Hi,spacing provided in the footing is explained by below example.
As per design, required reinforcement is 497 sqmm along B direction. Provided reinforcement is T10@250mm which amounts to 471sqmm only for 1500m width of footing, whereas the calculation report shows Ast provided as 549sqmm.
Width = 1500mm
Ast required = 497sqmm
Reinforcement provided = T10@250mm
In RCDC the number of bars required are calculated and spacing is calculated. While presenting the spacing rounded to 5 mm.
In this example, number of bars as per spacing would be calculated as below –
(1500/ 250= 6 which is 6 spaces). Hence number of bars provided on site would be 7(6+1).
Thus, actual Ast-provided would be (7x78.5398 = 549.78) 549.78 sqmm which is more than required.for more FAQ's, please check link: 5. RCDC Support Solutions - RAM | STAAD | ADINA Wiki - RAM | STAAD | ADINA - Bentley Communities
but how this 250 spacing was coming ? as we know spacing is calculated from following formula
spacing = (area of one bar * length of footing) /Ast then in my case if i am using the 10 mm dia bar the 78.5*1500/497 + 236 spacing while rcdc reported 250mm
Dear Sir,Please share the design calculation report to give the clarification of 250mm spacing. it must be maximum spacing allowed in the footing reinforcement setting for calculated for the Ast.when we provide the rebars on site, to maintain the spacing we always provide the n+1 rebars. in your case, the number of rebars required as per Ast are 6, however on site finally 7 rebars will be provided to maintain the spacing. Now for the width of 1500mm there are 7 rebars are provided. so, if we recalculate the Ast provided for 1500mm width is more than the actual required.
ok but is should reported as actual that is calculated by manually in drawing we are not writing how much bar is placed instead of it we write 10@ 225 or 200 this is wrong . whoever in calculation of quantity this no of bar +1 is taken not in Ast calculation. I hope you get my point
Hi,Please check this option available in RCDC where actual number of bars are available in design calculation reports and drawings.
above marked option gives the actual number of rebars to be provided.