During construction the pile head (pile cut-off) was not adequately checked from site supervision. Concerns over the following items remain: - Inadequate (locally no) concrete cover to reinforcement (ca.3%) and/or poor quality concrete close to pile head (upper 1-5m) outside the rebar cage. - Construction joints pile head to pile cap are not cleaned/prepared adequately.
A) How could the pile group behave (- considering inadequate construction methods applied-) during large lateral forces/moments e.g induced by earthquakes (Magnitude is up to 7) ?
B) What affect have the defective pile(s) in compression, what in tension ? (Lack of concrete outside the reinforcement cage)
C) What affect has a potential liquefaction in the level of pile head - pile cap ? (I guess rotation - but to what significance?)
D) Long-term durability consoiderations ?
E) What possibilities do I have in order to proof - in case of doubts - that there are no defects around the pile head (after the pile cap is casted) ? Sonic tests just give information within the rebar-cage. Any other methods ? Or is the problem not significant enough (except the durability concern) ?
Thanks for your kind effort and help. I appreciate it.
Inadequate cover to reinforcement is only a durability problem unless it is very inadequate, i.e. enough to cause spalling. Reo will corrode if exposed near water table. If chemicals are present in soils that can corrode steel then problem.
Steel is really only for flexural / tensile strength - if concrete cross section is adequate then compressive bearing capacity should be OK. In case of flexural / tensile loading then capacity may be reduced.
Poor concrete near pile cap may have inadquate shear strength under lateral loading.
Liquefaction will likely affect the pile group as a whole...there may be rotation if eccentrically loaded.
No way, I know, to prove if piles are installed properly. You could perform field load tests to verify there present capacity but if the steel corrodes then who knows!
Just wondering how you have arrived in this situation?