Some thoughts on building safety appraisal

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With the rapid development of China's economic construction and the continuous improvement of people's living standards, large-scale capital construction has been carried out in China, and a large number of civil and industrial buildings have been built. Due to the influence of building construction age, service life, different natural disasters and other factors, the safety of many TPUs used in 1 series of 3D printing buildings needs to be evaluated; In particular, some completed or under construction buildings have been damaged to varying degrees due to the influence of various factors to be identified. Therefore, it is necessary to conduct building safety identification. Due to the commercialization and marketization of building products, the building appraisal work and appraisal conclusion will have a direct economic interest relationship with all relevant parties, which also leads to some legal problems. As a building safety appraisal unit and appraiser, various technical and non-technical problems in the appraisal work are worth discussing and studying, Therefore, according to the problems encountered by the author in the structural safety appraisal of some buildings, the author puts forward his opinions, hoping to play a role in attracting jade. If there are any improper points in the article, please correct them.

II. Some thoughts on the safety appraisal of buildings

there are various problems to be solved in the safety appraisal of buildings, some of which are purely scientific and technical problems, and some of which have nothing to do with the level of science and technology. Many problems may be encountered in the safety appraisal of buildings. Therefore, some opinions on the following issues are given:

1. The qualification of inspection and appraisal is not a problem on the surface, but it is not. The development of any building safety appraisal work depends on the inspection data. If the inspection data are comprehensive, detailed and accurate, the appraisal work will be more scientific. However, what kind of inspection data can have legal effect? According to the provisions of the Metrology Law of the people's Republic of China, "a product inspection institution that provides notarial data to the society must pass the appraisal, testing ability and reliability assessment by the metrological administrative department of the people's government at or above the provincial level", that is, a unit that has been metrologically certified, obtained the testing qualification and has the CMA seal, and used the testing instruments that have been metrologically certified to test the test data by certified technicians, The test data stamped with CMA seal on the test data issued by them shall have legal effect, and the data provided by other units or individuals shall not have legal effect. However, in practice, it seems that the qualification of building safety appraisal is not completely clear. The appraisal work and appraisal report carried out by the expert group recognized by the relevant administrative department have legal effect, and the appraisal report provided by the unit with inspection qualification also has legal effect. However, the question is whether the appraisal report with the seal of the research institution and relevant academic groups has legal effect, The people's courts in some places recognize the legal effect of the appraisal report, while the people's courts in some places do not recognize the legal effect of the appraisal report; This has caused some social problems, which should be highly valued by the relevant competent departments

2. Scientific problems of detection and appraisal projects building safety appraisal is a complex work with high scientific and technological content. Because building construction involves many problems and departments, such as geological survey of construction site, planning and approval of buildings, design, construction, supervision and building management, However, this paper mainly discusses the technical problems in the safety appraisal of building structures. The first is the problem of material strength testing

due to the level of science and technology, detection technology, equipment and other reasons, the accuracy of the inspection data of the detected objects may be problematic. For example, it is difficult to accurately evaluate the strength grade of mortar in masonry structures, and there are many uncertain factors affecting the sampling data (sampling parts, mortar joint thickness, used time, etc.), so the scientificity and rationality of the testing data are worth considering; It is also difficult to determine the design value of the compressive strength of the built masonry columns. At present, there is no relevant literature on the in-situ test technology of masonry columns; Another example is the on-site testing of concrete standard compressive strength. The testing results of different testing methods are often inconsistent; The difference of detection quantity and location will also affect the detection data

secondly, at present, the relevant specifications are not perfect, and the operability of relevant data processing is not easy to grasp. Although the specifications adopt the mathematical statistical theory, the statistical processing method needs to be further studied due to the different nature of the problem. For example, the compressive strength of rock mass in the code for design of building foundation is now the requirement for the number of test samples of a popular material, and the national standard is different from the local standard, Different testing units in the same location may adopt different testing methods for the same project, and the design strength calculated according to different standards is also different, especially when the sample variability is large

in a word, there are many such problems, which will not be solved one by one here. However, it should be pointed out that the measurement data provided by the inspection department with the room type level should be scientific and fair, and the data provided by each technician should bear the corresponding legal responsibilities. In addition, the existing problems are the basis of the appraisal work. The design specifications include national and local specifications, as well as specifications of the same industry without test piece thickness of (2.0 0.2) mm. According to different specification requirements, there are different sampling standards and evaluation standards for the same problem. Sometimes the evaluation results of the test data vary greatly. The question is which specification will be used as the evaluation basis? At present, different scholars have different views on it, and both the design unit and the testing unit hope to have a clear statement

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