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Construction tolerances

4 replies [Last post]
Lo Gary
User offline. Last seen 1 year 28 weeks ago. Offline
Joined: 6 Feb 2010
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Dear,

 

My problem, in fact , is not related to project management,, but it seems that I couldn't find appropriate area to discuss and that is why I would like to post here for discussion.

It is ususally that there are tolerance for individual structural elements , no matter beam, slab, column etc. and there are also tolerances for finishes. If unluckily all the tolerances go to one direction say positive , all the tolerances would be acculmulative and added up rather than cancel out to certain extent (though the chance may be rare). But the fixing of some final fixtures do not allow any accumulative tolerance or adequate tolerance to cater for. Do the main contractor have any grant to gain all the accumulative tolerance ?

 

 

Thank!

 

 

Regards,

 

Gary Lo

Replies

abrugar jons
User offline. Last seen 7 years 8 weeks ago. Offline
Joined: 23 Jan 2017
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Hi! What an amazing list. I can’t imagine how much work this took.  Is there a certain criteria for being added to the list? I’d love to be added if possible.

Best,

Mike Testro
User offline. Last seen 1 week 4 days ago. Offline
Joined: 14 Dec 2005
Posts: 4418

Hi Gary

It has to be calculated - Bottom up 5mm Mid up 5mm Top down 5mm should do it.

Best regards

Mike T. 

Lo Gary
User offline. Last seen 1 year 28 weeks ago. Offline
Joined: 6 Feb 2010
Posts: 49
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Dear Mike,

 

My problem is if for example there are totally 3 layers each allow +/- 5mm tolerance, the bottom is actual +5mm higher, the middle layer is also +5mm higher, while the top layer is also +5mm higher , it comes out total +15mm higher, but the specification say the finished road level should be +/- 10mm only.

 

Do the contractor have any grant to say that the specification does not allow accumulative tolerance and who should bear the responsibility?

 

 

Regards,

 

Gary Lo

Mike Testro
User offline. Last seen 1 week 4 days ago. Offline
Joined: 14 Dec 2005
Posts: 4418

Hi Gary

A prudent contractor works to the tolerances to achieve economies.

For example a tarmac road will be in 3 layers Base - Bearing and Wearing.

The lower courses are cheaper than the higher ones. If the tolerence for each layer is + - 10mm the the cheaper layers are increased and the upper layers decreased still achieving the finish level.

Best regards

Mike T.