₦airaland Forum

Charisdesigns:
Last month someone approached us for a hotel structural design with columns span of 7.8m at all sides and going to 4 floors.

After our calculations, we arrive at a beam depth of 750mm with y20 reinforcements.

It was after the whole process that the person told us that, they want to use the design for approval but their intent is to use secret beam (not the one we designed with a beam drop of 750mm) for the entire project, and I almost jump out of my skin upon hearing that. He said they have seen so many beamless slabs and they are still standing.

We have to take out time to school them on different types of slabs (solid,flat,ribbed,waffle) and how it has its own design/construction principles and how that flat slab is not a function of secret beams(that’s actually disastrous)

The problem is that most of all this people are truly not in the know (In this case, they were obviously mistaken solid slab for flat slab(beamless slab) and as such they believe it is hidden beam that will hold their 7.8m span slab.

I wrote this recently about secret beam / a span of 7.8m

Aforxzy:
I was on a site yesterday to resolve a structural issue and the iron bender suggested putting a hidden beam on the slab. This I have noticed on alot of sites even some owners do it.

I told him no and he said he knew I won't accept he goes along with it.

The issues of hidden beam on a slab is a bad practice and is fast becoming a norm. It makes no sense and has no technical or structural backing.

Hidden beam on floor slabs are just imaginary strength enhancement concept.
The use of hidden beam are not beneficial to the behavior of slab. The principle that deflection of solid slab obeys still remains constant, “Depth”

The longer the slab span, the deeper the beam should be.

Show the runoff where to go

On this project, we simply sloped it away from the building.

temizeee:
Why is flat roof design/hidden roof not really common concept of roofing in this country… they seem cool and elegant…

This still falls within the premises of what is been discussed (roofing sheet thickness and all)

planning/design is everything, and it should be gotten right from inception. Most atimes it’s not about the roofing sheet thickness but the installation process.

In the construction of flat roof, you must show the water where to go and how it can self drain effectively, also pay attention to the part where the roofing sheet meets the wall

About flat roof not been common, not everybody likes it and some people already have a fixed mindset that you will have to do a yearly maintenance on it.
Meanwhile most people have embraced it especially people in the island (Lagos)

Attached is a design we did recently, we were driving pass yesterday and I took a shoot

Proposed 4 bedrooms duplex + self contain

Flat roof

n3xt:
Ilé Ode 2 | Bevelled Glass Wall

This is nice, is the glass placed symmetrically (like partition wall) or on the wall facing just the room?

Tims4real2002:
Yes, I need the cost of approval for structural drawing.

Good morning

Structural design don’t have a fixed cost sir, It is a professional service whose costing is based on value and differ from client to client.

2)Location matters, the cost of designing pile might differ slightly with one to design raft or strip foundation

3)In other to ascertain the cost for your drawing, you may need to request the cost using your architectural drawing.
Without the architectural drawing, the actual cost can’t be determine, also the structural drawing can only be done using the detailed architectural drawing provided by the architect.

However, for an average design with strip or raft foundation you may need to budget between 300~500k for the structural design

This will include the design of all the structural members.
2) calculations sheet
3) coren stamp and seal
4) letter of approval from a registered engineer

Tims4real2002:
Goodevening everyone,

Can someone please help with how much can one pay for an approval of structural building to Lagos state building planning, for a story building with 5 bedrooms duplex and 2 bedrooms flat x 4?

Please help me with the price.

Thanks and best regards.

You might need to rephrase your question so one can answer accordingly.

1)Are you asking about how much you will need to pay to get a approvable structural drawing?if yes, negotiate with your structural engineer.

2) Are you asking if you are to pay LASPPA to approve a structural design for you? If yes, you are not paying for that.

3) Are you asking about the cost of structural stability test for the said building (5 bedrooms duplex and 2 bedrooms 4 flat)? If yes, that’s between you and your engineer, LASPPA don’t have anything to do with it, their own is to receive and vet the result you provide.

