SR99 Bored Tunnel-Assessment of Settlement Impacts ... - SCATnow

cover section north of Thomas Street. The cut-and-cover section would unbraid thetunnel’s stacked northbound and southbound roadways into a side-by-sideconfiguration that matches the existing grade of Aurora Avenue N. near MercerStreet. Where the bored tunnel emerges at Thomas Street, the cut-and-coverexcavation would be about 85 feet deep. There would be a north tunnel operationsbuilding over the tunnel on the east side of Sixth Avenue N. between Thomas andHarrison Streets. The lowest level of the building would be around 75 feet below theground surface. The cut-and-cover section of the tunnel would extendapproximately 450 feet to a portal on the north side of Harrison Street.The entire tunnel would have continuous six-foot shoulders on the roadway’s westside to maximize access to an enclosed emergency walkway along the west side ofthe tunnel (Figure 2).Figure 2. Proposed Bored Tunnel Cross-Section.The Alaskan Way Viaduct & Seawall Replacement Program March 2010Proposed SR 99 Bored Tunnel - Assessment of Settlement Impacts to Buildings 8Public Disclosure Request 11-0123 for Elizabeth Campbell - 2nd installment