Common quality problems of steel structure canopy in LNG receiving station

Domestic LNG transmission pipelines and supply generally show a statistical analysis trend of positive correlation, so the overall construction quality of the shed steel structure project is also open to question. The design and construction technical standards of many steel structures canopies are inconsistent, and it is easy to have common quality problems such as roof panel bending and bar bending, which will directly affect the normal use of various gas filling equipment and devices under the canopy. In the process of centralized investigation of quality problems, it is also necessary to ensure the safety of the overall structure.

一. Common quality problems of the steel structure of the canopy of the LNG receiving station

1. Rod specifications and components do not meet the design standards within the construction area of the domestic LNG receiving station, there are many common quality problems in the design and construction stages of the canopy project, which can directly restrict relevant construction technicians and information sharing among managers. Rod specifications and components do not meet the design standards, which is one of the common problems in the design stage of canopy steel structure projects and can be directly reflected in the quality inspection process of subsequent construction materials and other related technical resources. Some canopy steel structure projects generally have strong professionalism, and the evaluation standards for the quality of relevant key materials and enclosure structure support are relatively high. The specifications and components of the rods do not meet the design standards, which is related to the fact that many designers did not conduct on-site surveys at the construction site, and were unable to dynamically coordinate the relevant material specifications and quantities according to the overall planning and design principles of related buildings such as LNG receiving stations information, so it is easy to expose more common quality problems in the design stage. The rod specifications and components do not meet the design standards, which is related to the inconsistency of the quality evaluation standards for the current steel structure construction projects of the canopy.

2. Unreasonable installation of supporting structure of the enclosure

In the steel structure project of the canopy in the domestic LNG receiving station, common problems in design and construction are very common. For example, the support installation of the enclosure structure is unreasonable, which easily exposes the true level of the strength and performance of the canopy itself. There are many hidden quality problems in the two main stages of design and construction, which will also directly affect the occurrence of problems such as abnormal support form and uneven force. The envelope structure needs to be comprehensively evaluated according to the relevant technical schemes and technical resources of the construction of the canopy, and the actual operation quality of the support installation will also be limited by many external factors. Due to the relatively large number of construction operations covered by the canopy steel structure construction project, it is even more necessary to strictly inspect the common quality problems in the construction process. According to the stress of the relevant components of the steel foundation structure, it is necessary to reasonably configure the support of the enclosure structure to accurately control the integrity of the mechanical structure indicators and the accuracy of the data results. The phenomenon of unreasonable installation is relatively common, and it will directly cause many problems such as substandard structural strength.

3. The bending and deflection of the rod are too large

In the steel structure project of the canopy in the domestic LNG receiving station, the problems of rod bending and large deflection are relatively serious, and can directly affect the integrity and correctness of the mechanical indicators of the relevant steel structure. Especially in the process of rationally distributing the steel structure materials of the canopy, the phenomenon of rod bending and large deflection is relatively common, which will directly affect the accuracy of subsequent welding operations, and have a certain impact on the design standards in the relevant design drawings. The common problems of construction quality, such as rod bending and large deflection, are relatively common in shed steel structure projects, but they will also be affected by related factors such as many design drawings and inconsistent measurement standards, and will also be affected by construction site technicians and managerial influence. In the process of detailed planning and deployment applied to the construction process of the canopy structure, the main factors that are prone to rod bending and large deflection are human misoperation and inconsistent design and construction standards, and it is easy to have a serious impact on the specific installation steps of the support of the enclosure structure.

4. The quality of the butt weld does not meet the standard

In the construction stage of the steel structure of the canopy, the quality of the butt welds does not meet the standard is also relatively common, but it will directly affect the integrity and reliability of the basic mechanical indicators of the steel structure. Since the rod needs to be re-welded after being cut off, but in the high-altitude or low-altitude operation site, the corresponding technical supervision measures and quality inspection measures are not strictly implemented, so it is easy to have the problem of unqualified butt weld quality. With the support of gas-shielded weld technology, many construction technicians and management personnel can quickly check the causes of problems such as unqualified butt weld quality, but they can no longer reduce the waste of material resources and give corresponding solutions. The construction quality of butt welds does not meet the relevant standards, which is related to the insufficient construction quality supervision ability of many steel structure engineering construction projects, and the professional training for construction technicians is not strong. Many construction technicians are easy to adopt aggressive working methods. It is not possible to predict the occurrence of such common quality problems in time. The quality of the butt welds does not meet the standards, which is related to the current quality supervision of the steel structure construction stage of the shed is not strong.

