Side Reinforcement in Beams

beam_side_reinforcement.png

 

To control cracking in beams with a total depth ˃ 750mm, side bars are provided in the side faces of the beam.1

Minimum diameter of bars in side of beam2, φsb      

φsb

> 

(sb* b / fy)0.5 

Where

 

 

sb 

=

bar spacing ≤ 250mm

b

=

breadth of section

IF

 

 

 b

>

500mm

THEN

 

 

b

=

500

 fy

=

Characteristic strength of reinforcement

The diameter of the bar to be used is subject to qualification by the user therefore;

φsb

=

MAX[φsb, φsb,min]

The maximum spacing of side reinforcement bars3 sb, max ≤ 250mm

The distribution of these bars is over a distance of two-third of the beam’s overall depth measured from its tension face.

The number of side bars in each vertical face of the beam is given by;

nsb

=

[d-(h/3)]/sb, max

where

 

 

d

=

effective depth of the tension reinforcement

 

Parent topic                

  Design Parameters for Longitudinal Bars

 

 

1.    BS 8110-1:1997 3.12.11.2.6

2.    BS 8110-1:1997 3.12.5.4

3.    BS 8110-1:1997 3.12.11.2.6