From: Alan Wolken [mailto:email@example.com]
Sent: Thursday, June 27, 2013 6:16 PM
To: Butt, Tom
Cc: Lindsay, Bill; Melissa Tigbao
Subject: Dornan Tunnel Update
Councilmember Butt, the following is an update on the Dornan Tunnel repair activities;
Last Friday and earlier this week, the contractor was preparing the final large void for repair. Our process for repairing the voids is to first make sure that the area under the proposed repair is safe for the workers to perform the repair. During this preparation fractured rock came pouring out of the of the area above the tunnel lining at an alarming rate and volume. The original plan to repair the tunnel lining at the void location is now being modified to address this situation. The engineers solution is to design a concrete band to go under the tunnel lining at the void location. This concrete band will be designed to withstand any potential falling rock in that area of the tunnel. We have a geologist analyzing the debris to assist with our plans to stabilize the soil movement in order to finish the repair in a safe manner for our workers. We’ve included a video of the fractured rock that fell through the lining last Friday.
The video is intended just for your viewing so you can see firsthand what’s going on.
At this point the tunnel will not be opening on June 30. We are hopeful that a repair can be done quickly but as you know the safety of our workers and public comes first. We should have a better estimate of when the tunnel will be open next week. Please let either Melissa or myself know if you have any questions, Thanks Alan