5. Anti-leakage and anti-corrosion measures are not in place

In domestic LNG receiving station shed steel structure engineering projects, the lack of anti-leakage and anti-corrosion measures will directly affect the comprehensive utilization rate of liquefied natural gas resources, as well as personal safety in a certain areas, and there will be more safety liability accidents. In the canopy steel structure project, the extensive application of anti-leakage measures is mainly concentrated on the component coating and the roof panel layer, so it will also affect the waterproof performance of the enclosure system. Some canopy steel structure construction projects will separately set up anti-corrosion coatings, but the actual application quality is still open to question. Insufficient anti-leakage and protective measures will also be directly reflected in the installation quality inspection of prefabricated components and other related processes, and can directly affect the overall safety of instruments, equipment, and personnel under the canopy. Since the specific application quality of anti-leakage and anti-corrosion measures mainly depends on the main mechanical properties of the steel structure of the shed and is sensitive to the surrounding environmental conditions and related climatic conditions, it will also directly restrict and limit the overall stability and safety of the roof system reliability.

二. Quality control measures for the steel structure of the canopy of the LNG receiving station

1. Material specification and quantity inspection

According to the overall construction status of my country’s liquefied natural gas receiving station, it is necessary to conduct a feasibility analysis on the construction requirements of the shed steel structure project in a timely manner, so as to further highlight the associated common quality problems, and under the guidance of professionals, timely provide come up with a corresponding solution. In the construction preparation stage, the relevant technical personnel of the construction unit needs to strictly check the material specifications and quantities, and under the cooperation of professional management personnel, record and statistically analyze the material resources and equipment that need to be equipped during the construction process of the canopy steel structure project. Due to the specific construction form of the LNG receiving station, the control over the fire safety performance indicators is relatively strong. Therefore, in the process of intensively carrying out the construction of the steel structure of the canopy, it is necessary to conduct strict quality inspections on the incoming materials and other materials. , among which the material specification and quantity inspection work is relatively simple. It can be strictly compared with the relevant content in the unified batch of product instructions and specification detailed documents. However, it is necessary to check whether the main material specification and quantity are consistent with the relevant requirements in the design drawings.

2.Component material and performance inspection

Before the construction of the canopy steel structure project, it is necessary to strictly check the main materials and performance indicators of various materials and components, so as to fully ensure that the mechanical indicators of the steel structure are within the controllable range. Many light steel canopy projects require strict inspection of component materials and performance indicators for abnormalities, and comprehensive quantification and statistical analysis of relevant performance data indicators based on the installation form of customized prefabricated components. In the process of strictly inspecting component materials and performance indicators, relevant departments and technical personnel need to follow the relevant requirements and standards in the design drawings and design schemes, benchmark the actual conditions in the construction site, and try to choose solutions with lower risks. . In the process of intensively carrying out component material and performance inspections, both the construction unit and the supervisory unit need to strictly control the relevant inspection environment at the construction site, and ensure that the accuracy of various data indicators is within a reasonable range. Especially in the surrounding area of the LNG receiving station, during the quality inspection process, it is necessary to avoid open flames, so as not to affect the stability of the mechanical indicators of the steel structure of the canopy, and directly affect the stability of the construction materials and performance indicators.

3.Node connection visual inspection

During the construction of the liquefied natural gas receiving canopy, it is necessary to carry out strict quality control on the specific construction stages, and conduct a comprehensive inspection of the connection appearance of the relevant steel structure nodes in accordance with the evaluation standards of relevant professional technologies, so as to fully guarantee the various enclosures can play its original role normally.On the basis of rationally allocating prefabricated components, bearing supports and other related construction materials, construction technicians and management personnel also need to carefully investigate various common quality problems and potential safety hazards. In the process of comprehensively inspecting the appearance of joint connections, relevant departments need to record in detail whether there are weak stress points in the steel structure and carry out the quality inspection in strict accordance with the relevant requirements and quantitative evaluation standards in the design drawings and construction technical plans. In the process of intensively carrying out the visual inspection of node connections, professional technicians and managers need to strictly compare the actual application quantity and specifications of steel materials, and fully ensure the stability and safety performance of the steel structure of the canopy within a scientific and reasonable range. At the same time, for related technical resources such as rods that need to be truncated, it is necessary to mark in detail whether the appearance inspection results are qualified at the connection nodes. In view of common quality problems such as large deflection and bending of rods, relevant professional technicians and management personnel also need to focus on checking whether there are abnormal protrusions and bends in the appearance of joint connections during the visual inspection of joint connections.

