Abstract
With the promotion of BIM Technology, prefabricated building is developed rapidly in China. However, BIM technology has been only partially applied to prefabricated building, and there is still a gap between prefabricated building and intelligent construction. This paper focus on BIM 5D, together with relevant information technologies, all of which will be highly integrated and applied to prefabricated building, with the mission to get related information and enable the rapid flow of information, as well as bringing human perception, memory, knowledge and wisdom into prefabricated building, driving the development of prefabricated buildings to intelligence and leanness.
Intelligent construction is an innovated construction model based on the combination of latest information technology and engineering construction. Thus, it is particularly important to train personnel with corresponding knowledge structure, knowledge system and professional ability for intelligent construction. This paper also discusses about how to train personnel on prefabricated building and intelligent construction.
Introduction
In recent years, the total output value of China’s construction industry is increasing. However, compared with other pillar industries of the national economy, fragmentation and extensive construction methods bring a series of problems, such as poor product performance, huge waste of resources, prominent safety problems, serious environmental pollution and low production efficiency [1].
The General Office of the State Council issued ‘the Guidance on vigorously developing of prefabricated buildings’ put forward, ‘the development of prefabricated buildings is a major change in the construction mode, an important measure to promote the supply-side structural reform and new urbanization development, which is conducive to saving resources and energy, reducing construction pollution, improving labor production efficiency, increasing quality and safety level, promoting the deep integration of construction, information and industrialization, cultivating new industries and new driving forces, as well as promoting the resolution of excess capacities.’ The Ministry of Housing and Urban-Rural Development issued ‘Notice of the Outlines on the Informationize Development of Construction Industry of 2016–2020’ pointed out, ‘Strengthen the application of information technology in prefabricated buildings, carrying forward the BIM-based architectural engineering design, production, transportation, assembly and full lifecycle management, to promote the industrialized construction. Establish cloud service platform based on BIM, Internet of things and related technologies to achieve the collaborative work of all participants in the industrial chain at all stages.’ To sum up, the construction industry is in urgent need of transformation and upgrading. Prefabricated building is the major direction of industrialized construction, and the integrated application of information technology is an important link of prefabricated building, and intelligent construction.
BIM Technology, as the core technology of prefabricated building and intelligent construction, achieves information sharing through 3D model cloud platform of related construction projects. With technology development, the BIM 3D model upgrades to BIM 4D model by associated with project information, with the functions of simulation, optimization and schedule adjustment etc. While associating with cost information, BIM 4D mange to upgrade to BIM 5D which control could the project progress and cost dynamically.
The research on prefabricated building abroad mainly include: the selection of prefabricated component materials and its physical and mechanical properties, the research of recyclable materials; the research of prefabricated structure system suitable for earthquake area, the research on how to lowdown carbon, to improve construction quality, to reduce construction time and cost; the research of production management, transformation strategy of prefabricated components, research on how to reduce supply chain cost, to achieve real-time data analysis and data tracking, etc. While China’s researches on prefabricated building are mainly focusing on prefabricated building structure, the quality management of prefabricated components in the production stage and the application of BIM Technology in prefabricated building, but the integrated application research of BIM 5D related technologies on prefabricated building is quite rare.
The construction process of prefabricated building includes three stages: design, production and transportation, assembly. In order to achieve the project information sharing in each stage, the integrated application of information technology is the key. The prefabricated building with BIM 5G as its core and integrated with relevant information technologies, could achieve collaboration of all participants in the industrial chain at all stages and links, and dynamically control the safety, quality, construction period and cost in real time, which would further prefabricated building to high-quality construction, safe construction, efficient construction and green construction.
Intelligent construction is an innovative mode of engineering construction formed by the deep integration of new generation information technologies and engineering construction [1]. It is particularly important to cultivate personnel with intelligent construction knowledge structure, knowledge system and professional ability. This paper also discusses the issues of personnel training in prefabricated building and intelligent construction.
Concepts and relevant overviews
Prefabricated building
Compared with traditional mode, prefabricated building is a kind of new construction mode supported by information management, with features of standardized design, industrial production, assembly construction and integrated decoration, which requires higher degree of informatization.
Intelligent construction based on BIM 5D
Overview of BIM 5D technology
The object of BIM is building, and the core of it is information, while the carrier of it is modeling. In the full lifecycle of the project, participants could use the BIM 3D model and its rich information as central database in the management process and the full-process system, to co-create, check and communicate project information through integrated application of information technology.
