Keywords

1 Introduction

The policy shows that in the coming decades, China should vigorously promote and develop Prefabricated building. In China, the vast majority of traditional residential buildings still adopt traditional construction models, which gradually show many drawbacks in the development of the times. Prefabricated building is an inevitable trend of building industrialization. Its components are prefabricated in the factory with little external influence. They are transported to the construction site by truck and then fixed on the building, which can greatly improve the development benefits of construction projects. In China’s engineering construction practice, the prefabricated construction mode has been introduced. However, due to the short development time, it has shown many shortcomings in the development process, and has not fully played the advantages of Prefabricated building. In the new era, with the acceleration of urbanization, the scale of urban construction continues to expand, and new requirements have been put forward for the quality and efficiency of construction projects. At this stage, it is urgent to discuss the factors affecting the construction quality of Prefabricated building.

2 Connotation of Construction Quality of Prefabricated Building

The Technical Standard for Prefabricated Concrete Buildings. (GB/t51231–2016) defines prefabricated structures as building construction structures that integrate structures, perimeter protection systems, pipeline equipment, and embedded systems. As the carrier of green buildings, prefabricated components based on Prefabricated building can effectively improve the construction efficiency, reduce the labor productivity of construction personnel, improve the construction environment, reduce resource waste, shorten the construction time, and improve the construction quality [2].

The sixth edition of the Project Management Knowledge System Guide(PMBOK) defines the construction quality of Prefabricated building as follows: the construction quality of Prefabricated building is a series of quality management processes that occur in the decision-making and planning stages, research and design stages, construction preparation stages and construction stages of Prefabricated building. Through data collection, analysis, and execution during the project implementation process, issue project quality management reports, project quality inspection and evaluation documents, and engineering change requests, enabling relevant organizations to take effective actions to solve effective problems. According to national laws and regulations, technical specifications, standards, design documents and relevant contracts, the construction quality of Prefabricated building refers to the participation in project construction with the construction unit as the main body under the guidance of the construction quality management system of Prefabricated building, and the implementation of reasonable and effective quality management for relevant personnel, materials and engineering equipment, so as to control the construction equipment, construction scheme and construction environment, To achieve the goal of promoting high-quality development of construction projects.

3 Factors Influencing the Construction Quality of Prefabricated Building

Through in-depth investigation and study of the representative Prefabricated building projects in China - Shenyang, Shanghai and Prefabricated building projects in Chengdu; Visit the site and analyze the project, and summarize the factors affecting the construction quality of Prefabricated building in China at this stage as follows. (1) The practical experience of construction personnel and management personnel is insufficient. From a cognitive perspective, during the construction of Prefabricated building, many construction personnel and management personnel do not understand the construction drawings, component categories and construction technology; From the perspective of operation, construction personnel are not yet mature in handling relevant construction techniques and differences between different types of work; The awareness of construction cooperation is weak, and construction management personnel significantly lack experience in preparing special construction plans and disclosing construction techniques. (2) Improper operation of PC components and unreliable connection. Due to the lack of proficiency in the operation of the PC component lifting plan and the lack of experience of the connecting personnel, the PC components encountered varying degrees of collisions during the lifting process, resulting in quality issues; Insufficient experience of operators has led to insufficient strength and reliability of connection nodes. (3) PC structure and adhesive structure are misaligned. In the process of Prefabricated building construction, due to the fact that the formwork is a rotary building material, there is an objective problem that the width of the slab joint is different, which leads to the size error of the expansion formwork, and it is difficult to obtain the required accuracy. During the grouting process, due to the low efficiency of the grouting equipment, it is easy to cause quality problems such as uncompacted grouting, thereby reducing the quality of grouting [3]. (4) The quality of each part of the project is uneven, and quality problems still often occur in the cast-in-place Prefabricated building. The concrete cracks in the cast-in-place section and the holes reserved for overlapping construction processes have not been effectively blocked in a timely manner, and the implementation of related work is still relatively weak. (5) The project quality control is not meticulous, and the emergency management of quality issues is ineffective. Due to the lack of construction quality acceptance standards for Prefabricated building, the quality control system for Prefabricated building formulated by construction enterprises is not detailed enough and functional enough, and the carelessness of management personnel affects the subsequent acceptance work. Once quality problems occur in the construction process of Prefabricated building, only operators and construction management personnel can cope with them based on their own experience, resulting in poor emergency management of quality problems [4]. (6) Poor quality management during the construction process. During the construction of Prefabricated building, the information that affects the quality of each part of the project is easy to be lost or distorted, and it is difficult to determine the influencing factors and the responsible person in a short time after the quality problems occur [5]. In addition, by distributing online questionnaires to various construction enterprises, design units, and professionals (200 questionnaires were sent out and 182 valid questionnaires were collected), as well as various literature analyses, factors affecting the quality of prefabricated building construction also include inadequate management systems and relevant standards, improper protection of finished products during the construction process, and environmental impacts. The factors that affect the construction quality of prefabricated buildings analyzed can be classified into three categories: management system, management subject, and management method [13]. The specific classification is shown in Table 1.

