Research on Optimization of Project Design Management Process Based on BIM

Abstract

With the rapid advancement of the informatization process of China’s construction industry, the requirements for the integration of engineering design and construction are getting higher and higher. The quality of engineering design and the level of design management directly affect the quality of construction. The emergence of the EPC (Engineering, Procurement, and Construction) model overcomes the shortcomings of the traditional contracting model, but it is still not ideal in terms of work integration and information transmission. BIM (building information modeling) is a collaborative process of creating, managing and exchanging information throughout the construction project. BIM has revolutionized the construction, engineering and construction (AEC) industry. This paper examines the problems related to current project design management in China and their causes. On the basis of summarizing the existing research on design management, it introduces a form of BIM integrating design BIM and construction BIM, so as to better depict the leading role of design in the construction process. By analyzing the changes in organizational management and communication methods brought about by BIM, this paper optimizes and innovates upon the traditional project design process in view of the problems in project practice. It advances BIM design work, increases detailed BIM design work and enables the downstream participants to intervene in the design stage, so as to develop a more smooth and efficient design workflow, which provides operable work detail guidance for BIM-based design management in the future.

1. Introduction

At present, the engineering project design consulting service in China is in a state of “fragmentation”. There is a lack of agents relating to technology and the management of the whole process of the project, and there are problems in the separation of design, construction and operation and the maintenance management of projects. Integration therefore has become an inevitable trend in project construction management. It has become the clear goal of the development of the construction industry that in order to achieve accurate, efficient and high-value-added design management effects, and thus to improve the design and overall quality of architectural engineering, a “design-oriented construction management” (DCM) mode based on building information technology should be set up, the collaborative work of all parties under the guidance of design should be emphasized, virtual integrated management should be implemented, and many procedural works that are difficult to avoid in the traditional construction mode should be reduced [1].

The traditional design–bid–build (DBB) method has been widely used in the construction industry as the main delivery mode [2]. It follows the design, bidding, construction and other phased linear sequence management ideas, but also raises a series of problems, such as frequent project changes and claims, inefficient project schedule control, limited project profits, and a large proportion of indirect project costs [3,4]. The builder is unable to participate in the design work, the organization and coordination relationship is complex, and the investment cost can easily get out of control [5]. The outstanding characteristics of engineering project construction are that it is only performed once and its irreversibility, thus requiring high-quality professional and integrated management. With the development of large-scale, comprehensive and complicated projects, the DBB model struggles to meet the requirements of large-scale project management. In order to meet these requirements, the integrated management mode of project general contracting and general contracting management has been greatly developed [6].

Lifecycle management is an integrated and information-driven engineering project management method which can guarantee the progress and quality of engineering projects effectively [5]. The EPC mode covers the full life cycle of a project, including the design, procurement, construction, and trial operation [7,8]. It can realize integrated management and overall optimization, which can not only shorten the planning and construction period of the project, but also ensure the project’s quality. The EPC mode has become a project contract mode that is widely used in developed countries, since it overcomes the drawbacks of the traditional contract mode in which the design, procurement and construction are out of line, implements unified scheduling and management, and effectively transfers investment risks [2].

However, there are still some deficiencies in the application of the EPC model in China. On the one hand, because the existing EPC project delivery model in China is still based on two-dimensional CAD technology as a design tool and information transmission medium, the existing EPC project delivery model is still not ideal in terms of work integration and information transmission, and the project integration has not been truly realized [9]. On the other hand, China’s general contracting model is not general contracting in the true sense, and the design, construction and operation and maintenance are obviously separated. Due to the game of the interests of many participants and the difference in management objectives, challenges regarding information sharing and organizational coordination among the participants can easily occur [10]. At present, although China has promoted the general contracting mode in the field of engineering construction, and the EPC mode is also popular, it cannot be ignored that there are still a considerable number of EPC projects that are not real EPC, with the mechanical binding of various businesses under the traditional construction general contracting mode. This will not only fail to give full play to the advantages of the EPC model, but will also limit the advantages of the traditional model, often leading to difficulties in project development [11].

In order to cope with increasingly complex construction projects, the use of emerging technologies, norms, contracting and delivery methods has become crucial. Building information modeling (BIM) is one of these promising technology developments [12], providing an integrated full life cycle construction information management method.

BIM is a digital expression of the entity and functional characteristics of the project, allowing AEC professionals to collaborate seamlessly across different life cycle stages. Its application can run through the entire life cycle of the construction project, including the design, construction and operation and maintenance stages [13]. In the 2019 work points of the Engineering Quality and Safety Supervision Department of the Ministry of Housing and Urban–Rural Development, the state clearly stated that it is necessary to strengthen the integration and application of BIM technology, organize the discussion of evaluation indicators and evaluation methods of BIM technology, and promote the integration and application of BIM technology in all aspects of design, construction, operation and maintenance.