BIM 3D will be upgraded to BIM 5D after associating with project process and cost information. BIM 5D enhances its information integration, which is reflected in professional integration (architecture, structure, hydropower and HVAC, etc.), namely BIM 3D model; process information integration (design, production, transportation, assembly and other stages) based on 3D model; and project indicator integration (progress, cost, quality, safety, etc.) based on 3D model as well. Thus, BIM 5D could support dynamic simulation, emulation, optimization, trial and error.
Overview of intelligent construction
Intelligent construction is an innovative mode of engineering construction formed by the deep integration of new generation information technologies and engineering construction [1]. It is a highly integrated and collaborative construction system with ability for real-time adaptive and changing requirements, and built on BIM, Internet of things, artificial intelligence, cloud computing, big data and relevant technologies (As shown in Fig. 1).
System of Intelligent Construction.
The ‘changing requirements’ include requirements on building site, supply network and requirements from builders. And ‘integration and collaboration’ are reflected in intelligent design, intelligent factory, intelligent logistics, intelligent building site (As shown in Fig. 2).
Integration and Collaboration.
BIM Technology is the basis for various information technologies (Internet of things, radio frequency, 3D scanning, VR technology, etc.), all of which take cluster advantages to achieve mutual perception and connection between resources and information. Also, BIM is the comprehensive database and interactive platform carrying related full lifecycle building information, that is the major technical means of intelligent construction. Within this infrastructure, IOT plays the role of information transmission and collection; radio frequency is responsible for the perception of of prefabricated components’ conditions; 3D scanning could record the construction progress quickly, while VR / AR could visualize the virtual scenes of buildings, etc. (As shown in Fig. 3).
BIM Infrastructure.
BIM 5D is based on BIM 3D visualized models, dynamically linking with the information obtained by participants through information technology to form a strong database with complete process and high integration, and to achieve timely information transmission and work coordination, which is upgrading the construction mode to intelligent construction and finally to green construction.
From the perspective of technology application, domestic design units usually do not use VR/AR simulation after applying BIM to complete prefabricated building designing, thus participants could not get a real experience of the building performance and construction process. For the finished prefabricated components, the quality inspectors usually use the traditional way to detect, record, evaluate the quality and report the results, which is difficult to avoid the influence of subjective factors. The same thing is also happening in the technical and security disclosure, that the administrators mostly hand over the information by person or through 3D model, rarely use VR / AR technology. Thus at present, the insufficient application coverage and low integration of information technologies in prefabricated building hinder participants from relevant information and collaboration.
Deficiencies:
Low standardization level, unable to play the advantages of prefabricated buildings.Not enough innovation in construction mode, fewer prefabricated projects of EPC.The informatization is lagging behind, overall level of intelligence is low.Uneven product quality, affecting the overall quality level.Lack of industry specific standards.Lack of planning and process control [5].
Prefabricated buildings adopt integrated collaborative design, all the parts and components are lean producing in factories, which are assembled on-site through reliable connection and construction techniques, and whose geometric dimension deviations are precisely controlled. So the integration and application of information technologies could lay an important foundation to drive prefabricated building to intelligent construction, and form an intelligent system which take BIM 5D as its core and supported by integrated application of information technologies [9].
The application of prefabricated building based on BIM 5D
The intelligent construction system of prefabricated building based on BIM 5D is consisted of information collecting layer, network layer, data layer and service layer [2]. The information collecting layer is the system’s basis, which utilize sensors, UAV and 3D scanning technology to timely collect the production status, quality, progress and other information of target parts or components. The network layer is responsible for timely transmitting information through wired and wireless networks. The data layer is a database storing various structured and unstructured information of buildings’ geometric or non-geometric data, progress, cost and quality, etc. The service layer is for all participants, enable them to get data by this layer, and finish relevant work through PC or mobile terminals.
The construction process of prefabricated building includes three phases: design, production and transportation, and assembly. The integrated application of information technology based on BIM 5D could help achieve the collaborative work of project participants.
