environment + Sustainability
MONUMENTAL LOGISTICS Renovation of St. Louis’ Gateway Arch landscape and museum involves numerous sitework challenges. By Michael Pranger
When the Gateway Arch opened in downtown St. Louis in 1965, the 630-foot monu- ment exemplified innovation in architecture, structural engineering, and construction expertise. Five decades later, the sitework challenges of renovating the Arch’s his- toric landscape and expanding its subterranean museum are a showcase of logistical complexity. Constraints on all four sides limited access points and the ability to transport materials to the iconic monument, which is situated at the center of a 70-acre site. To the east is the Mississippi River, the region’s foremost waterway (and the source of two flood events that significantly impacted construction activities). And to the west is a major interstate highway that separates the Arch from the densely occupied downtown area. Further complicating this scenario, the Gateway Arch had to remain open, accessible, and fully operational throughout the three-year project. Because this tourist destina- tion attracts about 4 million visitors annually, our team had to be constantly vigilant in managing pedestrian traffic while maintaining a safe, orderly site so visitors could fully enjoy their experience. As a designated National Historic Landmark, the site was subject to requirements that included archaeological monitoring as well as protection and documentation of existing historic elements. The project’s scale and complexity necessitated development of a comprehensive site logistics and phasing plan. This coordinated strategy involved completing all sitework on the north and south park areas prior to executing the museum expansion portion of the assignment. Essentially, it was the opposite approach to working from the inside-out. Construction barriers that were erected to allow visitors to safely access the Arch also restricted site-wide access for construction workers. To overcome this obstacle, we had to use duplicate equipment in some cases to facilitate efficient transporting of materials between the north and south parcels of the site. Creating a pedestrian-friendly experience The goal of the project’s first phase was to create a more pedestrian-friendly experi- ence for visitors, with easier access from downtown St. Louis and the riverfront. This includes a new land bridge that spans over the highway to provide safe, convenient access to the Arch from downtown. The renovated park grounds feature a new circulation loop that encompasses more than five miles of accessible pedestrian pathways. Our work involved re-grading the site and installing new landscaping, a new irrigation system, and amended soil and sod. However, as sitework began we discovered that the condition of the existing soils
The renovated park features a new circulation loop with more than five miles of accessible pedestrian pathways, a new irrigation system, and amended soil and sod. Photo: © JohnLangholz, 2017
The 70-acre Gateway National Park is constrained by the Mississippi River, an interstate highway, and downtown St. Louis, creating sitework challenges. Photo: © JohnLangholz, 2016
View from the top the Gateway Arch, showing theWest Entry of the museum (foreground), the new land bridge over the highway, and the Old Courthouse and downtown St. Louis. Photo: Katharine McClellan, JCDA
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csengineermag.com
july 2018
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