Use spirals as ties in piers?
Use spirals as ties in piers?
(OP)
I have designed a large residence in California which is supported by 16 inch diameter drilled piers (caissons). I have specified #3 ties with a spacing of 6" o/c for the full length of the piers. The contractor is proposing to use a continuous spiral instead of individual ties. The code (UBC 1997) specifies that the maximum clear spacing between spirals is 3". I believe this is because when you use spirals, you are counting on the additional vertical load capacity provided by the confinement of the spirals. In my case, the vertical loads are very low (compared to the capacity) and I only need to provide shear reinforcing. Does the 3" minimum still apply?






RE: Use spirals as ties in piers?
But in California, perhaps the UBC has a tighter restriction in high seismic zones.
RE: Use spirals as ties in piers?
Don't mis-understand me, contractors and their criticism of designs are essential, and desirable! I love hearing feed-back and always pay close attention to concerns: Helps me become a better engineer. But I do not breach code clause for contractor convenience.
Good luck,
YS
B.Eng (Carleton)
Working in New Zealand, thinking of my snow covered home...
RE: Use spirals as ties in piers?
RE: Use spirals as ties in piers?
RE: Use spirals as ties in piers?
RE: Use spirals as ties in piers?
RE: Use spirals as ties in piers?