Deepening of Integrated pipeline - based BIM

The traditional electromechanical design using two-dimensional drawings conveys information that is relatively abstract, which means simple profiles and elevation drawings can’t reflect the three-dimensional effect of the pipeline. And that will cause some problems such as collisions during the construction process, disordered pipeline layout, and unreasonable space utilization. As a three-dimensional design technology, BIM can solve the above problems well. This paper describes the deepening and construction methods of pipe comprehensive based on BIM technology in detail. On the basis of refined modeling, combined with on-site construction experience and the comprehensive layout specifications of various professional pipelines, NAVISWORKS is used for collision detection, which is carried out with the designer and the builder, and the optimization of the original design drawings of the project. The deepened model can be used directly to guide on-site construction, that can reflect the important application value of BIM technology in electromechanical engineering.


Introduction
With the development and promotion of BIM technology,it plays an increasingly important role in construction engineering [1]. It shifts the focus of Party A from the problems of design drawings and construction units to the data integration of design parties, construction parties, suppliers and operators. The traditional two-dimensional drawings can't reflect the three-dimensional effect,and the unfavorable points and collision points between the professional pipelines can't be found in time and accurately. If the project hasn't been deepened, the construction unit directly according to the original design drawings construction, different installation teams according to their respective construction experience to solve the collision problem, lack of overall consideration, that will lead to the installation of later support and hanger problems, that will also affect the duration of the project and increase the cost of manpower and material resources [2]. BIM technology optimizes the design drawings,on the premise of minimizing turn-over and ensuring clear height, considering the aesthetics of basement and feasibility of construction, the problem of pipeline collision will be solved, that can't only improve the engineering design quality, but also improve the construction efficiency and engineering quality.

The importance of BIM technology
2.1. The core value of BIM electromechanical engineering optimization BIM electromechanical optimization is to establish a visual three-dimensional model, sort out and review all design blueprints in the early stage of construction, find out drawing design problems and IOP Conf. Series: Earth and Environmental Science 568 (2020) 012026 IOP Publishing doi:10.1088/1755-1315/568/1/012026 2 disadvantages in advance and solve them in time. In the process of deepening, each functional area is reviewed, considering the economic, practical, beautiful, feasible, normative and other conditions, maximizing the net height of the basement, making all kinds of mechanical and electrical pipelines arranged in an orderly manner, and improving the owner's awareness of use. The completed model can also assist the construction, so that the site workers can understand the pipeline installation direction and complex node installation situation.

Electromechanical optimization workflow
2.2.1. Modeling basis. Modeling basis including design drawings of building, structure, water supply and drainage, electrical, heating and ventilation provided by Party A/Design Institute.

Work content and work flow.
The deepening of BIM comprehensive management is to combine the experience of electromechanical installation and construction, the conditions of the construction site and the principles of electromechanical installation, to optimize the BIM electromechanical model reasonably, to achieve standardization, coordination, and beautiful appearance, and finally to implement on the ground, and to guide the construction on site. Main work flow of electromechanical deepening: Obtaining construction drawings from Party A/designer, reviewing drawings, planning construction model, drawing building model and electromechanical model, discovering problems during modeling, and submitting problem report. Secondly, the net height analysis of the whole building, the optimization of parking spaces, the design coordination meeting to review the drawings and discuss the comprehensive management principles for the drawings and models. The designer optimizes the design blueprint for the problem report and conducts preliminary deepening design. After the design optimization is completed, ensure that the BIM results can be used as a construction reference, and make a detailed explanation with the construction party, further review the comprehensive design results of the comprehensive management, and confirm that the drawings are correct and deliver the results.

Principle of electromechanical optimization
Underground garage: The basement pipelines are arranged in the parking space area as far as possible, and the pipelines are concentrated over the rear of the parking space to maintain the overall perception of the basement. As far as possible don't arrange the pipeline above the carriageway, leaving enough space for the carriageway. As far as possible integrated pipeline installation, the same professional and functional pipeline as far as possible adjacent installation. If the pipeline meets the wind pipe, the pipe must be turned up, and must bypass the fire shutter door. Garage spray all open up three-way treatment, they should be arranged in the bottom of the secondary beam, spray supervisor as far as possible to stick the edge. Pay special attention to the layout of the exhaust outlet, to avoid the installation of pipes or pipe accessories and other obstructions in front of the exhaust outlet. Main building part: The pipelines are all concentrated on the passageways and should be arranged in rows as far as possible. If the width of the walkway can't meet the level of the pipeline, or there are two layers and three layers of pipeline, the pipeline all go through the comprehensive support, the construction should pay attention to the pipeline installation sequence. The pipeline of the elevator hall should be arranged as high as possible, for the late fine decoration reserved sufficient space. Due to the frequent maintenance lines, there should be sufficient space for the maintenance of weak bridge. Air duct should be arranged to observe the tuyere orientation. High voltage bridge and weak current bridge is more than 30 cm away to avoid electromagnetic interference. Due to the large difference of support type selection, it is suggested that air conditioning water and thermal pipeline should be arranged separately.

Notes for drawing building information model
 The single-storey building area of more than 50,000 square meters needs to be divided and built to avoid computer lag and affect efficiency.  A single professional model is suggested to be done by a single person.  Ensure the integrity of the model.  Model accuracy requires reference to model accuracy standards.  The base map of the modeling process should be placed in a professional file for easy inquiry.  Any model must have a fixed axial network to prevent reference shifting and model management confusion.  and collision detection are carried out to each other, and the design modification is carried out in advance to reduce the change in the construction stage. Collision detection is mainly aimed at integrated pipeline, including internal detection of pipeline system, internal detection of HVAC system, internal detection of electrical system and detection between various specialties [4].

Check key points
 Ramp: whether the ramp meets the minimum net height requirement and whether it affects vehicle access.  Sump: Sump should not be set behind the door or at the entrance of the ramp.

Problem reporting
The problem report is composed of text,2Dand3D images, reflecting the problem in multiple dimensions.

Tracking
Check the completeness of drawings; Check the standardization of drawings; Check the drawing design standards; Check surface error, missing information, pipeline collision and other problems; Check the rationality of each system design; Check function and effect. For each verification content, relevant written problem reports shall be submitted to the construction party, the design institute and Party A in a timely manner, and the problem solving shall be tracked and fed back to Party A.

Effect and Contrast
Before：Heat pipes, smoke pipes, strong and weak electric Bridges and spray pipes are staggered. IOP Conf. Series: Earth and Environmental Science 568 (2020) 012026 IOP Publishing doi:10.1088/1755-1315/568/1/012026 5 After：The pipeline is arranged in a neat way to meet the clearance height and maintenance functions. Reporting the project to Party A in terms of the relationship between models, the relationship between drawings and models, the guiding role of BIM results in the site construction, the key difficulties and disadvantages of the project. Technical support can be provided if necessary to enable each participant of the project to clarify the value, process, requirements and relevant tools of BIM construction.

Conclusion
Application of electromechanical construction BIM in field construction is described in this paper. With the progress and popularization of BIM technology, BIM technology will be widely used in the process of engineering implementation. BIM technology is actively used in theechanical pipeline actively adopts BIM technology, focusing on the application of integrated conflict detection based on BIM, three-dimensional pipeline synthesis, clearance optimization, virtual construction. Especially in the key parts of the project, such as garage, machine room, public area, commerce and so on, we should give full play to the advantages of BIM technology. On the basis of pipeline collision detection and 3D optimization, the construction site layout and factory prefabrication are integrated into it.