Removal of soil nails 2

[snsl123]

I am not a geoengineer, but I have some geoengineering questions and I hope you don't mind me posting it here. As part of a construction project next to our house (they are building a house), a shoring company began drilling grouted, threaded soil nails into the hillside between our two houses. In weeks prior, an excavation company had excavated all the earth in the side yard next door right up to our property line, which left a 20' drop to the property below where they are building the house (we are on a hillside). In order to prepare for a retaining wall, the shoring company began drilling these nails into our yard, but neither the builder nor the shoring company told us they were going to do this work and they did so without our permission (It is unbelievable--at least to us!) Since they began drilling the nails into the hillside right along our property line, and the nails are approximately 16 feet long, the nails breached our property line by about 15 feet (there is a foot of nail still sticking out of the earthen wall). We were able to stop them just as they were finishing the installation of the sixth nail, but apparently dozens more were planned to be drilled into our yard to hold up the wall. Of course, all work ceased, and has been stopped for one week now. The builder apparently had other methods to shore up this earthen wall, but utilizing our yard was the cheapest route. We are now in need of a geotech expert (something I am working on) to help us figure out what to do with these metal rods in our yard. Do they stay or do they go? We want them gone.

My (curious) question is; can grouted soil nails be removed without taking our yard out with them? Do the rods come out cleanly or does the grout come out with them? Will pulling them out (and the dirt with them) create a sink hole in our yard? One of the rods was drilled into our yard at only about a 25 degree angle and a 18" depth (I saw that one go in). I am wondering if we can ever trench for sprinkler repairs at that depth. We have lots of other questions regarding this, but we are mostly curious if grouted soil nails can even be removed without causing greater problems for us. We really want them removed in case we need to or have to excavate our yard some day. They are probably tying up about 20 feet of our yard.

In the meantime, I have some calls in for a referral for a geotech/soil engineer in my city to help us sort out this mess. I am, unfortunately, learning more about soil nails than I ever wanted to. It will probably take weeks to get answers, but in the meantime I am curious if grouted soil nails can even be removed. Thank you.

 

[dgillette]

There are electromagnetic geophysical methods that might find the nails at fairly large depths. Could get costly, however.

http://en.wikipedia.org/wiki/Archaeological_geophysics

http://en.wikipedia.org/wiki/Exploration_geophysics

The depth you need for burial of pipes depends on climate and potential depth of frost. Maybe even 8 feet in Havre, Montana.

 

[PEinc]

I agree with dgillette's first response. I guess we are in the minority.

 

[snsl123]

What do you mean, PEinc? I am not following it. That the rods will never be an issue?? It very well could be (probably is) that these rods will never bother us, but I certainly want to explore all potential problems. Then we feel that we made an informed decision about them. The builder certainly hasn't given us any say in regards to our property up to this point.

And, PEinc and dgillette, since you are geotechnical, could it be that we will have a difficult time getting a geotech engineer to consult with us?? The company I called today never called back. I wonder if this is too hot of an issue to touch. It is a can a worms, but we are very reasonable people. We certainly aren't greedy. I haven't told you the second half of this story (I didn't want to muddy this thread) about the $40,000 worth of drywall, window, stucco, and patio slab cracks (all documented through our insurance co and a structural engineer) that we've sat on for a year and not pressed with the builder or insurance co; just to keep a good relationship with the neighbors. We were willing to bear that financial burden oursleves. I don't think most people would do that. This trespassing issue just became the final straw for us. Now we will press compensation for all damages, because the builder's disregard for our property hit its peak with this drilling. It was so reckless. And, the cracks. . . all due to heavy machinery vibrations. It is another long story, but they had to compact the soil next door for five days with a large rolling compactor. My house shook; my walls, dishes, stoves, can lights, everything, for five days. They settled our house. Cracks appeared all throughout the construction side of our house. This could be another thread in and of itself. This latest excavation of this side yard (and the drilling of the screws) caused two ceiling cracks in our master bedroom and one ceiling crack in our livingroom. We have run out of patience.

 

[dgillette]

No, I don't think it would be such a hot issue that they wouldn't want to touch it without even looking into it. Not knowing whether they were busy, had key people on vacation (yes, some engineers do take vacations - we just don't like to), or what, it's not terribly surprising that they didn't get back to you immediately. I have a goal of returning all phone calls the same day, but I have to prioritize that with other tasks - reports due, coworkers needing technical assistance, real or perceived emergencies, etc. Sometimes, I'm just out of the office.

