1. Smart construction in the construction industry has become inevitable
As a labor-intensive traditional industry, China's construction industry has long followed an extensive construction model with a low level of informatization. Engineering-related information is still stored in paper form, making information retrieval difficult. Project participants cannot effectively share information or collaborate, and rework often occurs due to poor information communication, resulting in significant resource waste.
With the development of emerging information technologies such as BIM technology, the Internet of Things, big data, and cloud computing, it is now technically possible to exchange and share large amounts of information in the engineering construction process in real time, accurately, and efficiently. Using BIM and other technologies to promote informatization in the construction industry can play a significant role in solving information silos in engineering construction, achieving collaborative operation among project participants, and thereby realizing smart construction.
1.1 BIM will become the main technical expression of the integration era
According to the development of computer technology, the design and construction process of buildings can be divided into the manual era, keyboard era, and integration era. BIM technology can effectively integrate data from all disciplines throughout the entire building lifecycle and has become the main technical expression of the integration era. The traditional project construction model will shift to a BIM-based integrated project construction model. 1.2 Application of BIM technology in various project stages
1) Planning stage: overall layout, intelligent planning.
2) Design stage: optimize building performance, create a highly comfortable environment, and increase building value.
3) Construction stage: reduce design changes, optimize construction sequence, improve construction quality, and reduce waste.
4) Operation and maintenance stage: establish a property asset management database, intelligent equipment, emergency handling, and 3D space leasing and sales.
Applying BIM technology throughout the building lifecycle can better improve design quality, better manage construction, and better manage operation and maintenance. 1.3 Professional division of BIM models
Taking building engineering as an example, the professional division of BIM models is shown in Figure 3.
1.4 BIM-based design collaborative integration
Using the overall BIM model, various disciplines such as architecture, structure, and MEP are coordinated together. Problems are communicated and coordinated in a timely manner to achieve seamless integration among disciplines (Figure 4). 1.5 BIM transforms the construction mode of the construction industry
During the construction stage, BIM technology is used for construction detailing and pipeline coordination. At the same time, BIM is used for construction simulation, schedule control, and cost control. Through comprehensive informatization management of the construction process, construction quality can be greatly improved, construction waste reduced, and project investment saved.
1.6 BIM promotes refined management of engineering construction projects
After receiving a construction project, construction enterprises usually set up a temporary project department and organize a large number of workers on site for construction. Due to the complexity of the project, numerous professional subcontractors, many construction personnel and equipment, construction management is mixed and very difficult. Using BIM technology for system integration can promote the intensification of management between the general contractor and subcontractors. It can make the construction industry equivalent to manufacturing, achieving streamlined production processes, standardized product fabrication, and modular construction methods.
1.7 Benefit evaluation of BIM application
Stanford University in the United States conducted statistics on 32 BIM application projects and obtained the following benefits of using BIM technology:
1) Eliminate 40% of out-of-budget changes;
2) Cost estimates controlled within 3% accuracy;
3) Time required for cost estimation reduced by 80%;
4) Contract prices reduced by 10% through finding and resolving conflicts;
5) Project duration shortened by 7%;
6) Early return on investment.
1.8 Bottlenecks in BIM technology application
1) The construction industry is large in scale, and it is very difficult to get many practitioners to accept BIM technology in a short time.
2) The processes in the construction industry are relatively fragmented. To apply BIM technology, workflows need to be integrated.
3) In the design stage, because there are no additional fees, designers do not care about BIM modeling. Designers are unwilling to consider the BIM model requirements of subsequent construction enterprises, believing that adding information unrelated to their own business brings neither obligation nor reward. They worry that once incorrect BIM information is input, they must bear responsibilities that designers can hardly afford.
4) Construction enterprises have doubts about the correctness, detail, comprehensiveness, and timeliness of the BIM models transmitted by design units.
Currently, Zhejiang Province has planned to issue standards to add corresponding fees for projects using BIM technology, as shown in Table 1. 1.9 BIM-based smart construction
1. Connotation of smart construction
The construction industry follows the path of sustainable development. Throughout the construction process, various resources are efficiently used to achieve low-carbon and energy-saving, maximize resource conservation, protect the environment, and reduce pollution. Advanced information technology means are used to realize intelligence throughout the construction process, with effective collaboration among all parties, effective sharing of information and data, refined and scientific enterprise management, and intensive and efficient construction modes.
2. Technical support for smart construction
1) Five-dimensional BIM modeling, 5D (BIM model) = 3D entity + 1D time + 1D cost.
2) Collaboration and integration of basic project engineering data based on big data and cloud computing.
3) Synthesis, simulation, and collision checking of BIM models for various disciplines such as architecture, structure, MEP, and installation.
4) BIM model management, sharing, visualization, and virtual construction based on cloud computing.
5) BIM construction supervision, operation and maintenance management, and realistic experience based on mobile data platforms and the Internet of Things.
2. Top-level design of prefabricated buildings accelerates
In recent years, the top-level design of prefabricated buildings has accelerated. The Central Committee of the Communist Party of China document Zhongfa [2016] No. 6, "Several Opinions of the Central Committee of the Communist Party of China and the State Council on Further Strengthening the Management of Urban Planning and Construction," proposed the goal of vigorously promoting prefabricated buildings. The State Council document Guobanfa [2016] No. 71, "Guiding Opinions of the General Office of the State Council on Vigorously Developing Prefabricated Buildings," divided key development areas, active areas, and encouraged development areas for prefabricated buildings. The Ministry of Housing and Urban-Rural Development document Jianke [2017] No. 77 issued the "13th Five-Year Plan for Prefabricated Buildings Action Plan," "Management Measures for Prefabricated Building Demonstration Cities," and "Management Measures for Prefabricated Building Industrial Bases," determining the phased development goals for 2020. After the introduction of national-level documents, various regions have actively implemented national policies, documents, and standards. Currently, all 31 provinces (municipalities and autonomous regions) across the country have issued corresponding policies to encourage the development of prefabricated buildings. The policy and standard system for vigorously promoting prefabricated buildings nationwide has gradually formed, and prefabricated buildings have developed from the pilot demonstration stage to the regional comprehensive promotion stage.
Prefabricated buildings have advantages such as reducing consumption, saving materials, shortening construction periods, and reducing construction waste (Figure 5). They are characterized by standardized design, factory production, prefabricated construction, prefabricated decoration, and informatization management (the construction site of a prefabricated building is shown in Figure 6). From the perspective of informatization management, it is inevitable to pay attention to cultivating BIM specialists and focusing on the application of BIM technology in prefabricated buildings.
Compared with traditional projects, the design and construction of prefabricated buildings place more emphasis on comprehensive evaluation of quality, cost, schedule, effect, and environmental protection. In the processes of detailed design, component fabrication, and construction hoisting, systematic comprehensive integration is especially needed. BIM technology has become an important means to improve construction quality. The industrialized building evaluation system is shown in Figure 7.