# Number of Bars

## Example 03: Finding the Number of 32-mm Steel Bars for Doubly-Reinforced Concrete Propped Beam

**Problem**

A propped beam 8 m long is to support a total load of 28.8 kN/m. It is desired to find the steel reinforcements at the most critical section in bending. The cross section of the concrete beam is 400 mm by 600 mm with an effective cover of 60 mm for the reinforcements. *f’ _{c}* = 21 MPa,

*f*= 140 MPa,

_{s}*n*= 9. Determine the required number of 32 mm ø tension bars and the required number of 32 mm ø compression bars.

## Example 02: Finding the Number of 28-mm Steel Bars of Singly-Reinforced Concrete Cantilever Beam

**Problem**

A reinforced concrete cantilever beam 4 m long has a cross-sectional dimensions of 400 mm by 750 mm. The steel reinforcement has an effective depth of 685 mm. The beam is to support a superimposed load of 29.05 kN/m including its own weight. Use *f’ _{c}* = 21 MPa,

*f*= 165 MPa, and

_{s}*n*= 9. Determine the required number of 28 mm ø reinforcing bars using Working Stress Design method.