Modeling to Monitoring: Evaluating Adjacent Structures Feet from a Boston Excavation-Video

Video Transcription

Video Summary

The presentation described a 34-story residential tower built on a tight Boston site, with excavation extending 30–45 feet beside a historic theater, a brick building, a transit tunnel, and busy streets. The team used finite-element models to assess slurry-wall design and predict approximately one inch of settlement for adjacent buildings. However, enabling works and slurry-wall construction had already used 20–70% of that movement allowance before major excavation began.<br /><br />Monitoring guided a risk-management response. The team increased brace preloads from 30% to 50%, then installed subgrade struts when excavation approached the Boston blue clay and the excavation was expected to remain open. During mass excavation, the theater settled only about a quarter inch more and the brick building about a tenth; measured wall deflections were also below initial predictions.<br /><br />Key lessons were to consider enabling works alongside the main excavation, account for difficult-to-model activities, communicate early with stakeholders, and use monitoring to adapt support systems. The project was completed successfully through proactive, observation-based engineering.

Keywords

Boston residential tower

slurry wall excavation

settlement monitoring

brace preloads

observation-based engineering