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SERA’s Portland Federal Building: Big Data, Big Buildings, Big BIM
From front-end design to back-end operations and maintenance, BIM is becoming the place where buildings come together
By Nalina Moses
The pen is mightier than the sword, but is it mightier than the computer? First, computer-aided design (CAD) threatened to pull the pen out of the architect's hand, and now building information modeling (BIM) appears to be luring the architect even further from hand drawing and model-making. It’s a transition that’s been alternately praised and decried, but when BIM is utilized best by a skilled designer, its quantitative logic can make it another creatively generative set of constraints. One example of this process is SERA Architects’ Edith Green/Wendell Wyatt (EGWW) Federal Building in Portland, Ore.
BIM integrates information from designers, engineers, and other consultants to create a comprehensive, intelligent digital building model. This model can be used to generate construction and management documents, and also to examine spatial conflicts, predict energy performance, and visualize the structure and its spaces in three dimensions. When managed properly, BIM systems can automate many types of routine architectural drawings and calculations.
Like CAD drawings, however, BIM models are constructed from fundamental design parameters—including dimensions, materials, and details—received from an architect. So an accurately constructed BIM model can integrate the most subtle design revisions throughout a project's documentation thoroughly and quickly, even at unusually early and late stages in the design process. In this way, its high-tech workings can support the designer's low-tech sketches and models, and the work of the computer can be harnessed to the architect's hand.
The way Portland-based SERA Architects has wielded BIM in its remodel of the EGWW might just be exemplary. It earned the office, which has used BIM for all projects since 2004, a 2012 AIA Technology in Architectural Practice (TAP) Professionals’ Choice BIM Award for Delivery Process Innovation. The project's development shows how BIM supports design, communication, and administration for a large-scale building project, saving significant time and money. At the same time, it shows how a BIM system can support supple and sophisticated design thinking.
Laying the groundwork
The existing building, which filled an entire block of downtown Portland, was a grim presence—an 18-story, 525,000-square foot Brutalist concrete tower built in 1974. The most notable feature of the remodeling (now in its final stages of construction) is a new screen of slender aluminum rods on the front facade, which filter sunlight from the windows and give the monolith a dynamic layered appearance. Planted vines and flowers along its bottom edge, which can grow as high as 35 feet, will give it a warm street-level presence. The building's remaining facades are covered in glass. SERA developed the scheme with the guidance of design architect James Cutler, FAIA, of Cutler Anderson Architects in Bainbridge Island, Wash.
A key condition of the federal funding used to renovate the building was to reduce the building's overall energy consumption by 60 percent. SERA brought BIM to the task, and modeled various facade designs to determine which performed optimally in terms of energy use. Team members used Autodesk Revit as the primary software and brought in other applications for solar modeling, clash detection, and digital markups, and to study smaller design components.
Working with BIM models can require an adjustment to the traditional design process, as it did for the EGWW renovation. While a building's design development traditionally moves from general ideas to specific ones, with a BIM-driven project it can move from one set of specifics to another set of specifics. Because so much information is required upfront to construct a complete model, assumptions are made about systems and details that won't be confirmed until much later in the design process.
“BIM projects are ‘drawn’ differently, and the workload over the course of a project is distributed very differently,” says Jim Riley, SERA associate and project architect for the renovation. “Our senior project staff had to learn what the cause and effect of a requested design change meant to our delivery process. Changing our model for delivering our design effort was far more challenging than learning the software.”
Studies indicated that in order to meet the required reduction in energy use, 50 percent of the new front facade—which faces 22.5 degrees north of west and is flooded with direct sunlight—would need to be shaded to minimize heat gain. As such, SERA analyzed several generic shading strategies and brought the most feasible ones to Cutler, who took the information and developed detailed facade designs for them by hand, with pencil on paper. The initial design, for a lush green wall, had been accepted by the GSA and then withdrawn after concerns were raised about maintenance. So SERA worked iteratively with Cutler, translating information from his sketches into the BIM model and vice versa. In the end, they arrived at an array of staggered vertical aluminum rods that met the building's energy requirements and required limited maintenance.
The back-and-forth between Cutler's hand sketches and SERA's BIM model ultimately saved time and effort. As Riley explains, having an energy analysis complete before design began “greatly increased our design efficiency, and reduced our design time, as we avoided creating and analyzing schemes that wouldn’t work, given the performance criteria.”
After completing the design, SERA used the BIM model to coordinate electrical and mechanical elements within the structure, and to detect potential spatial and sequencing conflicts during construction, a process known as “clash detection.” This was especially important because the project was a retrofit. “In order to achieve the design vision, we had to compress our mechanical and electrical systems into very confined areas,” Riley says. “The results are very congested crossovers where the construction sequencing was critical to meet the schedule.”
The BIM model became an important tool for communication and collaboration between team members from different trades during construction, facilitating assembly and administration by reducing the number of requests for information (RFIs) submitted to the architect during construction by about 30 percent.
While the GSA is still in the process of incorporating BIM standards into its construction project guidelines, Patrick Brunner, the GSA project executive for EGWW, and his team wholeheartedly supported SERA's decision to use BIM for the remodeling. “The tool is more scalable, can be shared more effectively, and results in a repository of information that has more utility than olden-day paper/CAD sets,” Brunner says.
The human touch
In addition to supporting day-to-day decision-making, the BIM model has been a powerful visualization tool. Designers are able to extract orthogonal architectural drawings (plan, section, elevation) from it at any scale, and also interior and exterior perspectives from any vantage point. But the most important role BIM renderings serve might be in client communication. “In larger buildings,” Cutler says, “[BIM] will allow people who don’t draw—and therefore have a less developed sense of the third dimension—to see the building better. I think that [BIM] is an exceptionally useful tool for larger projects, but it’s unlikely that BIM adoption will ever stop drawing from remaining an essential part of the design process. The language of architecture is drawing.”
Riley's thoughts echo Cutler’s. He explains, “While it’s a great tool, we know that it takes incredibly talented people to extract the greatest value out of BIM. A BIM tool can show your great ideas to the world, but a BIM tool can’t have the great ideas for you.”
BIM's most long-lasting legacy, however, might be in building operations and maintenance. Once a building is in use, its BIM model remains a vital tool with which the owner, architect, and contractor can track its performance. The GSA is still determining how to put the BIM model for EGWW to best use. “As a minimum, it will provide an electronic [operations and maintenance] set and the ability to access critical building information remotely,” Brunner says.
If maintained conscientiously, a BIM model serves as a living portrait of a building—a powerful record of its structure and systems that can be tapped into by owners and tenants to optimize its energy consumption. As powerful a tool as BIM is during the design and construction process, its greatest rewards might lie in its potential to reduce energy costs and pollution after the fact. When wielded this way, a BIM model is relentless; its work is never done.
Construction photo of the new front (west) façade of Edith Green/Wendall Wyatt Federal Building and its aluminum reed wall system. All images courtesy of SERA.
Model constructed with Navisworks software showing elements inside a chase.
Rendered building section completed with Revit software.
Front (west) façade of original building.
Construction photo of new aluminum screen on front facade.
A rendering of the completed Edith Green/Wendall Wyatt Federal Building. Rendering by Scott Baumberger.
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