I belive a geotechnical engineer shld be contacted for dt, he will be d one to analyse d soil n recomend the foundation type to be use from his analysis and shld wrk hand in hand with the structural engineer to ve d most econimical foundation but my opinoin is a raft foundation shld be use is more economical than pile.
Engr David Jacob

LasBonBoi:
As a geologist that you are, I will believe its unethical professionally to make such specifications.

and that's why I instructed him to consult me, if need be for more articulate details

richeyy:

Thank you! I was beginning to wonder what a geologist has got to do with investigating ground conditions for foundation design

I as a Geological engineer can do ground investigations with my small background in;

1. Soil Mechanics
2. Rock Mechanics
3. Foundation Engineering
4. Rock Mechanics
5. Strength of materials I & II
&
6. Fluid Mechanics I & II

All with hands on and practical experience.

Mr Aboki:

I as a Geological engineer can do ground investigations with my small background in;

1. Soil Mechanics
2. Rock Mechanics
3. Foundation Engineering
4. Rock Mechanics
5. Strength of materials I & II
&
6. Fluid Mechanics I & II

All with hands on and practical experience.

you'r right bro, all that falls under Engineering and structural geology, let's make them understand

@Reference,
In this case at hand, if pile is used if it would be to transfer the load to a good soil strata that has the capacity to bear the load from the structure, you cannot talk of densifying (or compacting) a cohesionless soil.

wandevincent: and that's why I instructed him to consult me, if need be for more articulate details

You are a good man, I believe you want to help in rightly guiding the ignorant op. Good to have people like you! However, I have reasons to believe that readers of this thread and the op who happens to be challenged with decisions like this would be misguided by giving uninformed foundation design specifications. Hope you understand my point.

LasBonBoi:
You are a good man, I believe you want to help in rightly guiding the ignorant op. Good to have people like you! However, I have reasons to believe that readers of this thread and the op who happens to be challenged with decisions like this would be miss guided by giving uninformed foundation design specifications. Hope you understand my point.

I perfectly understand u, I was only recommending and I expect him to at least use his discretion where necessary.Hope u do get me too?

wandevincent: I perfectly understand u, I was only recommending and I expect him to at least use his discretion where necessary.Hope u do get me too?

Yes I do, thanks wandevincent. Cheers.

LasBonBoi:
Yes I do, thanks wandevincent. Cheers.

you'r welcome brother

Fadelex:
the length varies from 300mm to 3.0m and you said they don't have to reach d bearing strata, then what's d essence of using pile when it won't reach d bearing strata.... bearing strata in dis case could be a rock or more solidified soil... if the pile is gonna be suspended then there's no case using it cuz the aim of d pile has been defeated

The essence of using Pile is not only/always to reach a bearing strata, some piles are held by friction exerted around it as it goes dipper into the ground, the frictional force will be so strong enough to support the pile just as a bearing strata would.

Rashzubair:


The essence of using Pile is not only/always to reach a bearing strata, some piles are held by friction exerted around it as it goes dipper into the ground, the frictional force will be so strong enough to support the pile just as a bearing strata would.

sure....but the major reason of pile is to transfer d load (especially dead load) to the bearing strata

Bro remove your mind from raft foundation since the area there is swampy, and the building is also highrising structure(more than 15m high). The reason for good soil test is to knw more of the bearing capacity of the area, to knw the depth at whch the stable physical element of soil wl b goten(mainly shale). These wl help in d design of pile(lenght and diameter).

Realdon1: Bro remove your mind from raft foundation since the area there is swampy, and the building is also highrising structure(more than 15m high). The reason for good soil test is to knw more of the bearing capacity of the area, to knw the depth at whch the stable physical element of soil wl b goten(mainly shale). These wl help in d design of pile(lenght and diameter).

bro, d building is a single storey building

hey guys! Nice to see the house growing. But why think of pile foundation when you are planing to build just a storey building. Pls tell your friend to use raft foundation without delay. Pile foundation is for high rise building.

lust20: hi sir, am a Quantity Surveyor, it all depends on d capacity of d soil, d type of soil wi determine d type of foundation dat shud b put in place. for more info contact me on 08180011419

is not bill of quantities o.

