What I don't know is the degree of rehab in each HTT project, I would need to see the details. It may be that the first rehab was a light rehab. On a quick look inside the tunnel I see what looks like strip florescent lighting fixtures, I don't think that is the original but that is old technology.
The post-1985 BHT project included a total replacement of the tunnel deck; a replacement of the tunnel lighting system; removal and replacement of the tiles on the walls; and removal of the booths for the police officers (they were replaced by video monitoring)
What MDTA has planned now for the tubes is as follows (note - from memory, not from reading the IFB as amended):
- Removal of the wearing surface (only) of the concrete tunnel decks with some sort of hydraulic demolition process, and then installation of a new surface using latex-modified concrete (MDTA likes to do this for some reason - MDOT/SHA almost never does, having a revealed preference for "complete" deck replacement). Note that a similar process was used on the westbound span of the WPL (Bay) Bridge in the early 2000's, and that did not end well, because the new surface did not ahere properly and started to crack and delaminate pretty quickly, and then a decision was made to do a total deck replacement with prefabricated sections so the bridge could be opened each morning to traffic (but on the flipside, the BHT, because of overhead clearance restrictions, does not carry as much truck traffic as the WPL). It was thought that the delamination might have been due in part to the presence of salt on the remaining "bare" bridge deck and perhaps because of truck traffic.
- Replacement of the tiles where the tiling system has failed (and there's quite a lot of that, especially in the northbound tube for some reason).
- Replacement or repair of the pipes that supply water for firefighting use.
- Replacement of the lane control signals in both tubes.
- Replacement of the lighting systems in both tubes.
I know there were some other items as well, but I think the above were the major ones.
Good summaries, thanks! Thirty years is a long enough time that I am OK with the above rehab schemes, which could be categorized at major rehabs. Do you know what is the plan with regard to ventilation systems?
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The original Downtown Tunnel in Norfolk was opened in 1952. When the second tube opened in 1987 the original tube was closed for almost a year for a major rehab, I don't have the exact details but it included new roadway, new lighting, and major upgrades to electrical, mechanical, drainage, fire, ventilation and surveillance systems
The 2013-14 rehab to both tubes --
Rehabilitation consists of structural, fire, life and safety improvements including:
§ Tunnel fireproofing for structural protection
§ A new jet fan ventilation system [plus removal of roadway tunnel ceiling which was also the floor of the plenum ventilation exhaust tunnel]
§ LED tunnel lighting which provides brighter lighting and uses less energy [LED is so much brighter that the new Midtown Tunnel tube doesn't need tiles, the walls are the fireproofing panels alone]
§ Tile and concrete repair
§ Exit and safety signage
https://www.driveert.com/wp-content/uploads/2013/08/ERT_factsheets_WestDowntownTunnel_Current.pdfWell worth the money spent, IMO, bring the tunnels into 21st century standards.
The original Midtown Tunnel tube was opened in 1962 and got the same rehab treatment, and its first, completed in 2017. I was down there a couple days ago and rode thru it for the first time since the rehab was completed and it looks very fine.