Professional collaborating design of prefabricated building based on BIM 5D
BIM5D design collaborating platform is built on cloud architecture, has unified data and model standard, which could connect and collaborate with different professional modules in the way of database interaction. The designing and production of prefabricated parts and components are all based on standard building component library, and the work mode of ‘designing separately and sharing data’ should be abandoned. The better mode is to build and make full use of the standard building component library under the coordination and integration from the project architect, and to communicate ahead with the producing and assembling units as well as to simulate the construction effects. In order to maximize production efficiency and capacity, the splitting and further deepening work should fully consider the project practical conditions, engineering cost, assembly ratio and other factors, and should be optimized, compared and selected targeted, in order to greatly reduce the cost while ensuring the constructability of the design [6].
The intelligent factory’s production and transportation of prefabricated components based on BIM 5D
Component production is an important segment for transforming design into products. In order to help the construction party efficiently arranges its schedule, the designing model data should be directly transformed into the parameter data required for component production, linking the designing information and producing data, which will improve the automation level and production efficiency of prefabricated component production, and the production information should also be conveyed timely to the construction unit. Or according to the construction plan and the production plan, the component production schedule could be intelligently arranged, to set up a proper component lead time of component order, and coordinate with the distribution and production arrangement, while connecting with factory’s MES system.
The integrated application of BIM 5D, IOT, GIS, GPS, sensor and related information technologies, could identify components, reasonably arrange the transportation path, dynamically track the key nodes and process in production preparation, production and transportation of prefabricated components, and could achieve information feedback and quality traceability. Participants could improve its fine management and project management level by querying the production process, analyzing data, assisting decision-making and collaborating work.
The intelligent construction site of prefabricated building based on BIM 5D
Relying on ‘Digital Twin’ technologies to create the physical-digital composite product form by merging physical products and digital products, participants could simulate, emulate, optimize, repeatedly trail and error the buildings’ performance and construction process in virtual space, and obtain high-quality construction products through ‘trial before construction’. Actually, as the virtual background, the digital construction site could provide guidance for the physical construction process. (I) Based on the simulation and optimization work of the BIM 5D cloud platform, the technique library, operation process and time could be intelligently generated, and the construction resources could be intelligently allocated, through the self-adaption and dynamic interaction between human and environment. Therefore, the construction process information becomes more transparent, the cost is timely tracked and controlled, and the construction efficiency has been increased, all of which help achieve the goal of human-oriented, green and sustainable intelligent construction [7].
Construction site layout
Simulation of the proposed buildings, temporary facilities, construction equipment, on-site layout in different working conditions, to demonstrate the spatial layout and time logic, and optimize the construction site layout.
Component management
Based on the construction plan, the MES system of the plant is seamlessly connected to reduce the transportation cost by identifying components, coordinating transportation and stacking.
Schedule management
Visualized project schedule management: real time viewing the 3D visual progress based on project feedback, viewing the Gantt chart of construction resources in 3D visual models, viewing the plan and schedule in 3D, as well as generating the resource request by one click.
Safety management
The BIM VR safety simulation experience hall will help the experiencer strengthen their safety awareness through immersive training. VR technology could be applied in the technical disclosure, and in the safety training to remind workers of strictly following the procedures. Meanwhile, BIM 5D, radio frequency and related technologies could be used to analyze potential hazards, which could be visualized in real time and transmitted to the platform. Once triggered, the alarm will be synchronized.
Quality management
3D visual simulation of collision inspection, check the assembly difficulties and key points, and determine the key points of quality control. Repeated trial and error, optimization of construction organization and construction scheme, will be conducive to technical disclosure and prior control of construction quality.
Cost management
The BIM 5D cost model links the construction schedule, cost, cost changes and other information, could achieve dynamic and efficient management of project cost.
The urgent problems to-be-solved of prefabricated building based on BIM 5D
Low level of standardization
The level of standardization and modularization of prefabricated building components is low, and there is a lack of industry specific standards. Due to the lack of standardization and modular guidance in the designing, there are many components with different sizes in practical application, result in large amount of molds. And the low level of general production causes relatively management difficulties in production, stacking, transportation, assembly and other segments, and causes low production efficiency, high mold amortization cost and labor cost, which fails to give full play to the advantages of prefabricated building and intelligent construction.
Less innovation in construction mode
There are fewer number of EPC projects using prefabricated building mode, and the management level of EPC projects needs to be improved. In most regions, the relevant guidance policy for EPC are not clear, and the number of enterprises with the ability to undertake EPC projects is insufficient. Thus the collaborative work among all the segments of the whole industrial chain is not in place, which can not maximize the overall benefits.
