15.1 COMBINED FOOTING.xls.xls

	A	B	C	D	E	F	G	H	I	J	K
1
2
3	Design Of Combined Foundation				CF1
4
5				0.35
6					5.2
7
8
9		0.6						3		2400	1.2
10											1.175
11
12			1.35		2.5		1.35
13
14
15								0.3
16
17
18								1.2
19									2.1
20
21								0.9
22
23
24	Constants :-
25				Unit Wt Of Soil =	1.8	T/m3
26				Density Of Water =	0	T/m3
27				Unit Weight Of Concrete =	2.5	T/m3
28				Comp. strength of concrete fc =	25	N/mm2
29				Yield strength of steel fy =	500	N/mm2
30				Coefficient Of Friction m =	0.5
31				Gross SBC =	20	T/m2 ------ Where increase in SBC is not allowed.
32				Gross SBC =	25	T/m2 ------ Where increase in SBC is allowed.(Wind / EQ 25% increase)
33
34	Shape Of Foundation :-
35				Length Of Foundation Lf =	5.2	m
36				Width Of Foundation Wf =	3	m
37				Thickness Of Foundation Tf =	0.9	m
38				Founding Depth Df =	2.1	m
39				Length Of Pedestal Lp =	0.35	m
40				Width Of Pedestal Wp =	0.6	m
41				Height Of Pedestal Hp =	0	m	(Support Reaction Considered at Base of footing)
42
43				Section Modulus Zxx =	1 / 6 x 5.2 x 3 x 3
44				=	7.8	m3
45				Section Modulus Zzz =	1 / 6 x 3 x 5.2 x 5.2
46				=	13.52	m3
47
48
49	Calculation Of Soil, Fdn & Pedestal Weights :-
50				Selfweight Of Foundation =	5.2 x 3 x 0.9 x 2.5
51				=	35.1	T
52				Selfweight Of Soil =	1.8 x 1.2 x ( 5.2 x 3 - 0.6 x 0.35 x 2 )
53				=	32.79	T
54				Selfweight Of Pedestal =	2.5 x 0.6 x 0.35 x 0 x 2
55				=	0	T
56				Buoyant Weight =	0 x 5.2 x 3 x 2.1
57				=	0	T
58
59				Total weight without buoyancy =	35.1 + 32.79 + 0
60				=	67.89	T
61				Total weight with buoyancy =	35.1 + 32.79 + 0 + 0
62				=	67.89	T
63
64	Calculation Of Restoring Moment :-
65
66				Due to fdn. Weight =	35.1 x 5.2 / 2
67				=	91.26	Tm
68				Due to fdn. Soil =	32.79 x 5.2 / 2
69				=	85.25	Tm
70				Due to Pedestal =	0 x 0.675 + 0 x 4.525
71				=	0	Tm
72				Due to Buoyant weight =	0 x 2.6
73				=	0
74
75				Total moment without buoyancy =	91.26 + 85.25 + 0
76				=	176.51	Tm
77				Total moment with buoyancy =	91.26 + 85.25 + 0 0
78				=	176.51	Tm
79
80	Support Reactions :- ( At foundation level)					All Units in Ton - Meter
81		JOINT	LOAD	FORCE-X	FORCE-Y	FORCE-Z	MOM-X	MOM-Y	MOM Z
82		79	301 1.0(DL+LL)	0.030	103.294	-0.488	-0.329	-0.011	0.007
83			302 1.0(DL+LL+WLX)	-0.188	103.327	-0.497	-0.335	-0.010	0.294
84			303 1.0(DL+LL+WL-X)	0.248	103.272	-0.477	-0.320	-0.012	-0.280
85			304 1.0(DL+LL+WLZ)	0.028	99.531	-1.477	-1.490	-0.010	0.009
86			305 1.0(DL+LL+WL-Z)	0.031	106.455	0.345	0.649	-0.011	0.005
87			306 1.0(DL+WLX)	-0.214	86.950	-0.523	-0.362	-0.002	0.309
88			307 1.0(DL+WL-X)	0.222	86.895	-0.502	-0.347	-0.004	-0.264
89			308 1.0(DL+WLZ)	0.002	83.154	-1.503	-1.517	-0.002	0.025
90			309 1.0(DL+WL-Z)	0.005	90.077	0.320	0.622	-0.004	0.021
91			310 1.0(DL+101)	4.039	93.886	0.937	1.291	0.045	5.379
92			311 1.0(DL+102)	3.936	81.476	-1.537	-1.643	0.027	5.243
93			312 1.0(DL+103)	4.039	93.886	0.937	1.291	0.045	5.379
94			313 1.0(DL+104)	3.936	81.476	-1.537	-1.643	0.027	5.243
95			314 1.0(DL+105)	-3.930	92.358	0.509	0.931	-0.032	-5.197
96			315 1.0(DL+106)	-4.033	79.948	-1.965	-2.003	-0.051	-5.333
97			316 1.0(DL+107)	-3.930	92.358	0.509	0.931	-0.032	-5.197
98			317 1.0(DL+108)	-4.033	79.948	-1.965	-2.003	-0.051	-5.333
99			318 1.0(DL+109)	1.370	107.829	3.674	4.588	0.040	1.835
100			319 1.0(DL+110)	-1.021	107.371	3.545	4.480	0.017	-1.338