Unexpected History Lesson and Contractual Deal Making: Lessons Learned from a Large-Diameter Force Main Replacement Project in Downtown Norfolk; Home to Historical Landmarks, High-Rise Buildings, Critical Stakeholders, and Innovative Contractors

摘要

In what may have been one of the most highly watched, publically visible, large-diameter pipeline projects in Downtown Norfolk's recent history, the Hampton Roads Sanitation District (HRSD) South Trunk Sewer Section G Force Main Replacement Project (Section G) was anything but normal. In a crowded, urban setting, constructing 30-inch force main is difficult and high risk. Section G coupled challenging open-cut work with a 50-inch microtunneling effort under a major thoroughfare and a contractor-proposed 1,000-linear-foot (LF) horizontal directional drill (HDD) alongside the oldest structure in Norfolk, Virginia. The scope of Section G included replacement of three 1940s-era, 30-inch to 36-inch force main segments totaling 6,000 LF in Downtown Norfolk. Understanding the history and evolution of this City was critical for design of the proposed pipeline. Abandoned infrastructure and previous-era land reclamation influenced how the engineer approached subsurface work such as open-cut and trenchless pipe work. In addition to the geological, historical, and urban challenges described, stakeholder involvement was a substantial endeavor during the design process. City of Norfolk agencies, hotel owners, a high-end shopping mall and several other downtown businesses and industries were very active during the design phase and alignment considerations. Construction began in January 2016 and beat the substantial completion date by 4 months, with the overall project ending in August 2017. Several unexpected obstructions and conflicts were avoided using innovative solutions developed from team collaboration. A significant highlight of the construction was the unusual proposal from the contractor to circumvent an especially challenging section of the proposed open-cut alignment by installing pipe using HDD technology. Negotiations resulted in agreement to $1.4 million in HDD costs in exchange for removing $1.4 million of bid-item costs (circumvented by the HDD), resulting in a no-cost modification to the project. Also extremely rare, the proposed HDD path was alongside the oldest structure in Norfolk: a colonial-era, historic church constructed in the 1730s. In the end, the construction went remarkably well, surprising many local residents and stakeholders. Major milestones were met well before deadlines, budgets were maintained, and overall stakeholder perception was decidedly positive. Major successes of the project included early substantial completion and savings of approximately $1 million to the owner. As a result of the project's success, the project team was awarded the distinguished 2016 Engineer's Club of Hampton Roads Engineering Achievement Award. This presentation details how the team strategically worked hand-and-hand with downtown stakeholders. This paper also presents the numerous challenges that many utilities face when installing large pipe in an urban or historic area using various installation methods and strategies to address corresponding design and construction issues. The contractor's proposal to use HDD made a significant contribution to the project's overall success and recognition. The significant time savings and true cost and value analysis are also discussed, comparing open-cut versus HDD in urban, downtown environments.