Civil Engineering - Strength of Materials - Discussion
Discussion Forum : Strength of Materials - Section 5 (Q.No. 20)
20.
A 8 metre long simply supported rectangular beam which carries a distributed load 45 kg/m. experiences a maximum fibre stress 160 kg/cm2. If the moment of inertia of the beam is 640 cm4, the overall depth of the beam is
Discussion:
18 comments Page 1 of 2.
Rajeev said:
1 decade ago
Sir please give me explanation of this answer.
Umesh said:
9 years ago
Anyone please explain me.
Asha said:
9 years ago
How to solve this?
Vishal kumar said:
9 years ago
As per my knowledge, it is,
Max moment M = (w * l * L)/8 = (45 * 8 * 8)/8 = 360kg - m;
M/I = (sigma)/y = y = (sigma * I)/M;
(160 * 640)/36000 = 2.84cm,
y = d/2;
So, d = 5.68 = 6cm.
Max moment M = (w * l * L)/8 = (45 * 8 * 8)/8 = 360kg - m;
M/I = (sigma)/y = y = (sigma * I)/M;
(160 * 640)/36000 = 2.84cm,
y = d/2;
So, d = 5.68 = 6cm.
Manjunath.R said:
9 years ago
Actually its M.I = bd3/12 then Already Given b=8, M.I=640, and now we need Depth, d=?
Now, bd3/12 = 640 As per he given then,
bd3 = 640 * 12 i.e, d3 = 960.
Only d = (960)whole power 1/3 therefore d = 9.8 Approxmtly d = 10.
Now, bd3/12 = 640 As per he given then,
bd3 = 640 * 12 i.e, d3 = 960.
Only d = (960)whole power 1/3 therefore d = 9.8 Approxmtly d = 10.
Akash said:
9 years ago
Answer is wrong 8m long doesn't mean b=8m, it means span is 8m.
Vikas said:
8 years ago
Agree @Vishal.
It's 5.68cm.
It's 5.68cm.
Murali said:
8 years ago
d= 5.6 is correct and over all depth.
D=(effective depth+cover) so D is 10 cm.
D=(effective depth+cover) so D is 10 cm.
D kumar said:
8 years ago
M=wl2/8=45*8*8/2=1440kg.m.
Y=d/2.
I=640cm4m/i=f/y.
B=8cm.
Y=d/2.
I=640cm4m/i=f/y.
B=8cm.
Chulbul said:
8 years ago
@Manjunath.
How can b= 8m and d= 10cm?
How can b= 8m and d= 10cm?
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