Transmitting Communication from Yi-An Huang, City Manager, relative to the appropriation of of $20,000,000 from the General Fund Employee Benefits Department Salary and Wages account to the General Fund Reserve Department Extraordinary Expenditures account to fund expenses related to the demolition of 221 Mount Auburn Street

CITY OF CAMBRIDGE Community Meeting July 10, 2025 www.cambridgema.gov/221mtauburnst 1 221 Mount Auburn Street Riverview Condominiums

CITY OF CAMBRIDGE 221 Mt Auburn Street – Riverview Condominiums Agenda • History of 221 Mt Auburn St/Riverview Condominiums • Structural issues • What’s next? 2

CITY OF CAMBRIDGE In February 2023, structural issues were identified in the nine-story building at 221 Mt Auburn Street, which is part of the Riverview Condominiums, during preparatory work associated with planned roof and drainage improvements. The Condo Association hired SGH , Inc. to evaluate the capacity of the concrete slabs through visual observations, drone photography, non-destructive testing and observations of the concrete slabs at exploratory openings. SGH identified and documented the following conditions: • Low Reinforcement – Reinforcement placed lower than specified on the design drawings • Low Concrete Compressive Strength -- Lower than specified concrete strength • Utility penetrations – Penetrations and alterations of the concrete slabs The low reinforcement and low compressive strength were found to be widespread throughout the building. With this updated understanding of the as-built conditions, SHG performed a structural analysis of the concrete slabs that support the building. This analysis shows “that there is a very low (to potentially zero) safety factor when the slabs are subject to code-required loads.” Code required loads include the weight of materials that make up the building (e.g. structure, walls, floors, roofing, etc.), loads produced by the use of and occupancy of the building (e.g. people and their possessions), and loads associated with snow. Residents of the 66 units in the nine-story building vacated the building in November / December 2024. And residents of the 14 units in the adjacent lower Bradbury building vacated in June / July 2025. Even with the removal of people and furniture from the building, analysis indicates potentially dangerous building conditions. The Condo Association has been working to evaluate alternatives for slab strengthening as recommended by SGH. They have determined that based on the concerns associated with working in a building with such significant structural deficiencies, rehabilitation is not feasible and the building must be demolished. The City is working closely with the Condo Association to have the building demolished. 3 Executive Summary

CITY OF CAMBRIDGE 4 History of Development • CRA Redevelopment Plan approved September 29, 1958 • Land assembled, cleared and prepared for development in 1959 • Sold by CRA to First Realty Company of Boston in 1962 ($150,000)

CITY OF CAMBRIDGE 5 History of Development Certificate of Occupancy issued in 1963. Bradbury Street and portion of parking lot transferred from CRA to the City. Riverview Parcel City Parcel

CITY OF CAMBRIDGE 6 History of Development

CITY OF CAMBRIDGE 7 History of Development Two separate buildings: 221 Mount Auburn Street – 9-story concrete structure with 66 units 3-story brick Bradbury Building with 14 units

CITY OF CAMBRIDGE 8 Structural Issues Identified Over Time More understanding of the extent of issues

CITY OF CAMBRIDGE 9 2023 2024 2025 Riverview Condo Trust determines demolition needed ('24/'25) Riverview identifies strategies for repair ('23/'24) Riverview vacated (Nov/ Dec '24) Structural Issues Timeline Bradbury vacated (July '25) City's help requested, additional inspections conducted (May/June '25)

CITY OF CAMBRIDGE 10 Structural Issues Identified • 2023 preparatory work for roof and drainage improvements to address leakage and ponding issues included coring new holes in the cantilevered balconies. • The coring contractor cut through reinforcement in the balconies. SGH identified cracks in the slab and observed that the slab reinforcement was substantially misplaced compared to the original design drawings. • Riverview asked SGH to evaluate the capacity of the slabs throughout the building and hired Consigli for construction management. Delivered to the City April 28, 2025 Report available on City website: http://www.cambridgema.gov/ 221mtauburnst

