Moment connection (Steel + bolted)

[Trop99]

Hi all,

The examples of bolted connection I could put my hands on are showing end of steel beam bolted to a steel column in a vertical manner.

My question is, given a situation where a square steel frame, loaded in all four sides, vertical loading is higher than the lateral loading, is it not better the bolted connection to be arranged in horizontal manner as compared to the typical vertical arrangement shown above?

 

[paddingtongreen]

Usually, the beam is deeper than the column so the standard arrangement gives a bigger interface than your suggestion.

Michael.
"Science adjusts its views based on what's observed. Faith is the denial of observation so that belief can be preserved." ~ Tim Minchin

 

[KootK]

Yes, for bolted moment connections, an efficient layout has a group of bolts positioned as close to each beam flange as possible. And that is what the examples in your link show. Remember, each bolt in the elevation sketches represents a row of either two or four bolts horizontally, depending on how wide the beam and column flanges are and how much space is available. You might consider getting a copy I'd AISC's design guide on extended moment connections. Once you work through a few example, you'll understand why the bolts are set out as they are.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[Trop99]

Usually, the beam is deeper than the column so the standard arrangement gives a bigger interface than your suggestion.

Ah! Do you mean it can be actually vice versa?

emember, each bolt in the elevation sketches represents a row of either two or four bolts horizontally, depending on how wide the beam and column flanges are and how much space is available.

So in elevation view, the bolt can be arranged in horizontal arrangment (i.e. where beam on top of column) instead of typical vertical arrangment (i.e. where beam besides of column) depending the space available?

 

[KootK]

I think that I misunderstood your original post Trop 99. Are you suggesting running the beam over the column? That's been done for reasons of constructibility but is usually not the ideal way to go for the reason that paddington mentioned. Even heavy vertical loading is easily handled by bolts in shear so there is little to be gained in that department by running the beams over the columns. Where significant moments are being transferred at a joint, spreading the bolt groups apart will usually increase connection efficiency. And that will lead to most designers to connecting beams to the sides of columns.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[Trop99]

Now I understand.
To summarize, the main reason for vertical arrangment of bolts is the available length for bolt group, where usually the beam is deeper than the column.

Thanks paddingtongreen and KootK!

 

[paddingtongreen]

Trop99, I have used shallow beams in power plants, refineries and chemical production factories where the clearance between equipment is limited, on those I have run them over deeper columns, using a fixed end at the column to reduce moments and deflections in the beam, much like your examples but rotated. It is not first choice though.

Michael.
"Science adjusts its views based on what's observed. Faith is the denial of observation so that belief can be preserved." ~ Tim Minchin