HOUSTON, TX — For over 50 years, Memorial Park in Houston, Texas, has been divided in half by Memorial Drive and its busy traffic, but all that has changed. Humans and animal traffic alike now have a safe way to enjoy both sides of the 1,500-acre park with the construction of land bridges over recently completed vehicular tunnels.

Western Specialty Contractors, Houston Branch was tasked with waterproofing the project’s two sets of 25-foot-tall, 54-foot-wide concrete traffic tunnels that replace Memorial Drive and provide for land bridges across their tops. In August 2020, Construction Manager at Risk Tellepsen Builders started moving dirt to facilitate erection of 300, six-foot-wide precast segments that would become the new tunnels.

Waterproofing work started five months later in January upon arrival of the first set of precast panels. Western’s experts applied approximately 160,000 square feet of the specified bentonite clay waterproofing with drain mat to the tunnels’ exterior walls. Bentonite is an absorbent swelling clay that is durable, long-lasting, and environmentally friendly. The waterproofing sequencing followed installation of the precast panels, and the entire process took about 15 months to complete.

“We are so proud to have been able to play a role in this innovative project for the Memorial Park Conservancy. And while it may have been a small part of this expansive project, waterproofing plays a critical role in maintaining the longevity of the concrete structures," said Western Specialty Contractors Branch Manager Brian Dolezal. "The Bentonite clay waterproofing we applied will mitigate the risk of water intrusion and small planting roots from penetrating into the tunnel through the soil backfill. Utilizing the right type of waterproofing system is vital to protecting the integrity of these underground tunnels long term."

The two sets of waterproofed tunnels were then each covered with 35-foot-tall dirt mounds that became a land bridge with a network of trails for pedestrians that overlooks the park with views of the city, and a greenspace covered with trees and grass for birds and other wildlife.

The architect on the project was Gunda Corporation, with Walter P. Moore and Henderson Rodgers serving as the structural engineers.