The problems existing in the construction mode seriously restrict the further improvement of the project management level in China. Therefore, it is particularly important to supplement and improve the current construction project management procedures to make them conform to the objective laws and management requirements that should be followed in construction work under the current situation. The purpose of this study is to take BIM management as the starting point, combined with the characteristics of general contracting projects, to design an application-oriented project organization structure and actual management process that can respond to the dynamic adjustment of construction objectives in a rapidly changing environment. It proposes the integration of design BIM and construction BIM as an achievable model for the transition from the traditional construction model to a real general contracting model in China, thereby promoting the integration of engineering design and construction integration in China.

2. Literature Review

2.1. Engineering Design Management Optimization

The economic and environmental costs of the full life cycle of construction projects mostly depend on the design stage [14]. The existing research on the optimization of engineering design management is carried out based on two aspects, namely technology and management [2]. For the former, extensive research mainly focuses on improving the performance of a certain part of the project or the entire engineering system technically through design optimization. For instance, Lavaei et al. [15] reported on the reliability-based design optimization (RBDO) of post-tensioned self-centering rocking steel frame structures with buckling-restrained bracing systems. This can reduce the weight of the single-layer structure by 2–23%. Sun and Leng [16] improved travel quality and efficiency by optimizing underground space design to reduce carbon dioxide emissions and improve energy efficiency. Baghdadi et al. [17] used artificial intelligence algorithms to optimize the design of a prefabricated wallboard building system, which greatly simplified the manufacturing process while satisfying the building parameters. Baradaran-Noveiri et al. [18] proposed an integrated design model, and the results reveal that the cost and time for air distribution system installation can be reduced by 23.9% and 21.3%, respectively. Yi et al. [19] utilized computational fluid dynamics (CFD) simulations and artificial neural networks (ANN) to predict indoor air movement with less computational time and load, which can maximize natural ventilation to reduce the risk of pollution caused by insufficient fresh air.

By contrast, only a few studies have explored the design optimization of engineering projects from the management perspective, where a case study or data collection was selected as the primary approach. For instance, Chen et al. [2] proposed a comprehensive method to explore the relationship between various factors affecting EPC engineering design optimization, strengthened the theoretical basis of influencing factor analysis, and extended it to engineering project design optimization research, from technical analysis to factor relationship investigation considering multiple stakeholders. Zhang et al. [20] found that the behavior of owners and contractors can affect the design performance through a questionnaire survey and hierarchical regression analysis. Cao and Lei [21] established a structural equation model (SEM) to comprehensively evaluate the risk factors of prefabricated buildings under the EPC general contracting mode and help project participants to obtain the best risk response measures in different situations. In summary, current research into the design optimization of engineering projects has a greater emphasis on technology than management. There are still many management problems to be studied, such as how to change the existing design and construction separation problem by optimizing the design and construction process.

2.2. The Application of BIM in Construction Projects

Robert Eadie et al. stated [22,23] that in order to efficiently implement BIM throughout the building life-cycle, detailed planning must be performed. This plan should be used in the project as a guide to key milestones and deliverables, which should detail the information exchange requirements as stipulated by the contract and specify the agreed roles and responsibilities of stakeholders. He et al. [24] took the BIM application of many large and complex projects in China as the research object, analyzed the BIM application and existing problems in various stages of the project, discussed the current obstacles to BIM application, and proposed measures and suggestions that can promote the implementation of BIM application. Zhang et al. [25] took the application of BIM in engineering construction as a research focus and developed a series of BIM models and BIM project operating procedures, thus establishing a set of BIM applications, including the BIM application framework, operating procedures and countermeasures during the project construction. Wang [26] introduced the overall design idea and work process of BIM and carried out a case study in combination with specific examples of BIM. On this basis, he combined the specific application scenarios of BIM in the entire life cycle and the specific operation process of BIM. Wang et al. [27] proposed a multi-person collaborative design model for BIM drawing that combines the blockchain and the Inter Planetary File System (IPFS). It is suitable for multi-person collaborative design, which can effectively ensure the reliability of drawings. Laali et al. [28] proposed a BIM-based framework for automating sustainability assessment and optimizing infrastructure projects. Azhar [29] pointed out that BIM represents a new paradigm within AEC, one that encourages integration of the roles of all stakeholders on a project. Zheng et al. [30] indicated that digitalization can improve both the cost and time performance, with greater potential for improvement in time performance for EPC projects. Sonmez et al. [31] presented a novel building information modeling (BIM) integrated smart contract progress payment administration system, in which as-constructed BIM is used to link the real world with the blockchain. They also indicated the potential of future research on semiautonomous BIM-integrated smart contract systems to accelerate the adoption of the BIM and smart contract technologies for progress payment administration within the construction sector. Tan et al. [32] highlighted the barriers to BIM implementation in China’s prefabricated buildings and provided technical and management solutions to improve BIM implementation in China’s prefabricated buildings. Habib et al. [33] helped to select appropriate BIM roles for BIM tasks. The BIM roles identified through this study include a BIM manager (design), BIM manager (construction), BIM coordinator (design), BIM coordinator (construction), information manager (design), information manager (construction), model manager, and BIM modeler. The literature review above provides useful information for determining the application of BIM in construction projects. However, there are few studies on solving the current dilemma regarding how to use BIM to solve the separation of design and construction in China. Consequently, this type of research will benefit the construction industry.

