Inspection of Large-Scale Metal Structures and Installations Using Bridges as an Example
Engineering discoveries, industrial development, and centuries of accumulated experience have transformed the trends and principles of bridge construction. Over the centuries, both the appearance of bridges and the materials used in their construction have changed. Wood and stone were replaced by concrete and steel, and eventually, fully steel structures. Why steel? This choice is due to its unparalleled characteristics of flexibility, strength, and durability.
The structural elements of bridges (beams, arches, suspenders, and trusses) worldwide are made from high-strength steel of various thicknesses.
The quality of the material used in construction directly affects the reliability and safety of the entire structure. However, even if the metal passed all inspections during construction, it is essential not to forget the need for ongoing monitoring for wear after the structure is put into operation. Timely detection and correction of deviations are critical for the normal and safe functioning of any elevated structures.
Monitoring the Hardness of Deep Layers in Metal Structures: Determining Stress State and Force Factors
The most effective method for detecting and analyzing defects in large-scale metal structures is coercive force measurement. The value of the coercivity of an element's external magnetic field provides insight into the material's texture and heat treatment regime. Significant deviations from the norm in measurement results indicate the presence of defects and the need for more in-depth inspection.
To measure magnetic field characteristics, the MA-412MM coercimeter (magnetic analyzer) is suitable.
Device Purpose – Non-Destructive Testing of Ferromagnetic Materials:
- local inspection of surface layers of steel structures;
- determination of bulk hardness, mechanical properties, and structure of parts;
- detection of stress state.
Advantages of MA-412MM:
- high stability and accuracy of readings;
- built-in battery for field operation;
- quick calibration of the device using samples.
Steel Hardness Monitoring
When monitoring large structures, laboratory inspections can be challenging. To measure hardness using a stationary hardness tester, it is necessary to extract part of the structure and deliver it to the laboratory, which is practically impossible when it comes to bridges. The optimal solution is to use portable devices.
Given the technical features of the structures, we recommend using the portable dynamic hardness tester TKM-359C for monitoring the structural elements of bridges.
Why TKM-359C?
- Low sensitivity to surface roughness and curvature allows for the inspection of unprepared surfaces.
- The device's memory includes settings for inspecting structural, corrosion-resistant, heat-resistant, and stainless steels, eliminating the need for additional calibration.
- The spatial orientation of the sensor does not affect the measurement results, allowing for inspection in the most inaccessible places.
For bridge structures, it is best to use the G-type sensor with increased impact energy alongside the hardness tester.
Material Integrity Inspection
During prolonged use, cracks may appear on the surface of steel structures. These can be detected visually or with a flaw detector. Timely identification of the degree of damage will help extend the safe service life.
To measure the depth of surface-reaching cracks, the 281M portable crack gauge is suitable.
Advantages of Using the Device:
- The electro-potential method allows for rapid and highly accurate determination of crack depth, much more precise than ultrasonic or eddy current methods.
- The device's memory includes scales for magnetic and austenitic steels, covering the main inspection tasks.
- Thanks to the availability of various sensor designs ("1x4", "2x2", or "3+1"), it is possible to inspect surfaces with the most complex configurations.
- Curvature of the surface does not affect the measurement results as the contact electrodes are spring-loaded and movable.
! To detect non-surface-reaching cracks, we recommend using magnetic particle, eddy current, capillary, and other methods.
The specialists at NPP "Mashproject" will help select the right device for your tasks, as well as advise on delivery times and the possibility of testing the equipment at your site.
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