2 - way slab design

SLAB DESIGN :- Out House Room(One long & one short edge discontineous)

(TWO WAY) in ft.Short Span (Clear) 11.00 3.35 mLong Span (Clear) 17.5 5.33 mLive Load on the Slab (LL) 3.50 KN / sqmComp.stess of concrete M - 15 (fck) 15.00 N / sqmTensile stress of steel (fy) 415.00 N / sqmUnit wt of concrete 25.00 KN / cumUnit wt of floor finish 50 mm 24.00 KN / sqmClear concrete cover 15.00 mmBearing of slab 230.00 mmOverall depth 111.76 mmProvide Overall depth D 125.00 mmDia of bars for short direction 10.00 mmDia of bars for long direction 10.00 mmEffective Depth d 105.00 mmLoading on the slabDead Load of the slab (DL) 3.13 KN / sqmFloor Finish 1.20 KN / sqmOther Load 0.50 KN / sqmLive Load on the slab 3.50 KN / sqmTotal Load on the slab (TL) 8.33 KN / sqmDesign Load = (Total Load x Load Factor i.e. 1.5) 12.49 KN / sqmEffective Span lx 3.46 m

ly 5.44 mRatio ly/lx 1.573From Table (26 or 27 of IS 456) BM Coefficients are as follows;

1.5 1.75For negative moments (at top) 0.075 0.077626757 0.084 0.047For positive moments (at bottom) 0.056 0.058043033 0.063 0.035

Calculated BM per unit width of slab are as follows;

For negative moments (at top) 11.59 7.02 KN-m/mFor positive moments (at bottom) 8.67 5.23 KN-m/m

Effective depth of slab will now be fixed up on consideration ofof flexural strength as well as control of deflection.Flexural strength consideration

Maximum BM = 11.59 KN-m/m

BM = N-mm/m

or 11590086.67or d = 75 mm

Tension R/F for the positive BM along the short span isBM = 8.67

Ast = BM / 0.87 x fy (1-0.42 x 0.48) x d= 8666133 / 0.87 x 415 (1-0.42 x 0.48) x 75= 401.7 mm2/m

Control of deflectionActual Span / effective depth ratio = 3458 / 75

= 46.20pt = 100 Ast/bd = 100 x 401.7 / 1000 x 75 = 0.54

From Modification curve, Modification factor = 1.2

ax ay

Mx = ax w lx2 My = ay w lx2

0.36 x fck x 0.48 (1-0.42 x 0.48) x 1000 d2 = BM x 106

0.36 x 15 x 0.48 (1-0.42 x 0.48) x 1000 d2 =

Basic value of span / effective depth ratio = 26Therefore permitted value of span / effective depth ratio = 26 x 1.2

= 31.2Actual S/d is > Permitted S/d

Hence effective depth "d" should be increaseTry an effective depth "d" = 100 mm

Tension R/F for short span +BM is given by =0.87 x fy x Ast (d - fy x Ast / (fck x 1000)) = 8.67 x 1000000 0.87 x 415 x Ast (100 - 415 x Ast / (15 x 1000)) = 8666132.809

8666271 OK 8666132.8Ast = 258.52

Actual Span / effective depth ratio = 3458 / 100= 34.58

pt = 100 Ast/bd = 100 x 258.52 / 1000 x 100 = 0.259From Modification curve, Modification factor = 1.45Basic value of span / effective depth ratio = 26Therefore permitted value of span / effective depth ratio = 26 x 1.45

= 37.70Actual S/d is < Permitted S/d

Hence effective depth "d" should be OKAdopt Overall thickness (D) = 120 mm

Minimum R/F in slab = 0.12% of area of slab= 0.12 x D x 1000 / 100 = 144 mm2/m 8 mm dia 349 mm c/c

0.87 x 415 x Ast (d - 415 x Ast / (15 x 1000)) = BM x 1000000 Effective depth for R/F in long direction will, therefore, be = 100 - dia. Of long R/F

= 100 - 10 = 90.00 mmTension R/F per unit width of slab calculated by above eq. For different BM are as follow;

Bendind MomentsShort Span Long Span

For negative moments (at top) 11.59 KN-m/m 7.02 KN-m/mFor positive moments (at bottom) 8.67 KN-m/m Increase Steel KN-m/m

ReinforcementsShort Span Long Span

Top R/F (At support) 357.00 233.00 mm2/mBottom R/F (At Mid Span) 258.52 160.00 mm2/mThese R/F will be provided within the middle strips in the two directions.Adopting 8 or 10 mm dia bars for the R/F, the calculated spacing of bars will be as follows;