Bottom line: you are only paying for assessment into LASG account, which is after your architectural and structural (mechanical and electrical)”if more than two floors” has been vetted and approved.

Hajivince:
I understand perfectly from the angle u coming from but softwares are made to make designs easier and AutoCAD isn't even a Structural Design software, it just helps for detailing manually.

That being said, Technology advancement is to purposely makes the world a better place and no actual Engineering software will encourage u to cut corners. What we have now is Clients not understanding Engineering designs thereby going for something someone somewhere conjure together because it's cheap and use that as Engineering Drawings.

A lot of people here jus pay an Architect to do an Engineering drawing and they inturn look for a Uni or poly student to draft something and present it and because of the country we are in, nobody really goes through this drawings thoroughly as they don't even understand what it entails.

I've seen a lot of Structural drawings here that there's no calculation whatsoever done on it and u get the same reinforcements provision and Hogging and Bending moments and even critical areas aren't catered for.

The amount of professionals that build here with top bars ain't up to 40% and all u see is "Secret Beams" as it's fondly called and because people won't notice or pay no mind, their building deflects when the even jump or place their Service loads.

U see people criticising the ones trying to do the right thing by saying I saw sb do it with like this and it stands or u hear are u constructing a bridge and so on...

Primarily cost is an important factor to b considered in Engineering practices but safety and "longetivity" should b seen as a Paramount attribute.

Lastly, The mistake most of us make is coz we have COREN or the necessary certificate, we think we can work on Deep foundations and highrise without trainings from experience experts and deliver successfully. The client might not see the signs in the early stages but every mistake hurried will resurface later in the future. Archaic methods aren't better than new methods, we jus lower our standards of delivering.

We have over 20stories in Lagos too standing today

Last month someone approached us for a hotel structural design with columns span of 7.8m at all sides and going to 4 floors.

After our calculations, we arrive at a beam depth of 750mm with y20 reinforcements.

It was after the whole process that the person told us that, they want to use the design for approval but their intent is to use secret beam (not the one we designed with a beam drop of 750mm) for the entire project, and I almost jump out of my skin upon hearing that. He said they have seen so many beamless slabs and they are still standing.

We have to take out time to school them on different types of slabs (solid,flat,ribbed,waffle) and how it has its own design/construction principles and how that flat slab is not a function of secret beams(that’s actually disastrous)

The problem is that most of all this people are truly not in the know (In this case, they were obviously mistaken solid slab for flat slab(beamless slab) and as such they believe it is hidden beam that will hold their 7.8m span slab.

somehow:
Please house, need prices for:
10mm and 12mm (iron rod)

Got Tiger TMt for 450k | tonne
Lagos

Zzyzxt:
Pls I need the contact of a good architect to draw a building plan for me. Must be in Ibadan.

Uncleteeh | Oak group

Jasobry:
God help us

Amen
Meanwhile

Bamboo possesses a higher tensile strength than steel, (NB, the major thing steel does in concrete is to provide tensile strength) One of the down side of bamboo in concrete is the bonding effect it will have with concrete, Even that can be enhanced with use of admixture.

2: about the caption on the pics your attached, (the picture I will attach) should be the major reason why one should be concerned about buying a building without knowing the structural integrity of the structure.

...

Y12 T&B foundation mat

Y16 column struts ( Starters bars)

Reinforement

Starter Bars

Starter bars are struts of steel rebar that are fixed into footings, slabs or walls in order to provide a reinforcement overlap, In this particular case, we are attaching our starter bar to the pad foundation footing. This serves as a monolithic structural connection between the foundation and columns

Reinforcement Used

Y16 dia steel bar ( for our columns strut)
Y12 dia steel bar (for our foundation mat)
Y8 dia steel bar ( for our stirrups)

Reinforcement Brand

Tiger TMT

Blinding

The purpose of this is to seal off underlying material and prevent dirt and soil from interfering with our structure.


Basically, it is made of weak concrete and it is applied both on our strip foundation as well as our Pad Footing.

