Civil Engineering - Steel Structure Design - Discussion

B is correct.

No stiffeners are provided if the web is more than d/85.

Vertical stiffeners are provided if the web is less than d/85 but more than d/200.

Vertical +1horizontal stiffeners are provided if the web is more than d/200 but less than d/250 (in this case this 1 horizontal stiffener is usual to place at 2/5th of the depth of neutral axis from the compression flange).

Vertical +2 horizontal stiffeners are provided if the web is less than d/250 (in this case this 2nd horizontal stiffener is usually placed at neutral axis).

A is correct.

No stiffeners are provided if web is less than d/85.

Vertical stiffeners are provided if web is more than d/85 but less than d/200.

Vertical +1horizontal stiffeners are provided if web is more than d/200 but less than d/250 (in this case this 1 horizontal stiffener is usuall place at 2/5th of the depth of neutral axis from the compression flange).

Vertical +2 horizontal stiffeners are provided if web is more than d/250 (in this case this 2nd horizontal stiffener is usuall place at neutral axis).

The answer is fine if you consider the following case as vertical stiffened web plate.

Here min web thickness is concerned so d/250 is the correct answer.

Vertical +1horizontal stiffeners are provided if the web is more than d/200 but less than d/250 (in this case this 1 horizontal stiffener is usual to place at 2/5th of the depth of neutral axis from the compression flange).

If the denominator factor is big, the thickness will be small. So if the denominator increases up to 200 thickness decreases to a minimum.

So, answer B. If vertically stiffened assumed. But I think it takes 250 because it hasn't differentiated between horizontal and vertical stiffener.

D is the correct answer. Because. They asking only about vertical stiffner they didn't mention whether there is need of hzt stiffner or not.

So, We can take a minimum value.

D/t=250.
T= D * 0.004.

Minimum D/200 max is D/85.

If the thickness exceeds d/85 then no stiffener required because. There is enough strength to carry the load as the thickness is more.

So, the minimum d/200.

According to me , when the d/t is less than 85 then vertically stiffened are not provided but if the value is in between 85 -200 vertically stiffened are provided so the ans is A

According to the question, The answer will be min. 85 and max 200 for vertical stiffness. So I think answer A is correct.

d/t<85 no stiffener.

d/t 85-200 vertical stiffener.

d/t 200-250 vertical stiffener and 1 horizontal stiffener.

According to IS 800-1994,
Vertical stiffened d/200 should not less than but according to IS 800-71 it's d/250.