When the San Francisco Public Works project team set out to design the retrofitting of the historic War Memorial Veteran’s Building, they knew they had their work cut out for them. Or at least they thought they did. But as it turned out even they had no idea what they were in for.
“It’s daunting,” said Tara Lamont, project manager. “The building is unique in that it is multifunctional and when complete will house two theaters, an art gallery, grand event spaces and office space for three city departments. The four stories and basement have large floor plates of 40,000 square feet, in the middle of which are the two theaters. Restoring the tall gracious architecture left very little space in which to insert large quantities of steel, concrete, conduits, ducts and piping. During the design phase, our team did not fully appreciate how difficult it would be for the trades to access these very tight spaces do to their work.”
Formally dedicated on Armistice Day 1932, the War Memorial building has been the site of numerous historic events, including the signing of the United Nations Charter in 1945. But the 1989 Loma Prieta earthquake caused damage throughout the 240,000 sq. ft. building and a 1996 seismic assessment concluded that a major earthquake would significantly damage the building and pose life-threatening hazards to people inside.
Work has been ongoing since July 1, 2013.
“The primary reason for the project is for the seismic upgrade,” said Lee Jones, project superintendent with Oakland-based Charles Pankow Builders Ltd., general contractor on the project. “Secondary was to replace all the mechanical, electric and plumbing systems. The third was to correct long standing issues with the building envelope, including leaks, repairing windows and fixing the terra cotta exterior. The building roof is zinc, a steeply sloping mansard roof and there are a lot of skylights. Replacing the sky lights was a major component. When originally constructed, the fourth floor was the city’s art museum and the ceilings of those spaces have glass ceilings and skylights above for light into that fourth floor.”
The biggest challenge is the competing interests of historical preservation vs. the extent of demolition in order to provide access for the structural work and the mechanical, electrical and plumbing replacement, Jones said.
“Structurally, the challenge is it’s like rectangular donut. You only have one floor above the first that is a solid plate all the way across the footprint. A lot of the access challenges were posed by the demolition and trying to work above partially finished spaces. There are safety concerns including fall hazards, so we went through the building with in-house safety and consultants and provided a lot of scaffolding to be used by multiple trades rather than make each contractor provide their own. After we removed the glass ceilings we extended scaffolding all the way up through the attic space. The building had some asbestos. Most of the paint was lead paint. Hazardous materials abatement was required prior to demolition.”
Using a 130-ft. (39.6 m) tall Liebherr tower crane with a 170-ft. (51.8 m) radius, crews removed skylights and maneuvered structural steel into the attic through the skylight openings.
“The daunting part in terms of equipment was getting material into the building into tight difficult spaces and then making all the connections,” said Lamont. “The steel was brought in little bits and pieces. Even with the extensive new zinc roofing and skylights, field installation of shop-fabricated elements were planned, but the roofing contractor discovered that the building isn’t quite square, so they had to manufacture the parts in the field. The new work is hand-crafted. People had to come and make things fit.”
In addition to the challenge of the tight fit, there is no loading dock, the elevators were out of commission since they were to be replaced, the windows were in terrible shape and covered in lead paint, there was no fire alarm and few sprinklers, Lamont said.
“Really it was a physical job,” she said. “People had to really reach up and do the work in very tight, difficult conditions. Those are the kind of things you don’t really imagine when you are designing all this. For example, at the four corners of the main corridors, 4,000-pound steel girders had to be inserted above historic vaulted cast stone and plaster ceilings that had to stay in place.”
Crews also replaced the orchestra pit lift and added stage rigging.
To add to the stress, while crews worked, they had to protect and/or salvage historic marble, terra cotta and granite finishes. They also had to work around a series of murals created in 1915 for the Pan Pacific International Exposition currently valued at $4 million, but in reality, “priceless,” Lamont said.
“The murals couldn’t be moved during construction,” Jones said. “ A good deal of attention was paid to protect those. We were doing concrete work right behind them. We engaged an art conservator and they installed data loggers in the wall cavity to measure wall temperature and humidity. These wall cavities were mechanically ventilated during the concrete work. We also applied a special protective film directly on the surface of painted murals. Those murals survived the job fine.”
Final completion is scheduled for September 2015.
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