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Reinforced concrete v steel frame 6 floor risks ^time

4 replies [Last post]
Sat, 2010-04-03 13:38
chris eaglen
User offline. Last seen 12 years 48 weeks ago. Offline
Joined: 21 Dec 2009
Posts: 9
Groups: Building Information Modelling, Civil Engineering, Petro-Chem / Oil & Gas
Greetings

Does anyone have a reinforced concrete frame and steel frame comparison please for a building with a footprint of circa 75m by 45m with the floor/roof and cladding included.

Floor can be post tensioned or cast in situ on steel sheet. Cladding is composite aluminium/steel or precast elements.

It would be helpful to know what timescale differences will be possible with the above options.

Specifically we want to apply a schedule uncertainty overlay to the shortest timescaled set of options.

The ground works are detailed and the grid is 6m.

What risk allocations would be applied for this size of building for the options please.

Thank you
Best regards
Chris Eaglen
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Replies

Mon, 2010-04-05 04:53
#1
Samer Zawaydeh
User offline. Last seen 5 years 8 weeks ago. Offline
Joined: 3 Aug 2008
Posts: 1664
Groups: Civil Engineering, Regional Representatives
Dear Anoon,

It ok, you can keep asking question until the day you expire. Learning never stops. Chris can have 40 years experience in a particular field, and now he is practicing something different.

The foot print of the model that he is studying is 45x75 = 3375m2.

For a steel building, we still need to ask another 50 questions to come close the a good approximation of the weight per square meter. This can be between 30-120kg/m2 approximately. For example let us take 50kg/m2 x 3375 = say 170MT. This can be Engineered and Manufactured in 2-3 weeks and installed complete in 6-8 weeks. So you are talking about a complete job within 2-3 months.

For a concrete building, you have the vertical elements (84 columns with shear walls) this will take say 1-2 weeks, slab work for 3375m2 might take 6-8 weeks, and removal of shutter will take another 2+1 week cleaning, and you end up with a skeleton without the sides within 3-4 months time. Maybe less if you have the necessary formwork and manpower.

So time wise, if you have a scenario where a RC building can be faster than concrete building, I would like to hear it. In RC you need huge amounts of scafolding and manpower.

With kind regards,

Samer
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Mon, 2010-04-05 04:23
#2
Anoon Iimos
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Joined: 22 Sep 2006
Posts: 1422
Groups: Pinoy Planning Planet Community
Hi Samer,

It is shown that Chris has 37 years experience in Design Related Planning (4 years more than Mike).

He should give us advices and not questions.

How could you say that Cost wise, RC Concrete is cheaper than Steel when Time wise you are going to finish longer when using RC Concrete?

All these things has to be calculated and concluded.

Best regards
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Mon, 2010-04-05 03:25
#3
Samer Zawaydeh
User offline. Last seen 5 years 8 weeks ago. Offline
Joined: 3 Aug 2008
Posts: 1664
Groups: Civil Engineering, Regional Representatives
Dear Chris,

In addition to what Mike said, I would like to add that this is "Location" dependent.

I would suggest that you send out the same inquiry to 3 steel fabrication and erectors, and 3 Concrete General Contractors in the same area. They will be able to provide you with cost and time differences.

But in general, the following might be correct

Cost wise (Cheapest): RC Concrete
Time wise (fastest): Steel

With kind regards,

Samer
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Sun, 2010-04-04 15:14
#4
Mike Testro
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Joined: 14 Dec 2005
Posts: 4418
Groups: Building Information Modelling, Content Moderators, GPCCAR Editors
Hi Chris

Generally if there is enough lead time for design and procurement a steel frame will go up quicker than insitu concrete.

Wrinkly tin sheet will go on a steel frame for an insitu concrete slab - usually the quickest combination.

Points against Steel frame include:

Ceiling Void Heigths for horizontal services
Fire Protection
Noise transmission

If you can ensure a design break between pile caps and ground floor slab then your steel frame can fly up and the GF slab can work under the 1st floor slab. (You didn’t mention a basement but this sequence still works)

Look out for lift shaft and risers which may have to be insitu concrete which can be slipformed if necessary.

I think that covers it.

If you would like to see a typical insitu concrete column and flat slab programme then email me at planning.services@xlninternet.co.uk

Best regards

Mike Testro

PS I have moved your thread to a more relevant topic.
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