CITY OF CAMBRIDGE 11 Structural Issues Identified SGH report documented structural issues (primarily associated with initial construction) • Low Reinforcement – Reinforcement placed lower than specified on the design drawings • Low Concrete Compressive Strength -- Lower than specified concrete strength • Utility Penetrations – Penetrations and alterations of the concrete slabs • Deterioration from Leakage and Corrosion • Previous Concrete Repair Work

CITY OF CAMBRIDGE 12 The slab needs to be strong enough to support the weight Structural Issues Identified Punching Shear Explained

CITY OF CAMBRIDGE 13 Slab Column Structural Issues Identified Punching Shear Explained

CITY OF CAMBRIDGE 14 Structural Issues Identified SGH analyzed the structural capacity of the building. Initial reports "show(ed) that there is a very low (to potentially zero) safety factor when the slabs are subject to code-required loads." Further analysis was completed after the building was vacated and indicated a potentially dangerous slab-to-column connections, even with the building being unoccupied and without snow.

CITY OF CAMBRIDGE 15 Structural Issues Identified Outreach to the City Condo Association shared SGH report with City of Cambridge Inspectional Servies Department (ISD) on April 28, 2025, and met with City leadership June 4, 2025. • Condo Board and their consultants shared their concern about low to zero factor of safety, particularly with additional snow load. • The initial SGH report focused on the structural analysis based on an occupied building and snow loads (consistent with code requirements) and recommendations for the repair of the building. Additional analysis indicates the building is over capacity and potentially dangerous even without snow loads. City leadership has been meeting with Condo Board and their consultants weekly and hired an independent engineering firm to advise the City. • The City's involvement is to protect public health and safety City coordinating with state partners, including Department of Environmental Protection (MassDEP), Department of Capital Asset Management and Maintenance (DCAMM), MBTA, and Department of Conservation & Recreation (DCR).

CITY OF CAMBRIDGE Next Steps Reducing Risk, and a Path to Demolition 16 • Additional fencing installed to secure the site. • Disconnecting utilities. • City staff directed Condo Association to conduct a visual survey by drone every 2 weeks to identify changing conditions. Beginning this week.

CITY OF CAMBRIDGE Next Steps Reducing Risk, and a Path to Demolition 17 • June 27, 2025, ISD notified owners that the building must be removed. • This week the Board of Survey is assessing the property and will issue a report for orders that it determines are necessary to protect the health and safety of the public and the occupants and owners of the building.

CITY OF CAMBRIDGE Next Steps Reducing Risk, and a Path to Demolition 18 • City staff has been meeting with direct abutters to update them and share the analysis. Will continue to make ourselves available. • Working closely with Condo Association to have building demolished with experienced contractor familiar with this type of work in a dense, urban environment. • Additional community notifications/updates posted on the website. • Additional community meetings to share progress and answer questions. • Closing access to adjacent public streets July 19th – Mt. Auburn Street & Sparks Street

CITY OF CAMBRIDGE Next Steps Closing Mt Auburn and Sparks Street 19 • Beginning Saturday, July 19th the following street and sidewalk closures will be in place: • Mt. Auburn Street will be closed around 221 Mt. Auburn from approximately 197 Mt. Auburn Street to 239 Mt. Auburn • Sparks Street will be closed from just south of Bradbury Street to Mt. Auburn Street • Access to residents' homes will be maintained. ABUTTERS ONLY ROAD CLOSED

CITY OF CAMBRIDGE Next Steps Closing Mt Auburn and Sparks Street 20 • Detours will be in place around the closure area. Detours will address: • Local resident access • Pedestrian and bicycle access • Bus routes • Truck routes • Hospital access • Re-routing of regional trips

CITY OF CAMBRIDGE Next Steps Closing Mt Auburn and Sparks Street 21 Local Car Access

CITY OF CAMBRIDGE Next Steps Closing Mt Auburn and Sparks Street 22 Bicycle and Pedestrian Routes People walking and biking will use the detour above in both directions: Gibson St., Foster St., and Willard St.

