Moment Connection - Steel Beam to Precast Column
Moment Connection - Steel Beam to Precast Column
(OP)
Hello All,
I have a design question for those familiar with precast and steel connections. I am designing the precast concrete for a 2 story podium style mixed use building. On the exterior of the building I have some precast columns which are supporting two wide flange steel beams. These connections have been called out by the EOR to be moment connections. I am looking for some advice/guidance as to how these members should be connected. The original detail the EOR called out for was simply extending the precast columns up to TOP OF BEAM elevation and butting the wide flange beams into a cast in embed in the precast columns. The problem with this detail was getting my studs to work in shear (I hadn't even got to the moment design issue). In discussing with the EOR we decided to drop the TOP OF PRECAST to BOTTOM OF STEEL BEAM and sit the wide flange members over the top of the column (with a 1" gap between both beams). This eliminated the need for two cast in embeds in the face of the columns. Now I just have to figure out (hopefully with your help) how these members are connected. Can I simply cast in an embed to the top of the column and weld the wide flange members to the column plate? Will this satisfy the "moment connection" needs?
Here are some examples of the loads to get a better feel for the project:
- 18x18 precast column
-Shear= 100-150kips (per beam)
-Moment = 290 k-ft
It's also important to note, most of the columns we typically design are simply supported, K=1.0, type columns. Does this change my column base connection?
Thanks in advance,
jReck
I have a design question for those familiar with precast and steel connections. I am designing the precast concrete for a 2 story podium style mixed use building. On the exterior of the building I have some precast columns which are supporting two wide flange steel beams. These connections have been called out by the EOR to be moment connections. I am looking for some advice/guidance as to how these members should be connected. The original detail the EOR called out for was simply extending the precast columns up to TOP OF BEAM elevation and butting the wide flange beams into a cast in embed in the precast columns. The problem with this detail was getting my studs to work in shear (I hadn't even got to the moment design issue). In discussing with the EOR we decided to drop the TOP OF PRECAST to BOTTOM OF STEEL BEAM and sit the wide flange members over the top of the column (with a 1" gap between both beams). This eliminated the need for two cast in embeds in the face of the columns. Now I just have to figure out (hopefully with your help) how these members are connected. Can I simply cast in an embed to the top of the column and weld the wide flange members to the column plate? Will this satisfy the "moment connection" needs?
Here are some examples of the loads to get a better feel for the project:
- 18x18 precast column
-Shear= 100-150kips (per beam)
-Moment = 290 k-ft
It's also important to note, most of the columns we typically design are simply supported, K=1.0, type columns. Does this change my column base connection?
Thanks in advance,
jReck






RE: Moment Connection - Steel Beam to Precast Column
It may not change your base connection but it will almost certainly mean K > 1.0.
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.
RE: Moment Connection - Steel Beam to Precast Column
RE: Moment Connection - Steel Beam to Precast Column
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.
RE: Moment Connection - Steel Beam to Precast Column
Not a concern. Project is in mid-west.
Good question, I can follow up with EOR and verify his intentions.
These columns in particular do not support 1st level members, they extend through the 1st level and just pick up these 2nd floor wide flange members.
Thanks for the replies.
RE: Moment Connection - Steel Beam to Precast Column
1) More robust because you're not trying to anchor an incoming horizontal flange force near the top of the column where you've got to contend with edge distances.
2) I like not having to deal with high panel zone shears within the concrete column.
3) Easier to make it look sexy.
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.
RE: Moment Connection - Steel Beam to Precast Column
Glad we are on the same page. I was thinking of something very similar. See below:
Not sure if a fillet weld (as shown) would be correct or not for this type of connection?
And I misspoke earlier, the columns are 16x16 as shown in the detail above.
Thanks again.
RE: Moment Connection - Steel Beam to Precast Column
Either way, I'd think that you'd want at least one vertical stiffener in there to help out with lateral torsional buckling.
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.
RE: Moment Connection - Steel Beam to Precast Column
Maybe, fabricate a column cap and shoe to provide for the 8 bolt connection (4 - 1 1/4" bolts per side). The column cap will have DBAs that lap with the precast rebar and will have side pockets to receive the bolts and nuts (MC4 facing out with cap plate and stiffeners?). The shoe will have matching holes and appropriate stiffeners to transfer the load into the beam.
RE: Moment Connection - Steel Beam to Precast Column
Thanks for the response, could you provide a detail or quick sketch of your ideas please? Trying to visualize everything.
RE: Moment Connection - Steel Beam to Precast Column
RE: Moment Connection - Steel Beam to Precast Column
Dik
RE: Moment Connection - Steel Beam to Precast Column
RE: Moment Connection - Steel Beam to Precast Column