Structural strengthening and waterproofing design help restore and preserve feature skylight
Commonly known as the Cantor Arts Center, the museum opened in 1894 and reopened in 1999 as the Iris & B. Gerald Cantor Center for the Visual Arts. The building features an expansive museum lobby with a large, oval-shaped, concrete-framed skylight with glass infill units. In 2012, Stanford University sought to restore the original lobby skylight and address chronic leakage. SGH was the lead structural engineer for the project and also provided building enclosure consulting services. We collaborated with the project team to restore the appearance of the original concrete skylight frame, remove the glass infill units, and provide an independent external watertight skylight enclosure. SGH analyzed the original partially-reinforced concrete frame, designed fiber-reinforced polymer (FRP) strengthening for the deficient concrete members, and peer reviewed the structural design of the new steel tube enclosure frame. For the building enclosure, we consulted on the roofing design and transition details around the skylight, provided recommendations for the skylight and secondary waterproofing systems, peer reviewed the skylight design, and provided engineering support during construction. The project team delivered a new external skylight structure that is aesthetically commensurate with the original appearance and improved both structural and weather protection performance. Click here to read more about this project.
In collaboration with Stanford University (owner), ARG Conservation Services, Inc. (project manager), and Architectural Resources Group, Inc. (preservation architect).
Distinction: 2013 California Preservation Design Awards, Craftsmanship/Preservation Technology, California Preservation Foundation.
Preservation reestablishes high-rise as one of San Francisco’s most prestigious office buildings
Completed in the mid-1920s, 140 New Montgomery Street is one of the early skyscrapers built in San Francisco. The Art Deco high-rise, originally known as the Pacific Telephone and Telegraph Building, served as the headquarters for the utility for nearly eighty years. Wilson Meany purchased the building and sought to renovate the iconic structure to offer premier office space. SGH consulted on the exterior waterproofing and restoration of the facade, which is primarily clad with glazed terra-cotta. SGH provided waterproofing recommendations and designed repairs that conformed to the City of San Francisco Planning Code and the Secretary of the Interior’s Standards for Rehabilitation. The repairs included replacement of deteriorated steel windows with new aluminum windows that match the appearance of the original windows, refurbishment of select existing steel windows, rehabilitation of the glazed terra-cotta and brick cladding, and replacement of low- and steep- sloped roofs. The renovated office building features an urban garden, a new restaurant at the ground floor, and exterior lighting to showcase the restored facade. The project team designed 140 New Montgomery to meet LEED Gold standards. Click here to read more about this project.
In collaboration with Stockbridge Real Estate Funds (owner) and Perkins + Will (architect of record).
Distinction: 2014 Preservation Design Award, Rehabilitation Category, California Preservation Foundation.
Concrete repair extends the useful life of the parking structure while limiting impact to facility operations
The two-level Reservoir Place parking garage offers 700 parking spaces below three levels of occupied office space and is critical to daily facility operations. When the owner observed cracked and spalled concrete throughout the garage, they asked SGH to perform a condition assessment and develop a rehabilitation program to extend the useful life of the structure. We developed a rehabilitation program to repair damaged structural elements and prestressing strands and to protect the elevated parking deck with the application of a vehicular-traffic-bearing waterproofing system. To minimize disruption to building occupants during the work, SGH specified hydrodemolition to remove unsound concrete. When the contractor needed to use pneumatic demolition equipment for certain structural elements, we installed seismographs to monitor vibrations. Monitoring the impact of construction vibrations was especially important for a laser eye surgery center that houses sensitive equipment and was located directly above the construction zone. In order to reduce odor transmissions into the occupied space, we coordinated mechanical system functions with the building engineer to verify that elevator shafts and stair towers were put under positive air pressure during waterproofing installation. SGH also worked with the owner to develop construction phasing to limit the loss of parking during the project. Click here to read more about this project.
In collaboration with Boston Properties (owner).
