Non destructive testing methods may cure our bridge issues

August 27th, 2018 Author: Doug Thaler

Current manual inspection of a bridge cable stay. Still in use today, above.

Since the first bridges were erected, bridges have been inspected manually or visually. Many of these manual inspections believe it or not, still exist today.

Latest in Cablestay bridge inspection services.

With many of the nations bridges exceeding their useful life expectancy, a good percentage of these bridges are in dire need of attention. Federal and state budgets are being squeezed and there is certainly not enough money in the till to start re-building every deficient bridge so how then do we properly maintain our bridges and infrastructure.

The best solution lies in non destructive testing, methods of inspection that leave the item being inspected exactly as it was found. These methods have been around for years.

Technologies like electro magnetics, ultrasonics, lidar, radiography and others have been used in labs for generations.

These technologies have been used to inspect everything from car parts to ski lifts and oil pipelines. By applying these technologies and incorporating robotics we have the ideal solution to re-writing the book on infrastructure inspections. Whats more, by better understanding a structures actual condition you can then set in motion a maintenance plan to properly maintain and repair deficient structures.

Whats more by better understanding a structures actual condition you can then set in motion a maintenance plan to properly maintain and repair deficient structures.

Nondestructive testing methods used in bridge inspection

Visual inspection – this is the most common form of non-destructive testing as they don’t need any special testing equipment. It can be done quickly and is more economical than the other non-destructive methods but the subjective nature of visual inspection can produce variable and inaccurate results.

Digital image processing – Earlier two methods Neuro-Fuzzy Recognition Approach method (NFRA) and the Simplified K-Means Algorithm (SKMA) method (Lee 2011) were developed to recognize surface defects like rusting by using digital color imaging processes.

The NFRA methods utilized artificial intelligence to separate rust pixels from the background pixels while SKMA method utilized a statistical approach to separate object pixel from the background pixels. These methods couldn’t generate reliable results under specific environmental conditions. Later on, another advanced method rust-color-spectrum-based rust defect recognition method (RUDERM) was developed which utilized color space unlike greyscale images used in earlier methods to identify rust spots and discriminate it from the background and other defects (Shen et al. 2013).

The eddy current method – It works on the electromagnetism principal and utilizes electromagnetic induction to detect defects in conductive materials. It has several advantages which makes it a practical option for field inspection. One of the advantages is that it can penetrate both conductive and non-conductive steel coatings to identify underlying cracks without damaging the integrity of the coating system of the bridge.

Radiographic method – This is oldest and traditional approach to non-destructive testing. It is similar to X-ray testing and used to inspect the quality of the butt welds. In this method, penetrating radiation is absorbed to generate a high contrasting image indicating the cracks and discontinuities in the welds. Although this is an effective method but the high radiation can be harmful to the inspection crew and the public.

Ultrasonic testing

This method works on high-frequency sound waves to detect and size the defects in the welds. Advancement in this method made it automated which utilizes robotics to ensure complete coverage of the area under inspection and minimize human interaction (Badar 2008). It can easily locate surface and subsurface defects but requires high skills to operate the system.

Infrastructure Preservation Corporation (IPC) develops robotic nondestructive testing inspection services for infrastructure assets worldwide. Currently focused on transportation infrastructure, IPC’s technology can be used across infrastructure assets world over. We assure the safety of the inspection crew and the public during the inspection by using advanced and automated inspection systems under the supervision of experienced and certified personnel.

To know more about our products and services or get a free quote, visit our website https://www.infrastructurepc.com/. You can leave your contact details with us and our team will get back to in shortest time possible!