BIM and steel structures create sparks of innovation

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According to research data from the Center for Integrated Facility Engineering (CIFE) at Stanford University, production efficiency in the construction industry is continuing to decline. These data show that production efficiency issues are fundamental problems faced by the construction industry, and they are also the main reason for unpredictable construction outcomes. To improve this situation, many companies have applied building information models, which are used to describe architectural design plans, to various related construction activities, including building construction and the digital manufacturing of building components. BIM can support the entire workflow from design to manufacturing in all building disciplines, including the digital manufacturing of steel structures using structural BIM models. Model-based design and manufacturing: For decades, the manufacturing industry has been using mechanical CAD systems to create digital models. These models can not only illustrate the product design, but also be used in other applications, such as stress analysis, field support, and, of course, manufacturing. CAD models can be used to generate controls for CNC (Computer Numerical Control) machines, thereby increasing the level of automation in machining processes. The construction industry can also adopt similar methods to automate the building construction process. Although buildings cannot be \"manufactured\" in their entirety like cars and then sent to the owner, many of the components used in construction can indeed be produced elsewhere and then transported to the construction site to be assembled into the building. For example, components such as doors and windows, precast concrete structures, and steel structures. Basic knowledge of steel structure construction: To understand how BIM can be used to automate the manufacturing of steel structures, we must know how the steel components that make up a building’s framework are produced. First, steel mills produce raw materials for steel structures using the hot rolling process (usually). Steel structure manufacturers purchase these raw materials and cut them according to the fabrication drawings (instructions that detail how each part of the steel structure should be manufactured) to produce beams and columns for use in construction. The finished steel structure components are transported to the construction site, where they are installed by steel structure installers. So where do the on-site construction drawings come from? The responsibility of a structural engineer is to design, analyze, and verify the structural framework of a building, as well as to create construction drawings that document the structural design. The structural drawings contain only the general requirements for the fabrication of the steel structure, namely descriptions of typical joints. Then, the steel structure detail designer uses these construction drawings and the overall node specifications to design the specific steel structure components and their geometric shapes, and creates fabrication details to accurately guide the steel structure manufacturers on how to manufacture each component of the steel structure in the building. The processing details include detailed information such as material specifications, size, dimensions, welding, bolt connections, surface treatment, and painting requirements. The steel structure construction drawings (left) contain only general instructions regarding the joints, while the fabrication details (below) include all the specifics required to manufacture each steel structure component. Detail designers usually create fabrication details \"by hand\" using drawing software, or they use specialized steel structure detail design software to create such details. Autodesk Robobat RCAD is a solution that uses digital \"manufacturing\" models to create detailed drawings for steel structures. It should be noted that in construction projects, the number of detailed fabrication drawings is much greater than the number of construction drawings. For example, to document the steel structure design for a 1,000-ton construction project (with 1,000 tons of steel used), approximately 70 to 80 construction drawings and 1,000 fabrication details are required. Before releasing the detailed fabrication drawings to the manufacturing process, structural engineers need to review each drawing to ensure that the information contained in it is consistent with the structural design. Steel structure manufacturers typically use CNC machines to automatically cut steel beams and drill holes. Some manufacturers manually program CNC machines based on the information in the machining drawings. Other manufacturers use the aforementioned digital manufacturing models to automatically program CNC machines. Extending BIM to the manufacturing phase: How can BIM meet the needs of steel structure manufacturers? Just as CAD-based models in the manufacturing industry can support manufacturing processes, specially developed building information models such as Revit® Structure can also support structural manufacturing processes. All graphics related to steel structures have been included in the Revit Structure design model. These design details can be imported into CIS/2 files (an industry-standard data format used for exchanging steel structure information), facilitating their reuse in steel structure detailing applications. The steel structure graphics and information in the Revit Structure design model can be exported as CIS/2 files, which can then be reused in steel structure detail design solutions. The design drawings and information from Revit Structure can be reused in building detail design solutions such as Robobat RCAD, as shown in the figure. Please note the additional manufacturing information added in the application of the detailed steel structure design. The Building Information Model is utilized in the detailed design and manufacturing of steel structures, thereby enabling a fully digital design-to-manufacturing process. Reusing design models not only improves work efficiency (by saving time spent on creating manufacturing models) but also enhances manufacturing quality (by eliminating discrepancies between the design model and the manufacturing model). Furthermore, the information used in the detailed design and manufacturing software for steel structures is based on digitally designed data from highly accurate, coordinated, and consistent building information models, data that is truly worth utilizing in related construction activities. After completing the detailed design for processing, the design team or contractor can also use this manufacturing model for 4D modeling, as well as conduct conflict checks in conjunction with other architectural disciplines and models (such as MEP and building design). The manufacturing model does not represent the final completed condition, as changes may still