Civil Engineering - Strength of Materials - Discussion
Discussion Forum : Strength of Materials - Section 1 (Q.No. 11)
11.
A uniform girder simply supported at its ends is subjected to a uniformly distributed load over its entire length and is propped at the centre so as to neutralise the deflection. The net B.M. at the centre will be
WL
Discussion:
37 comments Page 1 of 4.
Shweta said:
5 years ago
@Asif
By deflection of beams first find out value of middle prop reaction as:
(5wl^4)/384EI = (pl^3)/48EI.
p = 5wl/8.
After this B.M at the center is;
for UDL Wl^2/8 n for point load Pl/4.
therefore we have UDL minus point load.
Wl^2/8 - Pl/4.
Wl^2/8 - ((5/8) wl)/4 substitute value of P.
then we get WL/32.
By deflection of beams first find out value of middle prop reaction as:
(5wl^4)/384EI = (pl^3)/48EI.
p = 5wl/8.
After this B.M at the center is;
for UDL Wl^2/8 n for point load Pl/4.
therefore we have UDL minus point load.
Wl^2/8 - Pl/4.
Wl^2/8 - ((5/8) wl)/4 substitute value of P.
then we get WL/32.
(18)
Asif said:
1 decade ago
By deflection of beams first find out value of middle prop reaction as:
(5wl^4)/384EI = (pl^3)/48EI.
p = 5wl/8.
Then reaction at each end is 3wl/16.
Therefore BM at centre will be = (3wl/16)*(l/2)-(wl/2)*(l/4) is the answer wl/32.
(5wl^4)/384EI = (pl^3)/48EI.
p = 5wl/8.
Then reaction at each end is 3wl/16.
Therefore BM at centre will be = (3wl/16)*(l/2)-(wl/2)*(l/4) is the answer wl/32.
(3)
Raghavan said:
9 years ago
@Asif, I think your answer is correct.
But the answer should be wl^2/32,
Because for uniform loading, BMD will be parabolic.
But the answer should be wl^2/32,
Because for uniform loading, BMD will be parabolic.
Subhasmita said:
1 decade ago
If we consider your answer to be the correct one, then the answer will be coming as -wl^2/32.
Abidha said:
6 years ago
BM= wl2/8 for simply supported beams.
When l = l/2.
Then BM = wl2/32.
= Wl/32( where W=wl).
When l = l/2.
Then BM = wl2/32.
= Wl/32( where W=wl).
(2)
Civil said:
8 years ago
@Ram.
The equation will be wL^2/32. Substitute W=wL, Final equation will be WL/32.
The equation will be wL^2/32. Substitute W=wL, Final equation will be WL/32.
Ammu said:
6 years ago
@Asif.
Could you please explain how to equate deflection values at first step?
Could you please explain how to equate deflection values at first step?
Roy said:
8 years ago
Ra+RB+5wl/8=wl so,2x+5wl/8=wl or,x=3wl/16. So, Ra=RB=3wl/16 @Anoop.
Honey said:
9 years ago
its in Kn, not in kn/m2
So W=wl that's why answer is Wl/32.
So W=wl that's why answer is Wl/32.
Nikhil said:
8 years ago
I don't understand how to solve this. Please help me.
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