Concreting while pile driving

[kuntay]

What is the standard for concreting while pile driving works go on nearby. Recently I have seen this application. 12 meters of concrete piles were being installed while there were the fresh poured columns and curtain walls 20 meters away. How long should be the waiting period to begin pile driving after concreting or is it not necessary at all. I will be gald to hear your opinios, thank you.

 

[Ginger]

Kuntay

I don't believe that you wil find a "standard" for this condition. The solution is more down to engineering judgement. You may wish to consider recording the PPV (peak particle velocity) generated by the piling operation, but most research on this is related to degrees of damage to types of structure (and not to construction operations carried out at the same time).

Without knowing the exact conditions, I would suspect concrete strengths in excess of 10N/mm2 would be required to ensure that you have no damage to your columns etc. I stress that this is just my gut feeling and is not based on any research.

 

[Ron]

Research done by the Florida Department of Transportation and Florida Atlantic University showed that drilling shafts adjacent to freshly placed shafts had little or no effect on the concrete.

As Ginger stated, the common sense approach will tell you that significant vibration (as noted by PPV)can damage structures. If a limit of 0.05 in/sec were placed on a new structure, you might want to limit PPV to 0.01 in/sec or less for new concrete. Just a guess though.

 

[par060]

I brought this issue up on a project some time ago and the contractor responce was "thats how we vibrate concrete down in Texas"...so be prepared to meet some resistance.

 

[dicksewerrat]

I would try to stay away from placing concrete while piledriving is underway. Not a problem if the piledriving is stopping as you finish your placement because that would give you a good consolidation of the fresh concrete. I would be worried about the driving after initial set, when the vibrations would introduce micro-cracks all the way up and down the walls before the concrete developed enough tensile stregth to take the vibrations. Especially between the wall and col. and col. and footing.

 

[RDK]

There are some different standards available on PPV for aged concrete and other buildings. Its been a while since I worked on this sort of project so I’ll not quote any numbers. We used the Province of Manitoba Blasting regulations as our guide.

What we did was set the maximum to one tenth of this until we had some 7 day cylinders back from the lab. If the strength was at least 70% of design then we raised the maximum to 75% until either design strength was reached or 28 days had passed. (If we knew that pile driving would be in the area we made a lot of extra cylinders.)

We had a seismograph available since another part of the job had a lot of blasting work and were able to monitor the PPV’s. Pile driving seldom reached the minimum trigger velocity (which was 10% of the regulation velocity) unless we were very close to the pile being driven(within 10 m or less). This would be a function of the local soil conditions pile design, driver type etc and subject to wide variation. We were easily able to set the pile driving schedule and the pouring schedule so that we kept the maximum distance away from the fresh concrete at all times. (often 60 m + away and no problems)

I would suggest that you look up the local blasting regulations or search blasting sites and get some PPV numbers and compare them to the results of your pile driving. The regulation numbers will be very conservative in the maximum allowable for buildings and you can then set some limits that sound good to you and that the driver contractor can live with. (Best to error on the side of safety in any case.)

Not very scientific but I think that we were very conservative and there have not been any problems with the structure.
Rick Kitson MBA P.Eng

Construction Project Management
From conception to completion

http://www.kitsonengineering.com

 

[TrimbleUser]

Pile Driving,
do you mean the famous wrestling move the "Pile Driver?"
or p-lease explain the kind of piling operations you mean for all us non-americans in the bunch.