Twin Tunnels (Veterans Memorial Tunnels)

The Westbound I-70 Twin Tunnels project widened the westbound bore of the tunnel in Idaho Springs to about 53-feet. This will accommodate a third lane along westbound I-70 when the highway is eventually widened. Contractor Kraemer Obayashi JV utilized a 11,000 p/f² prefabricated drainboard with a 18 g/min/ft flow rate to waterproof the tunnel walls and ceiling. The drainboard was installed on the excavated tunnel walls utilizing a Hilti gun and nails. The seems were then covered with a specialty waterproofing tape. The entire area was then covered in shotcrete.

• 510 4' x 50' rolls of prefabricated drainboard
• 29,000 clips
• 595 rolls of waterproof tape

With a wider, brighter tunnel entrance, the traffic flow on westbound I-70 will improve as motorists will be less likely to slow down when approaching the tunnel. Driver safety will also improve with the removal of rock from the walls above the tunnel portals and along the north side of the highway along the outside each portal.