ground vibration - course 1

[okdb]

Hi,

I'm a consultant in noise&vibration and I've to improve my knowledge in gound vibration. I've some books but I think a course would help much as well. Does anyone know where I could find such a course? A place in Europe would be best since I work in Norway.

Thanks a lot,
OKdB

 

[exploengineer]

Hi Okdb,

I teach ground vibration seminars as regards construction and mining induced vibration (blasting, pile driving, etc.)

We offer courses mostly in the Americas.

Before embarking on a course, I would buy a few books on the subject such as the following:
Applied Explosives Technology For Construction and Mining – Stig O. Olofsson/Dyno, 1997
Blast Vibration Monitoring and Control – Charles H. Dowding, 1985
Construction Vibrations – Charles H. Dowding, 2000
Efficient Blasting Techniques – Blast Dynamics, 1994
Explosives: An Engineering Tool- Giorgio Berta, Italesplosivi, 1990
Explosives Engineering, Construction Vibrations and Geotechnology, Lewis Oriard, 2002
Engineering Geology – Richard E. Goodman, 1993
Explosives and Rock Blasting, Atlas Powder Company, 1987
The Effects of Vibrations and Environmental Forces, Lewis Oriard, ISEE, 1999
Guide to Underwater Explosive Excavation, J.S. Bower, 1977
ISEE Blasters Handbook, 17th Edition, 1998
Surface Blast Design, Konya and Walter, 1990
Terra Dinamica LLC Research, 1998-2003
Various Bulletins and Reports- US Bureau of Mines, OSM, etc.
Vibration From Blasting – David E. Siskind, 2000

The best two to get started are Oriard's and Dowdings (2000).

You can purchase the from the International Society of Explosives Engineers (

http://www.isee.org)

Good Luck, Frank Lucca

http://www.terradinamica.com

 

[okdb]

Hi and thanks a lot Frank!

I've already ordered Construction vibrations of Dowdings. I'm supposed to get the book in a couple of weeks. I hope this will answer most of my questions!

Regarding your courses, I'm confident that it would be very helpfull but I doubt that I can get the budget to fly over the ocean, though it might not be impossible.

One question more: I've to calculate structure borne noise from thoses contruction vibrations. Is there any method available to calculate those levels in a multistorie building or I've to rely on a software using SEA for exemple?

Thanks for your help,

OKdB

 

[exploengineer]

Sorry it took so long to respond, I've been on the road.

Its near impossible to calculate airblast for blasting,for other noise, wow, but here's a formula for airblast associated with blasting. Sorry, don't have it in metric.

Frank

AIR BLAST PREDICTION
There are formulas to predict air blast, but there are so many variables that they are not accurate.

W= (D/SD)³
SD= D/W·³³
PSI= 1.0 (SD)¯¹·¹ Average Burial
0.1(SD)¯¹·¹ - suppressed airblast conditions
dB= 20 log(psi) + 170.75

W= Weight of explosives in pounds (lbs.)
D= Distance to Structure
SD= Scaled Distance
PSI= Airblast overpressure lbs./in.²
dB= Decibels
133dB = 0.013 psi- project limit
170.75= Constant
9 = SD for 133db at depth of burial for airblast suppression
46.8 = SD for 134 db at depth of burial = average

Example: Suppressed Airblast
Maximum Lbs.
Distance (D) = 500 feet to Structure
W= (500ft/9) ³ - covered by mats, use SD 9 for airblast suppression
W= 171,467.76 lbs. = 172,000 lbs.

Prediction of Actual- Using for this example 20 lbs./delay
SD= 500ft/ (20lbs·³³)
SD= 500/2.687
SD= 186

PSI= 0.1(186) ¯¹·¹
PSI= 0.1(0.003188)
PSI=0 .0003188

dB = 20 log(.0003188) + 170.75
dB = (20(-3.496)) + 170.75
dB = 100.82
dB = 101


Average Burial
Maximum Lbs.
Distance (D) = 500 feet to Structure
W= (500ft/46.8) ³ - no mats, maybe under-confined, blast on surface, use SD 46.8 for airblast suppression
W= 1219.47 lbs. = 1220 lbs.

Prediction of Actual- Using for this example 20 lbs./delay
SD= 500ft/ (20lbs·³³)
SD= 500/2.687
SD= 186

PSI= 1.0(186) ¯¹·¹
PSI= 1.0(0.00318)
PSI= 0.0032

dB = 20 log(.0032) + 170.75
dB = (20(-2.495)) + 170.75
dB = 125.85
dB = 126
Frank Lucca

http://www.terradinamica.com

 

[okdb]

Hi Frank and thank you very much for your help! I've now something to start with... I feel much better!

regards,
OkdB

 

[NicolasJobert]

Hello OKdB,

You need to carry out 2 kind of computations

- predict the vibrations transmission in the building
- predict the sound radiated by this vibrations in a particular room.

A rough answer to your question will be found in the "Structure Borne Sound" (Cremer, Heckl, Ungar) textbook.

Anyway, you will need to know the vibrations spectrum that will be applied at the bottom of your building. If these vibrations are created by construction equipements, it is likely that it will exhibit a very low frequency content and will not generate a significant of noise.

SEA may be a solution only if your problem stands in the "mid or high frequency domain", which in your case will unfortunately start above 200 Hz.

Nicolas