This five-block long site includes waterfront improvements, construction of four new buildings, and the renovation of the landmark refinery. A new 16-story building, known for its distinctive u-shape is located along Kent Avenue and three new 40 to 55-story buildings will be located along the waterfront. Each new building will have a cellar. The renovation of the refinery includes a complete interior demolition and construction of a multi-story building within the exterior walls, which are landmarked.
The Solutions Unearthed
- Considering the new building heights, it was recommended that they be supported on piles. For the new building foundations, driven piles with an allowable compression capacity of 200 tons and caissons with allowable compression capacities greater than 200 tons were recommended.
- The support of excavation (SOE) system was designed for excavation depths that ranged from approximately 15 to 20 feet. Considering that the groundwater elevation was primarily below the excavation elevation, the SOE consisted of soldier pile and timber lagging with tieback anchors. For excavations below the groundwater elevation such as elevator and ejector pits, the SOE consisted of sheetpiles with bracing.
- To preserve the walls of the refinery, it was recommended that the existing and any additional loads be supported with a mat foundation. The mat foundation would bear on a combination of the existing foundations and the soil between the existing foundations. Considering this, additional geotechnical analyses and coordination between the structural engineer and geotechnical was required.
- Internal and external bracing systems were designed to preserve the walls during demolition. Micropiles were recommended to support this bracing system. These were sufficiently embedded into the pile cap to create a fixed head condition in order to obtain higher lateral capacities.
Client: Two Trees Management