Bridges have played an important role in the progress of developed countries worldwide. Many bridges have been constructed in the beginning of the twentieth century in the US but now these bridges are performing poorly as they have lived past their useful life. Some of the bridges are eighty years old and the average age of the bridges in the country is 42 years. According to the American Society of Civil Engineers, most of the bridges (approx. 25 percent) across America are structurally deficient which may pose threat to the safety of people commuting over these structures on daily basis. Bridge were built to withstand a certain amount of traffic that as neighbourhoods have grown and the number of cars increase past the loads that the bridges were originally intended to carry. |
Regular and frequent bridge inspection are a necessary step to maintain and prolong the life of the existing bridges and to create a baseline of quality assurance for newly constructed bridges. Conventional bridge inspection techniques like coring, chipping and sampling are destructive and invasive in nature which may cause addition to the existing damage to the bridge. Therefore nondestructive and non-invasive testing “NDT” methods must be used for bridge inspection.
Some of the features of non-destructive testing methods are:
• These methods don’t affect the integrity or functionality of the structure
• Bridge inspection completes in short time without any risk to public or crew
• Quantitative results can be obtained unlike destructive methods where results subjective results are obtained
• There is no need of bridge or lane closure during bridge inspection
• Accurate location and position of damage can help in early repairing which will strengthen the structure
• Results can be seen as easy to understand 2D and 3D illustrations on computer
• Results can be stored for later analysis, future reference and monitor the progress of internal and external deteriorations
• It can also find subsurface damages, corrosion, and delamination
What are the technologies that come under Non-destructive testing?
The technologies which can evaluate the metallic and concrete structures without causing damage to it come under nondestructive testing methods. Some of the techniques that fall under non-destructive testing are:
Acoustical techniques – Acoustical testing is used for detecting delamination, the separation of coating or the splitting of a structure. It is performed by using a hammer or chain drag and changes in sound pitch are identified by the inspector. Benefits of this technique are the low cost of equipment and no training requirements to perform the test. Bridges with asphalt overlays cannot be tested by this method and results are mostly subjective due to hearing biases. The likelihood that an inspector can accurately hear delamination while cars are flying by at 70 miles per hour make it subjective in nature.
Infrared rays – Infrared is also used to detect delamination on the concrete surface. Changes in infrared radiation are noted down to get the results. Benefits of this technique offer quick results, minimum bridge down time and can be performed in moving vehicle.
Visual inspection – Although this method is non destructive but results obtained from this technique are subjected to change. Visual aids like magnifying lens also have limitation like it can't show microscopic cracks or voids. Condition assessment of subsurface is not possible with this technique. This service is also subjective in nature and cannot be relied on.
Ground penetrating radar (GPR) – This technique can inspect the non-metallic elements of any structure like reinforced concrete very easily. It can be performed on deck, floor, walls, and roofs. Its low and high-frequency electromagnetic radiations can detect the variety of internal and external deteriorations such as delamination, small as well as deeply seated voids, corrosion, cracks, cable duct and other defects. It can also investigate the quality and integrity of reinforced concrete.
There are many other nondestructive techniques such as Electromagnetic Testing, Laser Testing method, Ultrasonic Testing, Vibration analysis, Radiographic Testing, Microwave Testing, Magnetic Particle Testing and Magnetic Flux Leakage.
Infrastructure Preservation Corporation (IPC) offers road and bridge inspection services by utilizing efficient non-destructive testing methods to assure the safety of the people and accuracy of the result. We have customized products for bridge inspections and to analyse the internal components of Post Tension Tendon and the integrity of cable stays and high mast light poles.
For more information about our services and products, please visit our website https://www.infrastructurepc.com/. You can also get a free estimate of our services by providing your contact details and we will get back to you as soon as possible.
To know more about please follow this link: Bridge Inspection and Ground Penetrating Radar.
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