huangyhg

pile driving monitoring
i'm preparing a proposal to monitor a four story brownstone adjacent to a new construction site where piles will be driven. im going to do a complete visual structural inspection of the building before work begins. then i will make periodic visits at owners request to see if anything has changed. besides monitoring for cracks and existing cracks getting larger, foundation settlement, and general structural problems is there anything else i should consider. if vibration seems excessive i would bring in a testing lab to monitor interior vibrations. i have a lot of experience in building inspection, rehab, and renovation...just wondering is anyone had any experience or advice on this specific topic.
jjeng2....have the vibration monitoring done...if claims are made after the fact, you have no way of knowing if the vibrations exceeded damage thresholds.
monitoring should be done on the exterior foundation of the existing building and in the ground at the point on the existing property closest to the pile driving.
you might consider going over the existing, and adjacent existing building to record all cracks and other observable distresses. a photographic record of these current distresses would be warranted.
that way, after the piles have been installed, you have proof that existing cracks were indeed existing and therefore not caused by the driving work.
good advice - use the same level of care you would for deep excavations near existing structures.
if the existig building foundation is not piled, like mat, or footing in bad soil, the soil balance can be very precise, better get some distance between the buildings, independently of vibrations.
put some strain gauges on some of the cracks. especially ones on the walls perpendicular to the pile driving. and at least one seismograph in the basement. take elevations on floor slabs and window sills to the nearest one thousandth of an inch. give a copy of the elevations to the piledriver's insurance company and the general contractor's also.

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