Inflection Points In Long Steel Beams 1

[nicholi]

I have a series of W steel beams that are pin connected. 30 feet - 64 feet - 30 feet. As steel beams are manufactured in 60 foot lengths, how do I determie my inflection (splice) points in the 64 foot section?

 

[Qshake]

That will, of course, depend on what you're loading diagram looks like.

If your loading is simple uniform over the entire length then the inflection points are located approximately at the three-quarters, quarter, three-quarters, and quarter points for a 3-span arrangement.

 

[LPPE]

If each beam is pin connected at the ends, then there are no inflection points.

 

[thaidavid]

nicholi,

Splice points are usually placed where the moment is least, to simplify the cost of the connection. For simply-supported, pin-connected members, this would be at the ends. As this is no help for splicing to extend length, simply move far enough back from the end of the beam to the nearest point on the beam clear of cross connections and design a moment splice there. A properly-detailed, full-penetration-weld moment splice should have moment-carrying capacity equal to the beam section.

David

 

[zliazmei]

Nocholi,
As i unerstand you are asking of beam that here we cell "Gerber" type. Something like this scetch.

*-------*------o---------------o---------*---------*

Try to do this:
Create continuous beam 30*64*30.
Load it.
find the 0 moment poins.
Create a beam with pins at 0 moment points.
Load it.
Check the differences.

Hope this helps.
If you have only uniform load Qshake is right (AS USUAL)

Zmei

 

[nicholi]

To all thank you for the answers. I have assumed a uniform continuous load across the entire length.

Zmei , in your comments to me can you clarify create a beam with pins at 0 moment points, load it and check the differences. What differences are you looking for?

nicholi

 

[zliazmei]

If the load is Static there will no be differences
Sorry Bu I am allways thinking about moving loads.
Profesion you know