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Dear All,
I am working on a project in Middle East. It is a 48 storeyed tower. The total duration of the Project is 27 months. The schedule prepared by the Contractor shows the Concrete Works finishing after 20 months. The Client is objecting that seven months after completing concrete works is not sufficient to complete the remaining activities. They are saying that as per Industry Standard the concrete works should not take more than 60% of the total project duration.
I want to know if such standard exists. If not what is the reasonable duration (%age of total duration) to complete conrete works for highrise tower projects.
It will be of great help if anyone can send me summary schedule of tower project (pdf file) showing the project completion 7-8 months after the completion of concrete works.
My email address is zohnad@hotmail.com
Best regards
Nadim
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Nadim,
It has been a little over two years science your last posting, your job must be close to completion. If you are still there it would be good to hear from you to know what finally happened.
Regards,
Rafael
Hi Nadim,
You client may have a valid point. Assuming that your facade is following the structure without a hitch, say 8 floors behind you will still need 2 - 3 months to complete it (depends on the complexity), so your builidng is weathertight only on month 23 which leaves you with 4 months for fitting out (less first fix) of at least 8 floors and commissioning of the whole building.. I wouldn't bet on such a schedule honestly speaking..
Hope it helps,
Alex
Usually in High Rise structures such as that 48 storey, Skeletal works are executed 24/6 with a 3-4 days cycle in each Level (Column+Slab). You should use the latest formworks design that can be stripped as early as possible without compromising the safety of the structure. Finishing works shall proceed as early as possible while the structural works rising up.
The owner have no right to tell how you will plan and schedule the works to execute your contract unless otherwise stated in your contract documents.
As Rafael said, it is tantamount to acceleration of works that will cost your organization.
Regards,
Depending on the design you can build the concrete superstructure at a rate of 1 week per story, not uncommon for shear wall short span flat slabs like Condos, but for commercial building 2 weeks per floor seem like the average a good contractor can attain.
60% of 27 months equals 16.2 months, 16.2-4(Foundations)=12.20 months for concrete superstructure. This means 1 week per story. Very, very tight.
But no matter what, even without access to the Contractor's schedule, I believe he might be correct, the 7 months to finish the job after completion of concrete works makes sense to me and not what the Client claims. If you add time to the 7 months then in order to make within contract time you will have to pour more than a story per week, you will be pushing him for the almost impossible.
Read the following link and you will see that in order to get a 1 week cycle you need to be able to strip slabs and beams 3 days after pouring. If you want a cycle shorter than a week are you to strip before pouring?
http://www.civl.port.ac.uk/rcc2000/pdfs/highsp.pdfo
Don't mess with his schedule.
Thanks a lot Rafael for your valuable comments. I agree that the time required change according to different scenario. However I want your suggestion if it is a 48 storeyed tower project. The Structure is Reinforced Concrete and not steel structure. The building envelop is Aluminum Curtain Wall and Glazing.
I am also looking forward to have some more feedback from other members so that I can conclude this issue
We do not use such rule of thumb, we have the following rule of thumb with the understanding each job is unique.
The job completion date shall be close to 3 months after concrete works finish, in the case of steel framed structure such as Shopping Malls the rule is applied to the enclosing of the structure, can be pre-cast, can be metal siding, can be masonry.
Say you have a development of 2000 housing units and you start 20 such units a week (80 a month) and the individual unit takes 7 months to build. First month for earthwork, second to fourth month for concrete work and fifth to seventh to finish the unit. The concrete work for the whole job will start on the second month and will end close to the 29th month, that is 28 months of concrete work out of a total job duration of 32 months, that gives me 87.5%. We build our homes 50% concrete and 50% reinforced masonry, hurricane proof, we are on hurricane alley, it takes us twice the time to build a concrete house than what it takes to make a similar wood house in the Continental US, there are no fixed rules.
I believe the Owner is looking for extra time to start tenant work on lower floors at the contractor's expense, he is forcing for acceleration, and there is a cost to this even if feasible. If concrete framed structure a 47 months duration is tight, if steel it might or might not. It all depends on the particular job, there are no fixed rules.
Best regards,
Rafael
Email: PPadmin@planningplanet.com
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