OWSJ Strengthening due to Mechanical Openings - Contractor vs EOR's responsibility 4

[Enable]

I've bidding a job where there are a number of additional roof penetrations due to mechanical upgrades (grocery store re-arranging things). The EOR provides a typical trimming schedule for the new openings and per usual has us doing the connection design for all structural steel on the project. That's fine and all. But they also have a note saying "OWSJ must be designed for the additional loading".

I don't do roof openings for others typically and so am a tad confused on what responsibility falls on the EOR vs me in this case. The note makes me think that it's also part of my scope to design the OWSJ reinforcement, if required. But that seems problematic for a few reasons: 1) they don't provide the additional loading from the mechanical units for me to use, and 2) I'm not going to review the OWSJ capacity prior to award to see what might be required.

Am I misreading what that note implies? If so, what's the purpose of it to remind themselves as the EOR to design the retrofit?

CWB (W47.1) Div 1 Fabricator
Temporary Works Design

https://www.enable-inc.com/

 

[human909]

Why ask us rather than the relevant parties? You haven't even stated your scope though it seems to be supplying the OWSJs. So from where I sit my interpretation would be that it falls under your scope. Seems pretty clear that you should be requesting the loads from the mechanical contractor or if not available make a reasonable guess and be explicit about what you have allowed for that in your bid.

 

[Enable]

A few things

A) I would certainly ask the powers that be except bid is due on Monday and it's the weekend. Didn't get to this one in a timely manner unfortunately. Yeah that would be my bad!

B) I thought I had indicated the scope but perhaps not so clearly. I am making openings in existing roof-deck to accommodate new mechanical units due to a grocery store repositioning its stations. I am not supplying any OWSJ.

At least you confirmed what I thought, which I still think to be a silly way to do this. What if the retrofit I design requires alternative mechanical / electrical / drywall / whatever to be moved? The GC wouldn't have carried for that and that wouldn't be known until after award.

Meh. I'll throw a number at it and tell the GC to add some contingency as well. Thanks



CWB (W47.1) Div 1 Fabricator
Temporary Works Design

https://www.enable-inc.com/

 

[human909]

Sorry. I think part of my misunderstanding was just due to different ways jobs are tendered and bid for in different places.

I can see your confusion here.

 

[dhengr]

Enable:
The EOR has probably framed the openings to carry the std. roof loads around the openings, plus a little, but who knows how much. Those frames are not intended to carry the weight of the mech. unit, they just frame the opening, knowing they do get some load from the unit. The weight of the mech unit, and its exact support point locations and conditions and their support is a separate issue. We are always fighting btwn. the Arch. and his Mech. consultant to get that info. in a timely manner, so that we can consider it in our Struct. design; at least that was almost always the case when I was still doing that kind of engineering work. Then, the EOR was called back later, on his own time, maybe at shop drwg. time, to verify that those loads could still be carried by the stl. jsts. and what that framing should be; many times above the roof and on down to three or more stl. jsts. to distribute the new load. It makes my ass tired that our construction system today allows every different level to pass this kinda crap (responsibility?) down to the next poor sucker. And, you happen to be at about the bottom of the pile. I think the Mech. Engr. or contractor should hire his own engineer to design this framing and verify that the existing roof structure will carry the new loads he is introducing. That should not be your baby.

 

[Settingsun]

Meh. I'll throw a number at it and tell the GC to add some contingency as well. Thanks

That's one way. Risk on you to an extent if the worst case eventuates, or at least an argument. Alternatively, slip in a no-allowance qualification in your price that gets passed on by the head contractor.

 

[XR250]

I think it is ridiculous that the EOR is passing the buck on this. What's next? - Delegated design for a 100 story structure?

 

[Enable]

Thanks for the sanity check team

I think it is ridiculous that the EOR is passing the buck on this. What's next? - Delegated design for a 100 story structure?

LOL it isn't that bad XR250. I can understand budget limitations (owner or architect not wanting to pay the structural guy more than necessary), and the timeline issues that dhengr mentions. I am quite sympathetic to these challenges as they are very real and a burden for the SEOR.

