Abstract
Purpose: To solve the problems of low integration accuracy and long integration time of traditional prefabricated construction information integration methods. Method: A method of assembling building information integration based on BIM and RFID technology was proposed. By analyzing the information integration principle of BIM RFID (Building Information Modeling Radio Frequency Identification) technology, starting with rfid technology, we use rfid technology to collect the information of prefabricated building components and obtain the coding information of component data. Experiment: Combining Markov model and fuzzy algorithm, the obtained coding information is preprocessed. According to the processing results, statistical feature clustering algorithm is introduced to integrate the construction information of prefabricated buildings. Result: The precision polyline of the prefabricated building construction information integration method based on BIM and RFID technology showed a steady increase, and it was close to 100% in the later stage. At the same time, the time consumed by this method was within 0.41 s, with high accuracy, high efficiency and high practicability.
Introduction
China is in a period of vigorous development of the construction industry, and the construction mode that occupies a leading position in the industry is the cast-in-place concrete mode. The traditional cast-in-place concrete construction method has obvious disadvantages: high labor and material costs, large environmental pollution, messy site, complex management, etc. [1]. In the face of various problems in the traditional construction industry, the prefabricated building is an ecological solution. The prefabricated building itself has the characteristics of separating the production site from the construction site. The production process of building components mainly takes place in the factory, and the construction can be completed at the construction site only by simple structural work. This construction model with production characteristics can effectively shorten the total construction period, coordinate project management, improve building quality, reduce production energy consumption, and reduce labor and material costs. The most remarkable feature of precast concrete (PC) buildings is the production mode of splitting first and then assembling. The general engineering process of PC building is to divide the building into structural modules such as columns, beams, slabs and shear walls, or functional modules such as independent suites, independent bathrooms and independent balconies for design and production, transport them to the construction site through the logistics network, and complete the construction through hoisting and splicing. In the production process, the pouring construction site of the building has been transferred from the traditional construction site with high noise, high pollution, high potential safety hazards and affected by natural climate to the PC component factory with industrial production line with low noise, low pollution, low potential safety hazards and free from natural climate [2]. In this process, the integration time of production and construction is an important guiding factor affecting the construction efficiency. Therefore, how to control the integration time by using information integration technology to form a more efficient operation mode is one of the current important issues in this field.
Due to the large number of participants in the construction industry, a wide range of related disciplines, and the complicated links between disciplines, the absence of a reasonable management plan will often lead to the loss of one or the other. Learning from the successful experience of other industries, we can find that the information technology industry has sprung up in recent years, rapidly occupying a huge proportion of market output value. Information integration technology is exactly the most effective technical means to improve industrial production efficiency. With the help of information integration technology, a brand-new building system is established to promote the sustainable development of building industrialization [3]. The traditional concrete building is not formed at one time, but built layer by layer. The key structural components, external enclosure structure and internal decoration structure have very large space for on-site modification and later adjustment, and the fault tolerance rate of design and construction is high. The prefabricated building directly assembles the finalized prefabricated building components, and the modification space on the construction site is only the cast-in-place assembly node. Once the components have defects, the modification of the components will take many times more time than the traditional pouring method. The reason is that the status of fabricated components in the construction life cycle of buildings should not be separated as simple factory products, but should be regarded as finalized building products considering the whole process. The possible construction process coordination needs and the professional coordination needs of hydropower and HVAC (Heating Ventilation and Air Conditioning) industry in the construction process should be included in the consideration of component deepening design. Industrialized production and the participation of more people put forward higher requirements for information management. However, the current education system in China does not advocate the cultivation of all professional talents. Instead, it focuses on the further study of talents in a single professional direction, such as across mountains. Obviously, it is impossible to change the talent structure overnight. In the case that there are not enough professionals in the whole process, the feasible method is to set up a special organization to analyze the positioning of prefabricated components in the whole life cycle of building construction, investigate and analyze the needs of technicians at all stages of the whole life cycle of building construction for prefabricated components, and implement overall management. However, there are no supporting management measures in the dimension of the whole life cycle of PC buildings, and the information transmission mode is more traditional. The working mode of information interaction and rework between the design party, the production party, the transportation party, the construction party and other participants will still lead to information loss and information lag in the information exchange process. It is imperative to introduce information integration technology to the prefabricated construction industry [4].
