Reinforced Concrete Design

Difficult to say, not knowing the style of the building and the amount of concrete.

You'll need the engineering plans.

That building can be full concrete or a concrete frame filled with different building materials.

It can have long spans, or short spans. All elements, that will affect your cost prize a lot.

Not exactly sure what a Quantity Surveyor is in the context. Are you the Engineer? What exactly do you mean by, "I am supposed to come out with a price for a contractor."? Do you mean you are supposed to tell them what you will pay, or what you will charge?

If it is you who is to design and specify the type of concrete, and how much and how thick the rebar is to be, sounds as if you need either to go back to school or hire someone who makes these sorts of plans and calculations.

You may as well call or visit a concrete supplier company and ask for guidance, which they may or may not feel comfortable giving you. They of course may recommend that you consult with some particular engineer.

Typically around here there are known standards specified by engineers employed by the Architect, if the Architect is not also an engineer themselves, and then the Building Contractor gives an estimate to the client that they derive from the building plans.

Without plans, well no estimate is likely to be very accurate.

What even is the building code where you are? If where you are does not have a Code Book, and you want to build a building properly, it would be wise to use a Code for a similar area.

Depending where you are in the project (speculative project, concept design, detail design) the way of estimating the concrete varies.

Let's say you are at the concept design stage, which is about as far as a quantity surveyor can go without getting an engineer to do the design.

3 storey 17m x 15m which suggests to me (assuming that you don't want the whole thing free spanning and column free) either a 3x3 or 3x2 or 2x2 grid of columns. The choice will depend on the usage, layout and also the foundations that you might have.

assuming 3x2 grid.

- slabs 250 thick 100kg/m3 of reinforcement

- beams 400x400 (beneath slab and therefore of overall dimension 400x650) 220kg/m3 of reinforcement

- columns 400x400 300kg/m3 of reinforcement

You might want to buy "Structural Engineer's Pocket Book" by Fiona Cobb which can help in these situations. Also "Architect's Pocket Book" by Charlotte Baden-Powell.

Personally, I don't think our Guest here has a blanking clue what is involved with the design of reinforced concrete elements and frames. To me, it appears that the Contractor is looking for a cheap way out asking for the information and avoiding the services of a Registered Structural Engineer.

Frankly, I wouldn't be so forthcoming by giving out hypothetical beams sizes and reinforcement requirements to our friend until he providesthe forum with a lot more detailed info regarding where he's located, his role in all of this, and the actual contractual arrangement he has with the Contractor. By giving out detailed info he may become liable in the event there is a future structural failure of any element constructed based on your detailed advice....be very careful and leery.

BTW, in my 32 years in this business I have never heard of the term "Quantity Surveyor?. What the heck does that mean?????

Always am leery of giving out design details......

have a great day!

Captmoosie i supposed you come from the usa. Most of you dont know anything outside your country. A quantity surveyor is a proffession developed in 19 century england(uk) and it spread to countries it colonised. Check www.rics.org. you could also have checked wikipedia. the closest similarity to a proffession in the usa is an estimator or cost engineer. i hope its a bit clear. i am writing from ghana, west africa.

Now i am preparing an estimate that a contractor will charge the client for the 3-storey reinforced conctere frame office buliding.

Yes the contractor does not want to employ the services of a structural engineer. i have repeatedly asked the contractor to do that but this is a third world mentality where he wants to avoid paying the structural engineer.

He intends using similar types of structure he has built.

I just provide an estimate to him. i have no contractual arrangement with the contractor. the structural soundness of the building is solely his problem. i will not be liable for anything. He can only scream at me if i underestimate. But i repeat i have advised him on several occasion that he needs to consult engineers on such issues.

My brother has the two books omw7 quoted and had some information from the net.

let me mention that i have the architectural plans i.e ground,1st,2nd floor plans, roof plans, 2 sections and 4 elevations. the grid is 5m x 4m

I used the following

columns 300 x 300 250kg/m3

beam 300 x 500mm 230kg/m3

slab 150mm thick double layer of 12mm dia reinforcement.

i am very sure this is an overestimate in terms of price.

thanks for contributions.

mikidei

The steel in the columns? 2 layers of steel in the slab, squared and connected? (crossed)

Well, heck of a way to do business if I may say so.......getting away with what the last guy got away with......well, at least until it collapses.

I've been all over the world and visited every continent, save for Antarctica, and never came across the old English "Quality Surveyor" terminology, but then again I was serving in the US Army. Hmmmm learned something new today.

I still feel that your Contractor is playing with fire by not hiring a Licensed Structural Engineer......basically he's playing "Russian Roulette".

Enough said.

So Mikidei just go ahead and do it your way.

Maybe we in the USA don't know how things work in other parts of the world. Still we've built all over the world and you have to work right hard to tear 'em down here in the USA, or anywhere else.

Far as I can tell you're nothing but a buyer. Doesn't sound to me you have any right to lecture anybody here about what they could have or should read.

You showed up here and asked for advice. The post was hard to understand. Some people gave you for nothing, not a thing, not a cent, some suggestions, and then you want us to do homework?

Then you want us to sympathize with your plight?

Then you say you're not libel?

What really is the point here mikidel? If you are sure you can't add up things correctly, its not our problem.

Transcendian i dont think i was lecturing anybody, i really needed help that is why i came to this site. someone had never heard of what a quantity surveyor and suggested that he could have checked the wikipedia.

If everybody understood my submission the way transcendian did then i am sorry but i really think it was not necessary to respond this way. i did not intend to be rude in my submission.

Forming Large Concrete Walls is a bit of info you may find useful. Nice links far as formwork is concerned.