Steel structure has become the most important type of structure in construction engineering today. Due to the characteristics of light weight, high strength, and strong deformation ability, steel structures have become ideal structures for many large-scale engineering projects. With the use of steel structures in various projects, not only has the construction power of the project been greatly increased, but also the construction cost has been reduced. Due to the characteristics of steel, there are many unavoidable problems, which are accompanied by the widespread application of technologies and methods for detecting and fixing steel structures. Although steel structural materials are widely used in construction projects, they also have certain drawbacks and require safety assessment to ensure the safety of people's lives and property.
1. Detection of cross-sectional thickness of steel structures
The thickness of steel structure sections is often affected by the precision of processing and section corrosion. Especially rust can cause thinning of the section and a decrease in load capacity, which has a huge impact on the safety of the entire steel structure. Therefore, measuring the cross-sectional thickness of steel structures is a very important task.
Currently, a thickness gauge is commonly used to measure the thickness of the section. Using ultrasonic pulse reflection method. When ultrasonic waves propagate from one uniform medium to another, they undergo reflection. When the ultrasonic waves from the probe reach the interface, they are reflected back and accepted by the receiving probe. Calculate the thickness of the tested object by measuring the time between the emission pulse and the acceptance pulse.
2. Measurement of coating thickness for steel structures
In the determination of steel structures, the quality of the coating will directly affect the firmness of the steel structure. Generally, the thickness of the coating is measured using a magnetic thickness gauge. When using a magnetic thickness gauge, it is necessary to adjust the instrument in advance so that it can work properly. First, confirm the measurement range. Next, start the measurement. During the measurement, first remove the dust and oil stains on the coating surface to prevent affecting accuracy, and then touch the tested coating with a probe.
Based on the actual situation, first confirm whether there is a coating. Due to long-term natural environmental impact, the coating may be damaged or even disappear. The presence or absence of residual coatings is an important limit for the degree of structural corrosion.
3. Deflection measurement of steel structures
Steel structures generally have a large span, making it difficult to measure deflection. It is necessary to use a large amount of force to tighten the steel wire, and it is also required that the steel wire has a certain strength, and completion records and reverse arch or deflection values should be kept. Due to the fact that only by confirming these two values can the stress deflection value of the roof truss under load be confirmed, a large number of steel structure deflection measurements in China have started to use level gauges and total stations. The characteristics of level gauges include high-quality telescope optical systems, sturdy and stable instrument structures, high-precision micrometer devices, highly sensitive tube level devices, and high-performance compensation devices. The total station features an automated, digital, and three-dimensional coordinate measurement system that combines automatic ranging, angle measurement, calculation, and data processing, as well as automatic recording and transmission functions.
4. Quality Inspection and Appraisal of Steel Structures
Steel structures have the following drawbacks during manufacturing: dimensional deviation, nonlinearity of components, low quality of structural welding and riveting, poor quality of primer and coating, etc. Due to the existence of these shortcomings and their mutual influence, all and part of the structure will be damaged to varying degrees.
Defect detection of 5 steel structures
Ultrasonic and electromagnetic methods are commonly used for detecting defects in steel structures. When inspecting steel structures, checking the material of the steel structure is an important aspect. The best method is to take samples from non main stress areas of the structure for testing, in order to confirm the corresponding strength target.
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