Hu et al. [5] studies the development and application of BIM
However, the above three methods have low accuracy and long integration time, resulting in poor integration effect. Therefore, in view of the problem of accurate management and efficiency in the construction process of prefabricated buildings, in order to improve the accuracy of the system while ensuring the operational efficiency, based on the idea of combining radio frequency identification equipment (RFID) and building information modeling (BIM), a method of information integration for prefabricated building construction based on BIM and RFID technology is proposed. This method is different from the traditional method. It can realize the dynamic management in the construction stage of prefabricated buildings while ensuring the computing efficiency, and solve the construction problems such as errors, omissions, bumps and defects in the construction process and information asymmetry in the management process. It is of great significance to the actual construction process of prefabricated buildings and provides technical support for the precise management and long-term development of prefabricated buildings.
BIM technology and RFID technology principle
BIM technical principle
BIM Technology is not only the product of industrialization and informatization of construction industry, but also the way and carrier to realize informatization of construction industry. With the support of BIM Technology, the prefabricated building information mode has been changed into a one-to-one information exchange mode between participants and BIM data. BIM Technology mainly establishes a new model through digitization. It has the parameterization of the actual object model, and the content of information is relatively large. It can make the design have the characteristics of visualization and achieve better deepening design effect [8]. In the process of deepening the design, it can be adjusted at any time according to different schemes, and the adjustment results can be seen from multiple angles.
BIM tool software can be roughly divided into vertical tools and horizontal tools. The vertical tools can solve one-way or a few technical tasks in a single stage of the whole life cycle of the building, while the horizontal tools refer to the project planning and control tools required for data resource configuration management, document management and BIM project management. BIM integration environment can be divided into three levels: the basic integration is the integration of vertical tools, the higher level integration is the integration of horizontal tools and vertical tools, and the high level integration environment can regard information production as a kind of product production. The process of information creation, extraction, application and management is regarded as a production line, which supports the information management of each stage of the building, effectively gives play to the role of various tool software in each stage of the building, and organically combines various BIM software to achieve interface integration, data integration and control integration. Users can operate different software under the same personal computer interface, and the underlying database of the software is interconnected into a database. The software uses the same workflow to control data and human-computer interaction [9].
Reasonably arrange the construction site in a dynamic way through BIM Technology to minimize secondary handling and improve construction efficiency; Use BIM Technology to conduct construction simulation, find problems in the simulation and formulate improvement plans to ensure the realization of objectives; With the help of BIM platform, the construction object and construction progress data can be integrated to realize real-time tracking and monitoring of construction progress, and then the resource dimension can be introduced to establish the “dynamic construction planning” of prefabricated buildings to implement dynamic management of quality, progress and cost [10]. BIM Technology can improve the integration degree of prefabricated construction engineering and the work efficiency of all participants, so that all project managers can quickly and accurately obtain the data required by the project, and realize the project information management.
RFID technology principle
RFID technology is a technology that uses radio frequency signals to realize non-contact information transmission through spatial coupling and to achieve the purpose of identification through the transmitted information. It can be automatically identified without human intervention and can be applied in various harsh environments [10]. RFID technology can identify multiple tags at the same time, which is fast and convenient to operate. The system consists of three parts, as shown in Fig. 1, namely, RFID Application Platform, reader and label.
RFID application system structure.
Label: also known as electronic tag, it is mainly a large-scale integrated circuit chip with identification code. Each tag has a unique electronic code, attached to the object to identify the target object, so the tag is the carrier of information and the identified target. Reader/writer: also known as RFID reader/writer, it is the link between information service system and tag, and mainly plays the functions of target identification and information reading. Application software, management software for various application fields [11]. During operation, if the special RF signal sent by the reader is received after the label enters the magnetic field, the reader reads and decodes the information and sends it to the central information system for relevant data processing.
As a non-contact identification, radio frequency identification technology has the following characteristics:
It is convenient and fast to read data without light source, and the effective recognition distance is large. The recognition speed is fast. When the tag enters the magnetic field, the reader can read the information, and can process multiple tags at the same time to realize batch recognition. Large data capacity, long service life, good anti-pollution ability and durability, reusable, and better security. Label data can be dynamically changed and dynamically communicated in real time [12].
