# Posts Tagged Guide to design of Doubly reinforced beams

### Design procedure for designing doubly reinforced section

Posted by Benzu JK in Building Construction on September 23, 2012

#### 7 step procedure for “Design of Doubly reinforced sections”

**In our article series for “Design of Doubly reinforced sections”, we covered the following:**

What are doubly reinforced sections?

Methods for determining Neutral Axis?

Solved numerical examples for determining Neutral Axis

Numerical examples for practice (Find Neutral axis)

Methods for calculating Moment of Resistance

Numerical example for calculating Moment of resistance

Types of problems in Doubly reinforced sections

6 step prodecure for determining stresses in steel and concrete

Numerical example | Stresses in steel and concrete

#### In our previous article, we discussed a detailed 6 step procedure for determining stresses in steel and concrete followed by a numerical example. Now we shall move on with the “design procedure for doubly reinforced sections”.

**Generally the following data are given:**

Breadth of the beam = b

Effective depth of the beam = d

Permissible stress in concrete = σ_{cbc}

Permissible stress in steel = σ_{st}

Modular ratio = m

Bending moment = M

To solve a problem, the following procedure may be followed.

Design the beam as a singly reinforced one (balanced section)

#### Step One:

Find x_{c} by

σ_{cbc}/ (σ_{st}/m) = x_{c}/(d – x_{c})

### Numerical Examples | Moment of Resistance Calculations

Posted by Benzu JK in Building Construction on August 1, 2012

#### Moment of Resistance calculations | Doubly reinforced sections

**In our article series for “Doubly reinforced sections”, we have covered the following:**

What are doubly reinforced sections?

Methods for determining Neutral Axis?

Solved numerical examples for determining Neutral Axis

Numerical examples for practice (Find Neutral axis)

Methods for calculating Moment of Resistance

Numerical example for calculating Moment of resistance

Types of problems in Doubly reinforced sections

Determining stresses in steel and concrete

Numerical example | Stresses in steel and concrete

**Now we shall move on with a solved example. This will help you understand the methods in a better way. I suggest that you do them yourselves too. Practice will help you make your concepts more concrete and clear.**

#### Numerical Example:

**An reinforced concrete 300mm x 600mm effective dimensions is provided with tensile and compressive reinforcement of 1256mm2 each. The compressive steel is placed 30mm from the top edge of the beam. If σ _{cbc} = 7N/mm^{2}, σ_{st} = 190N/mm^{2} and m = 13.33, find the moment of resistance of beam by following two methods:**

**1) Elastic theory method**

**2) Steel beam theory method**