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what is the best connection for this? round timber pile to steel beam?
8

what is the best connection for this? round timber pile to steel beam?

what is the best connection for this? round timber pile to steel beam?

(OP)
I can't figure out the best connection to do this.
if the timber pile was square, I could have used seat angle at the bottom of the beam.
but I prefer to use the more common round timber pile.
is there a round seat angle?

I could also install anchor bolts on top of the pile and bottom flange of the beam?



RE: what is the best connection for this? round timber pile to steel beam?

Notch the face for seating and provide thru rods in one direction. For the other direction, offset your beam from the pile.

Or, notch 2 sides and box the pile with heavy timbers and thru bolting to form a 4-sided haunch.

RE: what is the best connection for this? round timber pile to steel beam?

Maybe an HSS post between the beams and the pile with a base plate and some lag bolts installed in end grain? That should solve most of your tolerance issues save top of pile elevation.

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: what is the best connection for this? round timber pile to steel beam?

(OP)
@teguci, I kinda get it. can you please sketch it if you can. thanks,

I got the notch on the seat beam side, the thru bolts will end on the other side with round surface. can nut and washer be installed on the other side?

RE: what is the best connection for this? round timber pile to steel beam?

Just make your column cap square. That's why they invented chainsaws :)

RE: what is the best connection for this? round timber pile to steel beam?

(OP)
I think I'm gonna do this


RE: what is the best connection for this? round timber pile to steel beam?

That is a very atypical detail. I don't like the mechanism of transferring the load through the angles into the pile. I think you should go for more of a bearing type connection with a seat/angle to restrain rotation of the beam/aid in erection.

RE: what is the best connection for this? round timber pile to steel beam?

(OP)
@mike, my intention is actually bearing. the top of pile is flush with bottom of beam.

RE: what is the best connection for this? round timber pile to steel beam?

I still feel as though my detail can win this with the right, persuasive sketch.

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: what is the best connection for this? round timber pile to steel beam?

For once Koot I must admit, I don't like that detail. Seems rather unstable to me. I don't have an alternative worked up in my head but I don't really like that one at this time. I'm also generally adverse to lagging into the end grain.

RE: what is the best connection for this? round timber pile to steel beam?

Quote (JR)

For once Koot I must admit, I don't like that detail.

Eh, can't win 'em all. In all honesty, I've never encountered such a condition in the real world personally.

Quote (RJ)

Seems rather unstable to me.

Wha? How? The only pin in the system is the beam to beam connection. And even that's debatable in practical terms with the double angles.

Quote (JR)

I'm also generally adverse to lagging into the end grain.

Yeah, we all are. However, it's really just a nominal tie-down for uplift. Any side face connection will suffer the adverse effects of swelling in the pile.

So far, I think that my detail comes out on top in terms of:

1) Constructabilty.
2) Tolerance provision.

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: what is the best connection for this? round timber pile to steel beam?

Usually when I work with steel framing and timber piles, I use (2) channels, one on each side of the pile. The channels are connected to the side of the pile with lag screws.

However, the details being proposed here don't rely on the lag screws, which is an advantage.

DaveAtkins

RE: what is the best connection for this? round timber pile to steel beam?

KootK, also lags into the end grain of timber! And in a wet environment!

The angle detail doesn't look too bad, but use a deeper angle so you have some edge distance.

Is your pile that big at the top? can you notch the sides of the beam as opposed to the front and rear?

RE: what is the best connection for this? round timber pile to steel beam?

Quote (Kootk)

Wha? How? The only pin in the system is the beam to beam connection. And even that's debatable in practical terms with the double angles.

There's bound to be some form of lateral load in the plane of the floor beams, granted your stub columns aren't very long, but they're like short stilts. I'll admit the instability feeling comes from me not trusting the lags to have any capacity (at least any appreciable capacity).

I would do Dave's detail with the two channels on either side of the pile, but instead of lags screws, they'd be threaded rod thru-bolts with nuts on each end. You could provide blocking or flange plates at some spacing to ensure the two channels acted as one. But that to me is much more positive of a connection.

RE: what is the best connection for this? round timber pile to steel beam?

Quote (Eric)

KootK, also lags into the end grain of timber! And in a wet environment!

Quote (Jayrod)

I'm also generally adverse to lagging into the end grain.

Quote (KootK)

Yeah, we all are. However, it's really just a nominal tie-down for uplift. Any side face connection will suffer the adverse effects of swelling in the pile.

I remain undeterred.

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: what is the best connection for this? round timber pile to steel beam?

Quote (JR)

There's bound to be some form of lateral load in the plane of the floor beams, granted your stub columns aren't very long, but they're like short stilts. I'll admit the instability feeling comes from me not trusting the lags to have any capacity (at least any appreciable capacity).

Ba Humbug! There's stability there in spades, even if the lag connection turns out to be a pin. If you don't trust the double angles as nominal moment connections, run with a single plate shear connection with nominal moment capacity.

