Pouring Pile Caps proximity to Piles Being Driven

[vandede427]

I need to provide the GC with a recommendation on the minimum distance between a pile cap being formed/poured/cured and the pile driving rig actively driving piles.

I've been provided with vibration monitoring results based on 25' intervals away from the rig. The PPV (peak particle velociy) is 0.2 inches/second for 25' and 50' distances and 0.05 inches/second for 75' and 100' distances.

Other info:
site - north shore of Lake Pontchartrain, LA
piles - 40' deep timber piles - 25 ton capacity
soil - typically stiff to very stiff clay
caps - 3000 psi concrete
hammer - 5000 lb hammer, 15000 ft-lb's striking energy, 60 blows/second

My gut feeling before the vibration monitoring results came out was 50'-100'. I'm thinking 75' based on the vibration results. But I'd like to have some actual scientific basis to make this recommendation, not just a feel good / rule of thumb / gut feeling.

 

[ishvaaag]

If driving is interrupted for some hours daily concreting operations should be made in such way that the concrete remains liquid while vibrations stand; then early gain of strength concrete might be used to ensure that at the start of the following day driving operations the joint is hard enough to not be macerated by the standing vibration.


The following link has criteria for vibration on adjacent structures. A new built pilecap might be thought similar to some in some class.

http://www.arctunnel.com/pdf/feis/04_07_appendix_4_7_feis.pdf

Follow somewhat related quotes from

UFC 3-220-02
16 January 2004
UNIFIED FACILITIES CRITERIA (UFC)
PILE DRIVING EQUIPMENT

Never allow unauthorized or unqualified people to operate, maintain, or come within 30 meters of the equipment.

Ground heave near adjacent structures should be controlled if this heave exceeds 0.5 inch. Methods of controlling ground heave include pre-excavation, increasing pile spacing, or by installation of small displacement piles.

Vibrations can damage nearby structures. Structures adjacent to the construction will be monitored to assess their integrity prior to and during construction. Assessment of the integrity of adjacent structures is required prior to construction to determine the initial status of the structures.

 

[Ron]

Don't cross post. Pick one forum and post your question there...don't do multiple forums.