The application of information technology lags behind
Prefabricated building is an important carrier for the informatization of construction industry. At present, there are a certain degree of R&D and practice work of BIM in China, but the overall progress is slow. Due to the differences in software formats and the incompatibility of underlying data, repetitive modeling still remains at the level of design or simulation and display. It lacks the collaborative application of the whole industrial chain of design, production, logistics and assembly, and can not achieve information sharing and collaboration.
The lack of professional personnel
The core value of the integrated application of BIM5D and information technologies is to achieve industrialized production and fine management, as well as expand the value chain of engineering construction, with the support of data and information technologies [10]. The designers are lack of deep understanding of BIM 5D and intelligent construction, they tend to believe that BIM 5D is only a kind of software, and still use the traditional design and workflow, which will hinder the application and collaboration of it. Meanwhile, production and assembly workers do not master the relevant techniques and operation skills of assembly procedure and information technology application, only get inadequate pre-job training which is far from enough. In recent years, the construction of prefabricated building projects in China has increased rapidly, thus the demand for relevant personnel is particularly strong, but the shortage of personnel becomes the ‘short board’ for the application and development of prefabricated building and intelligent construction.
The Countermeasures for the application of prefabricated building based on BIM 5D
Prefabricated building is the developing direction of construction industrialization, while informatization is the cornerstone of prefabricated building and intelligent construction. To upgrade prefabricated building to intelligent construction, BIM 5D should integrate with information technology to form a complete database, all the participants in the industrial chain joined as an organic whole driven by informatization, and relevant standards should be formulated and improved, so that the prefabricated building and information technology could be deeply integrated [8].
Improve the standards
The level of prefabricated buildings also reflects the industry standard level and national construction status. So far, China’s relevant standards are not perfect, a case in point is that there are many types and sizes of components designed, large-scale production could not be achieved.
Improve the standards
Organize experts and scholars from research institutions, universities and units of prefabricated construction industry chain, to participate in the formulation of industrial standards and national standards. To develop the standards and specifications suitable for the industrialized production of prefabricated buildings and intelligent construction, and promote the intelligence level of prefabricated buildings.
Improve the standards
Encourage the benchmarking enterprises to formulate enterprise standards, techniques and procedures that are superior to industry and national standards, to promote the rapid development of prefabricated buildings and intelligent construction.
Promote the research on key technologies and the innovation on construction techniques
Scientific research is an important guarantee to promote technological development. Governments or administrations should formulate relevant policies, support key technology research on the industrialization, informatization of construction, and should encourage scientific research institutes, universities and enterprises to tackle key technical problems, such as: design and application integration collaborative platform run on BIM data; MES system with independent intellectual property to lay the foundation for undertaking factory production line and designing data transmission; self-developed stacking yard system to improve its efficiency by achieving whole process control covers production, stacking yard, logistics and on-site assembly. Independently research should be encouraged to reate an industrial ecosystem of prefabricated building and intelligent construction.
Training for professional personnel
Prefabricated building has been promoting profound changes in the construction industry, while the key supporting factor is professionals with high level. With the development of intelligent construction, new requirements will be put forward for the knowledge structure, knowledge system and professional ability of personnel [1].
The knowledge structure for professionals of prefabricated building
A significant feature of intelligent construction is the interdisciplinary integration, which also requires to be able to solve specific engineering problems. From the perspective of knowledge structure in intelligent construction, professionals are required to have a wide range of knowledge, who must master the basic theory and knowledge of related disciplines, as well as organic integration of various disciplines. This requires intelligent construction professionals to be thoroughly acquainted with complex knowledge system related, becoming true talents. At the sametime, one aspect of in-depth knowledge is a must for intelligent construction professionals to improve their knowledge structure and system, while a practical way advanced with times is the knowledge and methodologies of information technology. Colleges and universities should comprehensively strengthen the basic education and comprehensive ability training, and achieve the integration of information technology and civil engineering knowledge [1].
Curriculum and contents of interdisciplinary integration
On the basis of the traditional teaching of civil engineering, the curriculum system and teaching contents (As shown in Fig. 4) for the interdisciplinary integration of civil engineering related majors are designed and updated by integrating different disciplines such as civil engineering, information, materials, mechanics, etc., so as to ensure that students can acquire deep and wide knowledge structure [3].
Multidisciplinary Fusion of Curriculum and Course Contents.