Quote (JR)

I would do Dave's detail with the two channels on either side of the pile, but instead of lags screws, they'd be threaded rod thru-bolts with nuts on each end.

This is appealing to me as well. I imagine that this would be taking us into beam over beam territory rather than beam into side of beam. If it could be made to work, it might be sexy to pack the double channels with timber in between as you suggested and then frame over top with timber fastened down to the packing stuff.

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: what is the best connection for this? round timber pile to steel beam?

(OP)
@eric, yes. I was looking at go by detail it uses lag screw for through bolt, i'll use FEMA guideline. 4d from top, 5d between bolt. I 'll use bent plate.

RE: what is the best connection for this? round timber pile to steel beam?

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: what is the best connection for this? round timber pile to steel beam?

You want a detail in the connection that allows the maximum variation between the top of the pounded in round timber pilings and the (hopefully perfectly flat) steel beams on top.

Seems a better solution is a round cap enveloping the round timber post, a flat plate on that round cap that supports a short vertical steel member, then the steel beams connecting to the vertical steel as in conventional bolt+hole plates.

RE: what is the best connection for this? round timber pile to steel beam?

If you're switching to steel beams instead of timber framing why not switch to H piles and save some headache?

How about making a pile cap with two plates in a T and knifing one into the pile with throughbolts. I've seen similar connections with round glulams.

RE: what is the best connection for this? round timber pile to steel beam?

Quote (EngineeringEric)

KootK, also lags into the end grain of timber! And in a wet environment!

The angle detail doesn't look too bad, but use a deeper angle so you have some edge distance.

My thoughts exactly. Sorry KootK :>

RE: what is the best connection for this? round timber pile to steel beam?

No need to be sorry. It seems I've something to learn here.

1) Are lag bolts inappropriate in wet service?

2) Is end grain deficiency not simply addressed by applying the appropriate end grain capacity adjust meant factor?

Teach a KootK to fish damn it.



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: what is the best connection for this? round timber pile to steel beam?

My issue with lags in wet service and in end grain is wood shrinkage and swelling. Depending on the conditions when installed it is possible to have the wood shrink entirely away from the lag. I have (only once) had a situation where you could shake the bolt in the hole, it must've only been grabbing the last 1/4" or 1/2" because I could wiggle it all around but couldn't quite get enough grip on it to pull it out.

RE: what is the best connection for this? round timber pile to steel beam?

My experience with this was the design of fixed docks on a river. I used 15" deep steel channels with multiple lag screws to create a moment connection--for lateral loads (I assumed it was pinned for gravity loads, as I recall, but then again the span was not large--10' or so). The lateral load was due to either a boat being moored to the dock (thus wind load) or an ice floe crashing into the timber pile.

Anyway, I kind of like KootK's sketch--you are not totally counting on the lag screws to support the load. There is a ledge below each channel, for redundancy.

And yes--you need to consider edge distance, spacing, wet service, etc. for the connection design.

DaveAtkins

RE: what is the best connection for this? round timber pile to steel beam?

Thanks for the anecdote Jayrod. Do end grain factors even apply to lags? I don't have time this morning to research it thoroughly but I'm starting to wonder now.

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: what is the best connection for this? round timber pile to steel beam?

I can't answer that with any certainty. I avoid end-grain lagging like it's a Trump supporter.

RE: what is the best connection for this? round timber pile to steel beam?

With KootK's sketch (based on MY IDEA, I might addglasses), there is no end grain issue--the lag screws go into the side grain of the pile. You do need to ensure the uppermost lag screw has adequate end distance to the top of the pile.

DaveAtkins

RE: what is the best connection for this? round timber pile to steel beam?

Hush. If he hears you he might make us build a wall. And there probably aren't enough of us to get it done. Granted, we've a few more available in AB now.

I generally avoid end grain dowel connections too. But, then it's usually somebody trying to stick a 1/2" lag in the end of a 2X. Here, I was imagining a long, large diameter galvanized lag in the clean cut end of a big old log. It doesn't generate the same negative visceral reaction in me for some reason. I'll try to imagine the piling 50 years in the future with checks and fungus growing from the top.

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: what is the best connection for this? round timber pile to steel beam?

2

RE: what is the best connection for this? round timber pile to steel beam?

Nice... Is it really that off putting though? I'd stand underneath it in the rain for 15 minutes if there were a case of beer on the line.

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: what is the best connection for this? round timber pile to steel beam?

The last time that I pulled this stunt (same load) it was much more dire. Teguci's definitely got me with regard to artwork quality however.

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: what is the best connection for this? round timber pile to steel beam?

11,000 lb test of an end grain connection at UBC: Link. And some related marketing material attached.

Quote (Dave)

With KootK's sketch (based on MY IDEA, I might addglasses), there is no end grain issue--the lag screws go into the side grain of the pile. You do need to ensure the uppermost lag screw has adequate end distance to the top of the pile.

