Easy foundation work or a trap? 3

[ANE91]

Local contractor sells underpinning services to homeowners. Jurisdiction requires a sealed engineering report before issuing a permit for the work. Their last guy retired; I’ve seen his work. Enter me: seems like a good potential source of revenue, low hanging fruit. Totally new line of work for me (though I’ve done basement wall repairs). Salient assumptions below:

1. No geotech report, but I could default to the lowest presumptive soil bearing pressures in IBC 1610 and 1806.
2. Contractor specializes in helical piers side-mounted to footings.
3. Contractor is likely promising to “fix the foundation” when they really mean that they’re arresting or at least attenuating settlement. No jacking applicable.
4. Loads are not high enough and walls aren’t long enough to warrant special attention for any eccentricity.
5. I cannot think of any codified reason for the jurisdiction’s requirement beyond the basic alterations stuff in the IEBC.
6. By and large, these aren’t life safety issues but rather serviceability concerns. I would pull in a geotech for a house that looks like it’ll disappear into a sinkhole or some such.
7. My reports would simply verify whether the contractor’s proposed underpinning sufficiently increases the bearing surface so as to justify an expected decrease in settlement, even though the house is probably done settling by the time they get involved…

The last point doesn’t 100% sit right with me. On the one hand, who am I to tell a contractor what he can/cannot sell? On the other hand, I doubt that I would find much of that work truly necessary. Would getting involved make me party to deceit?

As much as I like to make money, I hate trouble more. Can I get a sanity check on this, particularly from others who design underpinning? Feel free to tear me a new one; I can take it. Thanks.

 

[jerseyshore]

As I recall, contractor was no longer in business coupled with a discreet and somewhat hidden note about Owner being responsible for engineering design that never occurred. In essence, the note was "this is our idea of a repair, but it is the Owner's responsibility if it does not work"

A classic shitty repair company contract always has something like "lifetime warranty on all work...warranty voided if preventative maintenance is not completed on all days that end with y".

 

[Ron247]

As I recall, the Client told me the contractor also used the line "I do all my work like I am doing it for my own mother."

 

[jerseyshore]

As I recall, the Client told me the contractor also used the line "I do all my work like I am doing it for my own mother."

And I bet he slapped the brackets and said "this baby ain't going anywhere".

 

[Ron247]

More like he kicked it with his foot and said, "That'll hold 15,000 lbs."

 

[jerseyshore]

More like he kicked it with his foot and said, "That'll hold 15,000 lbs."

"can land a chopper on this thing"

 

[phamENG]

"can land a chopper on this thing"

If only he knew helipad loading was the same as for his mother's living room...

 

[jerseyshore]

If only he knew helipad loading was the same as for his mother's living room...

Shh don't give them any ideas. It's already bad enough that parking garage loading isn't anything special.

 

[Greenalleycat]

@Ron247 amazing, a clause like that would never stack up here
It's explicit in our building law that you provide a warranty with your work, can't contract out of it, and can't do non-compliant work
Though if the contractor is out of business you are stuffed regardless

 

[Ron247]

Many projects may have a 1-year warranty, but the failure happened during an extended period of no rain. Probably 3-4 years after the service was provided.

 

[Greenalleycat]

There are 3-4 different avenues you could pursue that against a contractor here, and all of them would very easily capture a 4 year horizon
I think the shortest of them would be 7? or 10? years that the contractor is on the hook and, for residential work with a private individual as the client, they can't be contracted out of

 

[human909]

There are a LOT of nuances with this work, and it doesn't sound like you're familiar with them all

Be careful

I've only vaguely followed along with this thread. But this advice stands out in my opinion. Behind that advice is the general advice of, stick within your own area of expertise! It is a simple statement but is rings true and should be at the back of your mind at all times.

Given my current relevant experience and knowledge I wouldn't touch an underpinning job. I did do so once but only because I was dragged into it and I sought suitable additional advice. On the flipside I regularly design complex structural/mechanical items that the average structural engineer should likely take a wide berth from.

I would assume that the majority of regular contributors to this forum are excellent structural engineers. But there are still many subsets of expertise involved and we all have taken different paths and have different skills.

 

[ANE91]

stick within your own area of expertise!

This is great advice for a lot of reasons, so I felt compelled to echo it. Valuable input for everyone.

Still, as safe as it is to put blinders up and keep cranking out the same work day after day, year after year, I fail to see how anyone is supposed to grow with that mentality. Finding someone to shadow is the ideal scenario. Sadly, my expert tree bore no fruit this year, so I can’t exactly just reach up and pick one. Unless the wonderful folk of ET are willing to share their redacted calcs/drawings and answer questions, which I don’t expect, then I’m on my own, as is anyone seeking to expand the peripheries of their competency. So I’ll keep reading about this.

 

[Ron247]

I fail to see how anyone is supposed to grow with that mentality.

I agree that you must venture out in this business unless you have plenty of the type of work you enjoy doing. There is nothing about underpinning that is "mysterious or secret". The systems respond to stress and strain like everything else does. It is a matter of getting familiar with each system, applying engineering concepts to it and being able to assess each situation you are asked to correct.

There is a learning curve that includes terminology, known pitfalls (example: unreinforced foundation), limitations of what you can provide etc.

It is very much like PEMBs, I know several structural engineers who shy away from anything to do with altering them or checking them for some new loading. I know because they have sent the work to me. College generally does not teach cold-formed steel nor tapered members. Those 2 things make it difficult to feel confident tackling a PEMB your first time. But for those who do, they eventually get comfortable working with them.

