Upon its completion in 1918, the building that is now the Atascadero (Calif.) City Hall was the very picture of stability. Intended as the centerpiece of Atascadero Colony—a planned utopian community—the Italian Renaissance structure featured a cruciform plan, with ornate central rotundas on the first and fourth floors.
Though the idealized colony never really jelled, the area did thrive, and the building passed through several commercial uses before the County of San Luis Obispo acquired it in 1950. When the city of Atascadero was incorporated 29 years later, the county handed the building over for city offices. The hall, with its grand pillared entrances and red-tiled dome, is featured on the city seal and listed on both the National and California Registers of Historic Places.
In December 2003, the 6.5 magnitude San Simeon earthquake ravaged Atascadero. As city workers dove for cover, the upper rotunda was twisted and wrenched away from its structural moorings. Interior walls and exterior masonry were extensively damaged, and the building was ultimately red-tagged. However, city officials were determined to restore, and improve, the beloved landmark.
Pfeiffer Partners Architects undertook a two-year assessment, including a laser-scan analysis as well as painstaking physical investigations and measurements. The Atascadero Historical Society, an enthusiastic collaborator, provided invaluable documentation of original conditions. Three packages of work were eventually developed: demolition, FEMA-funded damage repair and hazard mitigation, and city-funded rehabilitation.
PLATINUM AWARD
ATASCADERO CITY HALL
Atascadero, Calif.Building Team
Submitting firm: Bernards (construction manager)
Owner: City of Atascadero
Architect: Pfeiffer Partners Architects
Structural engineer: Nabih Youssef Associates
MEP engineer: Davidovich & Associates
General contractor: Diani Building Corp.General Information
Size: 58,900 sf
Construction cost: $21.7 million
Construction time: June 2010 to September 2013
Delivery method: CM agency/multi-prime
The 2008 economic crash posed financial difficulties, and anticipated state funding was eliminated in the subsequent recession. Meanwhile, water infiltration caused additional damage despite the owner’s best efforts to keep rain out. Under the management of Bernards, construction finally began in 2010, nearly seven years after the quake occurred.
Stabilizing the structure was obviously the most pressing need. The original building consisted of cast-in-place reinforced concrete floors and unreinforced masonry infill walls between a structural steel, concrete-encased post-and-beam skeleton. Above the fourth floor, the building was essentially an unreinforced masonry structure.
Crews strengthened the existing foundation by drilling 248 micro-piles 80 feet deep into bedrock, and pouring pile caps below the foundation. A new structural concrete slab-on-grade was installed at the basement level. Interior perimeter walls up to the fourth floor were stripped to reveal the structure, which was reinforced with more than a million tons of shotcrete and 80,000 pounds of rebar—in essence, creating a building within a building.
To fix the upper floors and dome, crews removed most of the exterior cladding, then rebuilt with additional steel and fiber-reinforced polymer instead of shotcrete, which would have been too heavy. Existing steel was horizontally and vertically braced, and roof dome framing members were retrofitted.
When structural improvements were complete, crews used as much of the original masonry as possible to rebuild the walls and roof. In the heavily damaged upper section, about 15% of the roof tiles and 80% of the bricks had to be replaced with color-matched materials. When possible, original tiles, fascia balustrades, and decorative plaster were repaired, cleaned, and returned to their original spots.
The lower rotunda benefited from a new paint scheme inspired by the greens and browns of the California landscape; the painter, a local artisan, donated half of his change-order hours back to the city. Second-floor window overlooks, once blocked, were uncovered and restored, providing views into the space from surrounding office zones. Light boxes behind frosted lunettes give the illusion of natural daylight. In reality, this dome is internal and is topped by a second rotunda housing the City Council chambers.
IMPROVING INTERIOR DESIGN
Interior reconfiguration was also crucial to improving functionality. Over the years, alterations had resulted in a confusing layout and awkwardly shaped spaces, as well as problematic ventilation. Crews removed most of the interior partitions and built new walls to establish a more sensible floor plan. Efficient HVAC and communications infrastructure was installed.
The lower rotunda was programmed as lobby space and a permit center. Three floors of offices surround this focal point. City Council chambers were constructed in the domed upper rotunda, which once held a library. A small historical museum received a place of honor, reinforcing the building’s link with the town.
More than 90% of construction dollars went to firms on the Central Coast, including $5.5 million to local glass, concrete, and masonry contractors. The final construction cost was $3.3 million less than the original $25 million estimate. Bernards credits the multi-prime contract process, encompassing 17 separately bid categories, for the savings. City Hall opened on schedule in August 2013, just in time for Atascadero’s centennial—an embodiment of civic resilience, determination, and pride.
Elegant detailing, a hallmark of the Italian Renaissance style, was re-established in the post-earthquake reconstruction.
Related Stories
| May 21, 2014
Architecture Billings Index in the negative for second consecutive month
The March ABI score was 49.6, up slightly from a mark of 48.8 in March, but still below the growth threshold of 50.
| May 20, 2014
Kinetic Architecture: New book explores innovations in active façades
The book, co-authored by Arup's Russell Fortmeyer, illustrates the various ways architects, consultants, and engineers approach energy and comfort by manipulating air, water, and light through the layers of passive and active building envelope systems.
| May 20, 2014
Gensler envisions 'law firm of the future' with pop-up office project
Called "The Legal Office of the Future," the pop-up demonstration project made its debut this week at the annual conference for the Association of Legal Administrators in Toronto.
| May 20, 2014
Using fire-rated glass in exterior applications
Fire-rated glazing and framing assemblies are just as beneficial on building exteriors as they are on the inside. But knowing how to select the correct fire-rated glass for exterior applications can be confusing. SPONSORED CONTENT
| May 20, 2014
World's best new skyscrapers: Renzo Piano's The Shard, China's 'doughnut hotel' voted to Emporis list
Eight other high-rise projects were named Emporis Skyscraper Award winners, including DC Tower 1 by Dominique Perrault Architecture and Tour Carpe Diem by Robert A.M. Stern.
| May 19, 2014
What can architects learn from nature’s 3.8 billion years of experience?
In a new report, HOK and Biomimicry 3.8 partnered to study how lessons from the temperate broadleaf forest biome, which houses many of the world’s largest population centers, can inform the design of the built environment.
| May 19, 2014
Why e-commerce won't kill 'bricks and mortar' retail sector
Despite emerging structural challenges and newly-announced store closings, such as those of Radio Shack and Office Depot, the U.S. retail sector has continued on its solid recovery.
| May 16, 2014
BoA, USGBC to offer $25,000 grants for green affordable housing projects
The Affordable Green Neighborhoods Grant Program will offer 14 grants to developers of affordable housing in North America who are committed to building sustainable communities through the LEED for Neighborhood Development program.
| May 16, 2014
HED expands leadership in San Diego
Neville Willsmore, Thomas Christian join leadership team for Harley Ellis Devereaux.
| May 16, 2014
Toyo Ito leads petition to scrap Zaha Hadid's 2020 Olympic Stadium project
Ito and other Japanese architects cite excessive costs, massive size, and the project's potentially negative impact on surrounding public spaces as reasons for nixing Hadid's plan.