What an interesting topic.

The suggestion of removing the surface soil till you get to sharp sand seems expensive to me.

What if the land has been filled with both broken blocks and red sand for 4 years do you still recommend Pile foundation for a single duplex.

Soil test result shows 9m, 12m and 14m at different points and recommended pile foundation. Meanwhile my neighbor did raft with 4 flats and duplex together and the building is still standing. No shaking. In same estate another neighbor did pile foundation and the building is tilted to the right and sinking also.

Which way will I go?

Alot of valid points have been raised here.

I will take it a bit further and spell it all out for you. Basically from the information you provided, you are looking at three options for your proposed building: deep foundations (i.e steel/concrete piles extending to the bearing depth), drilled shafts (same concept as deep foundations with shorter piles), or a rafts/mat foundation.

Now, your building can be supported on mat/raft foundation; however, you will have to put into consideration the cost of excavating, to the bearing depth, the entire surface area (plus some) of your building. Judging by the height of your building, this may cost alot of time and money. You will also have to consider the added cost to buy all the concrete needed for the mat foundation and factor in the amount of disturbance this option will cause to your surroundings during construction (excavation).

Drilled shafts on the other hand may cost as much as mat foundation depending on the availability of material and/or equipment. Using this option, you will eliminate the added time necessary for excavation as well as limit the disturbance to your surrounding during construction. However, you will have to confirm with a registered geotechnical/foundation engineer that the soils at your proposed site can indeed support your building on drilled shafts.

Finally, your soils have to be really bad to require that a 5 story be supported on deep piles. Now, I have no idea what your site looks like so this scenario is not entirely impossible. Depending on how deep your piles have to be, this option can definitely be more expensive than using mat/raft foundation.

I advice you to put all the points stated into consideration when making your final decision. The foundation recommendation for your building should be provided by a registered geotechnical/foundation engineer. The geotechnical/foundation engineer should carry out the necessary soil test/analysis needed to make his recommendations. Although using a registered geotechnical/foundation engineer may costs a bit more, having one provides you the option of who to hold if your building should ever fail as a result of a foundation issue *God forbid*. I hope this clears things up for you. God bless Nairaland

Irokoroots: Alot of valid points have been raised here.

I will take it a bit further and spell it all out for you. Basically from the information you provided, you are looking at three options for your proposed building: deep foundations (i.e steel/concrete piles extending to the bearing depth), drilled shafts (same concept as deep foundations with shorter piles), or a rafts/mat foundation.

Now, your building can be supported on mat/raft foundation; however, you will have to put into consideration the cost of excavating, to the bearing depth, the entire surface area (plus some) of your building. Judging by the height of your building, this may cost alot of time and money. You will also have to consider the added cost to buy all the concrete needed for the mat foundation and factor in the amount of disturbance this option will cause to your surroundings during construction (excavation).

Drilled shafts on the other hand may cost as much as mat foundation depending on the availability of material and/or equipment. Using this option, you will eliminate the added time necessary for excavation as well as limit the disturbance to your surrounding during construction. However, you will have to confirm with a registered geotechnical/foundation engineer that the soils at your proposed site can indeed support your building on drilled shafts.

Finally, your soils have to be really bad to require that a 5 story be supported on deep piles. Now, I have no idea what your site looks like so this scenario is not entirely impossible. Depending on how deep your piles have to be, this option can definitely be more expensive than using mat/raft foundation.

I advice you to put all the points stated into consideration when making your final decision. The foundation recommendation for your building should be provided by a registered geotechnical/foundation engineer. The geotechnical/foundation engineer should carry out the necessary soil test/analysis needed to make his recommendations. Although using a registered geotechnical/foundation engineer may costs a bit more, having one provides you the option of who to hold if your building should ever fail as a result of a foundation issue *God forbid*. I hope this clears things up for you. God bless Nairaland

Thanks for ur input.
Propose building is one story

seedgie: hey guys! Nice to see the house growing. But why think of pile foundation when you are planing to build just a storey building. Pls tell your friend to use raft foundation without delay. Pile foundation is for high rise building.

