ARCHITECTURE, CONSTRUCTION AND DESIGN Application of bim model in technical infrastructure design for newcity thu thiem residential project

. In the field of construction, many new technologies have been developed and applied to the design, construction and management of construction works. One of these new technologies is the application of Building Information Model (BIM). BIM is applied in all fields of the construction industry from design, construction management, gives almost absolute accuracy, saving time and costs in survey, design, construction and project management and brings us economic benefits very clearly. BIM helps to reduce costs, construction time, reduce construction risks and design changes. Based on the results of the BIM model, the projects are estimated easily, estimating a suitable capital arrangement plan, avoiding unnecessary risks. In Vietnam, there have been a number of investors are applying BIM in technical infrastructure works, especially buildings in recent years. However, high cost and qualifications of engineers are barriers for applying BIM. There are few technical infrastructure projects that are applied BIM, especially in infrastructures field. This paper researches the application of BIM for in technical infrastructure design for the NEWCITY Thu Thiem, Ho Chi Minh City, Viet Nam. An diagram of implementing BIM process in design and process for design coordination for operating the design and coordination between the stakeholders is built. Software are applied as well as exported files with levels of detail (LOD) and levels of information (LOI) from 200 to 400 to helping stakeholders to retrieve, check, handle information and interacting by the parties during life cycle of the project.


Introduction
BIM is a new technology, developed on digital technology basis, being deployed and widely applied in the construction industry in many countries. BIM is considered as one of the important solutions to approach the 4.0 technology revolution of the construction industry in Vietnam. There are many different definitions of BIM as Autodesk [1], UK's strategic plan for BIM [2], In the US national BIM standard [3]. Although there are many different definitions of BIM, the most common way to understand BIM is the process of creating and using a digital model for the entire life cycle of a building, from design, construction, to construction, operation, maintenance and dismantling works.
All information and data related to the building during its entire life cycle is stored and exploited through a unified and linked information model. Any changes to any component in the model will be updated automatically for the entire system. Therefore, the application of BIM will facilitate the exchange and cooperation between the parties involved, optimizing the design, construction and management of the project. BIM Database used throughout the life cycle of the project (Fig. 1) [4] During the design phase, BIM is used to create a threedimensional (3D) model containing the building's information. This model is used to demonstrate the design, analyze and select the optimal design option, observe, detect conflicts between disciplines, automatically create and update drawings, calculate blocks, quality, cost estimation, performance analysis. The application of BIM in design brings the following benefits: Visualization; Increased productivity and design quality; Improved volume measurement and cost estimation; Enhance the sustainability of the building; Enhance cooperation. However, the application of BIM still has many challenges, related to 04 factors: People, technology, process and legal [5].
Currently, BIM has been applied compulsorily in the construction industry in many countries such as the US, UK, Singapore, and some other countries at different levels. In Vietnam, the application of BIM in design, construction and operation management is being implemented with the project on  After that, the project implementation plan and provisional guidance on the application of BIM in the pilot phase were also issued by the Ministry of Construction [6]. Therefore, the application of BIM in design, construction and operation management activities in Vietnam has a basis for development.
Modeling in BIM Application process The BIM application process can be applied throughout the life cycle of the project. Depending on the goals of each phase of the project in construction investment sequence and the order of project implementation in order to apply the BIM process appropriately.
General application process Construction investment sequence and general application process of BIM are showed in Fig. 2  Construction investment sequence and application process of BIM [6] With the IPD Design and Construction Project (Without  Bidding) BIM process for design, construction (non-bidding) IPD projects are illustrated in Fig. 3.

Figure 3
BIM process for design, construction (non-bidding) IPD projects [6] With the IDP Design, Bidding and Construction project Pre-bid period: (Fig. 4)

