Impact Echo (or dynamic impedance) is an acoustic non destructive test method used to assess the dimensions and integrity of concrete and masonry. GBG has undertaken a large number of NDT projects using Impact Echo method. Typical applications include: Pile Depth Testing, Measuring Slab Thickness, Locating the extent of delamination and voiding around reinforcing bars and concrete cancer. GBG Australia has done a number of projects to determine the depth of piles on railway stanchion Overhead Wiring Structures (OHWS).
GBG utilise impulse radar, cover meter, Schmidt Hammer, ultrasonic testing and dynamic impedance testing to cater to a wide range of slab investigations. We can provide full slab specifications including reinforcement detail, concrete strength, delaminations, thickness and service and post tension location. NDT is vital before penetrating a slab where plans showing post tensioning cables or utility services are nonexistent or inaccurate.
NDT can provide invaluable information on the subsurface condition of bridge components. Our methods allow for detection of internal problems far more effectively than a visual inspection alone. GBG Australia has had experience surveying concrete, masonry and wooden bridges to determine material conditions and integrity, reinforcement detail and strength and construction problems. We have had experience surveying concrete bridges for structural assessments as well as determining the amount of timber in good condition in historical wooden bridges.
We can offer complete building specifications where plans may be lacking or unreliable. We can extend our slab investigations to walls, columns and ceilings to produce important information which may be vital when planning new developments on existing buildings. We are able to locate voids in structures; moisture content and corrosion levels within concrete. GBG Australia has undertaken work on heritage buildings to determine the nature of the construction materials.
With the limited time frames available for investigations in most airports and the requirements for full clean up and no foreign object debris on operational sections of the airport our non destructive investigation methods can provide large volumes of engineering information on the construction thicknesses and condition of pavement areas in a limited time frame and with no physical impact on the pavement (Non Destructive). We can work at night or during the day using DGPS linked multiple Ground Penetrating Radar profiling to collect a full picture of the pavement construction and condition on runways, taxiways or hardstand areas. This information can be used with targeted cores or other pavement investigation methods such as Falling Weight Deflectometer (FWD) to provide a holistic approach to pavement life assessment and pre planning for maintenance or replacement.
We have undertaken investigations in major and local commercial airports as well as military bases within Australia providing information on construction layer thickness, delaminating in asphalt layers, voids under slabs, reinforcement detail and changes in pavement construction.
The collected information is analysed and interpreted to provide engineering information in usable format often as ACAD drawings with a written report detailing and discussing the results. We can often provide recommendations for remediation and repair strategies if required using our in house geotechnical and engineering capabilities.
Large hardstand areas in ports or major distribution centres are often in full use and cannot be taken out of service for considerable periods of time. Using non destructive assessment methods such as Ground Penetrating Radar (GPR), Falling Weight Defelctometer (FWD) or dynamic impendence structural information on the hardstand construction and condition can be provided over a large area in a limited time frame. GBG have provided information on construction layer thickness and condition, concrete defects, reinforcement detail, location of support piers/piles, and presence of voiding within and under slabs and around storm water systems.
We are able to provide detailed information using one of the premier tools for road pavement investigation, GPR. Expected results include: pavement thickness, pavement construction, location of buried utilities, delaminations and voids, and pavement condition. Thicknesses of construction materials can be resolved down to one inch thick. We also utilise other geotechnical methods including DCP testing and MASW to provide a more thorough dataset, depending on the scope of the investigation.
We offer a suite of investigative techniques to locate underground utilities. We correlate our GPR and cable/pipe locator results with any known information and accessible service pits. GPR is superior to the standard cable /pipe locator as it can detect pipes not made of metal (eg. PVC). The knowledge of the location of utilities can avoid unnecessary, costly and dangerous disruptions to planned works. Utility provided information is used but can be erroneous, geophysical techniques can quickly and easily identify the precise location of buried services.
GBG Australia has undertaken a number of surveys of water aqueducts and culverts as well as sewer pipes. Objectives of surveys can vary from determining concrete thickness, harness and strength to mapping reinforcement detail with GPR, visual inspections looking for cracking or voiding in the soil under the concrete. GBG is also able to detect the location of water infrastructure at a site without drilling or digging. The use of geophysical techniques provides a quick and effective characterisation of any faults or defects in construction and greatly reduces the cost of repair.
GBG Australia can survey the concrete of water retention structures such as water tanks, swimming pools and wells. Using Ground Penetrating Radar (GPR), the condition of the concrete and reinforcement can be characterised. In some instances radar can detect zones of honeycombed concrete, leaking of the construction joints, voiding around reinforcing bars or variations in reinforcement detail. GBG Australia provides reporting on the location and type of fault in the concrete to aid in the repair of the structure.
