Halifax Transit

[GTG_78]

Originally Posted by swimmer_spe

Historic property vs side of the road on non historic property. I would never suggest that historic properties be ripped up. Besides, Halifax already did that with Africville.

Good Lord. Africville was not about demolishing 'historic' properties. It was about the forcible dislocation of an entire community that was already subject to neglect and racism.

[Keith P.]

Originally Posted by GTG_78

Good Lord. Africville was not about demolishing 'historic' properties. It was about the forcible dislocation of an entire community that was already subject to neglect and racism.

It was a horrible slum and a dump with very poor/hazardous living conditions. The reasons why that was the case are tied to longstanding societal issues that were unfortunate although not totally unique to Halifax, but the relocation was well-intended by the govt of the day as a way to alleviate those conditions. The narrative has since been rewritten to suggest it was a bucolic community which was far from the case. There was little historic about the structures, most of which were ramshackle shacks with no services or sanitation. It was shameful that people were allowed to live in those conditions for so long. However, the rewriting of history is not useful in any case.

[IanWatson]

Originally Posted by swimmer_spe

As MacKay Bridge nears end of its lifespan, N.S. eyes replacement or repair
It needs to be shut down and refurbished to last another 60 years. If it is just the decking like the other bridge, then they already have a method of doing it.

It's looking like it will very much be a full replacement. The "Big Lift" on the Mcdonald was also essentially a new bridge. They kept the towers, but they refurbished the cables and the deck is entirely new.

They have the option to do the same at the MacKay, but it's likely they'll just build a new bridge next to it and then tear the old one down. The Big Lift cost as much as building a new bridge because of all the logistical complications of working on an active bridge. There's more space at the MacKay so they likely don't need to do that.

[Haliguy]

Originally Posted by IanWatson

It's looking like it will very much be a full replacement. The "Big Lift" on the Mcdonald was also essentially a new bridge. They kept the towers, but they refurbished the cables and the deck is entirely new.

They have the option to do the same at the MacKay, but it's likely they'll just build a new bridge next to it and then tear the old one down. The Big Lift cost as much as building a new bridge because of all the logistical complications of working on an active bridge. There's more space at the MacKay so they likely don't need to do that.

I agree, building a new bridge is the better way to go. With volumes of traffic expected to increase dramatically over the coming decades and a third bridge seeming unlikely, putting a cable-stayed 6 lane bridge with a possible LRT line is a good option. Also feel the MacKay Bridge was built kinda cheaply, I could be wrong.

[Phalanx]

I've heard (here or in a news piece) that the MacKay is fine, it was just built exactly to spec so doesn't have much room to grow. When the MacDonald was built, modern suspension bridges were still a relatively new concept, so it was overbuilt for safety purposes, but that meant it could take more upgrades over the years. How true this is I have no idea.

[Saul Goode]

Originally Posted by Phalanx

I've heard (here or in a news piece) that the MacKay is fine, it was just built exactly to spec so doesn't have much room to grow.

I would seriously question your source. The need to replace the MacKay is well documented.

When the MacDonald was built, modern suspension bridges were still a relatively new concept, so it was overbuilt for safety purposes, but that meant it could take more upgrades over the years.

That's simply not accurate. Suspension bridges with spans longer than the Macdonald's had already been around for about a century when it was built. And it's a virtual copy of the Lion's Gate Bridge in Vancouver (designed by the same firm) which preceded it by about 20 years.

[Phalanx]

Originally Posted by Saul Goode

I would seriously question your source. The need to replace the MacKay is well documented.



That's simply not accurate. Suspension bridges with spans longer than the Macdonald's had already been around for about a century when it was built. And it's a virtual copy of the Lion's Gate Bridge in Vancouver (designed by the same firm) which preceded it by about 20 years.

You misinterpret what I wrote. MacKay is at capacity and has no room to handle more because it was built exactly to spec. So yes, it does need to be replaced, it cannot be upgraded.

Also, I specified MODERN suspension bridges... the technology that was used in the MacDonald dates to the 30s/40s.

[swimmer_spe]

Originally Posted by GTG_78

There was nothing simple about refurbishing the Macdonald, and there is a wholly different set of challenges to repairing the MacKay. You don't need to be an engineer or in road construction, but you really need to at least know what the underlying issues are before opining about how simple or difficult something will be.

Simple,as init could remain open while the work was being undertaken, and only closed for the actual work. That is quite easy.

Originally Posted by IanWatson

It's looking like it will very much be a full replacement. The "Big Lift" on the Mcdonald was also essentially a new bridge. They kept the towers, but they refurbished the cables and the deck is entirely new.

They have the option to do the same at the MacKay, but it's likely they'll just build a new bridge next to it and then tear the old one down. The Big Lift cost as much as building a new bridge because of all the logistical complications of working on an active bridge. There's more space at the MacKay so they likely don't need to do that.

So, why not build a new bridge beside it, then redo the current bridge. Have 8 lanes? Kind of like the Burlington Bay Bridge in Hamilton.

[Phalanx]

Originally Posted by swimmer_spe

So, why not build a new bridge beside it, then redo the current bridge. Have 8 lanes? Kind of like the Burlington Bay Bridge in Hamilton.

