With the widespread application of prefabricated concrete structures in the construction industry, corresponding quality inspections are crucial in ensuring their overall stability and safety.
1. Development Status
Currently, the inspection of prefabricated concrete structures focuses on material inspection, component inspection, and connection inspection.
1.1 Material inspection
Material inspection mainly includes inspection of steel bars, post-casting strips, connection materials, etc.
1.2 Component inspection
Component inspection mainly includes quality certification documents and on-site inspections. On-site inspections should include appearance defects, internal defects, position and size deviations, etc., and structural performance inspections should be carried out when necessary.
1.3 Connection Detection
Connection detection mainly includes the fullness of sleeve grouting and the fullness of grouting of grout-anchor lap joints, the quality of welding connections and bolt connections, the fullness of grouting at the bottom joint of prefabricated shear walls, and the quality of cast-in-place concrete in the cavity of double-sided superimposed shear walls.
2. Existing Problems
The overall status of quality detection of prefabricated concrete structures is currently good, but there are still some details that may affect the overall quality and efficiency of building construction.
2.1 Standards and specifications are not perfect
With the rapid development of prefabricated buildings, the development of prefabricated concrete detection technology is relatively lagging. The corresponding detection standards and specifications mainly refer to the "Technical Standards for On-site Detection of Concrete Structures", "Technical Standards for Detection of Steel Bars in Concrete", "Technical Regulations for Application of Steel Bar Sleeve Grouting Connections" and other specifications or quality inspection station requirements. There is a phenomenon that similar projects may adopt different detection standards; in addition, with the rapid development of non-destructive testing technology and the addition of Internet technology [2], more new equipment or methods will be developed. If the detection standards and specifications are not updated in time to keep up with the pace of technological development, it will inevitably lead to a decrease in project efficiency.
2.2 The overall detection is relatively weak
The existing detection technology has mature detection methods for the quality of concrete raw materials, steel bar materials, and component quality, but it is difficult to detect the overall structural performance. The detection of nodes only focuses on the strength of grouting materials, grouting fullness, etc. There is no more detailed and in-depth research on whether the insertion depth of the steel bar in the sleeve is sufficient, the internal defect detection of the joint, whether the roughness of the concrete bonding surface is sufficient, and whether the structural entity inspection is necessary.
2.3 There are few high-quality talents in the industry and insufficient innovation ability
The detection industry is at the end of the industrial chain and the salary is not high, so it cannot attract high-quality talents. In addition, there is insufficient thinking about technological innovation, and new technologies cannot be applied to detection work as soon as possible, resulting in slow technology updates in the industry. The work is relatively "low-end" and often not taken seriously, and then the unfavorable factors will be further aggravated, thus forming a vicious cycle and restricting the development of the detection industry. In particular, the fierce competition in the industry has led to some detection units being eager for quick success, or because of various external factors, the equipment technology is updated slowly, and few detection personnel are organized to train and learn new technologies and new equipment in the industry, which further restricts the development of the industry.
3. Solutions
3.1 Improve standards and specifications and update and revise them in time
To improve the quality of prefabricated buildings and make sure that every step and every detail of the current prefabricated concrete testing work has a basis, we need to improve the prefabricated concrete testing technology system as soon as possible, check for omissions and shortcomings, improve the standards and specifications for prefabricated integral concrete structure testing, and update and revise them in time so that the corresponding standards and specifications can adapt to the development of new technologies.
3.2 Improve the content of overall testing
Prefabricated building quality monitoring is a systematic work. From the design stage, scientific and reasonable force calculations must be carried out, strict quality inspections must be passed by the factory, and assembly accuracy and node tests must be carried out on-site. At present, some provinces and cities (such as Shanghai, Jiangsu Province, and other regions with rapid prefabricated development) have taken the lead and added content such as structural entity quality testing in the landmarks. The content of node testing is also richer, and it is expected to be promoted nationwide based on actual application results. At present, our province has also published corresponding local standards, leading the country.
3.3 Increase R&D investment and improve innovation capabilities
Increase investment in R&D, increase the attractiveness to high-end scientific research talents, actively cooperate with universities or research institutes, accelerate the application and transformation of detection research results, accelerate the upgrading of detection technology, and improve the efficiency and accuracy of engineering detection. Regularly carry out skill training for detection practitioners, encourage detection practitioners to think about detection work, and improve innovation capabilities.
4. Summary
With the rapid development of the prefabricated building industry, the detection of prefabricated concrete structures has received everyone's attention, relevant policies and regulations have been introduced one after another, more and more technical research and development have been carried out, and the team of relevant practitioners has also grown rapidly. I believe that through the efforts of all aspects of the industry, the domestic prefabricated concrete structure detection industry will usher in a new development trend!
