Transbay Transit Center
Location: San Francisco
Subcontractor: Best Contracting Services, Inc.
GCP Solution: PREPRUFE® waterproofing
When the mayor of San Francisco, state legislators, city councillors, and other dignitaries gather together for a building event, you figure it’s a high-profile ground breaking or ribbon-cutting ceremony, not a technical presentation of a below grade waterproofing solution for a transport infrastructure. Such are the sky-high stakes surrounding the $4.185 billion Transbay Transit Center.
“We literally had 20 to 30 people standing over my shoulder as we presented mock-ups of our alternative waterproofing solution, from the mayor on down,” explains Dean Edwards, project lead for Best Contracting Services, Inc., the waterproofing subcontractor on the transport business project.
THE CHALLENGES
The officials had good reason to be concerned. The transport infrastructure project had fallen up to 2.5 months behind schedule. The top challenges included: a below grade waterproofing method “… that was taking forever to cure” in the damp, deep immensity of a four block-long excavation. The budget clock was ticking, costly workers were waiting, and water extraction pumps were thundering 24/7.
At issue was the original asphalt-based fabric solution. It wasn’t curing as predicted due to jobsite conditions. In addition, the hydraulic forces compressing the worksite on all sides were incredible. If the pumps stopped even briefly, the walls started to immediately weep. “We were at least 30 feet below the water table,” Edwards says.
THE SOLUTION
“We brought GCP to the table,” Edwards states. “GCP’s PREPRUFE® is a pre-applied, zero-cure waterproofing membrane proven across hundreds of major infrastructure projects over the past 25-plus years. And by removing time for curing, we knew we could expedite the schedule.”
PREPRUFE waterproofing is designed to deliver exactly what the transport infrastructure needed, with:
- Fast and easy installation
- A robust product design able to withstand the rainy San Francisco weather during installation, as well as in situ performance lasting the life of the structure
- Permanent adhesive bonding to the concrete in all circumstances, be it after UV exposure or after water immersion to the concrete
- A clean, neat, asphalt- and clay-free product that is highly resistant to contaminated and aggressive soils, and no impact of TCE/PCE to the waterproofing performances
- Immediately trafficable with same-day rebar setting and tying
After approval to use PREPRUFE, the transport business contracting teams set to work, sealing-off the walls and floor. With cure times off the table, installation proceeded swiftly.
THE OUTCOME
Today, the Transbay Transit Center continues to operate with no below grade leaks, accommodating more than 100,000 passengers each weekday, adding an estimated 10,000 daily transit trips in the Caltrain corridor by 2030. The multi-modal Transit Center is the “Grand Central Station of the West,” centralizing the region’s transportation network.
CLOSING THOUGHT
With more than 1.5 billion square feet installed around the globe, in the most challenging situations, PREPRUFE waterproofing is trusted by owners, architects, building envelope consultants, and contractors. Like the Transbay Transit Center team, many rely on PREPRUFE to help accelerate project completion, gain greater peace of mind, and improve the durability of their structure. The PREPRUFE comprehensive waterproofing system has been protecting structures across the globe for more than 25 years and brings together pre-applied and post-applied waterproofing into a complete, best-in-class system.
For More Information
For more information about GCP PREPRUFE®, visit gcpat.com.
Modern Contractor Solutions, June 2023
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