PROJECT OVERVIEW
Phoenix Project #2204
705 Mount Auburn Street in Watertown is an iconic landmark of the town. It was Phoenix’s honor to work with Consigli to provide for them SOE (Support of Excavation) for not one, but FIVE different pits inside of the building as they were renovating it for the owner. Additions of elevators and PH-pits inside the existing building required excavation that had to have vertical faces. PH pits, for the non-chemist and as explained to us, are holding tanks for waste chemicals generated by laboratories and research companies. The chemicals in these tanks are neutralized and removed to be transported to properly be disposed of off-site.
One of Phoenix’s favorite products was employed to meet the need here, a Micropile SOE system. Consisting of relatively short drilled micropiles and fixed lagging boards, this solution was ideal for the task at hand. Each of the five DMP SOE systems were designed to reduce the amount of concrete slab-on-grade that had to be removed while also providing the earth support to ensure that the workers setting reinforcement and placing concrete were protected against soil collapses. The deepest of the pits required ring walers to support the extra lateral load of deeper excavations.
A bonus to this project was that the bottoms of some of these excavations were to be below the bottom of the existing structural footings. To ensure stability and prevent any unwanted settling, the footings were either underpinned with conventional methods or were supported by brackets installed on the micropiles used for the SOE. The bracket piles were deeper and contained an additional inner pipe inside the pile to strengthen and stiffen the pile to support the extra load. These brackets were installed once the excavation was deep enough to allow for it and the lagging elsewhere had been installed to ensure worker safety. Ultimately the brackets were encapsulated in the conventional underpinning with grout, thus locking them in place.
