Originally the site of an old theatre, this two-story, 20,000-square-foot Spanish Colonial Revival Style building in downtown Napa was rebuilt as the “Gordon Building” in 1929. In the following decades, its prominent tenants included a candy and ice cream shop, grocery store, and confectionary. The notable original architecture, including terra cotta siding and ornate floral details, garnered it a spot on the National Register of Historic Places in 1985.
Following the 2014 Napa Earthquake, ZFA performed a structural condition assessment of the historic building that revealed various structural vulnerabilities. Much of the structure was constructed of unreinforced masonry (URM), with walls and parapets lacking anchorage and out-of-plane stability. The terra cotta and masonry veneer needed adequate anchorage and connections between existing lateral force-resisting systems, and the roof diaphragm required strengthening. Overall, the building lacked global stability.
ZFA also performed an extensive retrofit in conformance with the California Historic Building Code. The rehabilitation needed to be strategic, as the building’s historic designation prevented any alterations to the exterior. Existing URM shear walls were strengthened where possible, and new steel frames were added to provide additional lateral resistance. Steel special moment frames were designed for locations where existing windows could not be obstructed and special concentric braced frames were added elsewhere.
Diaphragms were strengthened using holdowns, plus new connections to new and existing lateral systems were provided. The original brick veneer was anchored to the existing clay brick walls with heli-ties for out-of-plane stability. Other improvements included the removal of interior mezzanines, the addition of two elevators, and the reconfiguration of a staircase. With these renovations, the Gordon Building remains an integral part of Downtown Napa; newly remodeled with its historic elements preserved.
Photo Credit: Courtesy of Wright Contracting, Inc.