Ground Penetrating Radar (GPR)

there are several co. produce the equippment. different aim different use. most of them use for highway measuring . what do you want it to do?

Basically we have a demolition work, and I'm in the engineering portion of it. We need to confirm the location of buried utilities, and would like to know the depth of foundations so we can make drawings that show what needs to be demolished. We are going to be paid based on quantities that we get from drawings. Also, the client is only alowing demolition to start once the drawings are ready.

I see that you mention that is mostly used in higways which have only supeficial depths...I wonder if it could find foundation depths of up 10 feeet...

it s out of my depth. i hant taken account of the things. I know people use remote sensing tech to implement.but I dont know how depth will it can penetrate. Im also interested in it. because many people like you ask me for the question. if you hve got the equipmet would you pls share me the information? info@ndt.cn

We have had this done with some success. It is highly specialized, tho, more than just buying some equipment and reading the manual to get started. You might try looking at these guys: http://www.penetradar.com/

They are among the biggest in the field and do good work. I belive they do sell the equipment and offer training as well as the service.

See www.geophysical.com for great info on GPR.

Re; Does anyone has good or bad experiences with this type of equipment that you can share. I'm thinking in buying one...

See www.sensoft.ca we are a leading manufacturer of GPR and on our web site we have an "Ask the Expert" section where any and all questions can be posed re GPR. Referrals and contacts can be provided for all application uses. GPR can be site specific, such as in its use for utiltiy location and also application specific, such as in frequency selection for concrete inspection versus ground investigation.

I have plenty of experience with GPR and periodically train people in its use. To determine feasibility of penetrating to a given depth, you have to define what you're trying to penetrate through. Reflecting off your target means getting through everything between you and it and then back again. For example, if you're on a concrete slab looking for something in it or beneath it, then metal rebar may be in your way. The low to mid frequency antennas (200-400 MHz) that may be recommended for penetrating 10 feet will see a rebar mesh as an impenetrable shield and receive only noise from beyond it. The higher frequency antennas (900-1500 MHz) have the resolution to see between the rebar peices with data processing but probably won't penetrate 10 feet even in the best of soil conditions because high frequencies typically attenuate faster.

Regardless of whom you ask about your specific application, make sure to give them as much information as possible about the ground surface you will be scanning and what you suspect is beneath it. Factors such as soil/rock type (mineralogy, not just grain size), moisture content, clutter (other stuff mixed in with the soil), and target orientation (parallel or perpendicular to your survey line) have an enormous impact on target detectability. If they say "this system will penetrate 10 feet no matter what," they don't know what they're talking about or they're outright lying. Since this critical information is not often available, your best bet may be to make a smaller investment in a short term rental and then re-evaluate whether you want to buy. Some manufacturers will apply some portion of your rental fee towards the purchase of a system.

The big three commercial GPR manufacturers, GSSI (www.geophysical.com), Sensors and Software (www.sensoft.ca), and Mala (www.malags.com), make some version of their latest systems available for rental. Another company like Exploration Instruments (www.expins.com) specializes in renting equipment and may provide a better rental deal though might not have the latest equipment.

Assuming you get all that worked out and operate the unit properly, the final challenge is interpreting the output of the GPR. GPR is rarely a bell ringer even in optimal situations. All of the manufacturers show examples on their websites and brochures where a CAD drawing of targets was interpreted by an expert and laid over the data (or completely replaced the data) to make it look simpler. Don't be fooled. Unless they have predicted your specific field scenario and focused a product on it, you will be stuck interpreting 2D squiggles on the display unit (or on a computer if you get their data transfer software). Your best bet is to have a clear idea of what you expect to see in the data before you collect your first data point and then look for differences from the expected result.

Finally, yes, it is possible to detect and image utilities 10 feet deep with a GPR. I've done it. Whether it will work in your specific work environment is a big depends-upon, though. 10 feet is on that border line where a practical antenna like a 200 MHz will see the target buried in one type of soil and completely miss it elsewhere. For example, if you're looking through gravel you've got a great chance but if you're looking through certain types of mineralogical clay, you'll be lucky to see 2 feet. Hopefully, what you're looking for was trenched in as the trench itself is usually easy to find.

Please email your telephone number at sshassany@yahoo.com thanks

Its a wonderful analysis for using the gpr. I want to know how much the max depth for the ordinary soil layer does it penetrate? If I would use it to find the pipe location undrground or cable in the building wall. How small object could be found by the set? and What is the gpr different from microwave remote sensing tech?

Thank you folks for some great leads, I will follow them and see where they get me, and yes cnpower if I figure it out I will share the info.

Thanks!!

One last tidbit. The USDA put together a soil suitability map for CONUS. I don't know whether your field site falls on this map but it may give you a general idea of what you're up against.

http://soils.usda.gov/survey/geography/maps/GPR/index.html

Of course, if you are trying to look through building anything other than the naturally occurring soil - eg building materials, fill, otherwise unnaturally disturbed soil - this map won't help.

works good with finding things in concrete and telling concrete depth but depending on soil conditions doesn't work too good in the ground part of it.But this also depends on soil conditions, were i live there is alot of clay in the ground and the clay destortes the signal in the ground and does not pick up objects on the computer screen.If soil conditions are mostly sand or anything that is not clay will work fine for you but again if you have clay in the ground will be hard to read because of the clay destorting the signal, but never had a problem with the concrete part.Had to drill over 200 holes in curling rink to raise up the floor because it was sinking used gpr to detect all the lines in the slab which were only spaced 6" apart. GSSI makes the best gpr system i would say, well hope that helped you.

Thanks for the post, yes I bought a GSSI system last month, and I'm trying it now on a refinery work. The most difficult thing is the interpretation, but up to know it seems my engineer is more or less up to par. The equipment is powerful but will se how we do with some additional training to lear more about the interpretation of things.

Thanks again.

Have you had much success in finding PVC "Plastic" conduit in concrete with radar?

We have had great success in locating PVC conduits within concrete. All of the hospitals in Kansas City require us to locate conduits prior to any concrete penetration (you can imagine why hospitals like this!). -Mark D, GPR Technician, Construction Solutions, www.construction-solution.com/conduit.asp

We have had poor results here in the north east.

Could you advise of type of equipment you use and any tricks you have discovered.

Phil

I work for Global GPR which specializes in concrete imgaing using ground penetrating radar and we have no problem locating PVC conuits in concrete slabs as thick as 24". We can also tell if there is live power going through the line. You can view additional information about using GPR for concrete imaging at http://www.global-gpr.com/services/concrete-inspection.html.

http://m12.hit.bg/gpr_eng.html

Hi, I saw your ad regarding the application of Ground Penetrating Radar. I am sending this email to inform you I have a GPR system currently for sale that would be perfect in locating utilities.

FOR SALE

SENSORS AND SOFTWARE, PULSE EKKO 1000, WITH 1200 AND 450 MHZ ANTENNAS, HIGH SPEED DATA ACQUISITION KIT, 10 METER CABLES, BASIC AND 3-D SOFTWARE, ALL COMPUTER CABLES AND MANUALS. PRICE $ 25,000 CANADIAN

CONTACT RANDY ZEBEDEE

BOX 2557, DRUMHELLER, ALBERTA, CANADA, T0J 0Y0

Phone: 403-821-0726

rzebedee@hotmail.com

I'm looking to rent/purchase ground penetraiting radar for gold detection .Can you help ? Thanks, Rick

call this number they are selling some 954-549-6037