Table 1. Summary of Factors Affecting Quality
Full size table

Using SPSS for confirmatory factor analysis, the above classified results were validated and tested. The analysis process is as follows:

Step 1: Analyze the KMO value (using an Excel table); If the value is greater than 0.8, it is very suitable for factor analysis; If it is between 0.7 and 0.8, it indicates that the data is more suitable for factor analysis; If the value is between 0.6 and 0.7, it indicates that factor analysis can be performed; If it is less than 0.6, it indicates that factor analysis is not suitable.

Step 2: If the P-value of Bartlett’s test is less than 0.05, factor analysis is suitable;

$$ {\text{X}}^{2} = - \left[ {{\text{n}} - \left( {2{\text{p}} + \, 11 \, } \right)/6} \right]{\text{In}}\left| {\text{R}} \right| \,\,\;\;\;\;\;{\text{df}} = {\text{p}}\left( {{\text{p}} - 1} \right)/2 $$

where: n is the number of data records; P is the number of variables in factor analysis; In() is a natural logarithmic function| R | is the correlation coefficient matrix R; X2 is the value of the statistic, and by looking up table X2 (0.01, df), the p-value can be determined.

Step 3: If there are only two analysis items, the KMO is 0.5 regardless.

(1)Analysis results of management system.

The survey data KM0 value is 0.805 > 0.6, which can be used for factor analysis. The Bartlett sphericity was used to test the data information, and the P-value was less than 0.05, indicating that the data is suitable for factor analysis. The correlation between items and factors is strong, and factors can effectively extract item information [12]. Name factor 1 as”management system”through information enrichment.

(2) Analysis results of management entities.

The KMO value of the survey data is 0.821 > 0.6, which meets the prerequisite for factor analysis. The data passed the Bartlett sphericity test, and the P value is < 0.05. The research data is suitable for factor analysis. The correlation between items and factors is strong, and factors can effectively extract item information. Name factor 2 as “management entity”through information enrichment.

(3) Analysis results of management methods.

The KMO value of the survey data is 0.755 > 0.6, which meets the prerequisite for factor analysis. The data passed the Bartlett sphericity test, and the P value is less than 0.05, making it suitable for factor analysis. The correlation between items and factors is strong, and factors can effectively extract item information. Name factor 3 as “management method” through information enrichment.

4 Control Measures for Factors Influencing Construction Quality of Prefabricated Building

4.1 Pay Attention to Various Quality Systems During the Construction Process

  1. (1)

    Construction process inspection and acceptance system

Prefabricated building infrastructure production, construction process control and approval system have a very important impact on the quality of Prefabricated building construction. For component production enterprises, the quality control process must establish a comprehensive system for receiving imported raw materials, certifying the quality of production processes, and certifying the quality of components and accessories. For construction units, when prefabricated components enter the construction site, a corresponding quality approval system must be established to ensure the quality approval system of the assembly process.

  1. (2)

    Pre employment technical training system

The construction of prefabricated facilities is carried out using new construction techniques, and the scope of the project is technical and comprehensive. At present, the management personnel of many construction companies and the first contact management personnel of production and construction units do not have sufficient experience in similar processes. Therefore, it is very important for prefabricated component manufacturers and construction units to establish a training system for management personnel.

  1. (3)

    Traceability mechanism for construction quality issues

Many structural quality issues themselves are not structural reasons, but may be due to errors in drawing design or component prefabrication. However, these errors were not discovered during the manufacturing and construction processes, but rather occurred after the building was built and used [5]. The building quality tracking equipment in the construction process of Prefabricated building can be built through RFID radio wave technology to realize the quality tracking process of Prefabricated building [7]. In the production process of prefabricated components, a single piece can be used as a basic control unit, and RFID chips or two-dimensional codes can be used as tracking technology to collect raw material information, production process control information, factory quality information, etc., quickly find the deep-seated causes of historical quality problems, further improve the quality management system and Prefabricated building control monitoring system, and better achieve the quality improvement goals of Prefabricated building.

4.2 Improve the Quality Management Ability of Management Entities

Improving the quality management ability of all participants in the Prefabricated building project will provide strong support and reliable guidance for the sustainable and healthy development of prefabricated building in China. Compared with the concrete pouring operation of traditional construction projects, the whole process of Prefabricated building construction, from drawing design, prefabrication to construction and sorting, has undergone significant changes. At present, the quality management concepts of participants such as development and construction units, measurement and design units, control and inspection units, production units, and construction and installation units have not yet fully changed [6]. For Prefabricated building, information exchange between building units should be strengthened, especially effective communication between component manufacturers and contractors, and technical training of management personnel should be strengthened, which is of positive significance for improving the construction quality of Prefabricated building and promoting their sustainable and healthy development.