3. Methods

The novel research methodology consists of 4 stages, as shown in Figure 1.

• Analyze the problems existing in design management process in China;
• Analyze the causes of problems existing in design management process in China;
• Plan the design management retrofit process;
• Develop the process maps for the design management.

3.1. Analyze the Problems Existing in Design Management Process in China

Modern engineering projects have increasingly higher requirements for management. Project management of all parties, no matter the owner or the general contractor, should focus on the progress, quality and cost of the project [34,35,36]. Project management is a systematic management activity that effectively plans, organizes, commands, controls and coordinates the whole life cycle of the project under the established constraints in order to achieve the project objectives optimally according to the inherent laws of the project. This process covers project planning, design and safety management [8,37]. The so-called design management is the process of ensuring the effective control, planning and guidance of the whole process or several aspects of the project. Its main purpose is to ensure the smooth realization of the construction project’s objectives.

In the traditional design management process, as shown in Figure 2, the developer firstly finds the conceptual designer to carry out the general plan design, which should meet the corresponding planning indicators. After receiving the approval of the Planning Bureau, the project construction permit should be obtained. After the completion of planning and construction applications, the conceptual designer will hand over the submitted scheme files to the construction design institute for further design. The construction design includes five major aspects: architecture, structure, water supply and drainage, electrical infrastructure, and HVAC (Heating, Ventilation and Air Conditioning). Some complex projects also include curtain wall design, steel structure design, intelligent design, etc. The constructors then deepen the construction design according to the scheme provided by the construction design institute, including checking the indicators, optimizing the scheme, and integrating the construction drawings of all professions. Then, the detailed construction design is completed. Before the project construction, each professional of the construction unit will review the drawings, put forward any existing questions and problems, and solve them together with the designer.

The traditional project delivery mode is based on the concept that “the more detailed the division of labor, the higher the efficiency, and the better the operation effect”, and has refined each work. In terms of project management, technical information transfer based on 2D CAD is adopted to carry out long process management according to the sequence of work occurrence. However, this information transfer will lag behind the actual project, which can easily cause rework. In the face of the increasingly prominent problems caused by the excessive division of labor, the emergence of the EPC project delivery mode has improved the problem of low project efficiency caused by the traditional design process to a certain extent.

In the process of the development of China’s project delivery mode towards the practice of “general contracting” and an “integrated delivery” mode, an exploratory product has been produced, which is called integrated projects—that is, the integration of some projects in “survey, design, construction and equipment procurement” is entrusted to a qualified unit for implementation, such as the integration of surveying and design and the integration of design and construction. Among them, the integration of design and construction is most familiar to the public, and the integration of design and construction needs to follow a certain process. Due to the actual situation in China’s current engineering and construction industry, it is still difficult to realize the real integration of design and construction.

Although China is in the process of vigorously promoting the implementation of the EPC mode in the field of housing construction and municipal infrastructure, in reality, even large-scale engineering companies are extremely short of professional talents with EPC project management capabilities and experience. Many enterprises still have the mechanical thinking of “knowing design for design and construction for construction, and only need to put two groups of people together to do EPC well”. It can be said that the existing design and construction are separated, and the majority of the performance of EPC general contracting mode in China fails to meet the expected goal.

3.2. Analyze the Causes of Problems Existing in Design Management Process in China

(1)

Problems and causes analysis of the existing design patterns in China

At present, China is vigorously implementing the architect responsibility system, but the main reason for the difficulty and slow implementation of this model in China is the architects themselves, owners, contractors and the government, causing the construction industry to lack international market competitiveness, to display slow technological progress, to demonstrate low construction quality and to produce a serious waste of resources. Analysis of the specific problems and their causes is shown in

Table 1. Problems and cause analysis of existing design patterns.

Category	Analysis of Main Problems and Causes
Architect	The architect only completes the main design drawings, and the design institute is only responsible for the design depth and design quality specified by the state, not for the final building.
Owner	The owner’s self-operated project management mode leads to the loss of the integrated status of the architect as the general contractor of design and the contractor as the general contractor of the project, as well as the dislocation of the social allocation of professional resources, which further weakens the technical capabilities of design consulting enterprises and construction enterprises.
Contractor	The core role of the general contractor was originally to precisely define the design, subcontract resource management, and project construction management. Under the existing industry management system, the general contractor was required to construct according to the drawings, and gradually degenerated into a collection of contracting teams that did not make the processing drawings or provide subcontracting resource overall control, and had no design technical capabilities.
Government	The architect system entered the historical stage after the industrial revolution. One of the important factors is the administrative license of the construction market and the outsourcing of government supervision. In this transformation process, the construction projects invested by the government have a decisive influence and demonstration effect on the market.