Yeah, I'm liking that scheme more and more too. I'd like to see it done with the framing in steel in one direction however (wood in the other). The main thing that was informing my earlier, flawed detail was the ability to accommodate tolerances in the location of the piles. With steel in both directions, and likely a desire to avoid field welding, a lot of the details that have both directions of the steel framing in the same plane would be problematic I wold think.

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: what is the best connection for this? round timber pile to steel beam?

Kootk, sorry for the hiatus on your end grain question. The reduction in capacity factors are for perfectly fine wood, the end grain will be partially rotten in a few years. If you drill holes that allow water to penetrate it deeper, well then rot will occur even faster. I will say this, as you are rarely ever wrong on here, your design will have adequate and surplus load at first but the longevity will get you, the top of the pile will get weaker quicker and you will first loose your lateral capacity and will soon loose bearing capacity.

bolting through the sides with notched seats will allow the most compromised area to be lower in the wood and will allow more wood to protect the connection. The bolts will bend, they will slide but they will hold up.

I work with a few 'attraction' owners, we have completely disallowed lag screws from being used on any of our projects... I have seen the effects of the connection in 5,10,20,30 years of service each time i look at their older buildings... So i may be biased due to what i have seen in a short period working with them.

RE: what is the best connection for this? round timber pile to steel beam?

Quote (Eric)

I will say this, as you are rarely ever wrong on here

That's gracious of you to say Eric. I've been tracking and I seem to be seriously wrong about something here about quarterly. You know: PT, obscure code provisions... statics. And I concede that I've been wrongheaded here. I'm just glad that I got my schooling via this venue rather than by way of a botched project.

Is it accurate to paraphrase your observations as follows:

1) no top side bearing solution should be employed because of the rot issues at the end of the pile and;

2) you don't advocate using lag bolts in any capacity in this context, even side grain?

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: what is the best connection for this? round timber pile to steel beam?

How can wood shrink away from a lag screw? If the wood shrinks, the hole shrinks.
When a concrete manhole riser ring shrinks, does the opening get bigger?

RE: what is the best connection for this? round timber pile to steel beam?

Shrinking is probably a imprecise word; certainly, it's most likely that the wood around an unprotected lag screw will probably deteriorate earlier than the rest of the wood, making it appear that the wood is "shrinking" away from the screw.

TTFN
I can do absolutely anything. I'm an expert!
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RE: what is the best connection for this? round timber pile to steel beam?

I do not like lags in end grain for the simple fact it is very easy to strip out the threads during the install. One or two extra turns and you can have close to zero capacity. In engineered lumber this is less likely, but in a good ol log this is not that uncommon.

RE: what is the best connection for this? round timber pile to steel beam?

Kootk,

1) Top side is not horrible IMHO. I would prefer a seated edge connection as you nearly sketched for stability, but a top seated connection is not anything i shy away from... It is actually a common connection when using post caps, or other exterior light framed connections (only when they are not laterally loaded because we need additional connection capacity)

2) I would advocate the use of a through bolt over a lag screw in all applications. The way i look at it, a through bolt is just more effective and has more longevity, it is close in cost and takes as long to install.

RE: what is the best connection for this? round timber pile to steel beam?

Did a lot of these for former employer. Standard detail was a square steel plate over top of pile, & 2 steel straps welded on underside of plate, running down 2 sides of the pile. 2 bolts through straps.

For 12" pile butt, use 18" sq plate x 1/2". Bars usually 3x3/8" with 3/4" bolts.

Shims can be placed between plate and steel & welded to make up for accuracy of chainsaw cut on pile.

We treated top of pile with hot creosote cover with asphalt roofing nailed down around sides of pile. Bolt holes were treated with hot creosote applied with a bent funnel. (Creosote not so popular now a days!)

Don't use lags in exposed wood connections - they loosen.

RE: what is the best connection for this? round timber pile to steel beam?

Quote (Sawbux)

Did a lot of these for former employer. Standard detail was a square steel plate over top of pile, & 2 steel straps welded on underside of plate, running down 2 sides of the pile. 2 bolts through straps.

For 12" pile butt, use 18" sq plate x 1/2". Bars usually 3x3/8" with 3/4" bolts.

Shims can be placed between plate and steel & welded to make up for accuracy of chainsaw cut on pile.

We treated top of pile with hot creosote cover with asphalt roofing nailed down around sides of pile. Bolt holes were treated with hot creosote applied with a bent funnel. (Creosote not so popular now a days!)

Don't use lags in exposed wood connections - they loosen

Yep. We work a lot around the logging industry and have done a lot of work on wood pile supported: lumber mills, logging and rail bridges and docks and that detail is the one most used. Not pretty, but hard for the average millwright to screw up. In the environments we are working in; pretty is not usually considered an issue.

If the pile alignment is ok then a full length (over the entire pile bent) single bent plate or sometimes a channel with the 3/8" plate straps is used. Steel shims as necessary. The straps are just welded on the outside of the channel.



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