CITY OF CAMBRIDGE Next Steps Closing Mt Auburn and Sparks Street 23 MBTA Bus Detours • The 71 and 73 MBTA routes are impacted by closures • Westbound bus detour: Mt. Auburn St. westbound, right onto Willard St., left onto Brattle St., left onto Channing St., right onto Mt. Auburn St. towards Belmont and Watertown.

CITY OF CAMBRIDGE Next Steps Closing Mt Auburn and Sparks Street 24 MBTA Bus Detours • The 71 and 73 MBTA routes are impacted by closures • Eastbound bus detour: Mt. Auburn St. eastbound, left onto Lowell St., right onto Brattle St., right onto Hawthorn St., left onto Mt. Auburn St. toward Harvard Square.

CITY OF CAMBRIDGE Next Steps Closing Mt Auburn and Sparks Street 25 • Temporary One-Way Conversions • Three streets will temporarily be converted to one-way traffic to accommodate the detours. • This will allow for the safe, efficient operation of MBTA buses and ambulances. • Channing Street will be one- way Southbound towards Mt. Auburn Street. • Lowell Street will be one-way northbound towards Brattle Street. • Willard Street will be one-way northbound towards Brattle Street.

CITY OF CAMBRIDGE Next Steps Closing Mt Auburn and Sparks Street 26 Truck Route • Brattle Street is a truck-restricted road. • This means only trucks with local destinations can use the street. • Through-trucks that would typically use Mt. Auburn St. will be directed to the Truck Detour

CITY OF CAMBRIDGE Next Steps Closing Mt Auburn and Sparks Street 27

CITY OF CAMBRIDGE Next Steps Demolition 28 • Disconnecting utilities in preparation for demolition and to reduce risk. • Bring a qualified contractor on board with experience in complex demolitions in dense urban environments. • Contractor will develop a demolition plan that would be permitted through MassDEP for Non-Traditional Demolition • Environmental consultant is a significant component of the team to address hazardous building materials like asbestos. Plan would typically include misting, air monitoring and other measures. • 6 to 8 weeks for engineering and permitting. • Once mobilized, 12 to 16 weeks for demolition. • We would have a community meeting in advance of planned demolition.

CITY OF CAMBRIDGE What’s Next for City Staff 29 • Committed to protecting public safety and public health. • Continue to be transparent throughout this process and sharing information as quickly as we can. • Continue to meet with direct abutters. • Hosting additional community meetings.

CITY OF CAMBRIDGE What’s Next for Residents 30 • Check website – http://www.cambridgema.gov/221mtauburnst • Sign up for email notifications • Structural analysis and reports are posted • Check for FAQs – posted next week and updated regularly • Attend Zoom meeting on July 24th, 6:30 –8 p.m. • Meeting link: https://cambridgema.zoom.us/webinar/register/WN_uwf8ZF7CS3epU5hSAvcU6A • Contact Kristen Kelleher, Community Relations Manager, with questions: • [phone removed] • kkelleher@cambridgema.gov

CITY OF CAMBRIDGE Instructions for Q&A 31 Questions? ▪Staff are available in the aisles with microphones. ▪Raise your hand and staff will hand you the microphone. ▪Once your question is done, please hand microphone back to staff. ▪*If you prefer to write your question, use a notecard. Please hand the card to a staffer.

CITY OF CAMBRIDGE Contact Information 32 Please send questions/concerns to: Kristen Kelleher Community Relations Manager [phone removed] kkelleher@cambridgema.gov Project website: www.cambridgema.gov/221mtauburnst Katherine Watkins Deputy City Manager [phone removed] kwatkins@cambridgema.gov Brooke McKenna Commissioner Department of Transportation [phone removed] bmckenna@cambridgema.gov