In the early days, pass on the hard jobs until your confidence level rises. If working some easy ones still bother you, maybe it is not a good path. The first hard job that comes along, tell them you are tied-up on something else. It is not a huge calc business as much as a "game plan" business. What are the steps you will use for a unique project such as the jacking sequence. As my structural professor told me once, "sometimes we get so focused on the applied loads we lose sight of the distortions". Learn to explain in layman's terms what is going on and what your solution will provide. Also, if you can find a knowledgeable and honest underpinning contractor, latch on to that unicorn. I got lucky years ago, the first one I met was both and he helped me a lot to understand the system he sold and was knowledgeable about his competitor's systems.

Essentially, do you want to end your structural career someday being an "underpinning virgin" or at least having one roll in the hay.

 

[ANE91]

I think I would enjoy working with you, @Ron247. Definitely hoping to get my roll in the hay soon!

 

[Ron247]

Chance Anchors is good one to look into for basic training. It may be Hubbell/Chance now. My unicorn from years ago sold that product. They have some training and many other anchor sellers, refer you to them for information rather than their own product's resources. That always scares me. I have always viewed that as "Buy my product, but if you need info, check with the people we copied from".

 

[Aesur]

The one thing I haven't seen posted yet is what kind of fees was the other engineer doing these for, that is probably one of the biggest reasons to do or not to do this kind of work. I would want to see in writing what kind of fees are expected on these types of projects as it's not all that easy considering what really needs to be checked and done to properly do this kind of work. There are the helical designs, verifying the footing can span between helicals, adding reinforcement as needed, eccentricities to consider, you are essentially turning a footing into a beam which behaves differently and probably isn't reinforced as a grade beam/elevated beam in the first place, you need to consider how to properly install without undermining too large of an area at a time or adjacent structures. I personally wouldn't do these for cheap, let along just provide a report without calculations and drawings to back it up. Far too often it seems these contractors are just looking for a rubber stamp and not the engineering required, but I'm hoping I'm wrong in this case.

 

[Ron247]

Of the ones I have been exposed to, I don't think I could even ball-park a fee structure. Each one is rather unique and the depth of my involvement varied so much. Other than an hourly rate and your estimate of how many hours this unique job will take, I know of no other methodology. But you do have to estimate properly and consider all your outside costs such as GeoTech, preliminary designs etc.

I have designed one anchor that was used 27 times on one project, and I have designed 7 unique anchors for 12 unique locations on the same building. One of your main values is spotting the probable causes. Sometimes, that is worth more than the calcs and drawings. I have seen several projects where the anchors did nothing to solve the original problem. Underpinning is that combo of structures and geotech that sometimes is difficult to get a good feel for until you have done several projects.

I know I turned down at least 3 jobs where the entire embankment was next to a drop-off that was migrating laterally. The Owners were willing to put in a bunch of anchors, but the anchors would have been supported by the migrating embankment. No use, in my opinion. The anchors would have just "been along for the ride".

 

[human909]

I fail to see how anyone is supposed to grow with that mentality.

I think you have taken my statement far too pedantically. I would think that it would be pretty clear that the statement doesn't mean don't ever grow, learn or change. Otherwise how would you ever gain expertise and competency. I have little doubt that all of us here have grown an expanded their expertise.

In my country it is an ethical requirement for an engineer to "practise within areas of competence". I've clearly changed the wording slightly but I would think the meaning is largely same.

 

[XR250]

The one thing I haven't seen posted yet is what kind of fees was the other engineer doing these for, that is probably one of the biggest reasons to do or not to do this kind of work. I would want to see in writing what kind of fees are expected on these types of projects as it's not all that easy considering what really needs to be checked and done to properly do this kind of work. There are the helical designs, verifying the footing can span between helicals, adding reinforcement as needed, eccentricities to consider, you are essentially turning a footing into a beam which behaves differently and probably isn't reinforced as a grade beam/elevated beam in the first place, you need to consider how to properly install without undermining too large of an area at a time or adjacent structures. I personally wouldn't do these for cheap, let along just provide a report without calculations and drawings to back it up. Far too often it seems these contractors are just looking for a rubber stamp and not the engineering required, but I'm hoping I'm wrong in this case.

Around here, most residential involvement is due to shrinkage and swelling of underlying plastic clay soils. The only calculation I usually do is the required helical capacity. I end up putting them 5-6 ft. O.C. on most jobs. I get about $1350 total for the site visit, drawing and a follow-up note on the drawing that it was done in general accordance after looking at install photos and boring logs. Probably 3 hours max. of my time. Pretty much the standard of care in my area.

 

[Ron247]

Around here, most residential involvement is due to shrinkage and swelling of underlying plastic clay soils. The only calculation I usually do is the required helical capacity. I end up putting them 5-6 ft. O.C. on most jobs. I get about $1350 total for the site visit, drawing and a follow-up note on the drawing that it was done in general accordance after looking at install photos and boring logs. Probably 3 hours max. of my time. Pretty much the standard of care in my area.

That is in line with projects I have done with similar scope. Once you learn what areas in general have plastic soils and that appears to be the main issue for the project, there are not a lot of calcs unless the structure itself is really articulated. Most of them are basic residences. The main factor at that point that influences price is how many anchors. If I am calculating one, but installing several, the total quantity affects my price some since I am taking more risk. I am not doing 2 for the same fee as 20.