Holes in I-Beams

[hungrydinosaur]

Hi All,

If we want to make a circular hole and a rectangular hole in an loaded I-Beam, which place is best place to put the holes (Center/or at beam ends, and mid-web/or near flange ends), so that there is the least stress in the beam near the opening. One beam is point loaded in the center, and the other is uniformly loaded. Thanks in advance.

Regards,

HD

 

[hokie66]

Near centre span and mid-depth, but preferably not directly below a point load. But first, you should analyse the loaded beam to evaluate how highly stressed it is.

 

[Agent666]

Check this document by SCI in the UK, its the most up to date information available in this field.

Link

You can put an opening anywhere as long as the design works out, as hokie66 noted, near point loads or the end supports should be avoided. The guide linked sets out all of the relevant criteria.

I've found the sweet spot is usually somewhere around the third points, mainly because the combination of moment and shear is maybe 70% of the maximum for a uniformly distributed loading scenario.

Small/medium circular holes can pretty much be put anywhere, larger holes can easily be accommodated if you have the flexibility to play with the location. You really hit the limits when the length gets upwards of double a maximum depth opening, but really it is dependent on the location and loading

Its actually scary how much you can slice out of the beam web and still get it to work, but I guess it works!
For example one I designed a few years ago (I think a 700 deep beam with a 500 deep x 500 long stiffened opening):-

 

[robyengIT]

Google

http://www.constructalia.com

It is possible to download (free) many softwares and for you "ACB - cellular steel beams with circular openings"

 

[hungrydinosaur]

Hokie,Robyeng,Agent, all thanks a lot.