Piling cost and experience using piles

[JestSetter]

The land we have is near a stream (about 30 m.) and rice paddies are about 20 m. away. I went to visit a Thai owner of a restaurant/inn that is 2 level high (and whose property also is flanked by a canal) and that is about 500 m away. He decided to use piles and recommended we did too. He suggested not to do a soil sample as he figured it would most likely reveal that we would need piles as our house has 2 levels too. We would save 15000 B. He recommended to use 12 of them for a 80 m2 area, which seems to coincide with the number of footings. We do not know where the rock is in our land, but he remembered his being about 8 m. long. Looks like the cost for piling 12 piles would be around 100 K. 

 

If you had to use piles, can you please share your story and tell us the price to put them in.

 

I never had to do this, but I have a few question related to the operation when the solid ground below happens to be uneven. Do they fill the hole to to even it out? With what? gravel? Concrete/cement? There are different shapes of piles too. Not sure why? How are the piles tied in to the foundation slab? We are told that they come in set lengths. Do they cut the lengths of those? Do those prefab piles have rebars in then? What type of concrete grade?

[JestSetter]

Addendum: A conversation with the man that does the piling (and the soil testing) seems to indicate that a soil sample is needed even if the piles hit the bottom rock. Assuming that the piles are connected at the foundation level and that unevenness of the rock is dealt with, I am surprised that they still need to test the soil. I hypothesize that perhaps the lateral motion of the pile needs to be controlled. By knowing the "tension"  that the soil will impart on the piles (laterally) they will know the shape and diameter size of the piles to be used. Is that what it is?

[Artisi]

Most driven piles in Thailand are "friction piles" which means they are not driven to rock but driven to sufficient depth that the relies on the friction between pile and below ground material being able to support the down force of the structure. Usually the local "pile driving" contractor has the experience in the area to give advice on depth, as for the number of piles that really depends on the size of the building - if in doubt on the number, you should consult an engineer. 

Usually the piles will end up at various heights above ground, these are then cut off to the same level and steel reinforced pile caps poured to a common height to suit. 

[JAS21]

Here is an option ... https://www.youtube.com/watch?v=ecZp53Evj1k   used them for our carport.

 

Across the road I saw them use 20M piles (Bangkok) ... they used the drill, tube and pour concrete method.

 

[JestSetter]

11 minutes ago, JAS21 said:

Here is an option ... https://www.youtube.com/watch?v=ecZp53Evj1k   used them for our carport.

 

Across the road I saw them use 20M piles (Bangkok) ... they used the drill, tube and pour concrete method.

 

Thank you. That is exactly what I was looking for. These are called helical piles. That seems like a smart technology. But I am told they are expensive. I will email them and find out.

 

The company you find that uses helical piles is in BKK. Now, the BIG issue is that I don't live in BKK, but Chiang Mai. Is there someone who has the machine to put this into the soil here? I will email them. Thank you.

[JestSetter]

1 hour ago, Artisi said:

Most driven piles in Thailand are "friction piles" which means they are not driven to rock but driven to sufficient depth that the relies on the friction between pile and below ground material being able to support the down force of the structure. Usually the local "pile driving" contractor has the experience in the area to give advice on depth, as for the number of piles that really depends on the size of the building - if in doubt on the number, you should consult an engineer. 

Usually the piles will end up at various heights above ground, these are then cut off to the same level and steel reinforced pile caps poured to a common height to suit. 

That's interesting! They rely on friction. I wonder how much friction they can "create".

[JestSetter]

I wonder what is most effective beside pile end-bearing piles and helical piles. Is increasing the surface area out of concrete (increasing the surface tension) of the foundation area outside the area of the house also effective in preventing settling, cracks,...?

[Artisi]

24 minutes ago, JestSetter said:

That's interesting! They rely on friction. I wonder how much friction they can "create".

At the correct surface area driven to the right depth sufficient to support your house. 

[Artisi]

1 hour ago, JestSetter said:

I wonder what is most effective beside pile end-bearing piles and helical piles. Is increasing the surface area out of concrete (increasing the surface tension) of the foundation area outside the area of the house also effective in preventing settling, cracks,...?

For a house, I would think there is virtually no difference between driven and screwed piles as far as load bearing is concerned. 

In reactive soil, you are not relying of foundation surface are  to support the structure - you are relying of the piles. 

As you seem to have a number of concerns, I would suggest hiring a competent architect or engineer to put your worries at rest.  

[JestSetter]

1 hour ago, Artisi said:

At the correct surface area driven to the right depth sufficient to support your house. 