Reinforcements SpacingDia of bars Short Span Dia of bars Long Span

Top R/F (At support) 10.00 210 10.00 330 mm c/cBottom R/F (At Mid Sp 10.00 300 10.00 490 mm c/cMaximum Spacing 300 270 mm c/c

No. of bars in slabShort Span Long Span

Top R/F 26.00 Nos. of Length 5439 mm 11.00 Nos. of Length 3457.8 mmBottom R/F 19.00 Nos. of Length 5439 mm 8.00 Nos. of Length 3457.8 mm

Very this steel area to make "OK"

Change as per curve for "pt"

Very these R/F area for the BM

G54

23.2.1 of IS 456 Cantilever = 7 Simply Supported = 20 Contineous = 26

G64


G68


E86

Very these R/F area for the BM

document.xls[Report] 4/11 04/08/2023(06:24:54)

SLAB DESIGN :- Out House RoomEdges conditions :- (One long & one short edge discontineous)

Room Size :- 11 x 17.5 Ft. Thickness of Slab :- 120 mmConcrete Grade M-15 (fck 15 N/Sqm) Steel :- HYSD (fy 415 N/Sqm)Live Load :- 3.5 KN/SqmFloor Finish + Other Load :- 1.2 + 0.5 KN/Sqm

Calculated BM per unit width of slab are as follows;Mx My

For negative moments (at top) Support :- 11.59 7.02 KN-m/mFor positive moments (at bottom) Mid Span:- 8.67 5.23 KN-m/mMaximum R/F(Flexural Consideration) :- 401.72 mm2/m, 8 mm dia. 125 C/C

Required Reinforcements & SpacingShort Span

Top At support :- 357.00 mm2/m 10 mm dia. 210 mm c/cBottom At Mid Span :- 258.52 mm2/m 10 mm dia. 300 mm c/c

Long SpanTop At support :- 233.00 mm2/m 10 mm dia. 270 mm c/cBottom At Mid Span :- 160.00 mm2/m 10 mm dia. 270 mm c/c

Minimum R/F :- 144.00 mm2/m 8 mm dia 349 mm c/c Maximum Spacing :- 270 mm

document.xls[1] 5/11 04/08/2023[06:24:54]

SLAB DESIGN :- Frontside Bed RoomEdges conditions :- (All four edges contineous)

Room Size :- 12.5 x 13.25 Ft. Thickness of Slab :- 125 mmConcrete Grade M-15 (fck 15 N/Sqm) Steel :- HYSD (fy 415 N/Sqm)Live Load :- 3.5 KN/SqmFloor Finish + Other Load :- 1.2 + 0.5 KN/Sqm







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8 mm dia.6" c/c

8 mm dia.7" c/c

8 mm dia.9" c/c

document.xls[1] 6/11 04/08/2023[06:24:54]

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document.xls[[2] 7/11 04/08/2023[06:24:54]

SLAB DESIGN :- Drawing RoomEdges conditions :- (All four edges contineous)








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10 mm dia.7" c/c

10 mm dia.8" c/c

document.xls[[2] 8/11 04/08/2023[06:24:54]

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document.xls[3] 9/11 04/08/2023[06:24:54]

SLAB DESIGN :- Backside Bed RoomEdges conditions :- (Two short edges contineous)

Room Size :- 15.5 x 17 Ft. Thickness of Slab :- 145 mmConcrete Grade M-15 (fck 15 N/Sqm) Steel :- HYSD (fy 415 N/Sqm)Live Load :- 3.5 KN/SqmFloor Finish + Other Load :- 1.2 + 0.5 KN/Sqm


For negative moments (at top) Support :- 0.00 14.01 KN-m/mFor positive moments (at bottom) Mid Span:- 13.24 10.90 KN-m/mMaximum R/F(Flexural Consideration) :- 558 mm2/m, 10 mm dia. 141 C/C


Top At support :- 0.00 mm2/m #DIV/0!Bottom At Mid Span :- 315.48 mm2/m 10 mm dia. 240 mm c/c


Minimum R/F :- 174 mm2/m 8 mm dia 289 mm c/c Maximum Spacing :- 300 mm

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10 mm dia.5" c/c

10 mm dia.6" c/c

document.xls[4] 10/11 04/08/2023[06:24:54]

SLAB DESIGN :- Study RoomEdges conditions :- (One long edge discontineous)








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8 mm dia.7" c/c

8 mm dia.7" c/c

document.xls[5] 11/11 04/08/2023[06:24:54]

SLAB DESIGN :- KitchenEdges conditions :- (One long & one short edge discontineous)








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8 mm dia.5" c/c

8 mm dia.8" c/c

2 - way slab design

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