All construction works begin at the bottom. Hitting an underground pipe or cable during construction causes severe effects. It has the potential to put lives in danger, delay the project and cost thousands.

That’s why better contractors and engineers are depending on Ground Penetrating Radar (GPR). It is rapid, non-destructive and is used to have a view beneath the ground or within concrete. It reveals the secrets before any one cuts, cores or digs.

The building codes and the seismic risks are very strict in Southern California. So, precision is essential. GPR has become its norm there. It is now the compliance of LADBS, Caltrans, etc. local agencies.

It is one of the most intelligent constructions technologies of today. We shall delve into what, how, where and why GPR is applied.

Ground Penetrating Radar or GPR is a technology that operates through electromagnetic waves. It is employed to identify an object or a material change below a surface. Imagine it is an under-scanner.

Short pulses are transmitted into the ground in a radar antenna. As the waves strike some object, such as that of a pipe, cable, or layer of concrete, they reflect.

The sending signals are recycled and reflected on a screen. These indications form a picture of what there is beneath.

The GPR is able to determine both metallic and non-metallic material including:
·         The post-tension cables and rebar.
·         PVC and metal pipes
·         Electrical conduits
·         Voids or air pockets
·         Alterations in soil layers and ground water.

GPR can scan depths of 30 feet depending on the preparation of soil and surface. It is enough to find utilities, test foundation conditions, and inspect a concrete safely. All this could be carried out without the need of a single hole.

A Ground penetrating radar uses simple working concept. The technology which empowers it is impressive though.

A GPR system has three key components to it:
1.       Interrogator – sends radar waves to the ground.
2.       Receiver – collects back the reflected signals.
3.       Control unit/ display – process and visualizes the data into an image.

When a wave strikes any surface underground it reflects in a different way. The reflection is what is dependent upon the object. A strongly reflected signal is produced by metal, which can be weak for soil or plastic.

The system notes the duration of returning of the signals. This assists the operator to determine the depth and position of object.

Accuracy is influenced by the conditions of soils. For example, dry sandy ground can be scanned deeper whereas wet or heavy soil can be scanned at a distance.

GPR works completely well in concrete. Before coring or cutting, it may easily identify all rebar, cables and conduits.

It is even shown that the modern GPR units have live radar images. It also allows real time decision making on a site by engineers.

The right inspections prevent project delays with underground or new construction projects. With our inspections, you can avoid problems before they begin.

GPR is the most multi-functional instrument. It finds application in construction, infrastructure, utilities, geotechnical, as well as archaeology. This is how it is transforming the project management in southern California.

Concrete Scanning
GPR is used by the inspectors before the drilling or cutting of a slab. It is mostly utilized to detect rebar, post-tension cables or conduits. It prevents the structure from weakening or bring about accidents.

The inspection of the cores drilled in the LA undergoes LADBS-approved GPR scans. They do it to ensure that it is safe to move on.

Utility Detection
Before any excavation, GPR detects underground pipes, electrical lines and cables. It mitigates interruption of services, diminishes risks and keeps excavation crews safe.

Caltrans and Metro have mandated the GPR survey for trenching or foundation works.

Pavement and Road Assessment
GPR is also used in pavement constructions by transportation engineers. It can verify the thickness, space among layers, and pore-holes within the subsurface. It is quicker and less intrusive as compared to drilling of multiple cores.

Environmental and Geotechnical Surveys

GPR assists in the detection of underground storage tanks (USTs). It is equally useful to locate underground debris or soil contamination. It also demonstrates soil layers to check the compaction and foundation stability.

Archaeology and Forensics
In archaeology, GPR is used in searching for underground artifacts or historical monuments. It is also set up in forensics when one wants to find evidence or graves without excavation.

GPR is an important tool that uncovers the secret beneath the soil. Up to now, GPR will assist the professionals to work smarter, faster, and safer no matter how they use it.

Because, then, is GPR becoming the standard through the construction sites? Since it is non-damaging, non-delays, and risk-free.