I was looking for a formula. 

[JestSetter]

This is my last question. I am trying to understand the physics behind those concrete piles. I am just curious. 

 

So, If my eyes are not failing me, even though those concrete piles do not seem to be shaped like nails, but more like elongated rectangular prisms, the soil around them would still exert enough friction to hug the surface of the pile after the hole has been made. Is this correct?

[JestSetter]

1 hour ago, Artisi said:

For a house, I would think there is virtually no difference between driven and screwed piles as far as load bearing is concerned. 

In reactive soil, you are not relying of foundation surface are  to support the structure - you are relying of the piles. 

As you seem to have a number of concerns, I would suggest hiring a competent architect or engineer to put your worries at rest.  

Thanks for the explanation. Fascinating.

 

I will. Thanks.

[Artisi]

12 minutes ago, JestSetter said:

This is my last question. I am trying to understand the physics behind those concrete piles. I am just curious. 

 

So, If my eyes are not failing me, even though those concrete piles do not seem to be shaped like nails, but more like elongated rectangular prisms, the soil around them would still exert enough friction to hug the surface of the pile after the hole has been made. Is this correct?

in theory - yes.

One of many articles - please enjoy ?

https://bestengineeringprojects.com/pile-driving-formula-engineering-news-formula/

[sirineou]

 if I remember my physics a long time ago at Uni, there is a coefficient of friction consideration,  where the ratio of force necessary to move  one surface  against the other and the pressure between then is considered in making calculations. I suspect the soil test required to determine the length of the piles necessary 

I dont remember the price because it was included in the whole build price.

We hit berrock after a few meters and you could feel the ground shaking  as the piles were hitting the rock and were not being driven anymore so we stopped driving as not to damage them, then a hole was dug a meter deep if i remember correctly, cut the piles at the bottom of the hole , a 1x1 m pad was poured and a footing column was poured to the desired height at ground level. 

and then beams to support the ground slab.

Good luck with your build. Look forward to seeing a thread of it in TVF

[BEVUP]

There is an equation, like I had seen when the piles were driven for a wharf

 

It went something like this 

 

After 5 belts with the Pile Driver, if they didn't go down a centimeter or 2 they were fine

[Artisi]

8 minutes ago, BEVUP said:

There is an equation, like I had seen when the piles were driven for a wharf

 

It went something like this 

 

After 5 belts with the Pile Driver, if they didn't go down a centimeter or 2 they were fine

Of course but it depends on the mass of the driving weight and the drop distance. 

[JestSetter]

It seems to me that extending the concrete foundation outwards (in a continuous manner with rebars, of course) should be a much more efficient way to stabilize or minimize settling than piles (if surface tension/friction are in question), if, of course, roof water is drained properly and there is not a river passing under the house, among other issues, like adding more weight, especially on one side of a house by adding another room,....

 

Do you think that it would be a better roi than piles (unless those piles are known to be touching terra ferma)? Would it make sense to make the "skirts" lighter as well? 

[sometimewoodworker]

2 hours ago, JestSetter said:

It seems to me that extending the concrete foundation outwards (in a continuous manner with rebars, of course) should be a much more efficient way to stabilize or minimize settling than piles (if surface tension/friction are in question), if, of course, roof water is drained properly and there is not a river passing under the house, among other issues, like adding more weight, especially on one side of a house by adding another room,....

 

Do you think that it would be a better roi than piles (unless those piles are known to be touching terra ferma)? Would it make sense to make the "skirts" lighter as well? 

You should really be talking to a structural engineer about that. The types of foundation suitable depends on a number of factors soil composition is just one. A structural engineer will know the different options available in the area you want to build.

 

As an example if you don't use piles for a reasonably sized house in Bangkok you may well soon find you have a concrete submarine!

[eyecatcher]

Personally I think there is a complete unnecessary overuse of piles particularly in Chiang Mai.

A lot of it is due to the amount of filled plots, another complete waste of money in 9 cases out of 10.

so, they fill a plot, sometimes over 2m and then "have to" drive piles through it all because you cannot build standard beam foundations on fill unless you want to see your house tipping in two years time.

 

its much easier and very likely more effective to set out  several pad foundations at say 1.5x1.50 or 2x2m and set up the stub columns from there.

you can fill up thereafter as much as you like, its not going to matter as the building already has its footings in.

Just my two penneth and that's exactly how I designed my footings.

 

as regards general driven piles its not a case of driving until the cows come home, not saying here but in the more advanced world the computerized reading on the pile driver will be computing the bearing pressures, the loads it can carry, sound waves through the pile itself, there should be no guesswork from a site operative.

