Mass General Cancer Center at Newton-Wellesley Hospital LiNAC Addition

As the structural engineer of record for the new vault and associated structural modifications to the existing building, SGH’s work included:

• Collaborating with the LINAC manufacturer, installer, and shielding physicists to incorporate equipment-specific requirements into the vault’s structural design
• Exploring how shielding options (e.g., high-density versus normal-weight concrete, and concrete-sandwiched steel plates ) affect schedule, price, and constructability
• Designing the vault’s high-density concrete walls (24 to 54 in. thick) and roof slab (30 to 42 in. thick) to provide shielding for the high-energy x-rays and detailing reinforcement to ensure continuity of shielding protection
• Coordinating wall construction joints and brick shelfs with the shielding physicists
• Consulting on mass concrete placement considerations with respect to the mix design and construction sequencing
• Designing and detailing new vault foundations abutting the adjacent building to avoid underpinning or adding load to the existing foundation
• Designing alterations of the existing structure, including lintels for new wall openings, slab trenches for piping, modifications to the fire pump room, and repairs to the base plate and concrete slab associated with replacing the new LINAC
• SGH also consulted on the building enclosure for the new addition and transitions to the adjacent building. We assisted with the design of:
• Below-grade waterproofing for the vault along with details to integrate the new assembly with waterproofing on the existing below-grade walls
• Modifications to the existing building’s exterior walls, including raising window sills, replacing the affected window units, and relocating egress doors
• Details to integrate the vault’s roofing with the existing metal wall panels, limestone walls, and brick masonry walls of the adjoining construction