.

(2)

Problems of connection between design and construction and cause analysis

The current design and construction in China are obviously separated, displaying a “two skin phenomenon” situation. Analysis of the specific problems and their causes is shown in

Table 2. Problems and causes of connection between design and construction.

Problems	Cause Analysis
The design is not responsible for the final building	Due to the fact that the owners are not responsible for the building for life, their needs and design indicators cannot be correctly transmitted and continuously integrated during the construction process, resulting in insufficient feasibility of design under the resource constraints of cost, construction period, process technology, etc.
Insufficient design depth	The design expression depth is insufficient, it is difficult to express complex spatial relations and nodes, the expression of indoor and outdoor interfaces is missing, and there is a lack of feedback mechanism for expression methods and information transmission effects. The final effect of information transmission cannot be fed back at the construction end.
Design rejection	Systematic vacancy exists in secondary design and special design. The owner often conducts bidding in sections, which causes the separation of different professions.

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These problems seriously restrict the further improvement of the project management level. Therefore, it is particularly important to supplement and improve the current construction project design management procedures so as to make them conform to the objective laws and management requirements that should be followed by the construction work under the current situation. Since 2016, the state has vigorously promoted the application of BIM, listed BIM as the first of the five major information technologies to be promoted in the construction industry during the “13th Five-Year Plan” period, clearly proposed the need to study the design, construction management mode and cooperative work mechanism under the BIM application conditions, and established the project management information system [38]. In 2017, the Ministry of Housing and Urban Rural Development promulgated the Building Information Model Construction Application Standard, which provides a reference BIM standard for China’s construction industry. On 15 March 2019, the Guiding Opinions on Promoting the Development of the Whole Process Engineering Consulting Service were promulgated, which proposed vigorously carrying out the application of BIM technology, striving to improve the comprehensive level of informatization and management application based on the current big data and IOT thinking, and comprehensively carrying out the consulting guarantee on engineering business. Therefore, it is urgent to take BIM as the starting point to formulate a design-centered integrated collaborative design management system of design BIM and construction BIM.

3.3. Plan the Design Management Retrofit Process

The most significant characteristic and superiority of the general contracting model lie in the leading role of design. Due to the needs of engineering construction project management and national policy implementation, as well as the current inability of Chinese construction enterprises to establish enterprises with general contracting capabilities in a short period of time, construction engineering general contracting project consortia have become a trend [39]. In recent years, with the vigorous development and promotion of the application of BIM by the country, the design process under the general contracting model has gradually been optimized. However, traditional design processes such as conceptual design, preliminary design, and construction drawing design with clear boundaries are still used. The separation between design and construction still exists, and the data between the two still cannot be connected. Based on this, further innovation is needed in the design management process under the existing general contracting model. The integration of design BIM and construction BIM proposed in this article is one means to achieve this.

3.3.1. The Integration of BIM and Collaborative Design

BIM provides tools and channels for collaborative design and promotes the development of collaborative design. From the design unit to the design and construction general contracting, from the two-dimensional drawings to the three-dimensional visualization model, the work of the whole construction industry has experienced an upgrade. Project management must give full play to the dominant advantage of “design”, extend to the two ends of the early and late operation and maintenance management stages of project planning, broaden the scope of services, and expand the concept of design management.

The integration of BIM and integrated collaborative design provides a means and channel for designers and constructors to share data information in real time. BIM can integrate all project participants together as a team to complete a project together. Members must trust each other, share information and cooperate with each other. The success of the project cannot be separated from the cooperation of the team. Therefore, it is necessary to maximize the use of information and digital technology to serve the project. Objectively speaking, BIM and integrated collaborative design are complementary to each other. BIM is a technology and means, and integrated collaborative design is a method. The effective integration of the two will play a multiplier effect in achieving the standard of project’s success. It can be said that BIM-based integrated collaborative design is a prerequisite for building high-quality projects. Thanks to the early involvement of various stakeholders, it is possible to ensure that each project member can work together toward the same goal at the same time and at the same level. At the same time, BIM can provide a project visualization model, design parameters and other data for the project management team, and can provide the owner with BIM model-based maintenance management for the whole life cycle.

3.3.2. Objectives of the Design Management Processes

The biggest difference between the integration of design BIM and construction BIM models and the traditional design management model lies in the integration of the organization. On the basis of fully considering the characteristics and advantages of BIM, by promoting parallel intersection of work between enterprises, the early intervention of downstream participants is emphasized, as well as the positive role of construction and operation units in design activities. Its design goals in terms of organizational structure are mainly considered from the following perspectives.