Figure 5
BIM process for IPD design in construction phase Application system of software in BIM BIM is a software system, used by engineers, departments, and specialties at different stages in the construction process… CDE is the environment for collecting, managing, transmitting and storing the data (geometric and nongeometric) of the project. CDE is the backbone of BIM. Information generated by the participants must be exchanged on the CDE. Each project has a unique CDE to help project members easily collaborate with each other and avoid information duplication and confusion. CDE is usually set up at the beginning of the project, going from designconstruction -handover, continuously maintained during the operation of the project and stores all information about the project ( Fig. 6-7).      New City Thu Thiem New City Thu Thiem has total project area more than 2,74 hectare ~ 2,94 hectare. Total construction area is 19,320.9 m2. Construction density is 24.78% of the whole area. Area for utility & community service: 4,392.5 m2 to build and develop utility service infrastructure, serving the needs of the population's well-being., including Kindergarten (1,260,6m2), Medical area (278.75m2), Community living room (967m2), Public utility infrastructure (1,886.2m2) ( Fig. 9) Overall diagram of BIM for infrastructure design of NewCity Thu Thiem project Overall diagram of BIM for infrastructure design of New City Thu Thiem project is built as Chart 1.
Process for design coordination The design coordination process to organize and implement the design of technical and traffic infrastructure according to the BIM model for the New City Thu Thiem Project for the purpose of operating the design and coordination between the stakeholders is built Chart 2.
Application of software in BIM model Currently, there are many software applications in BIM. Depending on each major and each subject, appropriate software

Chart of design coordination process
Steps for design implementation Step 1 -Initialize the project Before starting the project, it is necessary to consider the options applicable in the design process such as using Step 2 -Build the 3D Model The preliminary design begins with the study of the building's geometry and the determination of the elevation grids and locating axes of the building. Proceed to build the basic building components. Build 3D models in Autodesk Revit software from 2D drawings. 3D CAD models are created from existing 2D drawings (architecture + structure). Parameters included in 2D drawings such as position, type of component, size, quantity of each component, etc… built fully and shown on the 3D model. This work is done by Autodesk Revit 2020 software. This software manages elements based on IDs and classifies elements according to the types of components we often use (manholes, pipes, etc.) sewers, water supply and drainage pipes, pavement layers, ...). Continue to evolve the design by adding more detailed components. Then, perform model refinement to finalize the design. In order for subsequent applications to be able to recognize and thereby automatically export the results to Excel, building a 3D model must adhere to a few basic principles: The drawing tools in Revit must selected as specified. Elements in the Revit model is selected from the respective Families.
Step 3 -Customize in Autodesk Revit 2020 software Customize in Autodesk Revit 2020 software to provide work titles and related work names in accordance with Vietnam standard. work sharing, duplicate or monitor, coordinate, check for conflicts to share work or project information to other members of teams, monitor, timely alert to changes and control conflicts between the components in the model.
Step 4 -Develop technical design documents Create and present floor plans, elevations, sections, details, statistical tables, and technical instructions in accordance with technical design documents. Then proceed to layout the drawings and export the documents into electronic prints (.pdf) or print on paper. Export data from Autodesk Revit 2020 3D models to other software according to business requirements. Step

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Storage and retrieve infrastructure items We can show the details of each type of structure. Besides, we can view the drawings directly on the construction site through the link of the drawings uploaded on BIM Glue 360 (Fig. 10).   Check and handle infrastructure items We can easily detect the number and position of intersections between infrastructure items. From there, the designing engineer will come up with suitable and optimal intersection handling solutions (Fig. 12-15).
Check infrastructure items:

Figure 12
Checking interfaces by NAVISWORKS software Figure 13 Interaction in parties using BIM 360 GLUE Handling intersection between rainwater sewer and water supply pipe: Figure 14 Detecting intersections between storm drains and water supply pipes Handling errors: After detecting the position of intersections, the designing engineer offers suitable and optimal intersection handling options and recorded on the system.    Interaction in the parties Client, designing consultants, project management board and contractors can interact with each other through BIM 360 Glue to final the product with advantages as: Solve problems quickly, no need to wait for documents to be exported; Parties can work anytime, anywhere; Acknowledge the problem clearly; All data is saved for reference by all parties (Fig. 18).

Figure 18
Interactions in parties CONCLUSIONS BIM is a useful tool for building design because it accelerates the overall design process in close collaboration with stakeholders. It also provides simulation and analysis of building performance, allowing designers to improve designs and select optimal design options.
For traffic engineering infrastructure design, BIM helps to increase design quality, significantly reducing conflicts between design in the office and construction in the field. Designs made through BIM when there is an adjustment, the changed information will be displayed on that object in another design department. With the use BIM, together with the integration of volumetric measurement software, this stage will be performed automatically, thereby reducing construction costs. In addition, the use of data on cloud computing technology in BIM also helps teams work together to design, deliver products and store more conveniently. The application of BIM helps to reduce the waiting time for unintended conflicts caused by design errors or inconsistencies between design and construction so that the project management board will monitor and supervise the implementation of design and construction smoothly, accurately, and to limit errors in deploying design drawings to construction, helping to detect and anticipate difficulties in the construction process right from the stage of accessing design documents.