So I don't mind so much that this is delegated. What I mind is the way this is being done. When I worked for a consultant, I was taught to think about the entire project (which includes the contractor as well as the owner) and put a tender together that was fair to all parties (insofar as I could make as much). In a case like this, if the owner didn't want to pay me as the structural guy to do a thorough design, that's fine, but then the fairest thing would be to put an assumed design in the tender and have the actual cost be drawn from an allowance. If the actual conditions are more or less like the assumed design, great, and if not, then it was the owner's decision not to do it ahead of time so they risked having it costing more. But that's also why the allowance is there to cover such increases (and I generally put in a large allowance for this reason not the $5000 fart in the wind that shows up these days).

That's one way. Risk on you to an extent if the worst case eventuates, or at least an argument. Alternatively, slip in a no-allowance qualification in your price that gets passed on by the head contractor.

Yeah definitely another go-to of mine. I have to have a scotch and take a step back to look at the entire thing and decide which is better. Sometimes people just want a price and know you'll do it without headaches vs qualifying to high-heaven. I don't have a scientific process to decide which way to go but it usually does involve scotch and some soul searching.

I think part of my misunderstanding was just due to different ways jobs are tendered and bid for in different places.

I'm curious, how are bids done in your part of the world? If you have a better way please share it because North America is in desperate need of a new system! Don't be hoarding the goods for yourself!!!

CWB (W47.1) Div 1 Fabricator
Temporary Works Design

https://www.enable-inc.com/

 

[Brad805]

These are poor projects as the EOR. When we have been involved in these our role has generally been an afterthought, and viewed as minor. Mech engineers usually only provide general locations and may or may not provide you useful curb information. The biggest problem usually is owners are terrible at maintaining any records of their building, or if leased space, they may not have it. I would be curious if the changes are largely modernization/replacement of equipment or if there was a major floor plan change. Moving units to different bays could be fun given the typical size of mech units for this type of occupancy. That said, this level of delegation is not appropriate, but it seems to be the trend. We are seeing more and more EOR dwgs that are pretty much beams, columns and braces with delegated design instructions. It is brutal for project scheduling. We have one right now that we had to wait until all the structural steel was detailed until we could finish our shop dwgs for the exterior panels.

 

[XR250]

When I did metal stud design, the level of delegation was typically absurd. That is the main reason I quit doing it.

 

[dik]

I would qualify my bid based on an assumed load of say 2K (10kN) or whatever, and no snow accumulation.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[skeletron]

Reinforcing the OWSJ should be part of the EOR scope, not the delegated scope.

 

[KootK]

My gut feel is that what has happened here is this: the EOR included a typical detail that was intended for new construction rather than renovation. Even in new construction it is a bit lazy not to supply the loads. However, in renovation, it's downright criminal to delegate a probable joist reinforcement exercise.

As you've correctly intimated, the costs of a joist reinforcement exercise can vary wildly depending on numerous factors, not the least of which is the goddamn loads involved. If it were me, I would either:

1) Pass on this one.

2) If possible, submit a bid that has the joist reinforcement component either NIC or included as time and materials.

 

[dik]

KootK... the detail is common for new or existing construction... attached is an SMath program that I use. My notes clearly stipulate that the OWSJ design has not been reviewed... also loads to be applied to panel points of the joist.

[URL unfurl="true"]https://res.cloudinary.com/engineering-com/image/upload/v1634502446/tips/Steel-Equip_Support_C_zyom7x.pdf[/url]

[URL unfurl="true"]https://res.cloudinary.com/engineering-com/raw/upload/v1634502448/tips/Steel-Equip_Support_C_jatelc.sm[/url]

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[KootK]

KootK... the detail is common for new or existing construction...

The detail is common to both new and existing construction but the requirement to "design" the OWSJ for any particular, new loading is not. That is something that is ubiquitous with new construction but not with existing construction. That's the point that I was making.

If an EOR truly wishes to delegate the joist evaluation and reinforcement design, that is indeed possible. I've done it myself. That scope shouldn't be buried within what, otherwise, presents as a relatively normal steel supply contract. Without being grossly conservative or very prescient, Enable can't price that work without some combination of:

1) Having existing drawings that indicate that the original joist loading is adequate without OWSJ reinforcement OR;

2) Designing the reinforcement based on existing joist drawings / calcs or field collected joist data.