(1)

It should be conducive to the realization of the owner of the project objectives.

One of the criteria for the owner to measure the success of a project is whether it is put into use on schedule. In order to better achieve the ultimate goal of the project, it is often necessary to divide the ultimate goal of the project into a series of stage goals. Therefore, the design goal of the design BIM and construction BIM integration model is to achieve the organic unity of the stage goal and the ultimate goal, closely combine the organizational structure of the participants, closely implement the work around the ultimate project goal, and combine the integrated organizational characteristics. The traditional process is designed to ensure efficient communication and standardized cooperation between the participants.

(2)

It should be beneficial for the functioning of organizational systems.

Project organization integration is simply the process of integrating different participants together, and its most significant characteristic is its integrity. The planning, design, and construction of the project are all organized by temporary teams composed of different units. They are independent in their work and only focus on their own interests, lacking mutual cooperation and assistance. Therefore, BIM-based organizational integration aims to reduce internal friction between organizations, form a community of shared interests and risks, fully leverage the functions of the organizational system, and work together to achieve the highest goal of the project.

(3)

It should be conducive to forming a collaborative and integrated organizational environment.

Unlike traditional application environments and 2D flat mapping methods, BIM can provide a new organizational model and new production tools. BIM is not only a modeling tool, but also a way to explore its management thinking. The design organization of different projects and the collaborative work of various disciplines and participants can effectively demonstrate the management role of BIM. Therefore, the integrated organizational model helps to form a collaborative and integrated organizational environment, providing better convenience for project design management.

(4)

It should be beneficial for controlling investment risks in construction projects.

For construction projects, investment control is very important. In the traditional organizational management model, each participant is independent of each other, and the work at each stage presents a characteristic of “fragmentation”, which directly leads to increased investment risks for homeowners. The integrated mode of design BIM and construction BIM integrates all parties involved, and the construction and operation units participate in the design planning stage in advance to provide design references for the design units. This can effectively reduce design changes during the construction process, reduce resource waste, and be more conducive to the owner’s control of investment risks.

3.3.3. Principles of the Design Management Processes

The design management system based on BIM should follow the following principles.

(1)

Principle of unity of objectives and balance of responsibilities and power.

The effective operation of the BIM-based management organization mode depends on whether the project participants have clear and unified project objectives. The project participants must agree on the overall goal of the project before and during the project’s implementation, as shown in Figure 3. In the design of the organizational structure, it is necessary to combine the characteristics of BIM informatization and digital management, and closely focus on the overall goal to form the stage goals of each participant, and the goals of each stage are related to the ultimate goal, so as to maintain the consistency of the ultimate goal, so as to ensure that the organization of each participant and the overall organizational structure of the project can also maintain consistency. When designing the organizational structure, the addition of BIM technology will affect the responsibility and division of labor of all project participants, and the power distribution needs to be readjusted. The adjustment scheme should be determined in the contract signed in the early stage, and the relevant parties should be given sufficient power.

(2)

Principle of taking “design” as the leading factor.

Promoting the whole process project management led by “design” is the key to maximizing the project benefits. Design plays an important role in ensuring project quality, schedule, cost and other aspects. Project design is the beginning of project construction, and its quality determines the construction quality of the whole project. In particular, the preliminary design of the determined construction scheme can affect the economy of the project by up to 95% [40], as shown in Figure 4. The construction investment of the project, the level of the later operation cost, the advancement of the technology, the rationality of the function and the level of the construction cost all depend on the design quality [41].

(3)

Principle of no hierarchy and flattening.

When planning and designing the management organizational structure, the management level should be reduced as much as possible to simplify the organization, in order to realize the flattening of the integrated organizational structure. The work of each participant is organized around the ultimate goal and core process rather than around tasks or functions. Based on the BIM organization management mode, the traditional “upload and release” communication mode has been completely updated. The BIM information management system can not only achieve real-time communication among all project participants, but also greatly improve the work efficiency.

(4)

Principle of multi participant cooperation.

In the whole process of BIM-based construction project design management, the BIM model is taken as the center to realize the cooperation of all participants at different stages. At present, the design, construction, operation and maintenance of buildings are still disjointed, which makes it difficult to collaborate effectively. The BIM-based organization integration is conducive to the real-time sharing and transmission of project results, reducing repetitive work, breaking the barriers between participants, and achieving connectivity. At the same time, the cooperation between multiple participants is conducive to the early intervention of downstream participants. By integrating the experience and expertise of different professionals, problems can be eliminated in the early stage of project construction, which ensures that the construction project can better meet the needs of later operation and maintenance services.

3.4. Develop the Process Maps for the Design Management

In view of the limitations of the design management organizational structure of traditional construction projects, in order to further promote the integration of engineering design and construction, the author has developed a project design management process suitable for BIM, and further set out the workflow of the whole project process under the new design process, so as to solve the problems existing in the traditional design management process, such as the difficulties in design coordination and communication and the lack of a design verification mechanism. It provides a standardized workflow for all participants to collaborate efficiently. The optimized design process is shown in Figure 5.

