History Being Re-Made: Stabilization of a 146-Year-Old Gatehouse in a High Hazard Class Dam

摘要

This historic gatehouse is a structural component of the High-Hazard Class Chestnut Hill Reservoir Dam in Boston, Massachusetts. The interior of this facility has experienced substantial deterioration due to seepage and age since it was decommissioned many decades ago. Preliminary designs were developed to mitigate the deterioration and stabilize the gatehouse structure. During final stabilization design, record drawings from 1870 were discovered that indicated subterranean arched chambers may have been constructed below the lowest gatehouse level. The presence of the sub-floor chambers needed to be confirmed and the design changed to address the chambers. This paper describes the facility history within Boston's water system for context, the explorations to confirm and better understand these subterranean chambers, the corresponding design changes, and the resulting comprehensive design for stabilizing the structure with concrete fill to meet current dam safety standards.