[JestSetter]

Thank you all for the advices. Soil test is next week and I will try to talk to an engineer. I must say I am at a loss as to where I can find one as the one I had left after the plans where made and the permitting took place.  Would the permit office have a list of engineers available?

 

Last question: I am getting quotes for twelve 8 meters long piles (20 or so cm wide) for 75 K B. including everything, but excluding soil testing (15 K for one hole). I am not sure if extending the foundation by, say, 2 meters around the house ( about 60 m2) is cheaper by a significant number. Any thoughts?

[eyecatcher]

21 minutes ago, JestSetter said:

Thank you all for the advices. Soil test is next week and I will try to talk to an engineer. I must say I am at a loss as to where I can find one as the one I had left after the plans where made and the permitting took place.  Would the permit office have a list of engineers available?

 

Last question: I am getting quotes for twelve 8 meters long piles (20 or so cm wide) for 75 K B. including everything, but excluding soil testing (15 K for one hole). I am not sure if extending the foundation by, say, 2 meters around the house ( about 60 m2) is cheaper by a significant number. Any thoughts?

You will find that 8m piles are quite short and get even shorter when they crop them leading me to think there are other options.

where in CM are you, the district office will be able to guide you to an i dependent engineer, and their own in house engineers may be able to help also.

If you are getting a soil analysis you will need the engineer to interpret the results.

[eyecatcher]

Widening the footing is just a logic idea you have but wide strips, standard strips, rafts, pads and piles all have their own criteria.

Piles are used for small buildings on really bad loose ground or very heavy high rise that will just puncture tbrough good ground.

Then there are other soil types that are not very loadbearing but still stable and unlikely to wash away, then you design a raft to float and act as one.

Rafts rarely used here, again they are obsessed with flooding and lifting everything up yet rafts are perfect here.

Pads can be used on typical good bearing soils and clays which are found in the top 2m of depth and save a lot of money agin a piling outfit.

 

Your start is a soil test, and that normally can be done with a jcb. Three test pits, after ten minutes standing watching an engineer can see the soil structure, job done. Augering a soil core can be doone if you see the jcb is diggi g through sand. Augering 20tests all over an 80m2 footing is overkill i.m.o

[JestSetter]

4 minutes ago, eyecatcher said:

Widening the footing is just a logic idea you have but wide strips, standard strips, rafts, pads and piles all have their own criteria.

Piles are used for small buildings on really bad loose ground or very heavy high rise that will just puncture tbrough good ground.

Then there are other soil types that are not very loadbearing but still stable and unlikely to wash away, then you design a raft to float and act as one.

Rafts rarely used here, again they are obsessed with flooding and lifting everything up yet rafts are perfect here.

Pads can be used on typical good bearing soils and clays which are found in the top 2m of depth and save a lot of money agin a piling outfit.

 

Your start is a soil test, and that normally can be done with a jcb. Three test pits, after ten minutes standing watching an engineer can see the soil structure, job done. Augering a soil core can be doone if you see the jcb is diggi g through sand. Augering 20tests all over an 80m2 footing is overkill i.m.o

Thanks. Very helpful.

 

jcb?

[eyecatcher]

1 hour ago, JestSetter said:

Thanks. Very helpful.

 

jcb?

You have just revealed your hand there.

 

I would not be the first to suggest, you seek professional advice here on in; and I say that with the greatest respect.

pm me, as a neighbor in your locale you may find a one to one useful

[sometimewoodworker]

14 hours ago, eyecatcher said:

Augering a soil core can be doone

It looks like this

 

University professor and students doing a soil compression test.

[Huckenfell]

What i the cost of steel for one concrete post in a ground level house. In Isaan.

 

[Artisi]

9 hours ago, Huckenfell said:

What i the cost of steel for one concrete post in a ground level house. In Isaan.

 

Start a new posting and give a lot more information, what you have asked is meaningless. 

[sometimewoodworker]

18 hours ago, Huckenfell said:

What i the cost of steel for one concrete post in a ground level house. In Isaan.

 

Similar question, how long is a piece of string in Chang Mai? ????

[Artisi]

5 minutes ago, sometimewoodworker said:

Similar question, how long is a piece of string in Chang Mai? ????

Depends if it's a short piece or a long piece. 

PS. or it could a medium piece. 

[Huckenfell]

OK !  What should it cost to place 6 concrete stumps.  I.e  Dig holes place steel in bottom, Mould stumps.