During construction, the RFID tag can read component information within a certain distance, and the stored data is safe, reliable and can be rewritten repeatedly. Because RFID technology integrates technologies such as positioning, electronic coding and the Internet, it carries out the overall scheme design of the construction process in the early stage of construction, uses BIM to model it, applies RFID technology to building construction, and uses the characteristics of RFID technology, Adding RFID tags to the components used in the construction process can make up for the defect that BIM Technology is difficult to obtain real-time data during the construction process by actively collecting engineering information, effectively improve the chaotic management of the construction site, realize the implementation control of the construction site, effectively improve the efficiency of building construction and shorten the construction period [13].
The essence of BIM Technology is the storage and expression of information. It can share information with multiple software in the construction field, so that the information interaction between the participants of BIM project can be realized, and information sharing and common management can be realized [14]. See Table 1 for the comparison of BIM and RFID technology application in the construction project.
Comparison of BIM and RFID technology in construction projects
Comparison of BIM and RFID technology in construction projects
Through understanding the problems in the implementation and application of BIM Technology and RFID technology, BIM Technology is mainly used in the early construction design work, which plays a guiding role in the construction process of the next building. However, the real-time dynamics of the construction process and the maintenance after the completion of the later building cannot be completed. RFID technology can solve such problems. After embedding components into RFID tags, components can be easily and actively obtained, Timely collection of information can monitor the progress of the construction process in real time. Therefore, it is of great significance to integrate BIM Technology and RFID technology in the construction process [15].
Firstly, the information storage system of prefabricated building components is built based on bim rfid technology, which can store and retrieve the encoded data. On this basis, the system is studied to obtain the detailed information of building components in digital form, and to avoid the negative impact of abnormal information, the data is uniformly preprocessed. Finally, according to the distribution of information characteristics, the assembly building construction information is integrated [16].
Information storage of prefabricated building components based on BIM-RFID technology
RFID (radio frequency identification) is a non-contact automatic identification technology, which automatically identifies the target object and obtains relevant information through radio frequency signals. Due to the wide variety of prefabricated components, prefabricated buildings often suffer from the loss, misuse and misuse of components, and one component may lead to the loss of the whole building. Therefore, the on-site management of prefabricated components must be strict. RFID reader can quickly identify and read the components of the construction site, and is used in the whole process of prefabricated building construction [17]. Therefore, during the component manufacturing process of prefabricated buildings, the staff can record the relevant information of components through RFID technology, and the information content is shown in Table 2.
Standards for recording data information of RFID tag
Standards for recording data information of RFID tag
According to the coding principle of RFID tag: namely, uniqueness and scalability, ensure that the component unit has a unique code identification corresponding to it. While ensuring the accurate information in the construction management process, other attribute information that may appear must also be considered, and a certain extension area must be reserved. Therefore, the coding needs to be constructed. The traditional material management method makes component information easy to make mistakes and has a certain lag. In order to solve the problem of disconnection between the production and construction process of prefabricated buildings, this paper applies RFID technology to the construction process of prefabricated buildings. The application process is shown in Fig. 2.
Process of building information in RFID.
As shown in Fig. 2, the BIM-RFID information integration system was established from the component production stage. The program is centered on technicians. Technicians use readers to read and write component tag information at the terminal, including name, type, manufacturer, installation location, etc. After translating the information, they enter the formation matching process. RFID tags are placed on the components, and each component has a relative ID number to match the BIM model with the actual component. The matched information can be saved and read at any time. Finally, the tags of each component are uniformly coded according to EPC (Electronic Program Control), so that the staff can uniquely identify the tags when they read and consult the relevant information later [18].
BIM-RFID information integration mainly combines RFID technology with BIM Technology, stores the component information in the tag code in the BIM information base, tracks and controls the components in real time, and realizes the effective transmission of component RFID information to the BIM model. BIM ensures that the data in the RFID chip tag is stored and updated in a timely manner.
UHF UHF USB reader is used in this paper. The model is ljyzn-105, the net weight is 80 g, and the size is 105 mm
Ljyzn-105 reader/writer.
Features of ljyzn-105 reader/writer:
Provide dynamic link library to support secondary development; Fully support the electronic labels conforming to UHF EPC Gen2 (iso18000-6c) and ISO18000-6B protocols; Advanced label collision processing algorithm, high recognition rate; The operating frequency is 902 Work in the form of broad spectrum frequency hopping (FHSS) or fixed frequency transmission; Output power: max. 10d BM, adjustable, powered by USB interface, without external power supply; The output format and parameters in the simulation keyboard mode can be customized; It supports USB1.1 interface, and the virtual serial port working mode, USB driveless mode and USB driveless emulation keyboard mode that are optional.
