Table-1
Grade of Concrete M20 M25 M30 M35 M40
(Ld) Factor 57 49 45 40 36
Bar Dia (mm) Area (mm2) Development Length (Ld) in mm. (Fe500)
6 28 340 291 272 240 215
8 50 453 388 363 320 286
10 79 566 485 453 400 358
12 113 680 583 544 480 429
16 201 906 777 725 640 572
20 314 1133 971 906 800 715
25 491 1416 1214 1133 1000 894
32 804 1813 1554 1450 1279 1145Table -2 provides the details of lap length requirement in main column reinforcement
of Pre-Heater structure.
Table -3 provides the details of total reinforcement requirement of the project
and lap length requirement for various grade of concrete and bar diameters.
Table -2Bar
Diameter
(mm)Total
Length
(m)Weight
(MT)No
of
LapsConcrete Grade M30
(Actual) Concrete Grade-M35 Concrete Grade-M40
Lap
LengthLap
Weight
(MT) %Lap
LengthLap
Weight
(MT) %Lap
LengthLap
Weight
(MT) %
32 22602 143 3768 5426 34 24 4823 30 21 4341 27 19
25 4788 18 798 898 3 19 798 3 17 718 3 15
20 2495 6 416 374 1 15 333 1 13 300 1 12
Total 168 39 34 31
Cost (In
Lacs)^117272422
% Savings w.r.t. M30 concrete - - 11% 20%