Civil Engineering - Strength of Materials - Discussion

Discussion Forum : Strength of Materials - Section 1 (Q.No. 23)
23.
The slenderness ratio of a vertical column of a square cross-section of 2.5 cm sides and 300 cm length, is
200
240
360
416
500
Answer: Option
Explanation:
No answer description is available. Let's discuss.
Discussion:
33 comments Page 1 of 4.

Kaushal said:   1 decade ago
According to me, Slenderness ratio is kl/b. where k is length factor, l is the length of column and b is the width.

Let us suppose k = 1 (pin jointed both sides).

Slenderness ratio = 1*300/2.5 = 120.

How could answer be 416?

Raju said:   1 decade ago
kl = 300.

r = (i%a)0.5.

Slender ratio = kl%r.

i = moment of inertia = b*d3%12.

a = cross section area = 2.2*2.5.

Pradhyumna said:   1 decade ago
Dear @Kaushal, clear the definition first.
Slenderness ratio = Unsupported length of column/minimum radius of gyration of cross-section.

Hence, SR = 300/rad. of gyration.

= 300/ sq.root of ((2.5^4/(12*2.5^2))).

= 415.692.

= 416.

Pawan kumar said:   1 decade ago
You are right @Pradhyumna.

Slenderness ratio = l/k = 300/0.7217= 415.692=416.

K = radius of gyration = root under(I/A) = under root 0.52.

I/A = (moment of inertia/area) = 2.5*2.5*2.5*2.5/12)/(2.5*2.5)=0.52.

Piyush singh said:   1 decade ago
Slenderness Ratio (lemma ) = L(eff) / R(min).
Rmin = under root of ( Imin / area ).

Imin = (b*d^3) / 12.
Area = (b*d).
(b=d).
Imin / Area = b^2 / 12.

Rmin = under root of (b*b / 12).
Rmin = 0.2886 b^ 2.

Slender ness Ratio = (Leff / R min).
= (300 / ( 0.886*2.5).
= 415.96 = 416.

Deepak goel said:   1 decade ago
Its value is wrong because slenderness ratio is l/r means 300/2.5 = 120.

Xyz said:   1 decade ago
In case of Strength of materials, slenderness ratio is eff length/radius of gyration, while in case of RCC it is eff length/least lateral dimension.

Anil Baral said:   1 decade ago
r = sqrt (I/A).
A = 2.5*2.5.
I = 2.5^/4.

There fore, r = 2.5*sqrt (1/12).

r = 300/2.5*sqrt (1/12).

= 415.69 approx=416.

Raj said:   1 decade ago
All you guys are correct and I want add a point.

Slenderness ratio = Effective length/Maximum radius of gyration.

Thanks.

Mohammad amir said:   10 years ago
L/r and eff L/k.

k = square root I/a consider both different formula guys.


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