Building an earth-friendly yet earthquake-resistant hospital
Administrators at Mills-Peninsula Health Services in Northern California don't like their odds. They are building a new hospital less than two miles from the San Andreas Fault, where the U.S. Geological Survey says an earthquake rivaling that of the 1906 San Francisco quake has a two-in-three probability of occurring within the next couple of decades.
But the odds don't worry them. When completed, the $528 million Mills-Peninsula medical center in Burlingame, California, will be one of the most seismically safe and family-friendly hospitals in the country. It will also be among the Golden State's “greenest” hospitals, achieving more than 30% energy efficiency over comparable healthcare baselines.
Following the destructive 1994 Northridge earthquake, the California state legislature passed stricter seismic safety rules for hospital buildings that required most of them to renovate, rebuild, or close by 2013; many opted to retrofit. Mills-Peninsula chose to build the region's safest, most technologically advanced hospital on the grounds adjoining the current Peninsula medical center. Mills-Peninsula medical center will be a six-story, 450,000-square-foot acute care hospital with a 200,000-square-foot medical office building.
Anshen + Allen, a leading healthcare design firm, was the architect for this new facility. Integrating its seismic safety, energy efficiency and family-centered architectural designs involved the use of building information modeling (BIM) technology by the project's design and construction teams. Mills-Peninsula is one of the industry's first to merge the plans of the architects and every contracting profession—from construction to mechanical and electrical—to generate a 3-D model of the entire project.
The Mills-Peninsula medical center will be the first base-isolated hospital in Northern California, meaning that it is built on friction pendulum bearings using seismic dampers so that it can remain operational after a major disaster. The building will able to move up to 30 inches horizontally and 2 inches vertically without incurring major damage during an earthquake of at least a magnitude of 8.0.
“We are the first hospital in California to use friction pendulum bearings,” said Oren Reinbolt, project manager for the new hospital. He noted that the technology has been used on other Bay Area structures such as the San Francisco International Airport terminal and the new Benicia-Martinez Bridge.
In the base isolation system, 176 bearings are positioned between the foundation and the columns in the building. When an earthquake hits, the building slides on the bearings in a gentle pendulum motion. The ground beneath may move violently, but it is independent of the building.
“Earthquakes generate strong forces that show up as strong lateral acceleration of the building,” said Reinbolt. “Building codes require California hospitals to be exceptionally strong, and most of the resultant structures are usually quite stiff. Unfortunately, strong lateral acceleration at the ground can magnify the problem at the roof, sometimes generating twice the acceleration at the upper levels of the building.”
To achieve this high level of seismic safety, architects from Anshen + Allen used Graphisoft's ArchiCAD to create the core BIM model of the facility. The project's subcontractors were then able to digitally model and integrate their respective systems in 3-D, including mechanical, structural, electrical, and plumbing systems. With this collaborative model, the project team imported the BIM model data into NavisWorks software to test the various systems. Navisworks detects clashes between building systems, helps with construction sequencing and reduces conflicts prior to construction commencing.
The building information model also enabled the design team to simulate and create “halo” areas, or clear zones, around each of the base isolators to ensure that their movement during an earthquake would not cause them to collide with anything else.
To improve real-time collaboration, the teams employed a mobile “mission control” system of sorts called the I-room—a souped-up trailer with three wall-size digital whiteboard/smart screen displays for viewing, modifying, and whiteboarding the 3-D construction plans. “The project employed a design-assist process involving the general contractor and the major subcontractors to reduce ‘deferred approvals' and to identify any potential clashes between the building's various physical systems,” says Mark Tiscornia, project manager at Anshen + Allen. “BIM helped facilitate this process by providing a virtual 3-D model of the building from which we could communicate our design intent with our partners, perform simulations, and spot interferences before they became expensive construction delays. The cost and time savings that working with a BIM model provides has been one of the project's greatest investments.”
Green and family-friendly
Creating a patient- and family-centered facility was another core design objective. To that end, the hospital will feature single-occupancy patient rooms and sleeping accommodations for patients' families, all with long distance views of the San Francisco Bay's beautiful natural panorama.
Family zones are integrated within each room, and ground-level and rooftop gardens will provide areas for contemplation and distraction. The interior will enjoy increased daylight through floor-to-ceiling windows and internal courtyards. These design elements were included in the BIM model to provide visualization and realistic video fly-throughs to simulate the human perspective of the building and its natural surroundings. When the Center opens in 2010, visitors will find a healthy environment inside and out.
Architects also took an integrated approach for sustainability in designing the Mills-Peninsula project. The building will employ many green building design features, including cool roofs, low-VOC materials and finishes, furniture and other content built from recycled materials, high-performance glazing, solar shading, and efficient ventilation that uses fresh outdoor air.
With the BIM model data, the team was able to perform a life-cycle cost and thermal comfort analysis to validate multiple permutations of building systems, as well as the building's exterior envelopes. This analysis enabled them to fine-tune the entire building as a holistic system to achieve maximum energy efficiency.
In addition to advanced engineering technology that provides the highest level of earthquake safety, the new six-story acute care medical center will contain countless energy-saving and earth-friendly features. Advanced BIM technologies being applied to construction of the new Mills-Peninsula medical center in Burlingame are making the building process more efficient, while enabling breakthroughs in seismic safety and green building features. In recognition of its commitment to green practices, the nonprofit group Hospitals for a Healthy Environment recognized Mills-Peninsula with a national 2006 Environmental Leadership Award. HD
IMAGES COURTESY OF ANSHEN + ALLEN Patrick Mays, AIA, is President of Graphisoft, North American Division. Contact him at 617.485.4203 or
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