huangyhg

problem with expansion joint
i am designing a 4-storey school building of reinforced concrete. the building is to be 100 metres long.the climate here in brunei is hot/wet with temperature range of 27 celcius to 35 celceius.(not so variablei guess). similar to singapore and part of brazil.the problem with having expansion joints here in brunei is that it always get damaged due to differential settlements or perhaps due to poor workmanships and material.can anyone suggest how to overcome this problem ? is expansion joint avoidable in this case?
if you are designing a reinforced concrete frame with infill panels, you may be able to make the frame 100m long. you will need to check the deflection of the frame and induced moments due to shrinkage and temperature movements. with such a long structure these forces can stack up towards the end frames. however shrinkage forces can be minimised by the construction sequence. if construction starts at the centre and works out both ways it works best.
however you won't have got rid of your movement joint problem because your cladding material will still need to allow for some movement. what is it going to be?
carl bauer
as carl noted, the frame concrete can be sequenced. i haven't used it for normal reinforced concrete, but it may be possible to have 'pour strips' in the frame to be cast in place a couple of months after construction.
for vertical differential movement, i've used expansion joints covered with a checkerplate material; movement has not been great enough to create a ramp effect.
thanks very much to both carl and dik. there will be no claddings but carl gave me an idea of another problem that may crop out : at the roof level. at this level there will be metal roof sheetings.will there be a problem ?
can dik kindly elaborate a bit more on checkerplate material.i have heard of flexible material but not checkerplate.
the roof sheets themselves will not necessarily be a problem but the steel structure that supports them may be. of course if you have a movement joint in the steel structure it will need to go right through the sheets. this can be done with a flexible flashing or a lap flashing. you can find these sort of details in any good architectural book on building detailing. however you will not often find them in engineering text books because waterproofing is considered the preserve of the architect. this often causes problems because putting movement joints in is the engineers job but then the architect has to waterproof them. a good architect will be familiar with these details but then a good architect is often a bit of an engineer too.
carl bauer

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