Rounding up on our foundation trench excavation

mexxy1:
I always admire your sketches and follow your threads here on Nairaland. But, I don't understand you covering your address on the document when it's an opportunity to advertise yourself/business. Or is there something I'm missing?

Thank you sir
I will take correction moving forward

Prinzton:
It's still not too good a measure as the samples previously excavated would have undergone geo-test if used for engineering works.

If am to assume; that means there is no structural design for this building.

All am saying is such assumptions Should always be neglected and all / full construction ethics be followed.


Shalom.

We use complete construction drawing (Architectural design, Structural design and its calculations sheet, Mechanical design and electrical design) for our project, and ensure to follow all professional recommendations there in

Thanks

twinskenny:
Beautiful design

Thank you sir

Prinzton:
This decision was it from the Geo-tech's report?

Or

Based on assumptions of any/all kind?

The subject site was originally a laterite excavation site.

Look across the gate of the attached picture to see how the site topography was originally.

It took 6 men a full day to dig trench for just two rooms

Substructure

Setting out was done and foundation excavation commenced immediately

Foundation Type
We will be using Strip and Pad Foundation for this project.

Strip foundations are type of shallow foundation that are used to provide a continuous and level (but in our case stepped levels) strip of support to a linear structure, such as a wall built centrally above them.


Pad foundation : They are a form of spread foundation formed by rectangular, square ‘pads’ that support localized single-point loads (basically columns). This load is then spread by the pad to the bearing layer.

See it this way, Strip is the foundation for block walls, while Pad will serve as the foundation for columns



What necessitated this foundation type decision?
The subsoil have a very good bearing capacity.

Good day good people of Nairaland, so we finally decided to open a dairy for this project.

Project type: Residential
Client : Nairalander
Project Cost: Not disclosed
Location: Lagos

About the project: Comprises of 5 flats

Ground floor
2 units of 2 bedrooms apartments
1 unit of 1 bedroom apartment

First floor

1 unit of 3 bedroom apartment
1 units of 2 bedroom apartments

Site Analysis

Plot Dimension = 12.3m x 30.75m
Plot Area = 368.75 square meters

n3xt:
Currently doing one on a drab facade.

#BriseSoleil

it makes daylighting interesting with added value.
Well done

However a normal plaster would come out fine if you get the right people for the job

Attach is a marvelous job done in the estate of our current build.

Meanwhile, who else noticed the sudden love for grey and dove gray color by all and sundry

n3xt:
Maybe it’ll cost a little more but at N3,000 / 0.6sqm (excluding studs and installation cost which is considerably reasonable), I think the cost would be cheaper than plastering/screeding/painting or plastering and applying tiles to achieve same result in the long run.



The pics below are naija installs. Currently working on one, would share final looks here and on kobocity.



I agree completely but it can’t be compared with the benefits of a material that offers more in terms of value.

1. Low maintenance
2. Durability (doesn’t crack or warp)
3. Aesthetically pleasing
4. Waterproof / Fireproof




Not new though. @dominionng has been using this for years.

Rightly put, please add
5. The best way to emulate wood especially when exposed to harsh weather conditions.

We are using and implementing it on our current build.

Attached is the 3D
Construction started yesterday

MrOkenwa:
Like how many?
I don't want the rooms to be en-suite.

6-7
Depending on your survey orientation

MrOkenwa:
By 1 bedroom apartment, do you mean a single room self contain or a single room, sitting room, kitchen and toilet?
I have a plot of 60 by 120 that I am planning to develop. Can I squeeze something similar into it?

Features

1 bedroom en-suite
Visitors toilet
Living room
Kitchen + Terrace

Yes you can
But will not be upto 9 units

You might want to see what we did with a little more than a plot

9units of 1 bedroom apartment




https://www.nairaland.com/5783134/thread-bungalow-designs.we-offer-planningdesigning/2

A proposed 9 units of 1 bedroom apartment

Footprint
38275 x 13125