thermal movement of structural steel /concrete buildings

[ralph-perez]

> has anyone got any notes on measurement variations, morn till night, summer to winter, on projects you have actually done over these distances.

Why are you asking for someone else’s information? What makes you think the displacement will be similar? (you sound like a local monitoring expert I once met) It appears like you’re in the South Pacific, possibly Australia.

If I were you I would start immediately and create my own baseline measurements, with a disclaimer like; what happened before I got here is none of my effen business.

Ralph

[hub-tack]

Wikipedia, Thermal Expansion

[davidinbrisbane]

ralph
dont sound so stuck up
if you read it says i am in china, so how do you get australia

all i want is people to say, yes i had a job like that and i got 20mm or 10mm or nothing or such and such, it was out of interest only
i am simply asking a question, the measurements i am taking now isnt a concern, its being dealt with, you cant set control if the building is clad and full of cross walls
there is no need to comment on the effen business remark, that has nothing to do with what i asked, i have been doing this stuff for 44 years, made a lot of money and have a good reputation, hence the overseas jobs and sorting out a well known usa companies mess,second time i have done this involving the same company. so please give me some credit
i asked for simple experiences only

[ralph-perez]

David
You’re right–
I am currently doing a project in china, 7 floors, 1 building is 250 metres long, the other 140 metres,110 metres wide, seperated by a 150mm gap,end on end rectangles, steel frame, concrete slabs.
I missed the China part, for that I apologize.

Now for your reply,
I don’t care if you’ve been doing this 44, 64 or 104 years. There is no way you are going to discern the historical movement of a steel structure Empirically. If you or somebody else didn’t measure it you don’t know what it did, period.
I could lead you the AISC steel construction manual and it’ll tell you the coefficient of thermal expansion of steel and the recommended acceptable tolerances. But you say “I know the ins and outs and principles, what engineers calc and what actually eventuates, but I would like input on the actual lengths you have measured and differences found.” So that’s not what you want, I believe you’re asking for someone who has done a project of comparable size to tell you what their building did (Please correct me if I’m wrong) and I’m here to tell you it’s irrelevant.
The fact of the matter is every building is unique with it’s own set of characteristics which give it’s own set of dynamics.
There are far too many variables associated with this for you to come up with a theoretical magnitude and a theoretical direction based on some rule of thumb or somebody else’s experience.
Everything from the amount size and spacing of the girders and the stringers to the size and spacing of the Columns affects the movement.

Let me give you an example of what can and has happened in my experience:

Let’s say the building is going up and it’s leaning, the procedure around here would be to adjust it by attaching a turnbuckle, a come-along or a chain-fall to the core to pull it in and or a Hydraulic jack or maybe the tower crane to push it out. This leads to a scenario where you can have bolts which are over-torqued in some areas and bolts which are under torqued in others. There will be no rhyme or reason as to what the structure will do, that’s why you’re supposed to monitor it.

BTW: I don’t care if it was a U.S. Company or a North Korean Company

Cheers,
Ralph

[davidinbrisbane]

hi
lets start again
all i wanted was a general reply on how much anyone has seen a large project like mine move, from their own experience, we all know things dont always go as designed, and i was curious as to waht others have seen on site, i wasnt looking for any solutions to my issues, i can deal with them quite well
i was on a job that moved 3 inches overnight, but the steel buildings here,multi storey are the largest in the world, i have seen bridges crack, runways move etc, but the designs here are so different.
thanks
david

[richard]

You mention morning till night and I think that has a big bearing and from my experience and speaking the obvious I would suggest the ambient temperature may be one thing but the sunny side of the structure warms up more than the shaded side and so stresses are different.
Here we have tin rooves that creak and groan as the sun suddenly bursts out and then expansion settles only to readjust as the sun goes behind a cloud.
On steep pitched rooves it quite marked from one pitch to another.
This is a very simplistic example.

I would expect on a high rise, temperature variations would vary considerably.
That would be true here where sudden weather changes can see 4 seasons in one day.
Can’t speak for your local conditions so all this may be poppycock.

[davidinbrisbane]

thanks
i am from brisbane but spent years in the outback, thanks for the input
i was just curious as what others have seen on big jobs
they have a multi storey car plant here almost 1 klm square, not just slab on groung
thanks
david