occur during the steel structure installation phase. However, it contains far more details than a structural model, making it very useful for conflict checking, especially in buildings with extremely limited space. Another advantage of using BIM in the steel structure supply chain relates to the overall cost of the structural framework. In the past, the raw material costs, manufacturing costs, and installation costs of steel structures were roughly equal. However, in recent years, manufacturing and installation costs have been rising continuously. To curb this trend, it is necessary to consider \"manufacturing simplicity\" in the design process (which is equivalent to the emphasis on \"machinability\" in the manufacturing industry). Using design models directly in the manufacturing phase can also create a natural feedback loop between manufacturers and designers, allowing manufacturing-related issues to be taken into account early in the architectural design process. Sharing design models with manufacturers participating in the bidding process helps to shorten the bidding cycle, allowing manufacturers to prepare more consistent bids based on the amount of steel required per the design specifications. Coordination between steel structures and other building components also helps to minimize on-site problems and reduce the ever-rising costs of steel structure installation. The digital process from design to manufacturing relies on collaboration among structural engineers, steel structure detailers, and steel structure manufacturers. In most cases, these three parties belong to three different companies. Therefore, it is necessary to adopt a project delivery method different from the usual one to connect the design and manufacturing phases. In other words, a cross-functional project team comprising the owner, builder, engineers, and contractors must be formed to coordinate the work involved in the design, manufacturing, and construction phases. Steps that originally had to be carried out in sequence (design, detailed design, manufacturing) can now be performed concurrently. The design model and the manufacturing details can be created simultaneously. The faster the detailed processing drawings are completed, the sooner orders can be placed with the steel factory, production can begin, and the steel structure can be installed more quickly. Digital manufacturing – success stories. In terms of using BIM for digital manufacturing, the renowned Canadian engineering firm Rutherford & Chekene (www.ruthchek.com) can be considered a pioneer in this field. Founded in 1960 and headquartered in San Francisco, this multidisciplinary company specializes in structural engineering and geotechnical engineering services, serving a wide range of buildings including hospitals, sports facilities, museums, historic buildings, and even aquariums. Since 2005, Rutherford & Chekene Company (R&C) has been using Revit Structure, and it currently holds 14 licenses for this software. They use Building Information Modeling for design, analysis (in conjunction with RAM and ETABS), and digital manufacturing. One of their recent Revit Structure projects is the Sutter General Hospital Sacramento in Sacramento. It’s an 11-story building with a floor area of 425,000 square feet; it serves as a replacement for the existing hospital. The building requires over 5,000 tons of steel, and approximately 5,000 detailed construction drawings. In this project, R&C worked closely with the detailed steel structure design firm (Dowco Consultants), the steel structure manufacturer (Herrick Steel), and the contractor (Turner Construction). David Bleiman, head of R&C Company and senior engineer, said, “The relative cost of hospital buildings is higher—commercial buildings cost between $150 and $250 per square foot, while hospital buildings cost around $600 to $800 per square foot, so such buildings are suitable for project delivery models that differ from those used in other contexts.” At present, we are planning how to collaborate with various parties on this project; our goal is to ensure that all data is digitized as much as possible, and to use digital methods for data exchange wherever feasible. ” Once these facilities are put into use, the existing hospital building will have to be demolished to make room for the new facilities. Due to the extremely tight schedule, they divided the work into several phases. At different stages of this project, various collaboration methods and workflows are required among the different stakeholders. Bleiman noted, “The first phase is to compare the preliminary manufacturing model (created using Tekla software in this case) with our Revit Structure model.” ” Before R&C began collaborating with the structural steel detailing team, the fabrication model had already been created; therefore, these two models needed to be manually coordinated. Bleiman explained, “You have to be able to walk before you can run; we need to first learn how to manually coordinate these two models.” But the ultimate result is the same: the manufactured model matches the design model, and all parties collaborate in the areas of structural design, manufacturing, and installation, thereby reducing costs and shortening delivery times. ”Any issues in the original design, such as dimensions, size, and location, will be corrected early in the design process, thereby reducing information requests (RFIs) and change orders in subsequent stages. Once the fabrication drawings are completed, the second phase of work begins: the fully digital review of the steel structure fabrication drawings. The review of the processing details (which previously required manually printing, transmitting, and checking multiple copies of each detail) will now be carried out electronically within the steel structure detailed design software in which these details were originally created. In addition, R&C will also use Autodesk NavisWorks software to compare and coordinate the complete manufacturing model with the original architectural model. The contractor, Turner Company, will also use Autodesk NavisWorks software to combine the structural fabrication model with models from other architectural disciplines in order to carry out conflict detection. Rutherford & Chekene utilizes Revit Structure building information models for digital manufacturing. Summary: The manufacturing industry currently boasts very high productivity, and one of the reasons for this is the use of digital data models to automate manufacturing processes. Similarly, BIM and digital manufacturing can also improve productivity in the construction industry. Just like the integrated project delivery method, digital manufacturing methods will drive the rapid development of the construction industry. Bleiman concluded, “We all know that achieving digital manufacturing requires overcoming many challenges.” But I believe that BIM solutions can definitely help us significantly shorten the building construction process and better control the project outcomes. ”