Is the contractor with the nails the same one that caused the other damage, and is the same neighbor's house involved? You should have raised hell back then, when there was demonstrable damage - $40k!! (I wouldn't have been that much of a good neighbor.) They could have/should have switched to smaller compaction equipment, thinner layers, better moisture control, etc., and they would still have been able to get the compaction they needed. (It would have taken them longer, but if the vibrations are kept small enough, that's not a problem for you.) There are plenty of legal precedents that say contractors are responsible for vibrations off the site. One judge's decision about damage caused by pile driving next door compared it to "...a giant striding past a kindergarten..." and I believe that's an exact quote. Got it in my files somewhere.

Restating what I said before, the neighbor and his contractor will probably have to swallow the extra cost and stabilize the slope on their side of the lot line. [Insist on the engineer's seal on the design!] Once that is done, the soil nails that have been installed already are simply pieces of steel rod in the ground, with no remaining purpose or effect. Unless those nails can be shown to have caused damage to structures or utilities at your place during installation, I believe you would have a hard time collecting much in court, unless the judge awards large punitive damages (which I don't think is very likely). He or she may consider that any impairment of the future use of your yard is hypothetical, and most likely limited to having to cut off a few soil nails with an acetylene torch if you need to excavate. You could spend a lot of money on lawyers, court costs, and geophysics with little potential recovery. The net cost of fighting for monetary damages would likely exceed anything you would ever spend on the extra work caused by the nails. While I understand that the soil nails come on the heels of the earlier problems and that you are seriously POed by the contractor's arrogance, the difference between the nails and the earlier damage is the difference between insult and injury. If the statute of limitations has not run out, I think it makes more sense to pursue compensation for the actual, proven damage caused by the earlier work, or make it a package deal if the same people are involved.

Depending on the contractual terms between the new neighbors and the contractor, the difference in cost for stabilizing the cut may be entirely on the contractor, and not on them. In that case, you are more likely to see them come over with the aforementioned Laphroig.

When this is all resolved days or months from now, please come back and tell us how it came out. We'll all be curious.

 

[snsl123]

dgillette, I agree with everything you wrote. And yes, I thought that maybe it was just a busy Friday for this geotech firm and they couldn't return my call. I understand that completely.

Yes, the contractor with the nails is the same as the cracks. Same project next door. We did raise hell last year during compaction. We've raised hell every time. A backhoe cracked our master bedroom and living room ceiling just a few weeks ago. The builder, of course, just listens as we take them on a tour of the damages, but he won't acknowledge they had anything to do with it. They pretty much just stare at the damage and shrug their shoulders. They don't say anything. I think their MO is, don't apologize or take any responsibility. If they get pushed with legal action, then they'll move. And, it is probably a MO that (they've learned) works for them, as it almost did this time around. Since we were willing to bear the $40,000 burden to keep the peace. They almost got away with it until they trespassed on our property and drilled those nails. That was just too underhanded and brazen. And, yes, they should have switched to smaller equipment, but didn't. Our structural engineer (who inspected our house--this was before the soil nail situation) wrote a 16-page report for the damages to our house (including photos). In his report, he refers to geotech studies that have been conducted in other locations in our city that demonstrates that our house sits within an area of "peak performance or peak velocity vibrations" from a rolling compactor (this damages part could be a whole other thread). Given the size and location of the compactor (they compacted only 40 feet from our house), the location of our cracks (only on construction side of the house), and the time period they appeared, he concluded that the heavy equipment caused our cracking. It was a huge compactor. Everything shook in my house. They did bring out a smaller compactor for a later project (the garage floor), but that "smaller" compactor shook my house and everything in it, too. From all the shaking and damage to our house, I wondered if our house was maybe built on a lot of unstable fill dirt. But, our structural engineer went through our (extensive set) of blue prints and found the foundation of our house was built entirely on native soil, so they just shook it up a lot.

A large back hoe is currently sitting three feet (albeit down the earthen bank) from my property line and has been sitting there since the day the rods were drilled and the builder inspector shut the project down. We'll see if they take that thing away. It is what caused the master bedroom and living room cracks a few weeks ago. The cease and desist letter that went out last week from the attorney put them on notice that they cannot create one more crack in our house or we will shut the whole project down and seek legal action for trespassing. We are already seeking compensation for all the structure damages. The soil nails compensation is still up in the air, until we can get a consult with an engineer.

I didn't know about the engineering seals on the plans. Thanks for the info. Our structural engineer's report for our house damage has a seal, but I didn't think twice about it. We are going to have to get the plans for the hillside project next door and investigate further. What does the seal mean?

