Use of Lightweight Fill Material
The site of the proposed Moody roadway, which has been industrial land for over a century, has contaminated soils which are prone to settlement. These conditions required new design techniques to protect existing and future infrastructure, below and above the ground, in order to raise the roadway up to 14 feet as required for future development. A lightweight fill material, low density cellular concrete (LDCC), was selected to reduce the weight of the raised roadway section. While this lightweight material adequately protected the 30-foot deep 72-inch South Waterfront Parallel Interceptor, the shallow 48 inch combined sewer and the future streetcar rail, it required innovative design and construction methods. The project team worked with both public and private entities to quickly develop these new standards of construction with the LDCC.
Bottom Up Construction
Much of the coordination of the design revolved around the LDCC which is placed within formed lifts similar to standard concrete. This required the design to support a bottom-up construction sequence with utilities, foundations and walls being installed prior to the fill being placed in and around them. This is opposite of standard methods and required extraordinary speed in coordination, review and implementation between the team and all the project stakeholders in order to meet everyone’s needs and make the project constructible within the required schedule.