GPR scanning does not produce a cut or a drilled hole. In contrast to the conventional traditional X-ray techniques, it leaves no structural harm. It also does not expose one to any radiation.

GPR provides real time images that are pinpointed in the same way. It identifies metallic and non-metallic materials. It also provides the engineers with the full picture of the lying below.

Proper information will help avoid accidents caused by hitting unidentified utilities or reinforcements. It also helps in adherence to the Cal/OSHA regulations for excavations and trenching.

GPR prevents rework, repairs and time wastage by detecting problems at early stages. The decreased number of surprises lead to the increased ease of operations. Hence, it decreases the overall costs.

GPR may be applied to the concrete, asphalt, soil, or rock. Due to its flexibility, it is suitable in all the forms of projects. It can be minor upgrades of big highway and rail undertakings.

You may ask; is not X-rays or electromagnetic locators sufficient? Here’s why GPR stands out.

GPR vs. X-Ray Scanning
·         X-rays require both access to a wall or slab on both sides. GPR only needs one.
·         X-rays include problems of radiation safety; GPR does not.
·         The GPR scans are also faster and cheaper to conduct.

Electromagnetic (EM) Carriers A Locators vs. GPR
·         EM locators merely locate metallic objects. GPR identifies both metals and non-metals.
·         GPR also delivers depth and image information and not merely the signal location.

Highly conductive soils or water-saturated have the ability to lower the GPR performance. Modern radar systems with sophisticated filters ensures proper images.

That is why GPR is preferred by the majority of the field professionals in non-destructive detection of the subsurface.

An expert GPR survey consists of some evident measures. These should be observed for accuracy and safety. Following is the process of undertaking GPR survey.
Planning and Site Review: The review of drawings is indispensable prior to the use of a GPR. One will have to write off utilities, and establish scanning zones.
Equipment Set up: Select the correct frequency of antenna use. Deep surveys are executed with lower frequencies. shallow work is performed by the high-frequency antennas.
Data Collection: This process involves moving antenna on the surface in a grid form. This antenna is being reflected by the system.
Data Analysis: Reflections are converted into radar images with the use of software. It depicts forms, volumes and positions.
Reporting: A summary of findings after data analysis is in form of a report. This report should be furnished with depth diagrams, cross sections and photographs.
Verification: The results are verified by certified engineers or ICC inspectors. It should be project and code compliant.
A properly implemented GPR survey is few hours and not days.

Safety and compliance are the main priorities in such places as Southern California. GPR can be a mandatory prior to the excavation, coring or concrete cutting.
Excavation Safety
GPR makes sure that workers do not strike the unknown utilities or voids. It belongs to the rules on excavation safety (Title 8, Section 1541) of Cal/OSHA. It embraces safe trenching procedures.
Quality Control
GPR helps the contractors to confirm the rebar spacing, embed depth, and formwork. This is in line with Chapter17 IBC and the special inspection of LADBS.
Documentation and Record Keeping
Examination records all GPR results in reports. The storage of photos, data files, and results are in digital format. This information may be communicated with either QA/QC teams or loaded to BIM to coordinate. This enhances transparency and the ease of closing down projects.
GPR assists the project because of combined safety, quality and recordkeeping. It helps the teams to attain the technical and legal specifications. Besides, it safeguards the employees and the general citizens.

Ground Penetrating Radar (GPR) is among the most significant technologies in construction. It is safe, fast, and accurate method. Besides being economical, it will identify problems even before they become expensive.
GPR increases the safety and smartness of construction. It is also applicable in scanning a slab to locate the rebar, planning utilities prior to excavation. GPR is able to check with LADBS and Caltrans.
GPR is not a choice in such a territory as Southern California. In this case, there should be accuracy in seismic activity and stringent rules.
Get GPR scan prior to cutting, drilling as well as digging. It safeguards your company, your work, and your image. GPR ensures that your work is in full meeting with the latest standards of work and safety.