Designed in 1975 by Skidmore, Owings & Merrill (SOM) in Portland, Oregon, Edith Green-Wendell Wyatt (EGWW, named after two former members of Oregon Congress) was a typical office tower of its era. - 18-storey box made of prefabricated panels filled with tinted glass. By the beginning of the 21st century, external structures had reached the end of their life cycle - the seals had failed, and the walls, which were not very well insulated from the very beginning, leaked like a sieve.
In 2004-2006, leaders in the field of sustainable design, sera and Cutler Anderson Architects, developed a project for the revitalization and restoration of this building. But in 2006, when the stage of detailed design had already begun, their activities were suspended due to lack of funding. The project was unfrozen in 2009 with the entry into force of the American Recovery and Reinvestment Program (ARRA), which included funding for energy and water efficiency improvements in government buildings. $ 133 million was allocated for its implementation.
Although the project was almost complete, new regulations for the construction of high-performance buildings, defined by the 2007 Energy Independence and Safety Standards (EISA), required stricter project requirements.
Sera held a two-day 2006 Design Analysis Workshop. Then, for two months, based on research focused on priority energy-saving measures, there was an intensive modeling of the building's insolation. Sera worked with Oregon Energy Research University to analyze lighting and shading systems. In the laboratory, in a special “artificial sky” environment that simulates cloudy weather, the architects tested several facade configurations to help them assess the level of natural light. In addition, the model of the building was examined on a revolving table called heliodon, which recreates the angle of incidence of sunlight at a particular time of the year. Sometimes goals such as daylighting and shading were competing with each other and engineering guidelines were required to optimize the holistic combination of elements to achieve the best energy efficiency results. The data obtained allowed the designers to fine-tune the shading and reflection systems.
It was decided to dismantle all external railing down to the steel frame and replace it with a new glass wall made of argon-filled Viracon double glazing units with a heat-saving (reflective) Low-E coating.
The architects ditched the old HVAC (heating, ventilation, and air conditioning) system in favor of more efficient radiant heating and cooling. The new wiring has been installed behind the false ceiling. The small section of the hydraulic pipes made it possible to raise the ceiling level from 2.6m to 2.9m.
The layout of the floors has also naturally changed - now it corresponds to a modern, more mobile and ergonomic organization of the office space.
And in order to minimize sun exposure and reduce cooling costs, it was decided to create a curtain over the glass wall. At first, the architects were going to make a living curtain of climbing plants climbing on a metal frame.
But the client (GSA, the General Services Administration - an independent agency of the US government) rejected the idea of creating a living wall because of concerns about the complexity of care, cost, and the two-year interval required for plants to achieve full shading power.
However, James Cutler (Cutler Anderson Architects) wanted to keep the organic look of the screen wall. In collaboration with cladding and cladding manufacturer Benson Industries, he developed a panel system assembled from extruded aluminum profiles, the most cost-effective and easy-to-use material.
The panels resemble thickets of reeds. "Reeds" vary in length and are connected with a shift, which gives the composition an arbitrary, natural look.
But the authors do not intend to abandon the idea of a living curtain at all - over time, when different plants are tested and the most unpretentious and adapted for creating shade are selected, it is planned to plant several lower floors with them and see how high they can climb.
Each façade meets specific lighting conditions.
In the west, where the sun is low and the light comes in at a slight angle, the architects used 50% shading with a vertical aluminum "reeds" system. If the tubular "reeds" were continuous, they would have reached a height of 85 meters, but since aluminum has a relatively high coefficient of thermal expansion (a measure that describes how materials respond to temperature changes), it was necessary to provide gaps that would allow aluminum tubes expand and contract.
Therefore, they were divided into sections of approximately 9 meters, and connected every two floors. The "reeds" protrude several tens of centimeters below or above the support, creating a rhythmic pattern.
“We spent so much time on these screens because they can be seen from the window, they are right in front of our eyes,” explains Cutler.
Reed tubes have a trapezoidal cross-section. With their narrow part they face the interior. This is done both for optimal shading and to visually reduce their size, "lighten" the structure. The corners of the pipes are rounded, since sharp corners would create harsh shadows, and the screen would look brutal.
When designing elements that are so complex and unpredictable in their behavior, the authors tried to anticipate all possible problems, for example, the sound of "reeds" or the whistle of the wind in them. As a result, this reed does not make noise even in strong winds when the trees bend.
The southern and eastern facades combine horizontal and vertical shading systems - vertical fins and horizontal shelves 60 cm deep.
These shelves create a light shadow below, and from above reflect daylight into the building by 9-10.5 meters, which contributes to the best insolation of the premises.
Good thermal insulation of the enclosing structures is provided by double insulation of window-sill panels enameled with green glass-cement - one layer of thermal insulation about 10 cm thick is an integral part of the panel, and the other, of the same thickness, is laid from the inside.
Iterative modeling helped reduce energy consumption by 55-60% compared to a typical office building.
In addition, the project achieves more than 65% water savings. Both new water-saving plumbing and a 770 liter tank that collects and stores rainwater used for technical needs such as toilet flushing, lawn watering and cooling reduce overall water consumption.
A pitched roof of the building is adapted to collect rainwater. By the way, it also has a 180 kW solar battery, which also provides additional energy savings (4-15%).
Energy-efficient lifts with a regenerative motor, which recovers potential energy during descent, are also part of the "green" modernization.
According to the calculations of specialists, the expected annual savings in the operation of this building will be $ 280,000.
However, Senators John McCain and Don Coburn expressed dissatisfaction with the way federal funds are being used, saying that it would be better to use the money to build a new building instead of upgrading the old one.
But for everyone involved in this renovation - from officials to designers - the project means much more than the conversion of one outdated government building. Many of the latest technologies were tested here - in construction, energy saving, design and in the organization of design.
The efficiency of the project was even enhanced by the fact that the entire team - architects, contractors, consultants and subcontractors - worked in the same building adjacent to the refurbishment project. This facilitated the coordination of work, saved time, and hence money. All firms did their drawings and calculations on the same computers and with the same Autodeck Building Information Modeling (BIM) software. Architectural, structural and engineering developments were carried out using a single Revit model. The solution cloud was used for data transfer, document storage and collaborative design.
It has been estimated that 20% of overhead costs have been saved by reducing duplication of effort. Engineers, electricians, plumbers and designers made their drawings together, in parallel, coordinating all the solutions, which helped to avoid mistakes and inconsistencies.
A significant amount of installation work was carried out outside the construction site. For example, complex plumbing units, screens made of "reeds" were first assembled, and then, in finished form, were brought to the construction site, which greatly simplified their installation.
As a result, the project, which usually takes five to 10 years, will be completed in 48 months. According to optimistic forecasts, the building will be ready by March 28, 2013.
