Full Session with Abstracts
Leland Stanford, founder of Stanford University and former California Governor, opened doors to the Stanford Old Winery in 1888. This red brick, unreinforced masonry building originally served as in-house production and manufacturing space for the Stanford family’s full-fledged winery in Palo Alto, providing a wellspring of welcome libations to an otherwise dry town for over a decade. The building’s core gravity-fed production space occupied a three-story tower flanked by two symmetrical one-story wings. The building survived the 1906 San Francisco earthquake despite the loss of a large portion of its original brick gable façade. The immediate repair simply rebuilt the missing façade with timber gable end walls.
PBE MINIMIZES STRUCTURAL INTRUSION
An initial conditions assessment and in-situ brick testing showed that the building had inherent strength. Holmes Structures proposed that a Non-Linear Dynamic (NDP) Performance-Based Engineering (PBE) approach would be ideal for this type of building.
PBE modelling revealed vulnerable structural deficiencies across the building’s full height, from the first floor to the underside of the attic. Identifying weak points such as long flexible diaphragm spans, out-of-plane wall deformations and rocking masonry wall piers, helped Holmes Structures devise the best location for inserting two new concrete shear walls along the peripheries of the two one-story wings. PBE helped the design team target the primary deficiency of the rear one-story wings which was out-of-plane deformation at the top of the masonry walls due to the pitched flexible roof. Horizontal high-strength cable bracing installed at the underside of the roof trusses restrained the walls. This cable bracing minimized the impact on the roof structure and diaphragm while eliminating the need for any new vertical structure within these spaces.
SYMMETRICAL RETROFIT UNLOCKS CLIENT’S GOALS
To champion the client’s overriding goal of keeping clients open for business onsite, through early coordination with the contractor, Holmes Structures implemented a phased retrofit that made use of the building’s symmetrical configuration. Given that the Stanford Old Winery had some flexible open space, the tenants were comfortably situated in one-half of the building at a time while the other half of the building was retrofitted. The retrofits were efficient, since they were approximately symmetrical in design and identical in implementation. By utilizing micropiles at the shear wall foundations to resist overturning, the foundation design sat within a small footprint to minimize the disruption to ground floor retail tenants and removal of floor structures and finishes. Overall, the retrofit solution was crucial for keeping the ground floors open with revenue generating tenancies (preventing the client from paying for any costly tenant relocations). Holmes Structures’ solution was also flexible; it allowed subtle changes in the connections of the diaphragm to the exterior walls to meet tenants’ needs by either placing the steel angle on the floor or the underside of the ceiling as required.
Client : Stanford University
Architect : Architectural Resources Group
Contractor : Hathaway Dinwiddie
Cost : $8.4 M