Steel Girder Lateral Restraint

[jar546]

Two part question. I get some resistance on this one. This is for a long span center bearing beam.

#1) If a steel beam such as a W8x28 gets spec'd out by a PE as required and they show no lateral restraint, do you request it?

#2) The sill plate that sits on the steel girder in my opinion is still as sill plate and needs to be secured to the beam just as it would the foundation. Do you agree?

Thoughts?

My answers:

1) Yes

2) Yes

I spoke with an engineer today that never specs out lateral restraint and when I asked him why, he was assuming the sill would be attached as required prescriptively and when the joist are toenailed to the sill, that would suffice so why spec it.

 

[Mule]

#1) If a steel beam such as a W8x28 gets spec'd out by a PE as required and they show no lateral restraint, do you request it?

Wouldn't that be part of the design?

So yes I would.

the sill would be attached as required prescriptively and when the joist are toenailed to the sill, that would suffice so why spec it.

How do you prescriptively attach a sill plate to a steel I-beam? Weld it with wooden dowel pins?

 

[TJacobs]

Steel beams are not prescriptive, however, I agree with your answers. I would use R502.9 as a code citation.

 

[Mark K]

#1:- This is a plan check question. Ask the engineer. Inspection should be per the drawings.

I would expect that the floor framing would provide the lateral support.

#2:- The proscriptive requirements for attaching a sill to concrete do not address the situation where it sits on the steel beam. The design should be revised to provide this information.

 

[GHRoberts]

The usual construction is that the floor diaphragm holds the joists in place and the joists prevent lateral movement of the beam.

What engineering do you want?

 

[Daddy-0-]

Sill should be bolted to beam IMO. That's what I see here all the time.

 

[jar546]

The usual construction is that the floor diaphragm holds the joists in place and the joists prevent lateral movement of the beam.What engineering do you want?

If the sill on the beam is not attached to the beam then how is the beam laterally restrained?

 

[tbz]

jar,

Depending on the project what are you really looking for here a simple call out note or drawn details showing the steel beam with a sill on top and bolts coming through noting attach sill to beam with xyz bolt every xyz inches?

I am not sure how big the home is, or it this is town houses, but showing the lateral support detail on the drawings vr's just noting on the drawings in the general list that the wood sill be secured to W8 bean with xyz bolts every xyz inches should be more than fine.

I fully agree that the attachment needs to be done in the field however if this was a wood beam are you asking for details on how the joists are going to be nailed to wood beam?

There are givens and yes I know many of you run in to where some half @$$ idiot drives some 12D nails through the 1/2" holes in the steel beam and then bends them over and says I done it this way for years. But how much information needs to really be on the drawings, are we now drawing basic homes plans like paint by number kits?

I guess I just see this as a given sort of like using that funky white paper in that tiled room in the house.

If I seem a bit harsh It's 4:30 in the morning and I just got done taking the tree limb out of my kitchen window and still need to figure out about the water on the floor. Just stopped to clear the mind.

 

[jar546]

The issue here in my case is that the contractors are not securing the sill plate to the center steel beam and when it is questioned, they point to the fact that the plans for the beam area stamped by a PE and there is no note of lateral restraint therefore I am an idiot for requiring it because the PE obviously doesn't think so or the PE would have put it on the prints.

 

[Rio]

Anyone can make an omission including a PE and just because they're stamped doesn't mean they're correct. IMO the sill should be attached to the beam with more than gravity. Tell the contractor that if they don't want to attach it to provide a stamped detail from the engineer addressing the issue.

 

[tbz]

Jar,

In a less conflicting time people seemed to do things the simple way which was just doing them right the first time. Today, everyone seems to want to put up walls and fight for no reason over common sense.

Bolting down the sill plate is just common sense, if you are having that much of a problem were you are, flagging and requiring bolting call outs on drawings is fully justified IMO, those that have a problem with it, so be it.

It just seems a bit of over kill to me for something so basic, I believe half of us here can and still remember 3,000 sqft homes being built with just 3 sheets of "D" size drawings, and they were built extremely well.

 

[brudgers]

Two part question. I get some resistance on this one. This is for a long span center bearing beam.#1) If a steel beam such as a W8x28 gets spec'd out by a PE as required and they show no lateral restraint, do you request it?

