Expansion Joint

[samay]

I am working in a contracting firm. I have got a design of 90*30m G+1 (class room) bldg with out expansion/contraction joint. I asked the consultant to consider it, but instead they stick to the design though the site of construction is desert where the temperature reaches 50celsius during summer and 5 during winter. besides there is great difference in temp. b/n day & night. Do u think the design is correct?

 

[Teguci]

If the slab is interior then the temperature change will be mitigated. However, the Owner has a choice of either providing straight contraction joints when you pour it or letting the concrete decide where it wants the contraction joints. If this slab is on grade, and there is a flexible finish over the slab (carpet) then I wouldn't worry to much aboutitother han letting the Owner know about the issue. Otherwise, oh well,we are only responsible for what we have authority over.

 

[lkjh345]

What kind of building is this? Steel framed? Concrete framed?

Just my opinion: While not knowing the specifics of your building and assuming the building is rectangular in shape, 90 meters ( 300 feet +/-) in length does not seem unreasonable to me for a steel framed building. It may be getting a bit long for a concrete famed building, but not eccesively long. We regularly go this far between joints, and most of our buildings are located in areas with summer to winter tempatures differentials of 100 to 120 degrees F ( approximately 50 to 60 degrees C ).

 

[Miner99er]

I like to use about 250ft so it is over that limit a little.

 

[OzEng80]

Seems too long + an ordinary aspect ratio (3:1).

Have you considered a pour strip?
Try to minimise end/corner restraint.

 

[firai]

The way I understand it, pour strips are only for preventing curing problems. Joints should be used for long-term expansion/shrinkage issues. What is the framing and wall system for this building?

However, if the design firm absolutely refuses to put joints in, I don't think there's much you can do but wait for a lawsuit/legal mess from the owner when stuff starts cracking.

 

[jike]

All right, since no one else ask, I'll bite......what is 90*30m G+1 ?

 

[concretemasonry]

Since there is no information on the geographic location, a term like G+1 is commonly refered to a ground plus 1 story structure. - The elevator button choices would be G (ground floor) and 1 (first floor or second floor to Americans).

Possibly India or Africa with a very uniform temperature slightly below the surface that is moderated even more with a structure over it.

dick

 

[asixth]

jike,

My guess is 90 x 30m are the dimensions while G+1 refer to a two-storey building (ground + 1st).

All,

What is mitigating the the interior temperature. If it is in the Middle East or the Indian Subcontinent, the most critical time when the expansion joint is required will be soon after the conrete pour. Depending on the local conditions, it may take some time from pouring the concrete to actually fitting out the building.

The Burj-Al-Arab in Dubai had to wait some time for finishings to be applied because the internal temperatures where just to extreme (or so I have been told).