Third Street Light Rail Program Phase 2 - San Francisco, CA - $860 Million

Sequential Excavation Method

First developed in Austria, the Sequential Excavation Method (SEM) is a tunneling technique that’s gained significant traction in the United States. We’re well-versed in this innovative technique, having completed numerous tunnels, subways and stations using this approach. Properly executed, the method allows for the construction of large and complex caverns using conventional equipment and materials, with very little surface settlement. It’s also the most resistant tunnel support system in earthquake endangered zones.