Mount Baker Tunnel

1983 ( third tube )

1986 ( third tube )

The Mount Baker Ridge Tunnel or Mount Baker tunnel located in the U.S. state of Washington and lead the Interstate 90 under the Mount Baker neighborhood of Seattle through. The system consists of three tunnels: the first two were in 1940 opened along with the Lake Washington Floating Bridge, the third 1991 The Tunnel lead eight lane highway, and a foot and bike path that in the third tunnel on the roadways of the Interstates. is performed.

The tunnels are listed on the National Register of Historic Places (NRHP ) under the number # 82,004,243 which Ostportale were listed by the American Society of Civil Engineers List of Historic Civil Engineering Landmarks. Next, the tunnel is a Seattle Landmark.

• 2.1 tunnels from 1940
• 2.2 tunnel from 1986

History

The first two tubes

Early 20th century has been looking for ways to improve the development of the east coast of Lake Washington from Seattle. With state funds that were made ​​available during the Great Depression, the Lake Washington Bridge Project was implemented, the 10 leading U.S. Highway Bellevue Mercer Iceland to Seattle. The project comprises in addition to the core, the Lake Washington Floating Bridge, the East Channel Bridge, which brings traffic from Bellevue by Mercer Iceland and the tunnel through Mount Baker, which brings the traffic of the floating bridge in downtown Seattle. Originally, only one tube was provided, the project was later expanded to two lanes and a sidewalk per tunnel.

The construction of the tunnel was awarded in 1939 for 1.37 million U.S. dollars to the Bates and Rogers Construction Company. Construction on the east portal started with a 115 - day delay due to Wegrechtsstreitereien - it was intended to ascend the entire tunnel from the east. When it was determined that the planned opening date can not be met, the construction loan was increased by $ 30,000, so that could be dug even from the west side. The outbreak in the shade of blue in the Belgian construction was done without explosives and drilling only through the reduction with pneumatic hammers, with a very strong expansion was necessary to stabilize the plastic material. The core was removed with an electric excavator loaded the material to an electric Loren web. The tunnel was accompanied by great difficulties. Reductions of up to 30 cm led to damage to the overlying mountain roads and houses. The construction of both portals triggered more landslides. Nevertheless, it was possible to pass the tunnel together with the Lake Washington Bridge on schedule on July 2, 1940 the traffic.

With the increasing traffic, the two interior lanes was equipped with variable message signs in the sixties, so that they could lead westward or eastward transport depending on main traffic direction.

The third tunnel

1986 U.S. Highway 10 were added to the existing two tubes Interstate 90 through a third tube, substantially larger than in the course of the expansion. The construction for a unique method was presented for 38.3 million U.S. dollars to the Guy F. Atkinson Construction Co. First, a pit depth of 30 m in diameter and 27 m were created before the future tunnel entrances ever. From this latter, the tunnel walls were created by 24 circular abutting jacking run with 3 m diameter, at all propulsion was pressed immediately with concrete after completion. After the outbreak was carried out starting from the ball in the protection of already finished lining. The interior for the three traffic level was done with prefabricated beams and plates.

All three tunnels were extended west of the Mount Baker Ridge for the purpose of noise control to a covering of 600 m. The replacement was the result of opposition from residents, who delayed the construction of Interstate 90 since the 1970s. The Mount Baker Tunnel belong to the last seven -mile section of Interstate 90, which was completed in 1992.

After the opening of the third tunnel, the two existing tubes were renovated in 1993.

Building

Tunnels from 1940

The first two tubes are laid out in a spacing of 18.2 m and have a horseshoe shaped cross-section with a width of 8.8 m, the coverage measures to the most powerful office 38 m. The tunnel at its disposal when it is completed in the most broken loose rock section. Each of the two tubes is aerated with three air channels leading to a common - Lüftungsschacht47.590054 122.293223 over the tunnels.

The Art Deco - tunnel portals on the east side were designed by architect Lloyd Lovegren. The artist James Fitzgerald designed the three originally therein can bas-relief panels with designs of the Indians of the Northwest Coast. The middle plate bore the inscription City of Seattle portal of the North Pacific, the other inscriptions The Orient and Alaska. At night, the portal was lit with spotlights. With the opening of the third tube two of the three plates were removed - they would have been at the new traffic regulations to drivers already in the rearview mirror only recognizable.

Originally dismissed each tube to two 3.7 m wide lanes and a 90 cm wide sidewalk, where the south tube was used by the eastward moving traffic, while traffic flowed in the north tube to the west. With the opening of the third tunnel, the two existing tubes are only used by the traffic to the east, with the south tube lane is with a hard shoulder and in the north tube two lanes with no hard shoulder.

Tunnel from 1986

Established in 1986, The third tube was with an inner diameter of 19.4 m turn the tunnel with the largest diameter in soft ground on its completion. The three levels of the roads are hooked into the shell with concrete beams and slabs. The bottom level is used by two lanes that lead depending on the rush towards the west or east, and are deprived of public transport, and carpooling. The three westbound lanes leading use the middle level and at the top there is a pedestrian and bicycle path. Over the portal of the middle level, the inscription Seattle was similar to the old tubes - Portal to the Pacific attached.