A San Francisco landmark's $90 million restoration includes panels made of glass-fiber-reinforced plastic to replicate multiple brick arches and terra cotta moldings.
The replication at the Ferry Building was ``hugely successful from an aesthetic point of view,'' said John Long of the San Francisco design and architectural firm SMWM.
``If you stand in the space, you cannot tell what was replicated,'' he said. As project manager, Long knows the difference: ``I know where to look.''
Equity Office Properties Trust of Chicago financed the project under a public-private venture and is leasing the Ferry Building from the owner, the Port of San Francisco.
The structure was built in 1898 with a Beaux-Arts Colusa Sandstone faÃ§ade and a 660-foot-long passenger concourse. The building survived the 1906 earthquake and served as a bayside transportation hub for half a century until changing traffic patterns led to its neglect and decline.
Ironically, the 1989 earthquake led to a leveling of the adjacent Embarcadero Freeway and spawned a historic preservation effort to restore the Ferry Building.
A reopening is scheduled March 21.
Despite interest in full restoration, Long said, ``We could not build new arches and moldings.''
``Use of substitute materials is allowable according to the Secretary of the Interior's Standards for the Treatment of Historic Properties, as long as the material is compatible with the size, scale, texture and color of the original,'' said David Roccosalva, associate principal with preservation architect Page & Turnbull Inc. of San Francisco. ``To achieve the color compatibility, the GFRP panels were faux-painted off-site.''
In qualifying for the job in 2001, Kreysler & Associates Inc. created a 4-square-foot mock-up of an arch section. ``Reluctantly, they admitted they liked it,'' said President Bill Kreysler.
The fiberglass fabricator took dimensions of existing architectural elements and replicated them in GFRP. The replication project totaled about $400,000, but probably would have cost twice as much with original materials, Kreysler said.
``To build an armature to support 3 tons of brick and meet new codes for earthquakes would be far more than what they needed to support fiberglass,'' he said.
Installation was fast. For example, an arch, header and window went together in a day.
The Kreysler firm produced 11 arches representing about one-fourth of the building's total, all of the pilaster capitals and cornices and about one-third of the terra cotta moldings.
``We rebuilt those arches that were demolished over the years to accommodate tenants,'' he said. ``We made plugs or patterns replicating the original shapes.''
The firm found each arch differed slightly, opted to pattern a typical arch in foam and wood and then made rigid fiberglass molds. Subtle pattern adjustments to individual bricks and grout lines built a realistic appearance into the panels.
Technicians sprayed a layer of gel coat, did the fiberglass layup and, behind the thin large arches, fabricated a light-gauge steel frame for stiffening.
Each sandblasted surface required multiple colors and was challenging to finish, aesthetically. Kreysler's wife, Jacque, the firm's sculptor and artist, was the key player in applying stain by hand.
Each left and right mold-half for the arches was used 11 times and discarded.
Work on the project at Kreysler's 20,000-square-foot facility in American Canyon, Calif., began in September 2001 and concluded one year later. The company employs 30.