Combined Footing Design Excel sheet.xls

	A	B	C	D	E	F	G	H	I	J	K	L	M	N	O	Q	R	S	T	U	V	W
1								4.50	ft				Ø12mm@	8.00	in c/c
2													Ø16mm@	12.00	in c/c				Ø16mm - 8 legged Stirrup
3			S =	8.08	ft								Ø20mm@	16.00	in c/c				@ 8" c/c
4										2.15	ft		Ø25mm@	26.00	in c/c
5				ft				ft									2.15	ft
6				4.67				9.33						2.13	ft						2.13	ft
7				4.67	CG			9.33
8								B=
9								B=
10			4.17	ft	3.91	ft
11
12	3.50
13	ft		7.500	ft		7.500	ft
14
15				15.00	ft							Ø12mm@	4.00	in c/c						Ø16mm - 4 legged Stirrup
16												Ø16mm@	6.00	in c/c						@ 16" c/c
17												Ø20mm@	8.00	in c/c
18				Ø12mm@	5.00	in c/c						Ø25mm@	13.00	in c/c
19				Ø16mm@	8.00	in c/c											Detailing of Stirrups
20				Ø20mm@	11.00	in c/c				Longitudinal Reinforcement in the Bottom of Footing
21				Ø25mm@	18.00	in c/c
22												Ø12mm@	1.00	in c/c
23												Ø16mm@	2.00	in c/c
24										2.15	ft	Ø20mm@	3.00	in c/c
25												Ø25mm@	4.00	in c/c		Ø12mm@	1.00	in c/c
26																Ø16mm@	2.00	in c/c
27																Ø20mm@	2.00	in c/c
28																Ø25mm@	4.00	in c/c
29
30
31				Ø12mm@	10.00	in c/c
32				Ø16mm@	16.00	in c/c
33				Ø20mm@	22.00	in c/c
34				Ø25mm@	36.00	in c/c								2.13	ft
35
36			Longitudinal Reinforcement in the Top of Footing							Transverse Reinforcement in the Bottom of Footing
37	Step-1: Data
38
39		Size of Column, S1 =	18.00	in =	1.50	ft	(Col. A)
40		Z1 =	12.00	in =	1.00	ft	(Col. A)
41		S2 =	10.00	in =	0.83	ft	(Col. B)
42		Z2 =	15.00	in =	1.25	ft	(Col. B)
43	Distance center to center of Colums, S =				8.08	ft
44		f'c =	3,000.00	psi
45		=	3.00	ksi
46		fy =	60,000.00	psi
47		=	60.00	ksi
48	Service Load on Column, A =			150.00	kips (Load taken from Staadpro)
49	Service Load on Column, B =			160.00	kips (Load taken from Staadpro)
50	Service Load with 10% self wt. of Footing, Ws =				341.00	kips
51	Allowable Soil Pressure, qa =			3.00	ksf
52
53
54	Step-2: Footign Size
55	Since the space between the bottom of the footing and the surface will be occupied partly by
56	concrete and partly by soil (fill), an average unit weight of 125 lb/ft3 will be assumed.
57
58			So, pressure of Soil, A1 =	125.00	pcf
59				Let, Top of the Footing below GL, B1 =	8.00	ft
60	The Soil Pressure at		8.00	ft depth, C1=		A1xB1 =	1,000.00	psf
61
62	The net bearing pressure of the soil to carry the Colm Service Load, qnet =						qa - C1
63						=	2.000	ksf
64
65				Hence, the required footing area, Areq =	Ws / qnet
66				=	170.50	ft2
67
68	The CG of the Columns will be, (from the left side of Col. A)
69	X =	[Load on Col.A* (S1/2) + Load on Col.B* (S1/2 + S) ] / (Load on Col.A + Load on Col.B)
70	=	59.06	in
71	=	4.92	ft
72	Y =	[Load on Col.A* (Z1/2) + Load on Col.B* (Z2/2)] / (Load on Col.A + Load on Col.B)
73	=	6.00	in
74	=	0.50	ft
75
76	So, the distance from the center of Col.A to Upper end side =						B/2 - Z1/2 - Y
77						=	4.67	ft
78	and the distance from the center of Col.A to Lower end side =						4.67	ft
79
80
81	The CG of the Columns will be, (from the center of Col. A)
82	=	50.06	in
83	=	4.17	ft
84	The CG of the Columns will be, (from the center of Col. B)
85	=	3.91	ft
86	Primary Length of the Footing will be, (from the left side of Col. A)
87	=	2* X	ft
88	=	9.84	ft	Say,	15.00	ft
89
90					Now, the cantilever distance from right side of Col.B =	69.00	in
91					=	5.75	ft
92					Or, the cantilever distance from the center of Col.B =	6.17	ft
93					Say, C1 =	4.50	ft
94
95	Let, the cantilever distance from the left side of Col.A, C2 =					3.50	ft ( d/2 distance considering
96							d=3'-0")
97				Finally, App. Length of the Footing =	18.50	ft
98
99				Say, Length of Footing, L =	18.50	ft
100				So, Width of Footing, B =	Areq / L