No sir, piles can be used to support ANY kind of load. Those shanties built on the lagoon are resting on 'piles'. The shacks weigh practically nothing. Why don't they use rafts: one - cost, piles are cheaper. Two and you raft lovers better know this. If the density of the soil changes particularly if the density falls due to water ingress (flooding), the raft can fail by submergence and this has happened in Lekki and happened in Bayelsa during last year's flooding.

I thank all for inputs made here. A lot hv been said and learnt from all the views advanced here by diff pros in this field.

I also know many more pple hv benefited immensely from d devise views advanced here.
Thank u all for ur time.

Cypost: Abt to commission a soil test, will come back with the result when out.

Wht do one look out for when doing soil test.
Everybody claims professional atimes is difficult to differentiate quack from pro.

I also will like to do a soil test. Please how did you go about yours? I'm looking at 2 storey building.

seedgie: hey guys! Nice to see the house growing. But why think of pile foundation when you are planing to build just a storey building. Pls tell your friend to use raft foundation without delay. Pile foundation is for high rise building.

OP, to be sincere and candid with you the more advice you seek the more confuse you ll become. I wish you take Mr Seedgie advice and regret it for live, but before you take this advice i want you to take a s drive through some Area like Arowojobe in Mende Area of Mary Land, Osborne foreshore Estate, Panti at Yaba (At Panti Multi storey building completed were pulled down for pile failure, and several house upstairs around that area have equally failed. In many of this area i just mention there are several buildings upstairs on raft that have failed woefully, i will find some of the pics i took in the course of my research on why structures faills in Lagos and post some here. Some house within the slum area of lagos state were supported by the so called wooden pile and yet they are small small houses. I am given you my vivid advice as an authority in this field by God's Grace.

x-fire:

I also will like to do a soil test. Please how did you go about yours? I'm looking at 2 storey building.

U ve to contact pple that does it. Ask around and discuss with them. Some pple on this post appear to do it or know more abt it, u can also contact and discuss further with them.
We ve not done yet and don't know much too, but in discussion with someone who claim he does it well
Goodluck to u on ur project

I am given you my vivid advice as an authority in this field by God's Grace.[/quote]
Oracle have spoken!

Get a soil test done, and also get a sound COREN certified Structural Engineer to do the drawings for you based on the report of the soil test.
NO AMOUNT OF MONEY IS TOO MUCH for a SOUND FOUNDATION so as to enjoy your house.

Pile foundation is always the ultimate foundation solution, even if its a storey building.
A lot of houses in Akoka, Yaba which employed Raft are now TILTING, as well as some areas in Sabo.
Take Professional advice from Senior people here who have Experience in construction.

Goodluck to you,

Kkonsults.

Mr Aboki:


For the purpose of being proper, a Structural Engineer should not be the one to design a foundation plan. Foundation analysis should ideally be done by a Foundation engineer. Its based on the findings of the foundation Engineer that the Structural guys would base their design.

You are right except for the bolded part which i will prefer the other way round. The foundation will be designed to safely transmit the entire loads coming from the superstructure. As such, the foundation or geotechnical engineer will require the total superstructure load for the foundation design.

It is not your responsibility or anyone for that matter, other than the Geotechnical/Foundation engineer to carry out the geotechnical investigation, recommend type of foundation and design the foundation. In my opinion, it will likely not be a pile foundation but rather a raft for the type of structure you require. Also note that the test required is geotechnical not geological, geophysical or whatever.

What i will do is to give you the order of professionals you will be meeting. Make sure that 3 and 4 are reputable and registered with NSE, COREN or any other recognized professional bodies.

1. Land Surveyor - he will give you the coordinates of your property boundaries for site plan/layout as well as elevations for site drainage design.
2. Architect - he will produce pictorial designs of the structure
3. Civil/Structural engineer - he will analyze and design structural elements for the stability of the building and determine total looad that will be transmitted to the ground from the building weight and all possible loading due to human activity that the building will be subjected to during its life.
4. Geotechnical/foundation engineer - he will test for the soil bearing capacity and design foundation to bear the loads expected from the superstructure.
5. Quantity surveyor - he will determine all quantities of materials required for the completion of the building project and the current market price for such materials and ultimately arriving at a total expected cost of project.
6. Contractor/Building engineer - he shall be responsible for construction of the building under the supervision of the Foundation and civil engineer.