#2) The sill plate that sits on the steel girder in my opinion is still as sill plate and needs to be secured to the beam just as it would the foundation. Do you agree?

Thoughts?

My answers:

1) Yes

2) Yes

I spoke with an engineer today that never specs out lateral restraint and when I asked him why, he was assuming the sill would be attached as required prescriptively and when the joist are toenailed to the sill, that would suffice so why spec it.

The moments have to be pretty substantial (>30kip-ft) before lateral support comes into play on a W8x24. Below that you've got 20ft of span.

 

[TimNY]

Ironic how the things that seem the simplest are so complicated.

It seems like common sense that the plate should be secured to the beam, but on the other hand we have brudgers saying it's not an issue.

I am not a big fan of getting letters to "say it's not needed". In a recent dealing with a certain municipality that requires rental permits, they asked to see my rental permit for an apartment in another municipality. I told them that no permit is required in this other municipality; they say "ok, just get a letter from them saying it's not required." Hmm. Why stop there? Perhaps I should get a letter stating I do not need a scuba diving license or a football helmet full of cottage cheese to rent an apartment as well.

So having been on the other side of the table recently, I don't think "a letter saying it's not needed" is reasonable. If you spoke to the PE and he says he thought it would be attached, then I would request the attachment detail and be done. I try to treat all RDP as allies, not adversaries, and am happy to place the call, as you did, to resolve a situation quickly. I would then call the contractor and inform him so he can get together with the RDP and solve the issue.

For any type of situation like this, I would furnish a code section that was violated; then let them furnish a letter as to why they did not violate the section. I would never request a letter stating something is not needed with no other justification.

 

[Mark K]

What difference does it make what another jurisdiction requires?

It is the building officials job to interpret the code to determine what is required. Design professionals can provide information and professional opinions to help the building official make up his mind but the responsibility to make the determination stays with the building official.

Allowing individuals to self certify that the work was done per code does not relieve the building deparment of the responsibility to inspect the work. I suggest that a number of the problems in NYC are related to their reliance on self certifications.

 

[TimNY]

What difference does it make what another jurisdiction requires?

That was not really what I was trying to emphasize (but believe me, I had to bite my tongue to stop from saying that same thing)

The primary point was the same as yours, the BO official determines what is required. You don't determine what is required by ruling out everything that is not required.

 

[GHRoberts]

Having read the posts and then the original question, I am at a loss. It appears that the floor diaphragm is sufficient to hold this central beam in place. And you want engineering done.

Lateral load not restrained by floor diaphragm: 0 pounds.

Bolts required: 0 1/2" bolts.

 

[Architect1281]

Well the answer is Yes, Yes, and ask for more.

Many times design professionals (I be 1 2) answer the questions they are asked to answer.

They answer that question to an absolute certainty.

They have designed a beam. and provided the appropriate calculations.

That beam will support the load listed.

The remaining Question usually unasked is

What supports the beam? A Column?, A base Plate?, Restrained?, Unrestrained? A Built up wood column?, whats its compressive strength?

What is its lateral Resistance?

The code requires us to be provided with "Continuous Load Path"

I make them supply that answer from the load origination to the ground. and here where Up is just as important as Down

I make them provide the Up analysis as well.

SOmetimes the installers call me names but in the course of events if I don't

Learn something,

Educate Someone,

or occasionally

P*#s someone off

I figure I'm not doing my job.

 

[TimNY]

2003 IRC:

R502.9 Fastening. Floor framing shall be nailed in accordance with Table R602.3(1). Where posts and beam or girder construction is used to support floor framing, positive connections shall be provided to ensure against uplift and lateral displacement

Yes, this is under the wood floor framing section, but if there was wood joists and a wood subfloor, I think it qualifies. This doesn't say "wooden beam", it says beam. That could be a wood beam or a steel beam.

For the sake of this thread, I will take the word of those trained in the profession that there is sufficient lateral restraint. However, uplift has not been addressed.

I would cite "R502.9- failed to provide lateral restraint and uplift at beam" I don't think you could design away "positive connection" nor the uplift requirement, but this section is the hook to prompt further evaluation. This is not "show me it's not needed", it's, "you failed to meet the prescriptive code, kindly substantiate your design". If the RDP says just shoot a few powder actuated fasteners in, then so be it, I did my due diligence.

 

[peach]

yes... and yes, it's not addressed in the code. When we see them here, they always sit in a beam pocket.