4. Weld quality inspection

In the steel structure construction project of the canopy of the domestic liquefied natural gas receiving station, the quality inspection of the weld seam is very necessary and critical, and it can also directly affect the resolution of common quality problems. In the process of feasibility analysis and economic analysis of the relevant design indicators of the canopy steel structure, the dynamic balance of construction quality and the safety of construction progress and cost need to significantly improve the application level of related construction procedures such as rod welding, and it is necessary to check for abnormal conditions such as abnormal protrusions in a timely manner on the basis of comprehensive coverage of quality inspection standards. In the process of quality inspection of welds, it is necessary to strictly compare relevant inspection indicators such as appearance quality and ultrasonic flaw detection results, and it is necessary to ensure that the comprehensive utilization rate of various steel structure materials is within a controllable range. LNG receiving stations of different construction scales need to deploy and apply different types and quantities of steel structure materials, but it is also necessary to strictly inspect the construction quality of connection nodes and butt welds to avoid problems such as substandard structural strength and quality. In the process of intensively carrying out weld quality inspection, it is necessary to dynamically coordinate relevant technical resources of steel structure materials in the construction site according to the relevant requirements and quantitative evaluation standards in the design drawings and construction technical plans, and to conduct professional non-destructive quality inspection With the support of equipment, data quality management is performed on the ultrasonic detection results. The quality inspection process of the butt weld can directly affect whether the basic mechanical indicators of the shed steel structure are scientific and reasonable, and can further affect and expand the implementation path of post-maintenance and operation and maintenance management.

5.High-strength bolt connection inspection

In the domestic liquefied natural gas receiving station, it is necessary to comprehensively monitor the construction process of the steel structure of the canopy, so as to fully ensure that the connection quality between various installation and welding operations is within the controllable range. The inspection of high-strength bolt connections is very necessary, and it also needs to be effectively linked with the node connections and weld construction procedures, and it is necessary to avoid prominent common quality problems. In the process of the comprehensive inspection of the connection state of high-strength bolts, it is necessary to gradually check the abnormalities and problems in the final torque test results according to the test results of the small hammer. High-strength bolts are widely used in light steel structures, and have relatively high requirements and quality standards for relevant construction materials and fixing measures, so they can also directly demonstrate the reliability of the strongest indicators of the canopy steel structure. In the process of the comprehensive inspection of the connection status of high-strength bolts, relevant departments and staff need to focus on checking the unclear position of the connection nodes, and conduct centralized investigation and solution to the possible expansion joint problems of high-strength bolts. For the construction site of the canopy steel structure, the connection inspection results of high-strength bolts need to be synchronized to the quality supervision platform of the project in a timely manner, and other quality evaluation results should be checked repeatedly to avoid related common quality problems.

6.Quality inspection of anti-corrosion and anti-leakage layer

In domestic liquefied natural gas receiving stations, the steel structure of the shed needs to have strong anti-corrosion and anti-leakage properties, and some steel structure materials also have excellent properties such as fire prevention. Therefore, in the process of comprehensive quality inspection of the anti-corrosion and anti-leakage layer, it is necessary to conduct a centralized quality inspection for the materials and main components used in the steel structure of the shed, and on the basis of sampling inspection, directional screening of unqualified steel structure materials. Especially on the basis of obvious corrosion or serious partial corrosion of some steel structure components, it is necessary to carry out anti-corrosion coating operation in time to avoid affecting the main strength performance index of the steel structure of the canopy. However, in the process of reprocessing the anti-corrosion layer, it is necessary to remove the floating rust on the surface in time and ensure the stability and safety of the main frame of the steel structure. If there are related safety hazards such as falling of the steel structure of the canopy, professional technicians and management personnel need to focus on checking whether the steel structure has uneven stress. In the process of comprehensive quality inspection of the anti-corrosion and anti-leakage layer, relevant technical personnel and management personnel also need to carry out targeted anti-corrosion and anti-leakage protection measures in a timely manner according to the local climate conditions and environmental governance effects.

In recent years, with the continuous improvement of my country’s economic level, the construction industry is also developing and progressed rapidly. People pay more and more attention to the quality and construction safety of construction projects. The most important thing for a project is the key technical points of construction. It is related to people’s life and property safety. Combined with the characteristics of its own balance system, considering the construction difficulties such as large structural span, few support points, and high-altitude installation hazards, the construction technology of integral assembly of ground parts, one-time hoisting by a large crane outside the span, and overall closure after unloading in partitions is adopted to ensure canopy steel structure installation accuracy.