At the Year in Infrastructure 2016 conference in London, the Be Inspired Awards attracted over 300 submissions. Many of these were impressive in how they applied digital technology to designing, constructing and maintaining buildings and infrastructure. The winner of this year's Utilities and Communications sector award was a remarkable full-lifecycle BIM project for a new substation in downtown Wuhan, a major city in central China.
The Miaoshan 220kV Secondary Transformer Substation is a newly built large indoor substation in Dongxihu District, Wuhan City, Hubei Province. The project integrated digital tools for construction, site preparation, mechanical, electrical, and protection. The 3D digital modeling approach enabled collaborative design of an indoor substation with restricted space with multiple voltages in a very congested urban area with minimal impact on the existing buildings and infrastructure and all of this within a tight timeframe.
The project faced severe challenges. Firstly, it was located in a congested area of downtown Wuhan and the substation was required to be very compact to minimize its impact on the surrounding buildings and infrastructure. Reality modeling the existing environment was essential because nearby buildings had to be taken into account in designing the site layout including feeder cables. Secondly, the substation is an indoor station, composed of a building complex with two floors above ground and and one basement floor. Because of the severely restricted space there was a high risk of clashes in a multi-discipline design environment, easily leading to problems of different teams placing equipment in the same space. Thirdly, the substation was intended to handle multiple voltages including 220kV, 110kV, and 10kV cables. Each voltage was handled by a different design team. Because many cables had to be routed into and out of the building in very restricted space, the risk of collisions and intersections among power control cables of different classes of voltage was high.
3D modeling was essential for this project. Because of the high risk of clashes and collisions between the designs from different design teams, a shared 3D model was essential to ensure a collaborative approach to design. The project used several different digital tools for different aspects of the project across disciplines, including electrical, construction, structure, general drawing, irrigation works, heating, ventilation, and site preparation. The electrical team used a substation design tool to perform the design of main wiring, electrical equipment layout, stress calculation and arrangement of wires, lightning protection and grounding, lighting and the layout of cables and supports. The construction team uses a building design tool to design walls, doors, windows, stairs, roof and louvers. The structure team used building design and structural engineering tools to design floors and columns. The master plan team used building design and site preparation tools to design the gate, enclosure walls, access road and the building site. Irrigation work, heating and ventilation programs used a digital building performance tool to complete air conditioner, axial flow fan, water and wastewater pipes
designs.
The digital modeling approach made it possible for people from different disciplines to work in a collaborative design environment within a unified model space, which greatly reduced clashes between different designs. One of the important benefits of the 3D model approach was that minimized the impact of the substation on the existing infrastructure. Since the transformer substation is located in the downtown of Wuhan where buildings are dense, reality capture was used to model the area surrounding the substation. This helped to ensure the substation site design did not conflict with surrounding buildings. A major benefit of the 3D model approach was that it made it possible to design a substation that fulfilled the requirements, but avoided having to demolish four nearby residential apartment buildings. To enable combining the model, the point cloud data, the digital terrain model and other external data everything was geolocated (geo-coordinated).
Geo-coordination, a term minted by Bentley, is key to integrating data from many different sources including reality modeling, 3D building models and associated information. Bentley recognized the value of geo-coordination very early on. With all Bentley applications in the last 12 years every infrastructure asset has geo-coordination in the form of real world x y z coordinates. Geo-coordination enables engineers and facilities managers to find things that are tagged,related, or close to a building element and it makes it possible to navigate the information environment, not only 3D design models (virtual reality), but also 3D models in a real world context (augmented reality). It is recognized as essential for full-lifecycle (design, build, maintain and operate) BIM. In this project it was fundamental not only for integrating the substation design and its real world context, but also for making it possible to reuse the BIM model and associated data during operation and maintenance.
The digital design approach reduced the project design time by 20 working days, verification time by 30 working days, and saved about CNY 50 thousand in design costs. According to project statistics, the collaborative approach enabled by digital modeling avoided more than ten potential cases of rework during construction, saving CNY 2 million. During the project review by external evaluators, the 3D digital model made it easier for the evaluators to understand the design intent, which played a decisive role in ensuring adequate communication of the design and implementation. This reduced the number of meetings required during the review. A side effect was that it enhanced the reputation of the Design Institute.
During construction, mobile devices were used in the field to convey details of cable placement to the construction unit. In addition, models showing the intended location of cables were converted into 3D PDF documents which were used in the field to ensure that the construction unit understood the designed cable placement. The result was that construction went smoothly, reducing construction time by 15 days.
Some of the key benefits were that reality modeling of the neighborhood enabled planning of the station site layout as well as site access that minimized impact on the surrounding buildings. The project uses 3D digital model and associated software made it possible for all disciplines to work collaboratively which significantly reduced the clashes between designs form different disciplines. 3D modeling made it possible to plan the arrangement of various types of cables a a very detailed level, which helped avoid crossovers and collisions and reducing fire risk and enhancing safety.
Perhaps most importantly for the total cost of the project including operations and maintenance, the model and associated data was brought into an FM tool that made it possible efficiently manage plant data, technical specifications, operation and maintenance manuals and other detailed information for operation and maintenance management of the substation after construction.
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