Fast-Tracked HDD in Biscayne Bay for Emergency Bridge Replacement

This paper describes two horizontal directionally drilled water main crossings beneath the Biscayne Bay to support the $31 million emergency replacement of the access bridges to Key Biscayne. The Miami-Dade Water and Sewer Department (MDWASD) replaced two sections of the existing 12-in. (300 mm) ductile iron water main between the City of Miami and the Village of Key Biscayne with 16-in. (400 mm) inner diameter high-density polyethylene (HDPE) pipe via horizontal directional drilling (HDD). HDD technology enabled the installation of the pipelines to be completed within the tight 10-month project schedule, minimizing environmental impacts and project costs. The installations were completed as part of the design-build replacement of the Bear Cut and West Bridge superstructures by Kiewit Infrastructure South Co. The existing water main was supported on the superstructure of the bridges, which forced its fast-tracked replacement. This is one of the most critical projects being completed in Miami-Dade County and will provide a new water main and improved access to more than 10,000 residents in Key Biscayne.