EARTHQUAKE ENGINEERING

Thorsen House
Location: Berkeley, California

The California Sigma Phi Society that owns and operates the Thorsen House as a residence for an average twenty student members near the campus of the University of California at Berkeley. Originally designed by Henry and Charles Green and built between 1907 and 1911, this large single family home is a classic example of the Arts and Crafts Architecture and is now listed on the National Register of Historic Places, the California Historic Register, and as a City of Berkeley Landmark. Sigma Phi recently donated a preservation and conservation easement to the California Preservation Foundation (CPF) covering the exterior facades and significant interior spaces. As a result of these recognitions, all repair and renovation construction performed must conform as much as possible to preservation guidelines to "protect the material, character and fabric" of the building.

BACK TO THE TOP


Century Centre II
Location: San Mateo, California

By using creative structural framing design, C+D Engineers were able to save its client construction costs. The 10-story office building with 177,000-sq. ft. is adjacent to a similarly designed building.

The structural system's 100-ft. piles through bay muds support a steel-framed building and concrete-filled metal deck composite with steel beams. The building is enclosed with "banded" architecture using glass and glass-fiber reinforced concrete spandrel panels.

As a cost reducing measure, a unique lateral framing concept was employed in the building. Four lateral-braced steel frames with 2-by 3-ft. composite concrete columns are used in the traverse (short) direction. This concentrated the lateral load resisting system in the building core and allowed open, column-free tenant spaces. This system, designed by C+D structural engineers, was tested during the 1989 Loma Prieta earthquake. The design successfully limited the movement of the building. Neighboring buildings had more damage from excessive motion.

BACK TO THE TOP


690 Market Street
Location: San Francisco, California

C+D Consulting Engineers prepared a comprehensive seismic assessment and retrofit design for this the existing conditions and improvements of this San Francisco high-rise property. Brick infill steel framing was used in this 1920's construction with replacement concrete shear walls added to improve earthquake performance.

690 Market Street is not considered an historic structure in its current form. Never the less, the building has an important place in San Francisco's Architectural history as one of the oldest surviving high-rise buildings remaining in downtown.





BACK TO THE TOP


Valley Medical Center
Location: Santa Clara County, California

The Valley Medical Center is the County's primary public health facility and has buildings that were designed and built in the 1950's. The County hired C+D Structural Engineers to provide the seismic assessment, retrofit strategies with different occupancy, license, and Earthquake Performance Level. The building is a 1956 constructed, seven-story reinforced concrete Main Hospital Building. This building included the patient beds, labs, surgery and support functions in the early years of the Hospital.

C+D used FEMA 273 and 274 Guidelines for the seismic vulnerability assessment, using push-over techniques. Similar technology was used with different earthquake intensity for design of retrofits for Collapse Prevention and Life Safety "Basic Safety Objective". The County intends to retrofit the building as part of the Long Range Campus Master Plan. Alternative projects retrofit and rehabilitation costs range from $42 to $82 million.

BACK TO THE TOP


Safeway Stores
Location: San Rafael, California

C+D provided structural engineering services for the remodel, expansion and seismic strengthening of this popular Safeway Grocery Store in San Rafael. Dealing with older stores in popular locations is a challenge for many retailers. In order to be fiscally feasible, updating and expanding these stores often requires minimal impact on day-to-day operations.

To facilitate this, we designed the side and rear additions to strengthen the existing structure and limit costly seismic retrofit work in the existing floor space. The contractor was able to complete the 5,000 square foot addition and 22,000 square foot remodel without shutting down the store. Work included adding new visible steel braced frame, plywood roof diaphragm, strengthening and load path improvements.

BACK TO THE TOP