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Title: Longfellow Tower – 16+ Years Later

Author(s): Timothy Gillespie

Publication: Web Session

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Date: 4/1/2021

Abstract:
The prestigious Longfellow complex is located in the heart of downtown Boston on the Charles River. This presentation focuses on two 38 story apartment buildings which were constructed between 1970 and 1972. Inspections conducted in 1997 identified numerous areas of spalls due to corrosion of the steel reinforcement. More recently, sealant joints at the sliding glass doors, ac units and windows were failing and allowing water to leak into the apartments. In 2001, inspecting engineers carried out a comprehensive investigation to determine the extent of damage and the root cause. Among other things, they determined spalling had increased by 25% since 1996. Exposed column faces, balcony edges and floor slab edges had the least cover and most spalls. There was chloride contamination, carbonation and low cover throughout. Wherever the cover was less than 2” there was high levels of active corrosion. The goal of the Owner and the Engineer was to repair the spalled concrete and leaking joints and to provide long-term protection to the building. A repair program was completed in 2004- 2005 with the goals to repair the spalls and leaking joints and protect the building by mitigating active corrosion. A preview was completed to confirm the design met the objectives. Finally, areas of the building were monitored to confirm effectiveness of the repair and protection program. All of this resulted in a repair program that will no doubt provide long-term durability for this Owner. In 2015, 10 years after the repair program was implemented, the 2 buildings were in pristine condition. In 2019 the repairs implemented in 2005 continue to perform. This presentation will review the history of the 2 buildings, the repairs implemented in 2005 and an update on their condition which includes remote corrosion rate monitoring.