abdulwastecx:


The problem is this type of foundation is not a raft foundation. It is more like beam on grade foundation but we always confused it with raft in this part of the world. The construction techniques and reinforcement pattern of this type foundation is quit different.

All raft foundation must have the beam and slab monolithically cast together and the slab is designed to have contact with the soil with reasonable bearing capacity to support the building , hence excavation must be done to a suitable soil specify by soil investigation. These raft may be only slab (an inverted flat slab) or with beams to reduce punching shear of columns (up stand or down stand beams). That is the major reason why all raft foundation comes with basement.

The type of foundation use for this structure is beam on grade foundation. The settlement problem results from the uniform settlement of expansive clay and not from bearing capacity failure. If water can be avoided along the foundation area then the building will stand

abdulwastecx:


The problem is this type of foundation is not a raft foundation. It is more like beam on grade foundation but we always confused it with raft in this part of the world. The construction techniques and reinforcement pattern of this type foundation is quit different.

All raft foundation must have the beam and slab monolithically cast together and the slab is designed to have contact with the soil with reasonable bearing capacity to support the building , hence excavation must be done to a suitable soil specify by soil investigation. These raft may be only slab (an inverted flat slab) or with beams to reduce punching shear of columns (up stand or down stand beams). That is the major reason why all raft foundation comes with basement.

The type of foundation use for this structure is beam on grade foundation. The settlement problem results from the uniform settlement of expansive clay and not from bearing capacity failure. If water can be avoided along the foundation area then the building will stand

semitunde:


Nice. Been a while I discussed construction/structural technicalities. Also, its been a while I made the post you responded to and can't remember the whole story but let's discuss based on your reply.

I don't understand the bolded.

I also don't get what you mean by "beam on grade foundation". I may be wrong but I'm not sure there's anything like beam on grade foundation. There's "grade beam" which is a component of mostly deep foundations like pile foundation.

A grade beam doesn't transmit loads directly to the ground. It transmits to the pile caps or piers as the case my be. It should withstand bending moment and hence the beam has some height. Sometimes as high as a raft beam. So unless the client has some piles there, those may not be grade beams.

I understand that in construction nothing is cast in stone and you can modify solutions to fit problems. But the solutions have to be cost effective. A grade beam in this case may not be cost effective (if it is at all effective).

Cancel "grade foundation", what kind of foundation do you again think is there?

The closest to what you might be talking about in terms of withstanding load pressures and load bearing walls is the use of is "spread footing". A shallow foundation system like the op should use a spread footing while a deep foundation should use a grade beam.

The height of the beam (as I can remember, I've not checked) looked more like for a raft like foundation. A spread footing would have sufficed. More cost effective if anything else.

As for the presence of water, this can affect the bearing capacity of the soil depending on the type that is there. If the channel can be diverted fine, since the building had already been constructed.

What do you say?

Qc1:


Every time I think I've solved the water problem, it keeps getting back. And brabus really messed me up with this one, he saw the other houses in the neighborhood and yet came up his? Anyway, all I need is a solution. The house seems to have stop sinking just before the roofing reinforcement. However, I now have water on my floors coming out just under the DPC to the surface. I've been told that it's because brabus failed to add just one more coach in height of the raft that's causing the problem. So far, we've raised the level of the DPC a little higher but I still need a permanent fix.

abdulwastecx:


You are right it can also be called grade beam and it can also be a component of deeper foundation ( pier and beam foundation) but can also stand alone, it can sit directly over loose soil or dry soil in a building construction.
This type of foundation is similar to wide strip foundation but the difference is that this foundation consist of heavy and well reinforced concrete deep beam that are designed to minimize deflection instead of transferring loads directly to the ground below.
This type of foundation is suitable for uniformly distributed load ( load bearing wall ) than point load (load from columns/pillars).

I still stand by my earlier assertion that the foundation is not a raft foundation. raft foundation is made up of a slab that must have contact to the soil whose bearing capacity and other soil properties is used for the design, it is not founded on filled soil and mustn't be confused with dpc.

raft foundation is design like isolated pad footings. A raft is use when individual pad will overlap due to low bearing capacity or high load from the columns of the framed structure.
Raft can be classify as : inverted flat slab raft and slab beam raft.

