Clerestory Beams Play Light Off Shadow in Intuit’s New Marine Way Building
1. Marine Way Office Building 2. Bayshore Office Building 3 & 4 Parking Garages
High visibility atria in the office buildings were key to creating a more vibrant, functional campus for Intuit. These centrally located all-hands spaces had to do many things: reinforce and lend definition to campus patterns, welcome up to 500+ people at a time, and serve different events with varying light, sound and capacity needs. As the lead corporate campus architect, WRNS Studio had proposed vast clerestory windows in the atria that filled the low, wide floor plates (up to 60,000 sf) with natural light and a connection to the sky — key to the experience of beauty and delight favored by the design team. When it came time to execute design for the first new Marine Way office building on the campus, however, it took a deep dive into Design Development to uncover a viable technical solution for the clerestory windows.
Suspended four floors above the deck, with a 60 foot span, the atrium clerestory windows presented no shortage of challenges: We wanted the atrium to be an uplifting, light filled space, with the clerestories lending texture to scale down its capaciousness. The long span condition, an aesthetic and experiential imperative, could not be broken up by structure; the clerestory windows had to support themselves. In addition to pulling daylight into the interior, the clerestories needed to be controllable, allowing the atrium to darken for presentations, and to transition back easily, supporting supplemental artificial lighting. Likewise, the clerestories needed to integrate with the building’s other systems, helping to balance sound (large atria can get loud), embed fire sprinklers and act as a passive smoke exhaust system. A strategy for cleaning the windows and general maintenance was required. Then there was constructability: How could we avoid installing a ton of expensive scaffolding?
Certainly not a first for WRNS — initial sketches to solve this head-scratcher happened late night over wine, progressing to a solution that is at once detailed and expansive.
Pre-cast to the Rescue
After many iterations, we landed on a pre-cast clerestory beam system. The advantages were many: pre-cast beams would allow for integration of vertical clerestory glazing, which would be much easier to maintain and present fewer waterproofing concerns compared with skylights. We knew the beams could span structurally (we’d designed them in parking structures), and they’d arrive on the site with a finished surface crafted at the shop, good for schedule and quality control. The pre-cast solution would allow us to create a custom shape to meet our objectives for drama and texture of light, sound absorption and views of the sky.
But could we actually do it? The span was long (60 feet!). The beams would have to be deep and heavy. Thankfully, Willis Construction was on the job. Of the many advantages to using a pre-cast system, we could work with our fabricator in real time to prototype and test ideas for shaping the beam, carving and bending light to our needs.
The pre-cast clerestory beam in Willis Construction Yard
The pre-cast clerestory beam solution was a true collaboration with Willis Construction: design aesthetic meets engineering, structural analysis and physical testing. Development of the beam’s shape and geometry was a lengthy and detailed dialogue: Willis conducted full-size, 6’ x 8’ mockups at their yard, which we reviewed together for shape and finish. These mockups complemented WRNS’ in-house computer model. We also sent a model of the pre-cast system to our acoustical consultant, who did a thorough analysis looking at ways that the beams' shape and surface treatment might mitigate sound reflection within the large space.
Panoramic rendering iterations
In all, eight iterations were explored, each investigating the beam’s specific shape, density and rotation. The different versions were illustrated as interactive panoramic renderings and presented to Intuit as part of a holistic analysis focused largely on the qualities of light in the atrium. The selected solution was further studied in a virtual reality simulation and presented to Intuit.
This section of the pre-cast beam illustrates its form, structure and integration with the building’s MEP systems — optimizing the shape to address every aspect, from structure to acoustics, to address specific needs. Intuit wanted their new workplace to be raw and informal, robust and monumental; as an integral part of the structure; the pre-cast beams allowed for a consistent and strong, but elegant surface. The beams were hoisted high above the roof; and slowly lowered between the cast-in place concrete girder-walls, then telescoping steel tubes were extended to take the primary gravity loads. Initial discussions focused on access and the ability for maintenance staff to walk across and service the roof & glazing safely, and we shaped the beams accordingly. Electrochromic glass used for the vertical clerestory glazing allows for easy dimming or darkening via controls. An acoustic plaster fascia panel on the inside face of each beam houses sprinklers and attachment points for multiple pendant tube-lamp fixtures.
Light and shadow
In early iterations, the clerestory windows were facing north, until our resident building technologies sage Moses, got involved. We were about to ask our client to invest heavily in an engineering feat — integrating these large, heavy beams into the overall systems approach to the atrium — when it was brought to our attention that the light we’d be pulling in from the north would be beautiful, but soft. Based on observation of similar clerestory windows we had researched, it became apparent we were missing an opportunity to capture the kind of strong direct sunlight that would make for dynamic shadow play traversing daily across the all-hands space. Moving through the space, the beams might appear to “unfold” as they bend light inward. By reversing the orientation of the clerestory lights from north to south-facing, we maximized the spatial drama through light, shadow and texture.
The pre-cast, clerestory beam portion of the project was technically a design-build effort; anticipating not only the design and engineering, but also how we were going to fabricate, transport and insert the beams into the structure. Significant engineering went into just the installation process itself. Given the individual beam weight (each at 88,000 lbs) we needed a heavy-duty crane with serious capacity. One of two cranes on the west coast rated for 80 tons was rented, pushing us to an even bigger “100 ton crane.” This added power brought its own structural and safety challenges, as the only site on campus that made sense for locating the crane was directly atop an existing culvert. This culvert services all of the Mountain View greenbelt, so the operation was understandably sensitive. We shored up the foundation around the culvert to ensure the crane’s weight was distributed on either side of the tunnel, ensuring it wouldn’t fall through.
The weight of one beam is equivalent to that of an adult humpback whale or railway boxcar.
Tectonics + Identity
The atrium is the ultimate connector: building to campus (as a mid-block crossing), interior to exterior, ground to sky and people to one another. With the beams installed, it became immediately apparent that the pre-cast clerestory beams would indeed conjure the kind of airy texture — light and shadow drifting down from above and playing off of the atrium’s surfaces throughout the day — that would endow the space with that timeless, inspirational quality we recognize in really good buildings. If place marks and reflects identity, then the spaces in which we come together as a community have the opportunity to put a fine point on aspiration. As the atrium advances coherence and vibrancy at the campus scale, so do its tectonics — and specifically, the innovative approach to pre-cast clerestory beams — make possible the atrium’s success on the programmatic scale as a multi-use, all-hands community space that reflects Intuit’s identity and aspiration.