This story will continue. I am afraid that their "Plan B" for the hillside might involve pile driving. Someone mentioned I-beams this last week, but I can't remember who. What does that mean for our house?? Stay tuned. . .

 

[PEinc]

Again, I agree with dgillette's last response. The bigger problem is the damage to your house. The nails are nothing more than trespassing.

If you can show that your house damages are new, since the new house construction started, then you should file a lawsuit or claim against the contractor's insurance company.

There are many geotechnical engineers that do not have experience with soil nail walls. That may be why the engineer did not return your call. Another reason is that the soil nails on your property probably haven't caused any problems yet and may never. What do you expect the engineer to do? The wall was never built so you can't complain about its design or performance. And, as I said before, the potential soil nail problems you talked about are highly theoretical. I wouldn't want to write a report about stuff that is slightly possible in the future.

If I were you, I'd focus my energy on addressing the house damages.

A seal on a design or plans indicates that the engineer who designed the work is, or was at some time, a licensed engineer. Unfortunately, having an engineering seal does not mean that an engineer is qualified to perform certain types of design. It is not uncommon for an engineer to engage in work beyond his or her capability or experience. If the soil nail wall was designed by an insured engineer, and if the performance of the wall caused you damages, then you could try to file a claim against the insurance company. If the engineer isn't insured, then you would have to sue. In some areas, before you can sue an engineer, you would need to get a Certificate of Merit from another engineer stating that there is merit to your lawsiut angainst the wall designer. remember, the contractor probably has a lot more insurance that the engineer has. And, you should go after the contractor because, ultimately, he is responsible for both construction and the design of the soil nail wall, if he hired the engineer.

If the contractor is not allowed to use soil nailing, then he may need to resort to installing steel sheet piling or soldier beams with timber lagging between the spaced soldier beams. Soldier beams are usually H-Piles but can also be wide flange steel beams. These beams may be installed by driving them into the ground (with associated vibrations and noise) or set into drilled holes (with less vibrations and noise). If the finished shoring wall is more than about 12 to 14 feet, the wall may need to be supported by inclined raker braces which aim down and into the excavation site or they could use tieback anchors which would need to extend under you property similar to the soil nails. For tiebacks, they would need your permission.

The house being constructed must be pretty big if it's been under construction for a year! Or, the contractor is very slow.

 

[snsl123]

Thank you for all those explanations, PEInc.

Drilling sounds most reasonable and I would bet they'll do that, since they are on notice they can't cause vibrations anymore. We'll see what plan B turns out to be. I would certainly hope that things will be quieter from here on out. The construction next door only has a few months to go before completion.

I have a very good witness to the timing of our damages. It couldn't get much better than this! I had a painting contractor come in, just before construction began next door (it was total luck), to give me a bid to paint the interior of my house. He inspected the whole house for holes, cracks, anything that he would have to repair, and thus would have to bid out. He said I had a very "clean" house, meaning not very much prep work. He came back to my house six weeks later (after the compaction work next door) and I showed him all the cracking, room by room. He said, "What HAPPENED!!?" He was completely shocked. This is the good part. . . he happens to be the painter for the builder's (next door) personal family homes. This painter stands by me because he's a good, honest guy. He is coming back this next week to bid out all the repairs to present the bill to the builder, which kind of puts him in a tough position, but he's going to do it because it is the right thing to do. (I would love to be an attorney on this case.)

Thankfully, according to our structural engineer, the damage to our home is cosmetic, except for one part of the house that we are watching (a topic for the structural engineering forum!) Thankfully, there are no foundation cracks, though. Nevertheless, we will still try to work it out with the builder rather than accelerate the legal route. I think/hope the builder will come through and take care of (most of) it. And, also give us a bottle of Laphroig (I had to look that one up!) It is all so damning that I just don't see how he could get out of this.

By the way, the house under construction is 8,000 sq ft and is a custom-built home. The houses in our development are big and the architecture and finishing work are known to be exceptional (even though they seem to be built by he three stooges!), so they take almost 18 months to build. This has been a long road for everyone. Our own house was built by this same builder, but seven years ago. We've owned this house only 18 months (it was inspected by a licensed house inspector as part of the purchase of the house 18 mos ago, so he's another witness to the changes.)

Thanks to all for your thoughts and ideas.

