On Going Problem

[Randy88]

Stock, I looked up the elevator failure and have some questions, first if I understand correctly they righted the silo, as in put it back upright and used it again? If so how did they do that, next, since the report only had the requirements needed to hold it up, what was the recommendations of how it should have been done to avoid the problem in the fist place? set down pilings, put in 50 feet of rock first, what? I'll admit I got lost in the lingo they used, but also was the study done in the 1950's to the existing silo site with the silo still on it or after the silo was down and gone?

Impact, I understand fully what your dealing with, farmers are excempt from the laws that govern most out there, it sounds like you have a good plan, even if its not required by law to be done, require it for your business to be done, no exceptions, if it were me, depending on how things are going, I'd hire the engineer out of pocket on the project and follow his advice, if he says its not safe to build on, then don't, give the owner the ultimatium of either doing it right or hire another contractor to finsih the project, its never too late to have stipulations on any job while your onsite and working there yet, get an attorney involved and right now, follow his recommendations and do as he says.

I've refused to do work that cut corners, and I've also left jobs where corners were cut, those are not jobs worth having or doing, if the owner has alrready cut corners, I'd toss up a red flag and start to put stipulations on things, before they get ugly or tied up in court later on, today you have a choice, tomorrow in the legal system you have none, but are dictated as to what happens, if things are looking bad, stop or correct it today, before its too late, any way you have to and if that means to leave the job uncompleted, so be it. Just my two cents worth.

 

[Impact]

Update on the current project. The foundation is in place. As stated in my first posts, the site was excavated 10-12' deep. Instead of the 18" of big stone, he used about 8-12". He used a bank gravel that was sopping wet until he firured out it wasn't working. He dug it all back out again, and started over. He started off right this time, but halfway up he let money dictate and he used a cheaper fill material. It seemed satisfactory, but barely. I feel the structure will be OK, but, barely. What's under the 12' of fill material? :beatsme Hopefull if it settles, there wouldn't be much differiantal settlement.

I'm on the verge of signing another contract on a larger tank for a commercial customer. The soil boring costs are in my contract. The proper fill materials (with allowances) are in my contract. If soil borings dictate special foundations be engineered, the procedures are in my contract. I suppose he could balk at the procedures, but, he'd be in breech of contract. (provided he does sign LOL) Dang it's hard to change my ways as I get older. :Banghead

 

[Impact]

Stock,

The transona elevator read was interesting.

I did a project couple years ago that seemed to have no bottom. We used auger casts. It's been in operation 2 years and we can't see any settlement issues. But, man, that is a sloppy procedure.

 

[stock]

Yes if the structure is of sufficient strength to take the stresses involved it can be possible to inject grout to raise the CBR of the ground. I hear that, on smaller structures it is possible to inject a two part chemical structural foam that expands and returns the building to a corrected position. The most famous righting of a building was the leaning tower of Pisa where the removed the better clay ie the side that was capable of holding the dead load of the building and letting it settle as the tower was not of sufficient structure to take the stresses involved be the injection process..............

Ultimately a good foundation or substructure will distribute the dead load of the building through to the ground.

http://www.wbdg.org/ccb/DOD/UFC/ufc_3_220_01n.pdf go to chapter 11 for some reading..........

 

[Randy88]

Stock thanks for the articles to read and replying. Do you have any articles of recent failures of bin setups, these size bins going up today, with none or little engineering scares me and I'm thinking its only a matter of time before something major happens, we've been taking down a lot of silo's in recent years and most have that leaning tendency, the base prep is about the same for new bins going up and it makes me wonder, just how right or adequate these sites are, with the major amount of weight difference there is to the old outdated small silo's of the past.

Impact sounds like you've got the system figured out, have it in writing to give you room to do what needs to be done so it is safe, as for getting set in your ways, I'd like to think of it as getting too told to be jerked around by someone wanting to save a buck. I've always been under the idea of do it right the first time, saving a buck only ends up costing way more in the long run.

While we're on the subject and since I'm not an engineer, can anyone tell me how sand can be an acceptable base material for a large bin? There was guy near me that built one last year, a big one, and he dug down till he hit sand and started building his bin from there, my question is what happens if someone were to do some excavating beside the bin and the sand is in a pocket and the collapsing or oozing of sand would literally erode it from under the bin, Now I understand that rock would make a solid base material or compacted clean rock even better but whats to stop the sand from shifting, expecially when saturated with water. We had to install some drain tile around the bin and the ground was so sandy we had to use socked tile to keep the tile from filling up with sand, and this is an acceptable base material for a bin, I"d think bedrock would be better, can anyone educate me on this.

