The Design Awards Jury awarded the Sierra Vista High School Music Building an Award of Excellence because the concrete masonry is a star. Completed in February 2009, the new Sierra Vista High School Music Building sits majestically on its hill as an upside-down, acoustically superior structure in which the roof holds up the hyperboloid walls. The 7,392- square-foot (686.7-squaremeter) building is designed in two parts with Vocal Music and Instrumental Music with a service core (toilets, storage, and practice rooms) sandwiched between.
Rather than the typical design parameter of using square feet or square meters, Osborn Architects used cubic volume to design the new music center. Lex Moloney of Osborn Artchitects, said, “This works better with acoustics. A trumpet gives off a lot more than a little voice, so instrumental music needs more volume even though the two programs need roughly the same square footage.” As a result, the walls on the instrumental side of the building approached 30 feet (9.1 meters) tall and were offset almost four feet (1.2 meters) from plumb.
With a limited school budget and a goal to improve acoustics, the architects chose concrete masonry units for the mass properties. Since the best way to stop sound transmission is with mass, fully grouted concrete masonry units achieved this. In addition, the concrete masonry units also provided ease of construction and durability for a public high school. Eight and 12-inch (203 and 305-mm) warm gray and cool gray precision concrete masonry units in medium weight were used to construct the school.
The creative design of the Music Building helps control two of the evils of music: standing waves and flutter echo by not making any surfaces parallel, a “warped box.” Moloney explained, “Every surface is at least seven degrees off of perpendicular or parallel. The roof is sloped and three of the four exterior walls are warped. At one end of the wall each course of masonry is straight but
stepped outward so one course progressively overhang the ones below by an inch (25 mm). The resulting geometry makes the wall gradually transition from plumb at one end to a seven degree slope at the other.”
According to the Design Awards jurors, the corbelled walls introduce a dramatic banding of shadows and light at the exterior walls, while enhancing the acoustical quality of the interior. In addition, the glass block filters in light beams of LeCorbusier’s Ronchamp Cathedral.
Structurally (see sidebar, below) because the building is in a very seismic active part of the world Moloney used twelve-inch (305-mm) block to get a secure grout column and have the ability to get a double curtain of reinforcing steel in the cell. Walls typically hold up a roof but in this building concrete in the roof was used to help hold the outward stepping walls as well as for the sound isolation properties of concrete.
One of the more challenging problems was to keep a running bond in a wall that grows by one inch (25 mm) per course. To solve this problem Moloney had to spend more time detailing the corners and add a half-block periodically.
With the outward step of the walls the interior space becomes magical due in part to the lighting from the glass block and expanding space. The interior space is punctuated with long metal stud framed gypsum panels that fold up and down is a jagged geometry that stands in counterpoint the gentle warp of the concrete masonry walls. The gypsum ribbons work as diffusers and sound absorbers to help tune the rooms. All materials were selected to help the acoustics, including the arrangement of casework and even door vestibules.
Outward corbelled walls support the structural steel roof beams that span the length of the building. The corbelling aids the acoustic values by reducing flutter echo and standing waves. To counteract the overturning forces of the outward corbelled walls, the roof diaphragm was made of concrete that stitches the structure together.
The corbelling also provides a subtle expression of depth through a phenomenological play of light and shadow. Glass block inserted into the corner helps express the interaction between the perpendicular side of the corner and the outward leaning corbelled side. The glass also provides a light connection from the interior to the environment outside. Its use in the interior expansion provides an uplifting feeling when the sun shines in. CMD