#1 is rare and would pretty much obviate the need for this thread or the EOR's note.

#2 represents a lot of unpaid work for a steel supplier to undertake ahead of bidding a job.

 

[Enable]

KootK has summed up my problem nicely

Usually I wouldn't have bothered too much about something like this, but in this case this is a project for a new client. Issue being that generally I sell myself as one stop shop metal guy who does all the structural metal + misc metal + engineering. I'm not by any means cheap but I tend to eliminate headaches by having that all under one roof, and so it really sucks when one of the first couple jobs you're bidding with a new client you to have to turn around and say "well I can technically do this all but...."

Hard to sell the premium that way! If I was more youthful I would go out to site and measure things myself to firm up a non-headache price. But I'm old and tired so fuck that.

Anyways, I had my scotch and it's going to be a bid with OWSJ work at T&M. There are other steel items on the job so it's not as bad as a full non-bid. I'll call the client Monday morning before I send just to explain why.

Much appreciated team.

CWB (W47.1) Div 1 Fabricator
Temporary Works Design

https://www.enable-inc.com/

 

[dik]

Yup... EOR to do the work... From my notes:

OWSJ
-OWSJ CAPACITY HAS NOT BEEN REVIEWED. EOR IS RESPONSIBLE FOR DESIGN AND REINFORCING.
-ALL MEMBERS FRAMING TO EXISTING SHOULD BE ATTACHED AT JOIST PANEL POINTS ONLY.
-WHERE MEMBERS ARE NOT SUPPORTED AT TOP PANEL POINTS OF OWSJ, PROVIDE A COMPRESSION STRUT WELDED FROM POINT OF SUPPORT TO CLOSEST BOT PANEL POINT OF SAME OWSJ. EOR TO CONFIRM LOCATIONS, MEMBERS AND WELDS.
-EOR TO CONFIRM WHERE MEMBERS ARE NOT SUPPORTED AT TOP PANEL POINTS OF OWSJ, PROVIDE A HSS 1X1X0.125 COMPRESSION STRUT WELDED FROM POINT OF SUPPORT TO CLOSEST BOT PANEL POINT OF SAME OWSJ. EOR TO CONFIRM LOCATIONS, MEMBERS AND WELDS.
-EOR TO CONFIRM TOP CHORD ONLY IS TO BE REINFORCED.
-FACTORED HANGER LOADS SHOULD BE STIPULATED.
-HANGERS FOR MECHANICAL EQUIPMENT HAVE NOT BEEN PROVIDED. CONTRACTOR TO ADVISE OF LOADS AND LOCATIONS.

and I cut or add as req'd... any additions become part of my ongoing collection of notes.



Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[Enable]

So not sure what has gone on but somehow word is out that I am Ontario's make small openings and reinforce joists guy because I received 4 separate calls TODAY for similar add new RTU type stuff. I'm making a point to mention it because I had to come back to give dhengr a star.

The latest version has unfolded damn near identical to what he said goes on. Permit is in place. DWGs finalized. Contract awarded. And even in this case the EOR said they reviewed the OWSJ for an assumed unit capacity and said nothing is required, just trimmers around curb. Now that's something I can work with!

And I'm like, great! Already designed, just gotta add some c-channels and angles? Quick job, keep a few guys busy, make some Christmas cash, no problem! Then I request the mechanical shop DWGS and find that the unit is 2x the assumed weight on the structural DWGS....and so they'll have to get back to me. Like for fuck sakes. It's just so stupid of a fucking system.

CWB (W47.1) Div 1 Fabricator
Temporary Works Design

https://www.enable-inc.com/

 

[dik]

Often the snow accumulation around these units is much greater than the unit itself.

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?

-Dik

 

[JLNJ]

It seems to me that the EOR should be responsible for the joists, but those calculations and reinforcement diagrams might chew up more fee than the fee for the entire remainder of the project structural work.

Rather than assigning the work to the most-responsible party, it gets “delegated” to a contractor who can bury the fee in his mechanical fixed fee price. Expedient, but if it went sideways and had to go before a jury, I’m not sure they would let the EOR off the hook.