 

[Impact]

You're right in one regard, sand is OK as long as it's contained. I've been on projects they've used rock around the perimet to contain the sand, with sand in the middle. I've also built a few tanks on the edgeof the Mississippi river where the ground has a tendancy to be sandy, and shift. Engineer speced it out expecting 12" of settlement. Again, 12" was OK if properly planned for, and it's not differential settlement. We shot grades on the structure before it ws filled, and after. It settled 12" in spots and as little as 9" in spots.

 

[watglen]

Impact.

I would say a soil bearing study is a must, and nobody in thier right mind would go without it on a bin of that size. Especially on the soil you describe.



You can do the math easily enough. Take the total weight of the bin and divide by the total area of the foundation circle. That gives you the pounds/sqr ft you need to support. Bin structures normally support the internal weight uniformly over the floor area. If your calculated load exceeds the load bearing capacity of soil, she'll settle. Of course, it won't just go down nice an even like. It'll start to drop on the edge somewhere, cracks will open in the concrete. It will take several years likely to get to the point of sidewall rupture. But by then you're (the owner) screwed because it takes 10 times as much to fix it as it takes to do it right in the first place.

You only get once chance to do a foundation right.

If you could find some pics of bin wall failures on the web, you should be able to convince the man of your point of view. Keep in mind though that an engineer is going to design a foundation structure so overblown you won't believe it. That has been my experience.

 

[watglen]

I took a quick look at the gsi website, that bin you're talking about is a 27 ring monster. Before i go any further, i want pics of her when she's done!

Your 20,000,000 pound estimate is likely right including the weight of the bin and foundation. Divided over 5280 sqr ft of foundation, and you have just under 3800#/sqr ft. That is higher than some of the best soils.

I simply can not believe even the bin provider will allow the bin to be erected without and engineers stamp on the foundation. That is just insane.

What i have seen done in this situation is the engineer will widen the bearing area by building a concrete apron around the the bin. I know of a 30' silo with a 60' diameter foundation. This was done because the bearing tests came up short. The foundation cost the same as the rest of the silo because it was thick with concrete and rebar.

If i was you, i would swallow the engineering costs on it and have your tests done, knowing full well that the soil is going to fail, and your "farmer" is going to balk at the solution.

What happens after that won't be your fault. You can walk away with a solid reason, or you can convince him to do the right thing. Either way you don't come out looking bad, or liable.

Good luck, and post pics!!!

 

[Impact]

Here's some photos of a project a couple years ago. Soil borings came back at 1,000# or so. We did 18" auger casts 58' deep. There were about 210 as I recall on a 105' diameter tank. Capped the top of the auger casts with a 2' thick slab 120' in diameter. Placed 8' ringwall type foundations on top of that.

Oops...going to have to work on the photos.

 

[Impact]

Ok, didn't want to start a new thread with this one, so just posing it here.

I get a call yesterday, (while I was running a crane on a job, but was idle at the time) from a guy wanting me to offload a locomotive from a flat bed trailer. Evidently it's going into a local new park/museum under construction. I have a 100T and a 60 ton hydro. My first question of course is...what's it weigh? 70 tons. My first comment was, there's NO WAY my 100 T will do that, you need a 200T. He starts argueing with me saying, you can get right next to it, and we only have to lift it high enough to clear the trailer, then right down to the ground. What makes people want to argue? I got back to the office and checked my load charts using both cranes. It takes 12' just to celar the outriggers. I'd guess 18' radius..My 100T is good for 105,000 pounds. The 60 is good for 60,000-65,000. 105,000 + 65,000 = 170,000 or 85 tons. Still, the guy needs to rent a 200 ton crane. Here's my take on it.

A 200 T will be as cheap or cheaper than me sending both cranes.
One foot makes a HUGE difference. The reality of actually getting an 18' radius? I'd allow 20-22'.
How can I be assured that the 100T will get the 105,000 and not 120,000 or 75,000.
If the 100T has 75,000 , the 60T is overloaded.
I don't even have rigging for that sort of load.
I don't know where to attached to a locomotive.
I think this guy is a broker somewhere trying to make a deal. I hate those guys.

How would you handle this situation? I just told him I can't do it, and refuse to argue with him.

 

[stock]

Impact don't forget the spreader bar /frame & rigging.............................

 

[DirtHauler]

Can you go rent a 200T and do the lift for him, and bill enough to cover the cost and add some money for your trouble?

 

[Impact]

Impact don't forget the spreader bar /frame & rigging.............................

Exactly. My spreader bar isshop built and I pick 10,000-20,000 pounds with it. Not designed for that kind of weight

 

[Randy88]

As far as I'm concerned you handled it right, just refused to do it and hang up, as for argueing with anyone on the phone over what your machines are capable of, I wouldn't waste my time, I tell them to just find someone else, I'm busy and that usually ends it there, remember your probably not the only one who's maybe wondering what kind of idiot they are, the ones with a crane capable of doing the job probably told them off aready and now they are desperate to get it done any way imaginable, and if something goes wrong, they are not responsible, you are.