DesignofSlabOneWay.xlsx

	A	B	C	D	E	F	G	H
1	SLAB DESIGN :-			Temp
2
3	(ONE WAY) Simply supported / Cantilever (Type S/C)					in ft.	c
4		Short Span (Clear)				3.50	1.07	m
5		Long Span (Clear)				40	12.19	m
6		Live Load on the Slab (LL)					2.50	KN / sqm
7		Comp.stess of concrete M - 15 (fck)					15.00	N / sqm
8		Tensile stress of steel (fy)					415.00	N / sqm
9		Unit wt of concrete					25.00	KN / cum
10		Unit wt of floor finish 50 mm					24.00	KN / sqm
11		Clear concrete cover					15.00	mm
12		Bearing of slab					150.00	mm
13		Overall depth					35.56	mm
14		Provide Overall depth			D		125.00	mm
15		Dia of bars for short direction					8.00	mm
16		Dia of bars for long direction					8.00	mm
17		Effective Depth			d		106.00	mm
18		Loading on the slab
19		Dead Load of the slab (DL)					3.13	KN / sqm
20		Floor Finish					1.20	KN / sqm
21		Other Load					0.20	KN / sqm
22		Live Load on the slab					2.50	KN / sqm
23		Total Load on the slab (TL)					7.03	KN / sqm
24		Design Load = (Total Load x Load Factor i.e. 1.5)					10.54	KN / sqm
25		Effective Span		lx			1.17	m
26				ly			12.30	m
27		Ratio		ly/lx			10.486	> 2
28		Effective Span =		1 + 0.15 =	1.22	m
29
30		Calculated BM at mid span of slab as follows;
31	For simply supported :-
32		Mu = (w x l2)/8 =		10.54 x 1.22 x 1.22 / 8 =			1.95	KN-m/m
33	For Cantilever :-
34		Mu = (w x l2)/2 =		10.54 x 1.22 x 1.22 / 2 =			7.80	KN-m/m
35
36	Effective depth of slab will now be fixed up on consideration of
37	of flexural strength as well as control of deflection.
38	Flexural strength consideration
39				Maximum BM =	7.80	KN-m/m
40	BM =	0.36 x fck x 0.48 (1-0.42 x 0.48) x 1000 d2 =					BM x 106	N-mm/m
41	or	0.36 x 15 x 0.48 (1-0.42 x 0.48) x 1000 d2 =					7800923.052
42		or		d =	61	mm
43			Adopt effective depth (d) =		96	mm
44	Tension R/F for the positive BM along the short span is
45						BM =	7.80
46			Ast =	BM / 0.87 x fy (1-0.42 x 0.48) x d
47			=	1950231	/ 0.87 x 415 (1-0.42 x 0.48) x 96
48			=	70.5	mm2/m	8 mm dia 713 mm c/c
49	Control of deflection
50		Actual Span / effective depth ratio			=	1217	/	96
51					=	12.68
52			pt = 100 Ast/bd =	100 x 70.5 / 1000 x 61 =			0.07
53		From Modification curve, Modification factor =					2
54		Basic value of span / effective depth ratio =					7
55		Therefore permitted value of span / effective depth ratio =					7 x 2
56					=	14
57					Actual S/d is	<	Permitted S/d
58		Hence effective depth "d" should be				OK
59			Try an effective depth "d" =			106	mm
60		Tension R/F for short span +BM is given by =
61	0.87 x fy x Ast (d - fy x Ast / (fck x 1000))					=	7.8 x 1000000
62	0.87 x 415 x 216.02 (106 - 415 x 216.02 / (15 x 1000))					=	7800923.052
63				7801231	OK		7800923.052
64						Ast =	216.02
65		Actual Span / effective depth ratio			=	1217	/	106
66					=		11.48
67			pt = 100 Ast/bd =	100 x 216.02 / 1000 x 106 =			0.204
68		From Modification curve, Modification factor =					1.6
69		Basic value of span / effective depth ratio =					7
70		Therefore permitted value of span / effective depth ratio =					7 x 1.6
71					=	11.20
72					Actual S/d is	>	Permitted S/d
73		Hence effective depth "d" should be				increase
74			Adopt Overall thickness (D) =			125.00	mm
75		Minimum R/F in slab =			0.12% of area of slab
76				=	0.12 x D x 1000 / 100
77				=	150	mm2/m	8 mm dia 335 mm c/c
78
79	Hence provide Main R/F Ast =					216.02	mm2/m
80				i.e.	8	mm dia	8 mm dia 233 mm c/c
81	Maximum Spacing (3d or 450mm) =						318	mm
82
83	Hence provide Distribution R/F Ast =					150	mm2/m
84				i.e.	8	mm dia	8 mm dia 335 mm c/c
85	Maximum Spacing (5d or 450mm) =						450	mm
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