Team collaboration leads to successful removal of suspended tunnel ceiling ahead of schedule
Portions of the Hynes Convention Center (Hynes) are located directly over I-90, the Massachusetts Turnpike. A fifty-year-old, cast-in-place concrete slab suspended from the underside of the Hynes served as the ceiling for the western portion of the Prudential Tunnel. On behalf of the building owner, who is responsible for maintenance of the tunnel ceiling, SGH performed annual condition assessments and recommended repairs for the ceiling and ceiling-support system. As the ceiling reached the end of its useful life, SGH designed new fireproofing for the exposed steel structure, developed a ceiling demolition plan, and observed the removal of the ceiling over a period of several months. The collaborative partnership between the owner, consulting engineers, the construction manager, and the contractors allowed the team to solve complicated technical and logistical challenges throughout the construction process. The construction team safely completed the work, including coordination of I-90 closures and traffic relocation, ahead of schedule resulting in cost savings to the owner and a reduced impact on the public. Click here to read more about this project.
In collaboration with Massachusetts Convention Center Authority (owner for Hynes); Tishman Construction Corporation (owner’s representative); Howard/Stein-Hudson Associates, Inc. (traffic subconsultant to SGH); J.F. White Contracting Co. (at-risk construction manager); LM Heavy Civil Construction LLC (civil subcontractor), Saugus Construction Corporation (steel subcontractor); and Massachusetts Department of Transportation (owner for I-90).
Leakage repairs result in restoration of monumental campus space
The Great Dome at MIT Building 10 houses the Barker Library and Reading Room. Library staff reported chronic leaks within the library stacks for many years. SGH determined that leaks originated within the stepped base of the dome. We designed repairs to address leakage that included removal and replacement of the limestone and copper cladding and installation of a new, reinforced, liquid-applied waterproofing system. With leakage mitigated, MIT sought to restore the Reading Room and oculus skylight at the top of the dome, which had been covered with roofing membrane since World War II. SGH led a multidisciplinary team for the skylight restoration. We designed a new stainless steel skylight frame to replace the existing deteriorated concrete frame; procured new glass blocks to match the original glass blocks; and detailed a new aluminum-framed, silicone glazed skylight over the top of the oculus skylight to provide additional weather protection. In conjunction with the oculus restoration, we oversaw new lighting, painting, and acoustical upgrades for the Reading Room. Click here to read more about this project.
In collaboration with Massachusetts Institute of Technology (owner); Walsh Construction (leakage investigation and repairs); Shawmut Design and Construction (oculus and Reading Room restoration); Sladen Feinstein Integrated Lighting (lighting consultant); Johnson Engineering and Design (electrical engineer); Acentech (acoustical consultant); and John Canning & Co (paint restoration)
Distinctions: 2014 Building Design + Construction Reconstruction Award (Bronze); 2014 Edwin F. Guth Memorial Award for Interior Lighting Design, Illuminating Engineering Society; 2013 Preservation Award, Cambridge Historical Commission; 2013 Best Projects in New England, Renovation and Restoration: Award of Merit, Engineering News-Record (ENR); 2011 Silver Engineering Excellence Award, American Council of Engineering Companies of Massachusetts; 2010 Aon Build America Award, Construction Management Renovation, Associated General Contractors of America.
Seismic retrofit to strengthen significant structure while preserving modernist aesthetics
The concrete building at 1101 Second Avenue, originally developed in 1967 as the headquarters for Washington Mutual Savings Bank, was designed by the northwest modernist architect, Paul Thiry. Rockwood Capital (Rockwood) acquired the building. As a precondition for restoring the building to occupancy, the City of Seattle required a seismic upgrade of the building to Life Safety performance under design earthquake shaking. Rockwood retained SGH to perform pre-purchase review of the structure. We identified seismic vulnerabilities, including non-ductile detailing common to concrete buildings of this era, a torsional shear wall layout, and perimeter columns along the street faces that were susceptible to damage during an earthquake. Following the acquisition, Rockwood retained SGH to design the required seismic upgrades. Working with the building owner and architect, SGH identified locations for new shear walls away from the exterior wall lines that would not impact the exterior appearance or the utilization of floor space. We detailed fiber-reinforced polymer (FRP) reinforcement to supplement the strength of the existing post-tensioned concrete waffle slabs and connect the slabs to the new walls. The relatively flat FRP strips served to strengthen the slabs without affecting the architectural floor finishes for future tenants. Click here to read more about this project.
In collaboration with Rockwood Capital, LLC (Owner); JT Costa, LLC (Owner’s Representative), Urban Renaissance Group (Property Manager), Mithun, Inc. (Architect), and Howard S. Wright (Contractor).