pile vs mat foundation

[ixv]

Would you recommended pile or mat foundation for ground conditions of fissured limestone rock with a safe bearing capacity of 950kN/m2 (9m below street level) and solid limestone with a safe bearing capacity of 1500kN/m2 (20m below the layer of the fissured rock and also a water table 7m below ground levels.?

Foundations are to be designed for 2 basement garages and a 15 storey building. Area is not seismic.

 

[bob33]

Why not individual footings as an option? The bearing capacity on the fissured rock is very good. Easier to control the ground water during construction than with a mat. P2 level is likely above water table and might be slab on ground with under floor drainage, but if tanking is necessary and doable then a mat option is probably the best solution. If you go with a mat, make sure the reinforcing is protected from corrosion due to salt from parking. I would discuss various options with the geotechnical engineer and a contractor then base my decision on price and feasibility.