Launch Slideshow

Building the Modern Cathedral

The Lord giveth and the Lord taketh away—although sometimes in reverse order, as in the case of the Cathedral of Christ the Light now nearing completion in Oakland, Calif.

Building the Modern Cathedral

The Lord giveth and the Lord taketh away—although sometimes in reverse order, as in the case of the Cathedral of Christ the Light now nearing completion in Oakland, Calif.

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    SOM/Cesar Rubio

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    SOM/Cesar Rubio

    The cathedral's site on the shore of Lake Merritt is 16 feet lower than the surrounding city streets.

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    SOM

    The cathedral's site on the shore of Lake Merritt is 16 feet lower than the surrounding city streets. This allowed the architects to nestle programmatic requirements, such as office space, underneath a large public plaza, leaving an uncluttered site.

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    SOM

    The cathedral's site on the shore of Lake Merritt is 16 feet lower than the surrounding city streets. This allowed the architects to nestle programmatic requirements, such as office space, underneath a large public plaza, leaving an uncluttered site.

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    SOM

    Chapel Form One of the biggest concerns for the SOM team was to create a sense of luminosity inside the space. Their strategy: layering a glass curtain wall over a series of curved Douglas fir louvers, all anchored in a seismically sound, base-isolated concrete structure.

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    SOM/Cesar Rubio

    The interior space is defined by a curving, arcing wall of fixed wooden louvers, which give off a warm glow when illuminated by the sun.

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    SOM/Cesar Rubio

    The louvers are anchored to vertical ribs, which are in turn anchored to the concrete reliquary wall that frames the cathedral's base.

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    SOM/Cesar Rubio

    A fritted glass curtain wall forms the outer skin of the building along with the Alpha and Omega walls-the sculptural walls at either end of the space. High-performance glass was tested to make sure that it admitted enough light but didn't contribute to glare or heat gain.

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    SOM/Cesar Rubio

    Glass is installed in a framework of vertical wooden members that form the canted and curving exterior wall. These wooden posts are secured to the interior wooden frame by a series of very thin steel cables and supports.

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    SOM

    INSIDE DETAIL Glass is installed in a framework of vertical wooden members that form the canted and curving exterior wall. These wooden posts are secured to the interior wooden frame by a series of very thin steel cables and supports.

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    SOM/Gerald Ratto

    The arrangement of the pews is circular, surrounding one half of the circular altar. The SOM team decided on this configuration specifically based on research suggested by retired SOM partner Walter Netsch.

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    SOM/Gerald Ratto

    The arrangement of the pews is circular, surrounding one half of the circular altar. The SOM team decided on this configuration specifically based on research suggested by retired SOM partner Walter Netsch.

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    SOM

    The sanctuary is flanked at both ends by sculptural walls: the Alpha Wall over the entrance, and the Omega Wall over the altar at the other end. Carefully engineered with the help of 3-D modeling programs to determine stresses on materials, the walls create a striking presence and allow light to enter the space unfettered.

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    ALPHA WALL Carefully engineered with the help of 3-D modeling programs to determine stresses on materials, the walls create a striking presence and allow light to enter the space unfettered.

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    Software The design team used a variety of programs to create the drawings and renderings for the project. Construction documents were created in AutoCAD ADT 3.3, otherwise known as version 2002, but for certain elements, such as the dynamic Alpha and Omega walls, the team turned to 3-D modeling program Form Z, version 4.0, to help determine angles and potential stresses. Structural models for the entire structure were created in SAP 2000. 3D StudioMax was used to create 3-D renderings of the building at all times of day, and Adobe's Illustrator and Photoshop, version CS, were used to create color site plans and elevations.

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    SOM

    Seismic Base Isolators To protect the building from future earthquakes on the surrounding web of fault lines, the building's cast concrete base rests on 34 seismic base isolators to help the building ride out any shocks. The individual base isolators are arranged in a matrix, with the load evenly distributed. SOM's in-house structural engineering team, led by director Mark Sarkisian, specified friction-pendulum base isolators, each one with a 4-foot-diameter steel bearing. This particular variety of base isolator employs a sliding system, with an interfacial material that slides across stainless steel.

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    SOM/Cesar Rubio

    Glue-lam Ribs The actual geometry of the interior space was based on more than just the desire for a certain volume; it was based also on necessity. The width and curve of the wood structure's vertical glue-lam beams was informed in part by the 110- foot-long-by-13-foot-wide bed of the flatbed trucks that could make it over the bridges and through the tunnels on the path between the wood's origin in Portland, Ore., and the Oakland building site. The width was based on the standard 1-1/2-inch-by-11-1/4-inch dimensions of the stock laminations used in glue-lam construction.