Also note that, mechanical and electrical designs may be required before the civil engineer carries out his design in cases where a mechanical or electrical equipment with certain weight and vibration is to be used especially on the superstructure. An example is a central cooling system sometimes placed on roof slabs.

Mr Aboki:

I as a Geological engineer can do ground investigations with my small background in;

1. Soil Mechanics
2. Rock Mechanics
3. Foundation Engineering
4. Rock Mechanics
5. Strength of materials I & II
&
6. Fluid Mechanics I & II

All with hands on and practical experience.

opalu:



Geologists are specialists when it comes †̥☺ soil, rocks, etc. Most Civil Engineering students run borrowed courses fø̲̣̣я̅ some semesters called 'Engineering Geology'. Carrying out Soil test and Analysis and preparing the reports can be done by Geologists (atleast they study those things!).

Civil Engineers who specialize as Geotechnical Engineers though can also do soil tests but they focus more on Heavy groundbreaking constructions like dams, tunnels, bridge foundations etc. Atleast those I know.

You guys should know that there is a difference between a geologist & a geological/geotechnical engineering, just as there's a difference between a computer scientist & a computer engineer. We're talking about foundation design here; a geologist is a scientist who is knowledgeable about the earth and it's content, he doesn't have the technical wherewithal to design for foundation.

I am a civil engineer, in my years of practise, i ve never heard or seen anyone use pile foundation for a single storey building. No matter how bad the soil is, raft is best recommended. I always advice clients building in very swampy area that are not too sure of the soil bearing capacity to the soil replacement. Soil replacement is done by replacing the top soil of your land with solid sharp sand to a depth of about 2m, depending on how poor your soil is. Upon doing soil replacement, a proper compaction must be done. After which you can use a properly reinforced raft of about 1m for your foundation. Soil replacement is the guaranteed way to improve your soil irrespective of how poor it is. This way i can guarantee you of a stable structure free from sinking or foundation tear. You can contact me on udoka.banye@yahoo.com for further advice

Fadelex: the engineer that quoted for pile foundation for a storey building is definitely a quack.... unless you are building an island in a river, Pile foundations are long, slender, columnar elements in a foundation that are installed into the ground.
They aretypically made from steel or reinforced concrete and possibly timber . A foundation is described as piled when its depth is more than three times its breadth.
Pile foundations are principally used to transfer the loads
from a superstructure, through weak, compressible strata
or water onto stronger, more compact, less compressible
and stiffer soil or rock at depth, increasing the effective size of a foundation and resisting horizontal loads

raft foundation is suitable for d design

I'm sure you are not talking from practical experience and you are not familiar with the area. I stand to disagree that the guy is a quack.

Consult Engr.
Omion Emmanuel

No 2 Bade Oyeleye street,

Off Command road

By Unity Busstop

Diamond Estate a.k.a Fashola Estate

Ipaja, Lagos.

Call 08026228682,08165678000 or omionick@gmail.com

Reference:

No sir, piles can be used to support ANY kind of load. Those shanties built on the lagoon are resting on 'piles'. The shacks weigh practically nothing. Why don't they use rafts: one - cost, piles are cheaper. Two and you raft lovers better know this. If the density of the soil changes particularly if the density falls due to water ingress (flooding), the raft can fail by submergence and this has happened in Lekki and happened in Bayelsa during last year's flooding.

@SIR BANYE; nice one

I am a geologist with key interest in engineering geology/ foundation design. i know what am saying, raft foundation has never failed me but it doesn't make it the best. in foundation design you put the nature of soil, structural load & the economics of the foundation design into consideration before you adopt a suitable foundation for the building. pile foundation is too expensive for the structure (a storey building). have u asked your self why the two engrs defer on the type of foundation to adopt without carrying out soil test?