The biggest differences between this process and the traditional design management process are as follows:

(1)

Adding detailed BIM design.

The detailed design fully reflects the designer’s design concept and design intent in the construction process, and makes the construction drawing more consistent with the actual situation on the premise of meeting the needs of Party A. In the traditional project management process, the detailed design is only applied in the construction stage. In order to better control the progress, quality and cost of the project, the author advances the detailed design from the construction stage to the design stage. Based on the principle of “construction feedback design in advance”, the feasibility analysis of the design and construction drawings is jointly promoted with the BIM personnel of the construction unit in the design stage, and the design side is quickly fed back to modify and adjust the design to ensure the quality of the design blueprint. The BIM design team will carry out collision detection and deepen the design in advance, give full play to the leading advantage of “design”, use BIM to control the clear height, optimize the pipeline routing, optimize the location of the machine room, and provide visual disclosure of the construction in complex areas and key locations. Finally, the owner will review and confirm the BIM construction model, and the BIM design team will ultimately produce the BIM construction drawings.

(2)

Advancing BIM design.

The BIM-based management process advances the BIM work, intervenes in the conceptual design stage, and directly starts the BIM scheme modeling of the architectural scheme. After completing the BIM scheme modeling, it is then handed over to the professional design teams to cooperate with the BIM design to perform the detailed BIM design. After the detailed design model is determined, the BIM construction drawing model is further determined and the BIM construction drawing is produced. The early intervention of BIM design can not only effectively reduce repetitive work among various professions, but also use its own professional knowledge to solve most of the collision problems in the modeling process, link other professions to check the model in real time, and correct errors quickly, so as to reduce the number of drawings and model modifications in the later stage, improve the work efficiency, and enhance the collaborative work ability among various professions.

(3)

Early intervention of downstream participants.

In the implementation process of China’s existing EPC projects, only the design unit utilizes BIM, or only the construction unit utilizes BIM. However, the design unit lacks experience in construction, and the deliverables often need to undergo multiple design changes, which will increase the duration and cost of a project. On the other hand, the construction unit lacks design experience, and the design depth often cannot reach the level that can directly guide the construction.

In the process of project design management based on BIM, the integrated design BIM team, cost consulting BIM team, general contracting BIM team and maintenance unit BIM team of downstream participants should extend their work focus forward, strengthen the cooperation between design, construction, operation and other management units, and improve the integrity of the organization and process. Using the integrated advantages of BIM, especially the integration of design BIM and construction BIM and the formation of design and construction integration, participants can improve the quality of design drawings, as shown in Figure 6.

4. Results and Discussion

4.1. Develop Professional Design Management Process in Construction

The whole project workflow is shown in Figure 7. Firstly, the general design management process based on BIM moves the focus forward to the design stage, which can effectively reduce the rework problem in the later stage of the project. The efficient operation of the whole process is inseparable from the technical support of informatization and digitalization. Therefore, it is necessary for the owner or the unit designated by the owner to build an information cooperation platform for the corresponding project design management in advance, so as to lay a foundation for the smooth implementation of the follow-up work. How to build this information platform is not discussed in this paper. Secondly, the owner, the designer and the constructor need to jointly prepare the “BIM Application Implementation Plan” and submit it to the owner for review and confirmation. The “BIM Application Implementation Plan” refers to the overall implementation of BIM in construction projects. Its contents should include: the purpose of applying BIM, information exchange standards, BIM implementation specifications, BIM application standards, delivery contents, etc. Finally, under the guidance of the owner, the operation and maintenance management database will be established to effectively manage the operation and equipment of the operation and maintenance unit and the property company, so as to reduce the operation costs and improve customer satisfaction.

The traditional process of detailed design is that the design institute produces construction drawings, delivers them to Party A, and then Party A submits them to the construction general contractor or professional company for detailed design through detailed design bidding. After introducing BIM management, although it cannot completely break away from traditional design processes, it can combine the characteristics and advantages of BIM to maximize the benefits of BIM application. In the integrated mode of design BIM and construction BIM, the design institute takes the lead, with the participation of Party A, the construction party, and the professional design team. BIM is used as a medium for information dissemination to optimize the design of the model, in order to further deepen and improve the project drawings and models.

In the integration of design BIM and construction BIM, participating roles include the owner’s BIM team, the integrated design BIM team, the cost consulting BIM team, the general contracting BIM team, and the maintenance unit BIM team. In the preliminary preparation stage, the owner’s BIM team will build a BIM collaboration platform and determine the overall goal of BIM application and the BIM lead unit. Afterwards, the owner’s BIM team collaborates with the integrated design BIM team and construction BIM team (i.e., the construction general contractor BIM team) to prepare the “BIM Application Implementation Plan” and submit it to the owner’s BIM team for review.