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    Omega Wall When the bishop voiced his desire to include a strong representational image of Christ in the building, Hartman wanted to make it integral to the architecture. As a guide, the church supplied a digital image of a carved stone relief at Chartres Cathedral. A team of architects, environmental graphic designers, and members of SOM's digital design group worked together to create an algorithm that sorted the pixels according to brightness. The image was tweaked to enhance its legibility before then being mapped onto the 3-D surface. In finished form, the backlit image will rise more than 50 feet high, composed of more than 90,000 holes, ranging in size from 4mm to 24mm, laser cut into the anodized aluminum panels.

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    SOM/Jane Lee

    Above the sanctuary hovers an oculus with a scrim of faceted acoustical panels. The panels help absorb sound in the cavernous interior and filter daylight from the skylight above.

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    OCULUS SECTION Acoustical panels are capped on the exterior by an articulated glass roof, hidden from ground view by stainless steel extensions on the perimeter.

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    SOM/JOHN BLAUSTEIN

    Panels were assembled just above ground level to ensure proper proportion and overlapping, as called for by the plan. Suspended en masse from tensioned cables, the whole oculus was then hoisted into place.

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    SOM/John Blaustein

    Panels were assembled just above ground level to ensure proper proportion and overlapping, as called for by the plan. Suspended en masse from tensioned cables, the whole oculus was then hoisted into place.

Critical to extending the building's longevity, and of crucial importance to the earthquake-wary client, was seismically isolating the sanctuary. A matrix of friction-pendulum base isolators rests beneath the sanctuary's thick concrete walls and floor slab. In the event of an earthquake, the 34 base isolators—each incorporating a 4-foot-diameter steel bearing—would allow the building to move back and forth much more gently than it would if it were fixed firmly to the ground.

The architects refer to the massive, cast-in-place concrete base of the cathedral as the “reliquary wall,” in part because it contains a series of small chapels. The twin 15-foot-tall walls that constitute this base create an anchor for the wood structure. The sanctuary's curved, tapering Douglas fir ribs spring from the top of the walls, held in place by steel pins at the base. A steel compression ring joins the ribs at the top. Weaving the vertical ribs together are hefty, glue-laminated fixed louvers that bind the ribs together like a diaphragm or shell.

The outer walls, shaped like segments of a cone, are formed by slender wood columns connected horizontally by thin steel members. The columns provide a repetitive framework for panels of fritted glass, whose translucency was carefully studied to produce the desired luminous effect. Joining the outer glass and inner wood shell are slender steel tension rods, most about 1 inch in diameter. The extreme lightness of the structure is one of its important assets, Sarkisian says. “The only way to achieve this solution was because we've isolated the building seismically. Otherwise, the structure would be robust or quite clumsy in proportion because the member sizes would be so large.”

A tubular steel framing system supports the Alpha and Omega walls. (The Alpha Wall is about beginning, a place where visitors enter the building and encounter the baptismal font, and the Omega Wall is about conclusion, rising behind the altar and above the mausoleum.) The dynamic shape of the Alpha and Omega walls, which appears at first glance to resemble an inverted wedge on either end of the sanctuary, created another set of challenges, but the organic form was important to Hartman, who likens the faceted panels to flower petals. In terms of the sanctuary's overall composition, the walls stitch together the building's spherical and conical geometries—curving at the base, tipping inward, and folding like a crease at the top.

Their complex geometry required a three-dimensional study to develop suitable details for installation and fabrication of the exterior glass and interior aluminum panels that enclose them. Using AutoCAD and Rhino 3D software, the team first experimented with rectangular panels or parallelograms for the enclosure, says SOM technical director Keith Boswell. “But we were trying to twist or bend material, making it do more that it could do.” That's when they settled on triangular shapes. Due to the shifting plan and section geometry of the end walls, the panels vary in size. The 3-D model facilitated the design and detailing of the panels with a high degree of accuracy, Boswell adds.

Given the function of the building, Hartman took care to consider the quality of light that parishioners will experience inside, seeking an ethereal effect produced by the combination of reflected light, the warm wood surfaces, and the glow of the transparent glass. An oval oculus at the top of the sanctuary will admit additional daylight through an arrangement of triangulated baffles. SOM repeatedly modeled the entire space in 3-D, but it also built and tested physical models to help predict the lighting effects.

From a mechanical standpoint, the firm's objective was to provide the most efficient system for occupant comfort without heating or cooling the air above the occupied height. The sanctuary will be tempered by radiant heating concealed in the floor. Air conditioning will occur through “displacement cooling,” in which cool air is fed through small floor openings. This allows pools of conditioned air in a 10- to 15-foot zone near the floor, says Boswell. As cool conditioned air warms, it rises to the top of the sanctuary and is vented outside through motorized dampers at the base of the oculus.

A structural tour de force, the Cathedral of Christ the Light—expected to be completed in September— promises to be an awe-inspiring gathering place of soaring proportions, luminous light, changing moods, and soothing natural materials. If that doesn't inspire wonder, what will?