curved pt slab on grade

huangyhg

curved pt slab on grade
i posted this in geotech/foundations with no responses.  i'm hoping maybe here in the structural area someone could give their opinion on my issue.
i am designing a club house that is curved and the builder really wants to use a post tension slab on grade foundation.  the shape of the building is almost a half circle.  rough dimensions are 40ft in width, 180 ft in length (if the curve is straightened) and the ends of the curve come to 140 degrees (so just 40 degrees short of making a half circle).  if i was to design this as post tension, do i run the cables in the long direction along the curve or do i stay with stright tendons that then create difficult locations and many various lengths to deal with?
i want to go with a elevated 2-way rein. slab, but the builder really doesn't like the idea (due to added cost).
any suggestions?
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why is the contractor insistent on using pt?  the curved shape is not the best for pt and makes it difficult to reinforce in the tangential direction.  post tensioning in the radial direction is possible.  what is there about the project that would indicate pt?
dik
the rest of the project is multifamlity with pt foundations.  so that is what the geotech is providing for a foundation criteria.  also, the builder feels he has had the best luck with pt and wants to stick with it.  
i want to tell the builder it's just not practicle to use pt for this curved foundation, but i wanted to check if anyone has done a curved pt foundation before i tell the builder he can't do it.
i have done circular slabs as the bases for water storage tanks. we kept the tendons straight in both directions and put up with the anchorage problems on the curves.
but we used a lot more pt than the pti design method requiresbecause we did not want any cracks, which is normally the main reason for using pt in a slab on ground.