Practical teaching is an important part of the curriculum system, which provide critical practical abilities to personnel majored in prefabricated buildings and intelligent construction. Practical teaching is an important way to cultivate practical ability, a foundation for understanding professional theory and an important source of professional perceptual knowledge.
The development of practice teaching has a lot to do with teachers and experimental equipment construction [4]. The practical teaching segment should stick to the combination of production, learning and research, and the integration of production and teaching, and universities and enterprises should be encouraged to establish practice base of prefabricated building and intelligent construction, while vigorously improving the experimental environment and equipment of colleges and universities. In order to make up for the teacher shortage of practical teaching, colleges and universities should adopt the ‘double tutor system’ to constantly cultivate students’ practical abilities, and regularly transport students to enterprises. Also, the connection between education and industry upgrading transformation should be promoted, to explore a one-stop talent training scheme, from school to enterprise, for prefabricated building and intelligent construction personnel.
Prefabricated construction talent training based on BIM5D technology
Strive to build close ties between governments, enterprises, and universities that are mutually beneficial, mutually beneficial, and win-win, and work together to formulate practical and feasible personnel training and operating mechanisms.
It is necessary to attach great importance to increasing the training and policy support for professional and technical personnel of BIM5D technology and prefabricated construction, support and help colleges and universities to set up BIM5D-based prefabricated architecture majors, and encourage relevant colleges and research institutions and enterprises to establish BIM5D technology Professional talent training and internship training base for the prefabricated construction industry, systematic professional skills training for technical personnel and construction operators related to engineering design, construction, engineering supervision, etc., and regular invitations of relevant prefabricated construction industry experts, Scholars, and professors conduct professional technical knowledge and management training to improve the BIM5D-based professional technical level, operational capabilities and personal professional capabilities of prefabricated construction workers, and effectively promote the technological development of the construction industry and the upgrading and transformation of construction management talents.
The prefabricated construction industry based on BIM5D technology has become the popular trend and development direction of the future construction industry. Only the joint efforts of governments, enterprises and universities can cultivate more prefabricated BIM5D technologies that meet the needs of technological development and social development. Construction skills talents.
Multi-level personnel structure and personnel training
The development of prefabricated building and intelligent construction needs professional technicians, administrators and skilled industrial workers at different levels. Thus regular learning and training system should be established to provide transformational learning and training opportunities. And based on vocational standards, industry standards and job specifications, we should optimize and innovate the curriculum structure, course contents and system of vocational education. Strengthen the cooperation with vocational skill appraisal institutions and enterprises, and integrate the knowledge, skills and professional qualities required by the job post of prefabricated building and intelligent construction into the skill identification. Various measures should be conducted to improve the training of prefabricated building workers, such as increasing the investment in vocational skills training and education; encouraging local and benchmarking enterprises to set up prefabricated building training bases; giving full play to the power of industry associations; strengthening job skill training; and extensively carrying out training activities such as technical lectures, expert seminars and technical competitions.
According to the development characteristics of ‘Three Integrations’ of prefabricated building, the curriculum database of BIM and information technology applied in prefabricated building should be developed. Make full use of cloud platform of construction, online MOOC platform, offline training bases, to combine theory and practices, achieving the mission of training three-dimensional and all-round personnel of prefabricated building and intelligent construction.
Conclusions
The intelligent construction of prefabricated buildings is the only way for the industrialized transformation and upgrading of China’s construction industry. The deep integration of BIM 5D and information technology can achieve the collaboration of all participants in the whole process of prefabricated building construction at all stages and segments, and can realize real-time dynamic control of safety, quality, schedule and cost, to promote the sustainable development from prefabricated building to intelligent construction, to lean production and green construction.
The intelligent construction of prefabricated building is an innovative result of the integration of information technology and engineering construction, and the personnel training should also adopt innovative mode and methods. Universities and enterprises should be closely linked to cultivate high-level innovative professionals in intelligent construction, who can master the cutting-edge technologies and the development tendency of science and technology, and can can adapt to the needs of construction industry reform [1].
Footnotes
Acknowledgments
This paper refers to the writings of Professor GUO Hongling from Tsinghua University, Professor ZHONG Wei from Tianjin University of Technology, Professor LIU Zhansheng of Beijing University of Technology, and the lecture of Mr. CHENG Peng, Director of the Information Management Department, MEIHAO Building Technology Assembly Co., Ltd. I would like to express my sincere thanks to the above-mentioned experts.