Uhfreader9 demo software is a software that matches the reader ljyzn-105. It mainly modifies the EPC number of RFID radio frequency tags through the software. By identifying the EPC number of each tag and converting the information into component ID, we can know the component information stored inside. The ID of each tag is different. The detailed information of building components is expressed in digital form to facilitate reader identification, When the label is placed on the column or wall of the building, it can be scanned by the reader to obtain the component information.
During label scanning, the card number, TID (THREAD Identifier) number and EPC number of the label can be read out with uhfreader9 demo software. The card number and TID number in each label are unique and cannot be changed, but the EPC number can be changed into the ID number of the component in Revit with uhfreader9 demo software reader software. The RFID tag displays and modifies the EPC number through the reader software. Reading the EPC number requires reading and writing through the reader’s analog keyboard com2key software. There are 23 ways to read the RFID tag, and the decimal method is adopted in this project. After the reader scans the tag, the EPC information of the component is displayed in excel through com2 key software. When coding components, rewrite the EPC number as the component ID number, which corresponds to the building components one by one, and use Excel to represent the component information. Because of the large number of building components, the component samples of prefabricated buildings are selected for representation. Then, import the component information into every BIM platform, and each component will generate the corresponding QR code. Importing component information through Excel saves the time of importing component information in the platform, and improves the input efficiency and accuracy of component information. Subsequent work can extract component information in the platform to achieve information transmission.
Each tag corresponds to a building component, and the tag information, including the corresponding card number, EPC number, type and size of the component, can be read and rewritten through the uhfreader9 demo software of the reader/writer, and uploaded to every BIM platform. Combined with the BIM model, the corresponding two-dimensional code can be generated, and the basic information of the component can be queried on the PC and mobile terminals, The QR code generated in every BIM platform can query the component label information and provide a basis for the construction simulation of the project.
For the information management system, whether the collected information is safe is particularly important, which is related to the stability of the overall operation of the system. If there are abnormal data in the system, it will not only occupy the system memory, but also provide false information, which will affect the decision-making of prefabricated building construction projects. Therefore, Markov model and fuzzy algorithm are combined to comprehensively analyze the relationship between information and track the information transfer status in real time. The abnormal information detection process is as follows:
Step 1: assume that the model order and forgetting factor are expressed as
Step 2: update the model coefficient
Step 3: update the variance
In the equation,
Step 4: check the indicators through the operation model of the following equation:
Step 5: compare the model index
Calculate the membership function solution by combining
Step 7: update the state transition matrix
In the equation,
In the information collection of prefabricated building construction, the information feature distribution shall be defined. The calculation process of feature distribution is as follows:
Where,
Extract the information entropy of the prefabricated building construction, use the association rule mining strategy for the information data fusion and independent scheduling of the prefabricated building construction, and use the operation status monitoring method to create the statistical model of the prefabricated building construction information data:
Where,
The statistical feature clustering algorithm is introduced to integrate the construction information of prefabricated buildings. The expression is:
Where,
In order to verify the effectiveness of the prefabricated building construction information integration method based on BIM and RFID technology in practical application, a simulation experiment is carried out. The main power house of a steel structure project is a pilot project of prefabricated building, 786 m long, 122.5 m wide, and 75503.5 m
The BIM-RFID system platform used in the project is every BIM software. The core technology of every BIM software is lightweight technology, which can carry large-scale models. It is a construction process management system platform for construction projects based on BIM and RFID technology. Every BIM cloud platform has web, PC and mobile terminals, which can be viewed and managed by all participants. Every BIM cloud platform is used to manage the prefabricated components in an information-based manner, and the component information and positioning are traced in the form of RFID tags and two-dimensional codes. In the design stage, the three-dimensional model is established by the combination of BIM Technology and traditional CAD; At the same time, the design BIM data information is attached to the RFID tag, and the RFID tag is used to trace the information of building components to obtain the tag information of prefabricated building components, as shown in Table 3.
Label information of fabricated building components
Label information of fabricated building components
Construction site of a prefabricated project.
