Extra 2'' concrete on PT slab
Extra 2'' concrete on PT slab
(OP)
Hello, friends,
We have finished calculation/drawings and passed plan check for a 10'' thick two way post-tensioned elevated floor slab. Everything is ready for construction. Right now, owner is planning to use 12'' thick and leave all PT cable and mild reinforcing at the same location/elevation as 10'' slab. This will bring us additional 2'' concrete dead load (25psf), which is not designed originally.
We originally designed by using ADAPT floor pro 1.5 based on slab self weight and 40 psf live load.
Anybody has better idea how to evaluate this situation rather than redo analysis?
Thanks.
We have finished calculation/drawings and passed plan check for a 10'' thick two way post-tensioned elevated floor slab. Everything is ready for construction. Right now, owner is planning to use 12'' thick and leave all PT cable and mild reinforcing at the same location/elevation as 10'' slab. This will bring us additional 2'' concrete dead load (25psf), which is not designed originally.
We originally designed by using ADAPT floor pro 1.5 based on slab self weight and 40 psf live load.
Anybody has better idea how to evaluate this situation rather than redo analysis?
Thanks.






RE: Extra 2'' concrete on PT slab
RE: Extra 2'' concrete on PT slab
Standard of care: what would another reasonable engineer do? I think most would at least re-check a number of typical spans to see the effect accurately.
RE: Extra 2'' concrete on PT slab
RE: Extra 2'' concrete on PT slab
No budget?
The plans is being changed by the contractor after you were done, sounds like a change order.
RE: Extra 2'' concrete on PT slab
RE: Extra 2'' concrete on PT slab
Mike McCann
MMC Engineering
RE: Extra 2'' concrete on PT slab
Also like rday said it sound like you have a case to charge for a variation.
RE: Extra 2'' concrete on PT slab
You also need to rationalise it a bit, can you check the extreme cases and then apply the assumed fix throughout?
You also need to check the load path to ensure that no other items will be effected by the additional weiight/bending moment.
RE: Extra 2'' concrete on PT slab
If it's a late change by the owner then someone has to pay for redesign.
Will the Contractor also provide a 12" slab for the cost of a 10" because 'there is no budget'? - I doubt it.
RE: Extra 2'' concrete on PT slab
RE: Extra 2'' concrete on PT slab
Fire rating?
Sound proofing?
Seems to me that an owner would want the building system as efficient as possible.
RE: Extra 2'' concrete on PT slab
It is kind of coordination problem between us, senior engineer, architect and owner. From structural point, we made 10'' thick to bring client extra savings.....For some reason, client never claimed they need 12'' thick until plans approved and going to site construction....
Thanks, all your guys are great.....
Your guys are great, thanks.
RE: Extra 2'' concrete on PT slab
RE: Extra 2'' concrete on PT slab
RE: Extra 2'' concrete on PT slab
RE: Extra 2'' concrete on PT slab
RE: Extra 2'' concrete on PT slab