tag:blogger.com,1999:blog-969156847256652198.post5859826083499874637..comments2023-06-21T11:58:47.093-04:00Comments on West Side Action: DOTT plans affect west side residents (ix): downtown west stationEric Darwinhttp://www.blogger.com/profile/01042460139621819388noreply@blogger.comBlogger3125tag:blogger.com,1999:blog-969156847256652198.post-52607109475461386022009-10-26T16:51:34.856-04:002009-10-26T16:51:34.856-04:00all facilities will be wheelchair and accessible. ...all facilities will be wheelchair and accessible. Indeed, there will be many long ramps since the ramp slope is to 20:1 !Eric Darwinhttps://www.blogger.com/profile/01042460139621819388noreply@blogger.comtag:blogger.com,1999:blog-969156847256652198.post-58211727098037558112009-10-23T14:59:21.315-04:002009-10-23T14:59:21.315-04:00The reason for the depth of the tunnels is twofold...The reason for the depth of the tunnels is twofold:<br />(1) to go beneath certain underground parkades, a requirement of the so-called "cross-country" routing<br />(2) to be able to mine out the stations from below in a cavern-like fashion<br /><br />The 1988 bus tunnel study also called for bored tunnels (one each under Albert and Slater, but going counterflow - i.e. east under Albert, west under Slater) with stations built by cut-and-cover. The stations would have been 'H-shaped' with the connecting segment underneath a north-south street - which is why the tunnels were to be counterflow. At any rate, the depth requirement this time is only partly related to rock conditions in the sense that it is the rock cover above the top of the station caverns that is defining the bore depth rather than the cover above the bores themselves. Since the caverns will be bigger than the boreholes, even more rock cover is required.<br /><br />This study is quite a departure from all previous tunnel studies/ideas (going back to the Holt Report). All previous studies had assumed either full cut-and-cover of the entire tunnel OR bored tunnels with cut-and-cover stations, but here we have bored tunnels and mined stations.<br /><br />The upshot is that the tunnel could be made considerably shallower by sticking to an alignment under a street or at least by avoiding going beneath buildings with deep foundations (it's notable that no one has thought to tunnel into the lowest level of an underground parkade... especially at the Rideau Centre) and by using cut-and-cover for the stations.Davidnoreply@blogger.comtag:blogger.com,1999:blog-969156847256652198.post-55209205321247394782009-10-23T14:40:53.670-04:002009-10-23T14:40:53.670-04:00First, I am recent to gathering detail on this pro...First, I am recent to gathering detail on this project beyond city releases and compliment you on your even handed and complete treatment of the issue. In Washington DC all transit is wheelchair accessible even the underground metro. Do we know if disabled access is planned?Kennoreply@blogger.com