682 Beacon Street
Kenmore Square, Boston, MA
Related Beal - Owner
Commodore Builders - Construction Manager
Hub began mobilizing onto the Kenmore Square Beacon Building site on January 14, 2021. This project consisted of a test pile program performed previously in April, 2020 and the installation of 214 expander bodies (EBs). We drilled the piles with 7 ⅝” drill permanent casing. Each pile was drilled a minimum six feet into sand, approximately 15 feet below grade, with the permanent casing. We lowered a one-piece expander body assembled offsite— a five-foot expander body and 21 feet of riser pipe, 26 feet total— into the cased hole. We tremie grouted the hole and retracted five and a half feet of permanent casing to expose the EB to the sand bond zone. We placed grouting caps on the EB riser pipes, and we pumped measured grout into the EB, expanding it within the bond zone. Once the EB was filled, the grouting cap was sealed off. Upon site excavation, we cut down the riser pipes and plated prior to forming and pouring pile caps.
On paper, this was a fairly straightforward project for Hub. There were no other contractors on site (except for Welch as site support). However, lack of real estate did hamper production somewhat, and the site layout had to be reconfigured often. The biggest hurdle to overcome was the EB product itself; we worked out a number of performance issues out in the field. Ultimately load tests did verify that the EBs would hold up to the required capacity, and Hub successfully completed this project under Boston’s iconic Citgo sign.