 

[msquared48]

From all the comments here, the most logical solution for everyone is a drilled H-pile lagging wall with temporary steel rakers as needed. This may end up being a significant design modification for the other owner though as the horizontal soil forces to the wall will eventually have to be resisted by the permanent structure of the new residence. However, that is not your problem. The redesign will probably delay the project one to three months.

PEinc:

I have reservations here as a structural engineer that the soil nails were intended to be anything but permanent as to not do so would significantly increase the lateral structural resisting requirements, and overall on costs,of the residence due to the 20 foot cut. However, this is conjecture, I admit.

Regarding the rotation, I consulted the 1998 USDOT pub FHWA-SA-96-069R and figure 2.8 on page 55, all based on the 1991 work of Clouterre, and Figure 2.9. For this 20 foot cut, the movement may be small, possibly in the order of 2 to 4 inches, but is there, and has to be there for the nails to load properly, otherwise, the nails see no load. If they see no load, why the need for them?

Mike McCann
McCann Engineering

 

[snsl123]

One thing I forgot to mention is that a good half to three-quarters of the dirt (removed for the 20' wall) was put back because our yard was starting to collapse. They needed an emergency support system, and so they spent three days putting back the dirt that it took four days to remove. The earthen wall has been stable since. The soil nails were going in to support this dirt, so they could continue removing the dirt again. I don't know how they were going to accomplish that. I can't work that process through in my mind.

So on that fourth day of removing this dirt, at about 6 pm, the backhoe driver came knocking on my front door. He wanted to apologize ahead of time that he was going to be working into the night (and the following days) to put the dirt back that he'd spent four days removing. He told me our yard was beginning to collapse, he was afraid we'd lose our entire side yard, the dirt was falling on their heads, and he said it was scarey (He ACTUALLY told me all of that). He said this project was very difficult and he didn't feel comfortable going any further with it. He said he was going to put this dirt back and his company was pulling off the job. I sensed he was pissed at the builder because he was so honest with me. I went out to look at what they'd done and I saw dirt clods popping out of the earthen wall and falling down the embankment. Of course, as the uphill homeowner, this was horrifying to watch. It reminded me of the videos I had watched on tv for the mine disaster in Utah this fall, where the earth was "bumping" and the dirt was popping away from the walls. I was just waiting for my house to start sliding down the hillside. The backhoe driver worked into the night and the next two days to put at least half (maybe 3/4) of the dirt back. He ultimately didn't pull off the job because about five days later he hit the natural gas line on the construction site and everyone had to be evacuated. He was also the backhoe driver that hit my $16,000 hand-crafted wrought iron fence with a backhoe bucket full of dirt. My beautiful fence looks like a car ran through it. (More damages that will be tacked onto the builder's bill--that was the only thing the builder said they would pay for). The day of the gas line break happened to be the day that my insurance company sent out a (general) building inspector (not the structural engineer, but the general building inspector--like the kind who comes out when you buy a house) and he witnessed the whole natural gas disaster unfold. I told the inspector that he should ask for hazard pay for coming to this job site. I actually was afraid we'd lose our insurance coverage after that day.

I could write a book about this experience. I guess this thread is turning into a book! It has been a long year.

 

[msquared48]

I don't knowwho the general was on this job, but he needs to be demoted to private. What you have described is utterly ridiculous. This makes the Keystone Cops look like good contractors.

Mike McCann
McCann Engineering

 

[PEinc]

If the contractor was originally attempting to make an open excavation (without shoring or a soil nail wall), then the new building must have been designed to support the lateral earth pressures. Therefore, the soil nailing was added only after the open excavation started to collapse. Therefore, the soil nail wall was probably intended to be a temporary structure.

The original post does not clearly describe the situation. snsl123 said there was excavation made to construct a retaining wall and that there was a 20' drop to the property below - whatever that means. It is not clear if this excavation was to the basement foundation wall or just for a site retaining wall that needed to be cut into a sloping side yard in order to provide a flat side yard for the new house.

I don't believe that snsl123 ever said how far away her house is from the face of the soil nail wall or how deep her basement is with respect to the proposed excavation. Therefore, it is not possible to determine whether or not the performance of the soil nail wall would even affect her house.

Again, it sounds to me like her only significant problem MAY BE the damages to her house caused by vibrations. The soil nails should not have been installed without permission but their presence should not create a problem, unless the contractor tries to remove them.