(1) Change traditional quality management concepts. The second phase of the XX region project in Shenyang was completed in 2020 and is the first prefabricated integrated structural residential project in Shenyang New Area, with an overall composition coefficient of 40% [10]. Based on the research and analysis of the entire construction process of the project, the author found that the professional literacy and management ideas of the project managers still remain in the traditional on-site development stage. The concept of quality control during on-site construction only conforms to the concept of concrete structure quality management. This requires enterprises to increase relevant training to help quality management personnel at the production and construction line change their own management concepts and methods, so as to better implement the quality management requirements of prefabricated buildings. (2) Strengthen information exchange between subjects. In the whole production and construction process of Prefabricated building, the quality of communication between participants will directly affect the process quality, availability and safety of the construction project. In the actual construction process, it is inevitable that some conditions such as design drawings do not match the actual construction site conditions. For example, floor slabs should be separated and laid between floors; Drilling a well not only affects the waterproofing between floors, but also damages the structure of the prefabricated floor slab. Therefore, if the construction unit communicates with the design unit in advance, the design unit can set exposed holes in positions that have minimal impact on the mechanical properties of the structure and do not affect normal construction work, thereby effectively preventing the occurrence of the aforementioned problems [8].

4.3 Improving Quality Management Methods

  1. (1)

    Quality Information Sharing Based on BIM Technology

High quality information sharing is an important component of project management. From the perspective of the entire project lifecycle, if real-time information sharing and exchange cannot be achieved among various builders and regulators, enabling timely communication and coordination among all parties, quality issues cannot be resolved [9]. Nowadays, the traditional tripartite communication methods are mainly on-site communication or modern communication methods such as phone and WeChat. However, when quality problems arise, they often do not actively communicate, which has a significant impact on construction quality. Therefore, in order to better understand the initial quality management of Prefabricated building construction, it is necessary to coordinate the relationship between the participants so that they can maintain effective quality information management at all stages of the construction process. Therefore, in the new era, it is necessary to establish a component quality information sharing platform based on BIM technology, as shown in Fig. 1.

Fig. 1.
figure 1

Quality Information Sharing Platform Based on BIM Technology

Full size image

Throughout the entire lifecycle of the construction project, BIM technology is relied on to create a high-quality communication platform for participants, which can improve information dissemination and problem-solving among all parties [6]. The preliminary management of quality issues during the construction process has important practical significance. In the architectural drawing design stage, the design unit uses the BIM model to insert the quality information of prefabricated building design (including the detailed design content of the building drawings and the split design content of prefabricated components) into the 3D model, and then imports it. During the construction of Prefabricated building, if the prefabricated parts manufacturer accidentally misunderstands the disassembly design of specific parts or has a more reasonable disassembly method, it can mark the problem in the relevant part of the platform model and send it to the corresponding designer. Management personnel inspect the quality issues of the unit on the platform and provide feedback after consideration. With this system platform, more efficient communication among production, construction and design units of Prefabricated building construction can be realized, and the trouble of having to go to the production and construction site for inspection due to vague expression of traditional communication mode can be avoided, thus improving the efficiency of construction.

The prefabrication rate of the main structure of the XX Phase II affordable housing project in Jiangsu Province has reached 32%, and the assembly rate has reached 67%. The entire process of this project utilizes BIM technology, effectively improving the quality control awareness and operational level of employees, and achieving good results [11].

  1. (2)

    Continuous Improvement of Process Quality Based on QC Activities

“QC” is “Quality Control”. It refers to the activities related to the management and coordination of the quality control system in construction projects. Its main function is to minimize the occurrence of quality problems during construction. QC operations are widely used in traditional engineering quality control, as well as quality control during the construction process of prefabricated structures. PDCA quality management and other related theories can be integrated into the construction, manufacturing, and construction processes of prefabricated structures. After discovering quality issues in construction engineering manufacturing and design through QC activities, they can be resolved in a timely manner, and plans can be formulated to guide further work to solve the same quality problems [9]. Considering the main factors leading to the construction quality problems of Prefabricated building, the research team can propose appropriate mitigation measures, including the development of specific technical solutions; Avoid construction on rainy days; Improve fastening methods; Implement construction technical information; The introduction and application of integrity monitoring raw materials, and the implementation of model navigation systems. Through continuous improvement of process quality based on QC activities, the structural quality of the external wall composite insulation board in the engineering project has been greatly improved, and the talents of team members have also been improved to varying degrees.

5 Conclusion

In summary, prefabricated buildings, as a manifestation of modern architecture, effectively support and inherit the dissemination and development of green building concepts. However, during the construction process, there are some factors that affect the quality of prefabricated building construction. If not managed in a timely manner, it will be detrimental to the healthy and sustainable development of China’s construction industry. Based on the case study method, this article proposes control measures for the factors that affect the quality of prefabricated building construction, aiming to contribute to the healthy and sustainable development of the future construction industry.