Flat slab raft is founded at a bearing capacity below the ground level at a depth with sufficient soil properties. this foundation is like an inverted flat slab with the contact area between the column and the slab (foundation) is reinforced against punching shear. this foundation thickness may range from 300mm to 600mm depending on the soil properties and load coming from the super structures.

slab - beam raft foundation can be further divided into up stand or down stand beam-slab foundation. in this type of raft foundation, the beams are introduce to reduce the shear stress from the column, the slab are design with contact pressure from the soil acting on the slab. The slab is design liken normal solid slab but up side down. The load from this slab are then transferred to the beam (like normal slab load on beam in normal suspended floor). The down stand beam is advantageous in area where basement is required while up stand beam is advantageous where only utilities is concealed underground. The major advantage of up stand BEAM-SLAB RAFT over down stand BEAM-SLAB RAFT is uniform settlement.

Note: ALL RAFT FOUNDATION COMES WITH A BASEMENT
ALL RAFT SLAB ARE FOUNDED BELOW THE NATURAL GROUND LEVEL

olumide4christ:


[b]What you have sketched or proposed here is a CELLULAR RAFT FOUNDATION, mostly used in water logged areas or where basements may be required for certain purposes. It can also be used where possible as a substitute for pile foundation, dependent on some factors. A case in point is Guaranty Trust Bank branch at Orile, Lagos, just before Alaba Suru/Eleganza junction. That was the exact type of foundation used for the building (I did some work for the main contractor on that project). It was a substitute for pile foundation dependent on some factors, because other buildings on that axis are constructed on pile foundation due to the soil characteristics. Funny enough, a few years later (2014-2015), I was the QS on the Diamond Bank branch by Eleganza junction, a few blocks from the GTB branch. Pile foundation was used throughout in that project.

The CELLULAR RAFT FOUNDATION should have done the trick on the Ikorodu mansion, though the cost would have been a major issue. NOT A SMALL THING OO![/b]

P291:
A cellular raft would have been perfect as the basement can give you a leeway to control underground water and seepage; and the beam serves also as a retaining wall.

But in this case; the grade beam foundation could have worked in order to save cost had it been soil investigation was done to determine the depth at which the soil have a good bearing capacity, having its minimum shear strength, or the beam penetrating into a properly compacted structurall fill.

It is not how high the depth of ground beam above the natural ground level that saves the building as most people thought but the depth at which it penetrates to a compacted structural fill or a competent natural soils. The saving grace for some buildings in part of Lekki was because of the presence of less expansive soils in some of this terrain, so structural loads can 'at least' be supported by this grade beam foundation with a spread footing not the 'so-called' raft.

Qc1:
The first pic show Muyesky doors, second pic display the master POP bedroom and the third was is my 1st (main) living room.


The last picture display the soak away reinforcement behind Qc-1.

abdulwastecx:


I am happy a civil engineering is in the house.. . That is what I have been trying to explain. My sketch above is not cellular raft, though it may look like one. a cellular raft will have two layer of slab, the upper layer (not to be confused as DPC will also be reinforced to be part of the foundation. The volume of the basement is stabilizing factor and the basement is not put into use.
A sketch below showing a typical cellular raft.

These are some of the major differences between cellular raft and other raft.
1. The vertical members are structural wall design to resist lateral (horizontal soil pressure) of saturated (wet) soil
2. The void or basement volume is a stabilizing factor
3. Both the lower and upper part of the raft are foundation member.

karleone:


From the Cellular raft diagram, don't you think it will be wise to compact the voided area?

abdulwastecx:


I am happy a civil engineering is in the house.. . That is what I have been trying to explain. My sketch above is not cellular raft, though it may look like one. a cellular raft will have two layer of slab, the upper layer (not to be confused as DPC will also be reinforced to be part of the foundation. The volume of the basement is stabilizing factor and the basement is not put into use.
A sketch below showing a typical cellular raft.

These are some of the major differences between cellular raft and other raft.
1. The vertical members are structural wall design to resist lateral (horizontal soil pressure) of saturated (wet) soil
2. The void or basement volume is a stabilizing factor
3. Both the lower and upper part of the raft are foundation member.

