why reinforcement of 2 bars of 12 mm dia in beam is not accepted where required Ast= 181 when Fe 500 is used
The Number of Bars suggested by RCDC are as per beam width and maximum spacing criteria given in codes. User can change the numbers of bars prior to design subjected to spacing criteria given in code. For zero bending moment zone RCDC can provide minimum two bars with minimum bar diameter.
Designing in RCDC - why reinforcement of 2 bars of 12 mm dia in beam is not accepted where required Ast= 181 when Fe 500 is used but it accepts when Fe 415 is used.
The reinforcement required is computed as per the effective depth for the number of layer of reinforcementas per table above.
Rebars will be arranged in multiple layers if requiredand the style of detailing selected. The maximum number of layers usedwill be limited to thoseassumed when computing the effective depth.
In case it is not possible to provide the required reinforcement using the largest rebar arranged in the maximum possible layers the number of layers will be automatically increased. With the increase in number of layers the effective depth and the reinforcement required will be computed again.
When providing rebars across the section of the beam, the minimum and the maximum spacing criteria and the preferred number of rebars will be considered. The rebars wil be symmetrically arranged across the section.
In case the number of bars are varying across the section, the auto detailing will ensure that the symmetry will be maintained.eg. 6 bars will reduce to 4 and not 5 bars OR 5 bars will reduce to 3 and 4 bars.
What is the recommended code for spacing criteria
Design Code Included in RCDC are
a. Indian Standard - IS 456 + 13920 - 1993
b. Indian Standard - IS 456 + 13920 - 2016