 

[ggmarch]

hmmm.........i can't answer this as a reviewer but i can explain it as an architect as to why it's not needed to be attached. there is no lateral load on an interior beam unless it is applied by an outside force. this being said, all load is vertical and the weight of the house holds everything down and the beam holds everything up. but everyone knows this already. the need to attach a 2x4 to the top of a steel beam to provide lateral support does not make sense. what is it going to do? the bolting of a sill on an exterior wall is another animal all together. the sill plate of a wall is parallel to the supporting structure and perpendicular to outside forces. bolting helps prevent wind/seismic from push one support system off the other into the abyss. this is not the case with an interior beam where loads are vertical and the structure cannot fall off it's base without serious serious effort, and in this case, that means there is something else at work that would trump any concerns of lateral stability of a single beam. beams aren't supposed to move and that's how they are designed..........so..........

all attaching the sill plate to the beam does is impart a Moment at the top of the beam while allowing the bottom to be free to rotate, doing this is not technically lateral bracing. actually attaching to the beam could/would impart forces not designed for that situatation such as wood shrinkage and expansion from being open to the weather during construction. this movement could damage exterior walls and foundations before it's even occuppied(seen this first hand with tightly bolted sill plates a whole other story)

i did a thought experiment and here it goes...(beam in regular house no special seismic conditions)... to allow the floor joist to float on the beam allows for small movement which occurs inside a structure. how far does that beam have to go before the sill plate falls off the top of the beam and the structure drops 1 1/2"? once that has happened....how much further does the beam have to move to get past the ends of the overlapped floor joist? this would be a pretty big load on the side of that beam and highly unusual without the house moving.

say the beam doesn't move but the house does, the outside force needed to push the building sideways by 1-2 feet to overturn a beam or to push the joist past its splice is incredible wouldn't ya say? are we to suggest that the difference between structural soundness and unacceptable lies with a 2x4 bolted to a steel beam. i don't think there is. even if we are in some sort of high wind area and calculating suction upon the structure, is a 2x4bolted to the beam going to be the difference between holding a building down and it flying away. answer, no....not to mention, this is technically not what a beam is designed for i.e dead weight.

............but most important is you NEVER, ever ever ever instruct someone to drill through, weld to or alter the flange of a steel beam ever ever ever!!!!! i mean seriously! the trouble someone went through to spec a specific beam and you go and have some yahoo go drilling holes throught it! big big mistake....if you want a lawsuit on your, , PE's, my, the contractors hands.......let em poke as many random holes in that thing as you want. as an architect we spec a simple beam, the contractor goes and buys that beam and they can cut the ends off, but that's it! flanges are for holes and only designed by a professional.

please please....if you decide that removing valuable material from the compression zone of a steel beam (to keep it in place laterally) is more important than the material is for it's intended purpose, go right ahead, but you've been warned. if there are holes in it, it better have an engineer design it and it would be in their best interest to have it manufactured by them and not done in the field. other wise, let it sit on the beam because if it wasn't designed for lateral stability , then lateral bracing is not required and as i've stated above, could be dangerous if done incorrectly.

as for the engineer's comment, he should have known better than to say that to a reviewer!

 

[Mac]

We require the ends of steel beams to be fully grouted in at the foundation pockets.

The local practice has been to place a 2X6 plate flat on top of the beam, drive #16 nails in the 2X6 sides, then bend the nails down around the flange. It holds surprisingly well, yet still allows for some movement. The joists are then be nailed to the 2X6.

I agree that drilling or otherwise modifying a specified steel beam simply ought not to be done.

 

[Mac]

Ooops... should read "....drive #16 nails HALFWAY in"

Glad it's Friday......

 

[ggmarch]

amen mac, it's been done like that for many moons and for a reason. happy weekend.

 

[TimNY]

My interp is there needs to be a positive connection that prevents uplift as per the code. How that is done is completely up to the RDP. I don't think you can design it away.

I don't think we should start down the road of whether or not the connection will be the factor in some failure. If we are going to go that way, maybe we don't need that jack stud or all those nails in those pesky straps etc.

I think the RDP should realize the code calls for positive connection and design something that will work. Doesn't have to be bolts. Heck, if the RDP said use epoxy to glue the 2x down, I'm good with that, it's his call. I just don't think you can omit something the code calls for.