P291:
You are right with your sketch and your write up Mr Abdulwastecx Sir. Have once seen a good slab and beam raft been done by Mr Aventures before.

abdulwastecx:


Mr Aventures is a very good civil engineer

nabiz:
Good day sir. I have noticed ur beautiful ongoing building project. Pls consider me if want to install a decorative stampped concrete floor.

abdulwastecx:

I may have a stamped concrete job for you

nabiz:
thank in advace sir. i will happy to work with u that u will happily come back here to testify lol

Qc1:



^^^


Take a look at the pictures of the house from page 1, how much do you think I should save up for your service?

nabiz:
lol my oga the price are d same. Just make ur choice and u will have it.

Qc1:







Oga you've not answer my question. Please give me something to work with. I want the land scarping to commence as soon as the raining season is gone.




.





i

nabiz:
COST OF INSTALLING A QAULITY STAMPED CONCRETE FLOOR: (per meter)

If i provide all the materials(both local and foreign imported materials)= 7,000.00.

If you provide all the materials(both local and imported materials)= 2,000.00 per sqare meter.

If you provide the local materials while i provide imported materials,= 4,200.00.

MATERIALS:
Local materials:
(1)Portland cement.
(2)Granite stone(chippings)
(3)Sand
(4)8mm iron rods or iron mesh
(5)Iron bar
(6)Binding wire
(7)Hydrochoric acid
(Diamond cutting dist/blde

Foreign/imported materials:
(1)Original colour hardener
(2)Original acrylic sealer
(3)Antic releas agent.
To see the pictures of some materials, just click on this link https://www.nairaland.com/2934399/welcome-new-construction-site-p.h

Pls feel free to ask me any other questions you may feel like.

MadCow1:



I been wan ask you for quote but I see 7000/sm so I moved on..

nabiz:
sir the 7k is the cost of materials ooo. i may even charge u 1,500 naira is u can provide all the materials above plus concrete mixer. believe me whoever charges u less than 7k is for stampe concrete is charging u on the expence of ur materials, which means he will reduce the ratio of cement to sand, number of iron rod for rainforcement, use of interlocking pigment instead of color hardener, the type of acrylic sealer, use water sealant instead of release agent etc

nabiz:
sir the 7k is the cost of materials ooo. i may even charge u 1,500 naira is u can provide all the materials above plus concrete mixer. believe me whoever charges u less than 7k is for stampe concrete is charging u on the expence of ur materials, which means he will reduce the ratio of cement to sand, number of iron rod for rainforcement, use of interlocking pigment instead of color hardener, the type of acrylic sealer, use water sealant instead of release agent etc

Qc1:



Na so oooo!!!

nabiz:
na so my oga the materials is now very expensive. u can click on this link to see the pictures of the materials so thst u will not fall for all this local contractor.https://www.nairaland.com/2840360/please-visit-office Even if u dont want to give me the job, at least the info will help u in negociating with other clients.

Let me also help u by offering u an average cost of buying a materials that will cover like one hundred sqm i think this will help u.


MATERIALS:
(1)Cements= 65bags@#1,600each= #112,000.00

(2)Granite stone= 15tonnes@ #2,300each= #34,500.00

(3)Transportation of granite from quary= #10,000.00

(4)Stone dust(sand)= 10tonnes@ #2,200.00each= #24,000.00

(5)Transportation of. Stone dust from quary= #7,000.00

(6)Plaster stand= 1 tipper= #14,000.00.

(7)Iron rod or wire mesh= 100meters@ #700.00per meter= #70,000.00

(2mm Iron bar = 6lenghts@ #3,500eah =#21,000.00

(9)Hydrochloric acid= 25lters= #7,000.00

(1)Diamond cutting disk= 3blades@ #2,500each= #7,500.00

(11)Black water-prove= 1role= #3,000.00

(12)Concrete mixer= 2day@ #15,000each day= #30,000.00

Total cost of local materials= #340,000.00

FOREIN MATERIALS
(1)Pave-creat Color hardener= 8bags@ #18500each= #148,000.00

(2) A-Z acrylic sealer= 20liters= #90,000.00

(3)Release agent= 1bucket= #45,000.00.

Total cost of foregn materials= #283,000.00.

Total cost of all materials= #623,000.00.

I dont feed on client material. Sincerity and qaulity job is my competitive strenght..

U can buy all the materials and pay me for my labour alone. If u even need a contact on where to buy the materials, i will give u but on a one condition.
Thank boss

Qc1:



^!^^

I have about 260 sqm. I don't think I can afford you. I don't want to spend more than N1.5m for landscaping.