During the design phase, the owner’s BIM team will determine the cost consulting unit. Then, the integrated design BIM team and cost consulting BIM team will work together to prepare the “Design BIM Application Implementation Plan”. After the owner’s BIM team has approved the review, design planning will begin, with the participation of the construction BIM team and the maintenance unit BIM team. Then, the integrated design BIM team should provide a BIM conceptual design model, and the cost consulting BIM team should conduct investment estimation. After the review is approved, the owner’s BIM team selects the plan and begins preliminary design goal decision-making, with the participation of the construction BIM team and the maintenance unit BIM team. Afterwards, the integrated design BIM team should provide a preliminary BIM design model, and the cost consulting BIM team should conduct engineering estimates. After the review is approved, the owner’s BIM team will determine the optimized design plan, and the integrated design BIM team will carry out the detailed BIM design. The construction BIM team and the maintenance unit BIM team will also participate in this process. After the owner’s BIM team approves the detailed BIM design model, the construction BIM team and the maintenance unit BIM team jointly design the BIM construction drawings and issue the BIM construction design model. The owner’s BIM team ought to determine the design results. It should be pointed out that the BIM construction drawings are directly issued by the integrated design BIM team.

During the construction phase, the owner’s BIM team conducts full process management based on BIM. The integrated design BIM team needs to coordinate design changes based on BIM, while the cost consulting BIM team conducts cost management based on BIM. The construction BIM team needs to continuously improve the construction BIM model and provide the completed BIM model to the owner’s BIM team before project delivery.

During the operation and maintenance phase, the owner’s BIM team, integrated design BIM team, and construction BIM team will build an operation and management database, which will be handed over to the maintenance unit BIM team for facility operation and maintenance management.

In summary, with the integration of design BIM and construction BIM, a large amount of work is carried out during the design phase. By advancing the BIM design work and involving downstream participants in the process in advance, the current situation of organizational division in China’s design and construction can be improved, which is conducive to the realization of design and construction integration.

4.2. Management Organization Structure

In the construction project, the owner will set up a BIM management team to be responsible for developing a BIM-based management platform, effectively establish the relevant functional departments to organize and collaborate related work, and realize the collaborative work between various professions and stakeholders. The BIM management team and the BIM-based organization integration structure of all participants are the factors directly responsible for the establishment and application of the management system. and play a role in the owner’s design management throughout the process. The BIM-based information management team organization structure is shown in Figure 8.

The BIM team members are composed of personnel designated by the BIM consulting unit. The BIM team members must have clear division of labor and clear responsibilities.

(1)

Party A’s BIM Management Team.

General Project Chief: supervises and organizes the implementation of the project, reviews the implementation plan, and assists the project coordinator in promoting the implementation, prevention and resolution of project risks.

(2)

Technical Management Department.

Project BIM Chief: is responsible for the formulation and implementation of the overall project BIM application scheme, planning, standards, objectives, processes, etc., and interfacing with all project participants.

(3)

BIM Design Team.

BIM Principals of all Professions: are responsible for the overall control and work arrangement of BIM technology application.

BIM Designers of all Professions: build BIM models for civil design, design BIM applications, coordinate with architectural and structural designers to solve design problems, establish a BIM model for electromechanical design, design BIM applications, and coordinate with designers of water, heating, electricity and landscape to solve design problems.

(4)

BIM Construction Team.

BIM Application Director: is responsible for the overall implementation of the construction BIM work of the project, ensuring the establishment of BIM models of various professions and the efficient coordination among professions, so that the BIM application can be implemented in the construction.

BIM Detailed Design Engineer: is responsible for building the BIM model of building structure and applications in construction and coordinating BIM applications with other professions, and is responsible for detailed design and BIM modeling within the scope of the profession and coordinating BIM implementation with other professions.

On Site Construction BIM Coordination: is responsible for BIM landing and coordination on site and reflecting on problems.

(5)

BIM Operation and Maintenance Team.

BIM Operation and Maintenance Director: takes up the matter with the operation and maintenance unit and is responsible for the follow-up BIM to complete all application work.

BIM As Built Model Engineer: rechecks and delivers the corresponding as-built model according to all the determined materials, equipment and completed parts on site.

4.3. Optimization of Construction Guidance Process Based on BIM

According to the survey, it is known that at the construction site, although the project has begun to apply BIM to guide on-site construction, and the design unit has also completed the corresponding precision BIM model, there are still some problems in the BIM-guided construction process. Grass roots constructors doubt whether BIM can directly guide on-site construction. They think that the application of BIM only stays at the level of display and publicity, which does not really reflect the value of BIM for the project and enterprise management, which causes the contact between constructors and BIM designers to still be limited to solving specific construction conflicts. The BIM design and BIM construction are seriously disconnected. Therefore, it is necessary to set up a BIM construction team in the existing project, which should stay in the project department for a long time, and assign a special person to be responsible for the BIM landing, coordination and problem feedback on the site, so as to effectively solve the “two skin phenomenon” problem of BIM design and BIM construction.