 

[snsl123]

PEinc-those are very good points, if I am understanding you correctly. The soil nailing was added after they removed all the earth in their side yard, because of this collapse. This hillside spanned 20 feet from the side wall of the new house to our property line. And, from our property line to our house is a span of another 20 feet. So, from house wall to house wall, the span is 40 feet. And yes, it is a sloping side yard, so the further down the property line you go, the earthen wall depth is not as deep. Our front yards walk out into the street above, our backyards walk out into the street below. They builder cut into this sloping hillside to make this new side yard (the houses themselves are cut into this hillside). I can't tell you what that elevation change is from street to street. Our houses are on 3/4 acre lots. If I went out to my property line and looked down from my FRONT yard to the house's foundation below (before they put the earth back that they removed), I could look down to the level of their basement floor, which was 20 feet down. If I went out to my backyard and looked down, the elevation change to their yard is maybe five feet. I guess you could remove our entire side yard, too, and there wouldn't be any issue as to a collapsing wall(??) The houses would just be sitting there on their own foundations without any great changes in depths between the houses. As I think this through in my mind, though, the bottom grade of my house is probably five feet above their grade. In other words, if I go out into the street that spans our back yards and look at the basement grades of both houses, I think my house might be five feet higher. I will have to look at that so I can understand this better.

So, if I am understanding you correctly, our side yard could collapse without support, but our house wouldn't collapse because our house isn't actually 20 feet higher than the house's foundation next door. They are independently sitting on their own foundations. Maybe mine is five feet higher, which isn’t that much change. It is just that I have so much dirt piled up against my house that it wants to collapse into their yard.

 

[snsl123]

I can now see that my descriptions have handicapped the discussion. I apologize and I am glad PEinc could see through them. I am sure that probably changes the loads on the rods. Yes, they still may cause issues some day tying up my yard, but at least I know my house won't collapse because of this particular earth removal.

I emailed our real estate agent, who is the top agent in our city and has been forever, to ask about any re-sale implications for our house. I will let you know her thoughts. Thanks again and, sorry Mike, for my handicapped descriptions.

 

[msquared48]

PEinc:

I disagree that the soil nails pose no problem here. If they were in fact permanent by design, then they could not be removed by snsl123 if the installation and design were allowed to go to completion. If they were temporary, then you are correct, and they could be removed or interrupted if snsl123 chose to perform construction on their property that would have to cut the nails. So the answer is, if the shjoring is redesigned, that they can be interrupted in any future construction if the neighbor's design does not depend on them. Snsl123 needs to make sure that this is the case as it is in their best interest.

Mike McCann
McCann Engineering

 

[PEinc]

They're probably not permanent nails. snsl1223 should confirm this by talking to the wall's designer and the local building inspector.

 

[epongra2]

Where I live and practice, these temporary excavation and property line issues are an everyday issue.

The following is straight out of the CBC (California Building Code), which is simply a modified version of the UBC. Of course, this or an equivalent section of Code may not apply in your area.

Chapter 33, Site Work, Demolition and Construction

Protection of Adjacent Property (Sec 3301.2 and Sec. 3301.3)

"Prevailing law shall decide the requirements for protection of adjacent property and depth to which protection is required. However, if the law does not define the requirements, then the following shall apply. Persons making excavations 12 feet or less in depth shall protect the soil on adjacent property from cave-in or settlement. At least 10 days written notice and access to the excavation must be given to adjacent owners so they may protect their buildings. Persons making excavation over 12 feet in depth shall not only protect the soil on adjacent property from cave-in or settlement, but shall also pay to extend the foundations of adjoining buildings below that depth."

So, why was this an afterthought on the part of the adjacent property owner, or the jurisdiction for that matter?

 

[msquared48]

Exactly.

Mike McCann
McCann Engineering

 

[snsl123]

Thanks for that info epongra2. I am going to research that for our state.

I would LOVE to know what they were thinking with this project. The only definitive piece of info I can add is the city building inspector, whom I called for help, told me the builder said they didn't know they had to get our permission to drill these nails into our property. Of course, that is ridiculous. The only reason I can think why the builder did this without consulting with us is to get the job done, come hell or highwater, and worry about the consequences later. As I have written in this thread before, soil nailing into our property was costing $16,000 less than the alternative. Maybe they figured they'd do the job, and the consequences, whatever they may be, would cost a lot less. They didn't bank on having 'the neighbor' being home and watching their every move. I caught them in this deceiptful act. I am sure they were disappointed they didn't get away with it. This builer has been around for decades and has probably learned these tricks. It all comes down to money and soil nails was a lot cheaper.

Anyone else have a guess?? That's mine.

 

[PEinc]

It sounds to me like the soil nails are the least of your problems.

 

[snsl123]

PEinc-you work for the dark side.