Survey existing building

[L-H]

Hi all,
I have a potential client asked me to help him with a renovation project. He hired an architect as well. It is an existing warehouse with no existing drawings. He wants to convert it into a restaurant (occupancy change so risk category change from I to II I believe). He asked me to do the survey first and provide as-built drawings, sign and seal them. Then analyze the existing structure to see deficiency. Then try to bring it up to code and incorporate new changes per requirements from the architect for the new restaurant layout. I can see a lot of work will need to be done on the field for this project (measurements, field verify location of the rebars in the exterior CMU walls, do a few excavation to find out size of existing footings...) My question is will you take in job like this and do all of the survey yourself or hire a company to do it? I think by doing myself I will take all the risk if some dimensions are not accurate. Usually I can do it for small renovation project but bigger project means higher risk.

 

[dik]

Sign and seal them for what purpose? be careful...

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[JAE]

I don't believe you should sign and seal any as-built drawings that you create from field surveys and measurements.
That is not an "engineering" effort but check with your state board of engineering laws - or better call them - and find out.
It doesn't take an engineer to measure up a building and draw the results so it may not be classified by your local state board as an engineering effort.

Yes doing this is a lot of work and time and money. Much more than simply designing a new building so your fee would be much higher than typical for a similar building design only scenario.

I would also suspect that after you do your survey and as-builts, you will still have a significant number of unknowns (rebar in footings, grade of bolts, etc) that would limit your full knowledge of the structure and your ability to fully analyze and check the design on every aspect. If you aren't in a major seismic area, you could take conservative assumptions and check the building for current code acceptability. Lots of your "engineering judgement" here would come into play.

Lastly - I think warehouse buildings are Risk Category II just like restaurants.

Risk category I is typically used for agricultural facilities, temporary facilities, and minor storage facilities...not major warehouses where people actually work on a day to day basis.

 

[L-H]

Thanks All

 

[lexpatrie]

I don't often see this much work put into an existing building renovation.

Usually what you have to work with is the architectural drawings with the dimensions on them and some rough idea of what's there (multi-wythe load-bearing brick, cast iron columns, wood joists, plank, plaster, wall thickness, column and beam locations (one hopes) etc).

Usually the work is to establish the existing conditions to a reasonable degree (perhaps not running profometers across the whole building and drawing up rebar shop drawings after the fact, who even knows if those are deformed rebar or the older twisted square rail bars).

Take a look at the IEBC, for one, and give some though to what sounds a lot more like a structural recertification ("the existing as built meets code!" or at least, it kind of did at the time it was built for the codes at that time).

It may change from Risk Category I to II but is the building so old that even the concept of RC I/II didn't exist? And isn't RC I "agricultural" building now? Residential and typical Commercial are RC II. The prisons and hospitals are the III and IV now. Risk category doesn't do all that much except for wind/seismic, it doesn't have much influence on the gravity system unless you have heavy snow loads.

If the live loading goes up from the previous use, that's where you'd most likely see structural work to reinforce, along with any added stairs, pads for heavy loads on the foundation, support of any added floor openings, infill of previous stair openings, new windows in existing walls, etc.

But typically Architecture goes first. They do the dimensions, too.

 

[L-H]

Hi Lexpatrie,

Yes, I usually work with drawings provided by the architect and then do the site visit to verify the existing structural systems, take measurements of the beams, joists...that are necessary for structural design.

I've figured out that the existing building was used an auto repair shop. So it's definitely risk category II.

I was concerned about the change in risk category from I to II which will increase the design wind load on the building. But seems like it's not the case now since risk category is still II.

Per IEBC the existing buildings are assumed to meet the code at the time they were constructed. But this building is about 70 years old and if the owner wants to bring it up to code (even though there is no sign of distress), I still have to verify all of the existing conditions and check the structural systems using the new codes I think.

 

[lexpatrie]

If nothing is changing you could potentially check it under the codes at the time, but there won't be too dramatic a difference. Most of the code changes are refinements and while they sometimes reduce strength, if you aren't changing something I think there's justification for checking it against the code at the time. Checking it for the current code (and sealing it) is a different creature as you are perhaps, or probably, legally replacing the prior engineer with your own as to design responsibility for the next 10 years or so. The sealing it part is what I'd have the most difficulty with, as you really need to confirm as much as you possibly can, with some generalities, i.e. checking a footing for rebar, or checking almost all of them or all of them, to ensure there isn't one that just doesn't have it at all, for example. Bearing lengths will be concealed for beams, bolts covered, steel grades unknown, rebar grades unknown (deformed or not?), etc.

There's a big difference between turning a blind eye to extensive corrosion, not pointing out a building has absolutely no lateral force resisting system, widespread deterioration, decay, and/or fire damage with significant section loss, and designing a stair that's attached to badly corroded elements you never wanted to see,

and

working on the building with the understanding that most of it looks "normal" and in good to fair condition, and designing attachments that get some measure of testing or inspection.

You wouldn't want to epoxy into powdered concrete but the special inspector has a job to do as well, and he's supposed to object to that as an unsuitable substrate for the new attachment as well, along with the contractor knowing full well it won't take any load because it's falling apart as they drill into it.