Under the above background, the assembly building construction information integration method based on BIM and RFID technology proposed in this paper, the assembly building construction information integration method based on BIM-RFID technology proposed in reference [6] and the integration method in the assembly building based on BIM Technology proposed in reference [7] are used to compare and analyze the assembly building construction information integration accuracy. The comparison results are shown in Fig. 5.
Comparison results of assembly building construction information integration accuracy.
According to Fig. 5, the precision of the prefabricated building construction information integration method based on BIM and RFID technology proposed in this paper can be up to 100%, which is higher than that of the reference [6] method and the reference [7] method.
According to Fig. 5, the accuracy of the reference [6] method was about 95% at the beginning. With the increase of the number of experiments, the accuracy line of the reference [6] method showed a trend of gradual decline, which was the most significant decline between 80 and 100 times of experiments, and finally dropped to about 80% of the accuracy value when the number of experiments was 140. The reference [7] method also shows a trend of decreasing accuracy with the increase of the number of experiments. Its initial accuracy is about 97%, and the significant decline is also reflected in the number of experiments between 80 and 100 times. Finally, when the number of experiments is 140, the accuracy decreases to about 90%. The precision of the prefabricated building construction information integration method based on BIM and RFID technology proposed in this paper is the highest among the comparison methods, and it gradually approaches steadily with the increase of times, and finally reaches 100% accuracy when the number of experiments is 120. At the same time, in the range of 80 to 100 experiments where the accuracy values of both the reference [6] method and the reference [7] method decreased, the accuracy value of the research design method was significantly increased. It can be seen that the overall accuracy and stability are superior to the methods in reference [6] and reference [7].
Comparison results of construction information integration time of prefabricated buildings.
According to Fig. 6, the consumption time of prefabricated building information integration in reference [6] shows a steady rising trend with the increase of the number of experiments. When the number of experiments is 20, the operation time is about 0.17 s. With the increase of the number of experiments, it finally rises to 0.36 s when the number of experiments is 140. The consumption time of prefabricated building information integration in the reference [7] method is similar to that in the reference [6] method, which also shows a steady increase trend with the increase of the number of experiments. When the number of experiments is 20, the operation time is about 0.28 s. With the increase of the number of experiments, the operation time finally rises to 0.62 s when the number of experiments is 140, which is much higher than the operation time of the reference [6] method at the corresponding location. The time consumed by the prefabricated building construction information integration method based on BIM and RFID technology proposed in this paper for prefabricated building information integration is within 0.41 s, which also shows an upward trend. However, when the number of experiments is 20, the operation time is about 0.14 s. With the increase of the number of experiments, it finally rises to 0.34 s when the number of experiments is 140, this is shorter than the method in reference [6] and the method in reference [7] used for information integration of prefabricated building construction. Thus, the research and design method has more advantages in the efficiency of information integration.
Due to the lack of information sharing, problems such as missing assembly components often occur in the installation process of assembly type construction. In addition, in the installation process of prefabricated buildings, components at different parts will have many deviations, which will affect their subsequent installation or future safe use to some extent. In order to solve this problem, the research is different from the traditional methods. From the perspective of information integration and sharing, a method of building construction information integration that will be similar to BIM and RFID technology is proposed. Based on the information integration principle of BIM-RFID technology, this method uses RFID technology to collect the information of prefabricated building components, obtain the coding information of component data, and integrate the construction information of assembly building according to the distribution of information characteristics, so as to finally realize the dynamic management in the construction stage of assembly building. The research uses the form of simulation experiment to analyze the effectiveness of the method. The research results show that the precision of the research design method is higher than that of the same type of methods, and it is close to 100% in the later stage. At the same time, the time consumed by the method is within 0.41 s, which has higher operational efficiency. It can be seen that the research and design method can obtain more accurate results in a shorter time, which is conducive to the improvement of the information integration efficiency of doctors’ prefabricated buildings, thus achieving the effect of improving the overall production and building efficiency. From the perspective of information technology, it can help the construction unit to obtain more advantages in construction efficiency in the production and construction process, and promote the construction unit to form an automated, integrated and standardized construction management control system, Improve construction efficiency and construction quality.
Footnotes
Funding
The research is supported by: Research on construction Information integration and application of prefabricated building based on BIM and RFID technology (2021KY1073).
