe design

#### First Maximum compressive stress ≤ Allowable compressive stress

#### Second Maximum tensile stress ≤ Allowable tensile stress

# Eccentric Loading

`It is applicable for cases where self weight is not negligible as compared to the external load. The example of such cases is a beam column. A beam carries transverse loads (bending loads) and a column carries an axial compressive load. Examples of beam column are chimneys, dams, retaining wall, trees, poles, buildings and structures. Axial compressive load is due to the self weight and the bending is due to the wind effect (or water pressure).`

Eccentric loading=Axil load +Moment = Axial and bending combined