PROJECT OVERVIEW
Phoenix Project #2022
Fenway Cener Parcel 7 was an innovative “air-rights” development project constructed over the Massachusetts Turnpike (I-90) in the Fenway neighborhood of Boston. After more than two decades of planning, development, permitting, and approvals, the Owner selected JF White to act as the project’s general contractor, as well as one of its specialty subcontractors. A foundation system using a combination of driven H-piles (installed by JF White) and drilled micropiles (installed by Phoenix) was selected by the design team to fulfill the structural requirements, while at the same time being mindful of the very challenging site constraints.
The project required that hundreds of high-capacity drilled micopiles (“DMPs”) be installed within very narrow work areas adjacent to the Mass Pike, and between two very busy elevated roadways (Beacon Street and Brookline Avenue). On the north (westbound) side of the site, 41 DMPs had to be installed between the highway and a series of abutting buildings in a work area ranging from 15 to 30 feet wide. On the south (eastbound) side, 206 DMPs were installed between the highway and a pair of live railroad tracks in a work zone that averaged only 18 feet wide. The final 15 piles were installed within the highway’s median and tight against Brookline Avenue, with the high speed lanes of I-90 Eastbound and I-90 Westbound serving as very intimidating bookends of a 30 foot wide site.
Planning for Phoenix’s work began roughly 18 months prior to mobilization, with numerous technical and logistical challenges considered during that timeframe. Drilling, grouting, and pumping equipment had to overcome unusually deep pile depths, with the top of bedrock said to be present more than 220 feet below ground surface (in many cases, the rock was actually much deeper!). Sonic drilling was used by Phoenix at 200 pile locations to core through a 3’ thick concrete foundation containing multiple layers of reinforcement. An elaborate water filtration system was utilized for the majority of the project which included treatment of all drilling fluid prior to discharge. And where this system could not be utilized, Phoenix contained and recirculated its drilling fluids for as long as practical before vacuum trucks were brought in at night to clean out the spoils tanks. All critical project support including equipment mobilizations, material deliveries, spoils removal, and relocation of work platforms was performed at night by JF White using highway lane closures, and in some cases during the day using the adjacent railroad track.
Overall, Phoenix installed roughly 60,000 feet of micropiles on the Fenway Center project. As many as four drill rigs ran concurrently between the overlapping sonic drilling and DMP installations, with drilling and grouting crews combining to work as many as 18 hours per calendar day as needed to complete the installations. Over 75 truckloads of steel casing and reinforcing bars were installed within the 261 piles, along with more than 2 million pounds of Portland cement. More than 25 union tradespeople worked on the job, logging close to 25,000 man-hours without injury or incident. Phoenix beat its originally scheduled duration by almost four weeks, despite having to complete a portion of the work during a pretty harsh New England winter.
