Press Release: 07.03.2018

Gateway Arch Museum Expansion, Constructed by McCarthy, Completes $380 Million Redevelopment of Iconic Monument

Gateway Arch Spanning Over Newly Renovated Museum

A 47,000-sq.-ft. subterranean expansion and renovation of the Museum of the Gateway Arch, constructed by McCarthy Building Companies, Inc., is the final component of a $380 million redevelopment of the iconic monument in downtown St. Louis. As a primary general contractor of the Gateway Arch Park redevelopment, McCarthy also oversaw the transformation of the north and south grounds surrounding the 50-year-old national historic landmark. 

The renovated museum and visitors center, which opens to the public on July 3, will enhance the overall experience for the 4 million individuals who visit the 630-foot-tall structure, on average, each year. A dramatic new circular entrance and upper-level lobby facing downtown St. Louis replaces the previous underground entrances at the base of each Arch leg. Visitors will now enter the monument at street level, through a custom-built glass and stainless-steel entry enclosure system.

The expanded museum’s reinforced roof deck features 2,400 cubic yards of post-tensioned concrete slabs, as well as 189,000 cubic feet of GeoFoam blocks, an innovative solution to eliminate additional excessive weight on the roof deck. 

“This highly complex project involved close coordination among multiple layers of consultants, architects, archaeologists, governmental agencies and subcontractors all working together to bring it to life,” said Ryan Freeman, McCarthy vice president of operations. 

Interior of Newly Renovated Gateway Arch Museum

Constraints on all four sides limited access points and the ability to transport materials to the 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 bisects 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 construction project. “Our team had to be constantly vigilant in managing pedestrian traffic while maintaining a safe, orderly site so visitors could fully enjoy their experience,” said Freeman.

Entryway to Newly Renovated Gateway Arch Museum

The monument’s new main entrance welcomes visitors into a daylight-filled, climate-controlled plaza that provides external views of the Old Courthouse landmark and downtown St. Louis. A grand mezzanine features a colorful terrazzo floor with a giant U.S. map illustrating the westward migration from St. Louis and other cities. It leads to several new galleries that trace St. Louis’ role in westward expansion from the mid-1600s to the present. A 100-foot video wall inside the tram lobby will project scenes from the original construction of the Gateway Arch and other examples of American innovation. The entrance, building and exhibits are designed to meet universal design standards so the museum can be accessible by all individuals regardless of age, size, ability or disability. 

Designed and constructed to pursue LEED Silver certification from the U.S. Green Building Council, the expansion is the facility’s first renovation since the 106,000-sq.-ft. Museum of Westward Expansion opened in 1976.

Embracing the City and Riverfront

The Gateway Arch Park redevelopment also included renovation of the north and south grounds surrounding the monument to create a more pedestrian-friendly experience, with easier access from downtown St. Louis and the riverfront. The renovated park grounds feature more than five miles of scenic bike and walking paths, an outdoor natural amphitheater, and a new land bridge that directly connects the Arch to downtown for the first time in its 50-year history. More than 800 existing Ash trees on the grounds’ processional allées were replaced with London plane trees that are resistant to emerald ash borer disease.

McCarthy collaborated with sister company Castle Contracting to re-grade the entire site and install new landscaping, a new irrigation system, and amended soil and sod. In total, the project involved moving 300,000 cubic yards of earth, which is the equivalent of 19 football fields each piled with 10 feet of dirt.

Because available records of buried utility lines and other hazards were incomplete and potentially inaccurate, Castle used a combination of leading-edge subsurface utility mapping technologies to ensure the Arch remained fully operational during construction, with no interruption to critical utility systems.  

“Ground penetrating radar (GPR) and other electronic locating devices helped us supplement historical data and other traditional approaches to underground surveying,” said Michael Pranger, vice president, operations at Castle Contracting. “This data now provides an accurate record of the site for future use.”

As St. Louis-based McCarthy commemorates its 100th anniversary in St. Louis this year, completion of the Gateway Arch Park redevelopment is particularly meaningful.

“We’re very proud to have contributed to dramatically reshaping this iconic landmark in our hometown,” said John Buescher, president of McCarthy’s central region. “Gateway Arch Park will continue to symbolize the spirit and ingenuity of St. Louis for future generations while serving as an economic engine for the city and region.”

The museum expansion was designed by Cooper Robertson and James Carpenter Associates, both of New York, with Trivers Associates, St. Louis. Michael Van Valkenburgh Associates, New York, oversaw the landscape design.  

Gateway Arch Park Foundation and the National Park Service led the Gateway Arch Park redevelopment projects.

About McCarthy

McCarthy Building Companies, Inc. is the oldest privately held national construction company in the country – with more than 150 years spent collaborating with partners to solve complex building challenges on behalf of its clients. With an unrelenting focus on safety and a comprehensive quality program that span all phases of every project, McCarthy utilizes industry-leading design phase and construction techniques combined with value-add technology to maximize outcomes. Repeatedly honored as a Best Place to Work and Healthiest Employer, McCarthy is ranked the 14th largest domestic general contractor (Engineering News-Record, May 2018). With approximately 3,700 salaried employees and craft professionals, the firm has offices in St. Louis, Atlanta; Collinsville, Ill.; Portage, Ind.; Kansas City, Kan.; Omaha, Neb.; Phoenix; Las Vegas; Denver; Dallas, Houston; Albuquerque; and San Diego, Newport Beach, San Francisco, San Jose and Sacramento, Calif. McCarthy is 100 percent employee owned. More information about the company is available online at or by following the company on Facebook, Twitter, LinkedIn, Instagram and Google+.

Did you enjoy this read? The McCarthy team regularly shares Insights posts about our latest projects and innovations. Sign up to receive Insights directly in your inbox and you'll never miss another exciting update. Sign up here.

sign up to receive insights

Sign up to receive McCarthy Insights