Because most of the existing projects use the “linear” communication method, the level of informatization and digital application is low, which leads to the serious loss and lag of design information in the transmission process, which can also directly lead to a decline in design quality. In the actual construction process, there is often a discrepancy between the building entity and the BIM model, which affects the smooth implementation of subsequent work.

To solve the above problems, this paper creatively proposes a BIM-based design construction control process and a phased work plan approval form, as shown in Figure 9 and Figure 10. The workflow of this work is mainly divided into the following steps.

(1)

According to the construction schedule and the on-site construction situation, the construction unit shall submit the construction work plan for the next month to the supervisor in the middle of the month, and submit the summary table of the (mid-month) phased construction work plan, as shown in Figure 11. The contents mainly include: the name of the planned work, the basic conditions for the implementation of the planned work (the completed work is consistent/inconsistent with the original design), the description of the inconsistency, and whether the BIM model needs to be adjusted. After being approved, signed and confirmed by the supervising engineer, it shall be submitted to the design department for review and confirmation. If the review is not passed, the supervision unit shall give specific review opinions. See Figure 12 for the review opinions of a (monthly) phased construction work plan. The contents mainly include: review contents, whether the review is passed, reasons for failure, and specific modification opinions. The construction unit shall readjust the construction plan.

(2)

After being reviewed and signed by the supervising engineer, it shall be submitted to the design unit for review. The engineer shall review the consistency of the physical construction with the original design drawings and the BIM model according to the submitted construction work plan, and judge whether to agree to the next stage of the work plan. The review results shall be signed and confirmed by the chief design director and the BIM design engineer at the same time. After both reviews are passed, the plan shall be confirmed by the person in charge of the supervision department and submitted to the employer for review. If one of the parties fails to sign for confirmation, it shall be deemed that the audit has not been passed. The design unit shall issue a specific (monthly) periodic construction work plan review opinion form, give specific suggestions, and the construction unit shall readjust the construction plan.

(3)

After the design department passes the review, the supervision department will finally send it to the employer for review. If approved, the construction shall be carried out as planned. If the review fails, the contractor shall readjust the construction plan. The review (approval) form of the phased work plan is in quadruplicate, which shall be filled in by the contractor and kept by the supervisor, the contractor and the designer, respectively.

5. Conclusions

“BIM + management” is not only the development direction of BIM applications, but also represents the need to improve industry information management. This research takes BIM management as the starting point, uses the organizational integration characteristics of BIM, proposes the integration of design BIM and construction BIM, and establishes a project design management process with “design” as the core, aiming to solve the problems of severe separation between design and construction in China. This study concludes that:

(1)

By analyzing the current situation relating to architectural design management in China and the issues related to the connection between design and construction, BIM is combined with design management to strengthen the dominant advantage of “design” and ensure the ownership of construction project management and control by owners.

(2)

This study fully utilizes the characteristics of BIM organizational integration, which can effectively overcome conflicts of interest among various parties involved, achieve management of the entire lifecycle of engineering projects, improve the scientific nature of project management and the effectiveness of design management for owners, and ensure the orderly and efficient implementation of construction project design work.

(3)

This article optimizes and innovates upon the traditional design process, adding a detailed design link. The BIM design team conducts collision detection and detailed design in advance, works with the BIM personnel of the construction unit to promote the feasibility analysis of the design construction drawings during the design phase, and provides feedback on design modifications and adjustments to ensure the quality of the design blueprint. At the same time, this process advances the BIM design work, avoids collision issues between different professions as soon as possible, improves work efficiency, and enhances the collaborative work ability between different professions. Finally, downstream participants such as construction and operation parties intervene in the early decision-making stage or design stage of the project to participate in design decisions, effectively enhancing the close connection between design, construction, and operation and maintenance, thereby improving the overall quality of the construction project.

(4)

This article innovatively proposes a BIM-based design and construction process control process and work methods through the application and summary of practical projects. This process incorporates BIM design into the construction process, effectively solving the problems of “two skins” between BIM design and on-site construction. Specific workflow charts are designed, including the “approval form of the phased work plan”, “(monthly) summary of the phased construction work plan”, “(monthly) review opinions of the phased construction work plan”. They provided actionable work detail guidance for future BIM-based construction process management.

Due to the author’s personal research level, time, and practical experience, there are still some shortcomings in this article that require further research. This article proposes the integration of design BIM and construction BIM, setting up a new BIM-based design management process. However, due to a lack of sufficient practical experience, this model and design process can only be promoted in the Shaanxi province of China, and further research is needed to continuously verify and improve this model through more practical cases. In addition, the model proposed in this study is only a transitional model from a traditional construction mode to a general contracting mode, and there may be other models to be explored.