Steel Stringer to Wood Chord Connection 1

[VAStrEngr]

I have a steel I stringer bearing on the top chord of a timber bent (Pedestrian bridge, light loads, etc). I am having trouble laying out the appropriate connection.

My thoughts so far:
1. Through bolt down from the bottom flange through the timber chord. Problem is that the timber chord is 16" deep and this would be tough to drill, expensive to buy a bolt for.

2. Find some kind of threaded insert which can be pounded into the timber and a bolt attached to. Problem is finding one large enough to accomodate 1/2"-3/4" dia bolt.

3. Through bolt the vertical sides of a 2 clip angles on either side of the bent and set bolts in the horizontal leg of the angle to secure the bottom flange of the stringer. Problem is that it seems like a complex detail and again requires precision drilling on a large piece of timber.

4. Similar to #2 except drill a large pilot hole, set a piece of threaded rod, and fill in hole with epoxy grout/resin to seal hole.

Apprecaite any advice/experience relating to this.

 

[MiketheEngineer]

Lag bolts???

What kind of loads are we looking at here??

 

[VAStrEngr]

I did consider lag bolts but from a constructability issue I wasn't sure. Can you get a drill in under the top flange of the stringer in order to set a lag bolt? Say you had a 6" lag bolt, that would only leave 6" to fit a drill in before you are up against the top flange. I suppose I could weld a baseplate on the bottom of the steel to get the lag bolts out away from the steel interference which would alleviate this problem.

Loads aren't much. 10-20 kips horizontal at each bearing.

 

[msquared48]

Can you provide a metal saddle over the timber bent with thru-bolts through the top chord, and extend the top plate of the saddle (making it a bearing plate) to either side in the line of the beam of sufficient length to install four bolts, thus attaching the bearng plate to the bottom flange of the beam?

Clear as mud, right?

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[nuche1973]

Simpson ECCU column cap with thru-bolts into the timber and steel. The steel will need blocking betweent the ears and the steel section. Simpson can rotate the saddle flaps as long as there is room to make the welded connection. And the load ratings are valid.