Adding more lanes to the same geographic location will inevitably lead to more congestion in and around the area. If you want more crossing points, then spread it out a bit, too. Completing the circumferential highway with a tunnel at the south end or similar makes more sense if you want to go to three crossings. All that said, an even better solution is just to give people alternatives to driving in with better/more reliable transit like BRT or even better, rail.

[Saul Goode]

Originally Posted by Phalanx

You misinterpret what I wrote. MacKay is at capacity and has no room to handle more because it was built exactly to spec. So yes, it does need to be replaced, it cannot be upgraded.

The need to replace the MacKay is not a capacity matter. It has to do with the limited lifespan of the structure.

Also, I specified MODERN suspension bridges... the technology that was used in the MacDonald dates to the 30s/40s.

Steel-wire cable suspension bridges - some of them very large - have been around since the latter part of the 19th Century. What "new" technology came into being in the 30s-40s that was applied in the Macdonald (and, presumably, Lion's Gate) bridge such that it was, as you suggest, overbuilt as a precaution?

[Nouvellecosse]

As someone who was here during the MacDonald's "big lift" I can see why that wouldn't be a good option for the MacKay. It was incredibly disruptive with frequent closures over several years. They closed it every weekend from around 7pm Friday to early Monday morning as well as overnight on some other nights. There were several times when delays prevented it from re-opening on time for Monday morning rush and the traffic on the MacKay was backed up all the way past Mic Mac Mall. If that were to happen with a MacKay closure, the traffic would choke all of inner Dartmouth since the MacDonald doesn't have a circ to store any long queues.

In fact that often happened to an extent with the big lift because even with the MacDonald open, things didn't always flow normally. There were lane closures, narrowing, and big bumps that slowed traffic to a crawl so there were queues for over a km up Wyse, Windmill, Victoria Rd. etc. I doubt many people have an appetite for a repeat. Especially since the MacKay is not attractive and not really part of regional heritage in the way that the MacDonald is. Partly because it's newer and partly because it's not really integrated into the urban fabric and therefore the urban identity in the same way.

[Keith P.]

Originally Posted by Nouvellecosse

As someone who was here during the MacDonald's "big lift" I can see why that wouldn't be a good option for the MacKay. It was incredibly disruptive with frequent closures over several years. They closed it every weekend from around 7pm Friday to early Monday morning as well as overnight on some other nights.

Of course over the last couple of years they have fallen into the habit of closing the Macdonald most weekends, or so it seems. It seems to have been closed every weekend this summer for reasons either of maintenance and repair such as this coming weekend and several of the last few as well, or for frivolous reasons like the Natal Day celebrations and other civic/feel-good events. I have a big problem with them closing it for those. It should never be closed except for vital reasons, and those should be done overnight if at all possible.

[Keith P.]

One thing that hit home for me this week on separate occasions was that the Bridge Commission needs to take some responsibility for ensuring traffic flows smoothly across the bridges, which they do not seem to do. The other day I approached the MacKay tolls on my way to Halifax and the rightmost lane was very backed up, almost to the point of being a hazard to traffic. I find it hard to understand why. Did those people want change? What else could put them in that lane? The bridges should no longer accept cash payments. Get a Macpass or if you are from out of town, get a bill (or better yet, just don't worry about that tiny volume of missed revenue).

The same issue also happens on the Macdonald, but the bigger issue there is the total lack of lane discipline as you approach the Dartmouth tolls, where one or two lanes of traffic split into 5. Unfortunately there is no direction offered or required. So if you are in the middle (left) lane heading to Dartmouth that typically backs up at busy times onto the span itself. Oddly enough most of (though not all) that traffic wants to turn left onto Wyse, which is also 2 lanes, yet nobody seems to have thought of having a double-lane left turn at the intersection. Meanwhile the 3 or 4 lanes to the right of that are usually far less congested and exercise no lane discipline at all. Speaking of small-town thinking, this has a great smell of that clinging to it.

[Phalanx]

Originally Posted by Saul Goode

The need to replace the MacKay is not a capacity matter. It has to do with the limited lifespan of the structure.

Found the article...
https://www.cbc.ca/news/canada/nova-scot...cdonald-mckay-plaza-tolls-toll-1.6814240

"The MacKay was built with a different standard back in the '70s," said Wright, explaining that its deck would need to be made thicker. "Macdonald for instance, the bridge is a 14-millimetre deck and current Canadian code would need to see us replace the MacKay Bridge with a 14-millimetre deck."
"Unfortunately the supporting structures, the main cables, the towers, the cable vents are not designed to carry a 14-millimetre deck, so the rehab that we're looking at would need to accommodate that."

According to Wright, that would mean having to hang new, stronger main cables and building additional support towers before any work could begin on replacing the deck.

"That's a pretty significant project," said Wright. "So we also have to look at the other option, which is a replacement altogether of the bridge."
Wright said that may be the less expensive and less intrusive option for those who use the bridges to travel across Halifax harbour.

So take it up with HHB...

Originally Posted by Saul Goode

Steel-wire cable suspension bridges - some of them very large - have been around since the latter part of the 19th Century. What "new" technology came into being in the 30s-40s that was applied in the Macdonald (and, presumably, Lion's Gate) bridge such that it was, as you suggest, overbuilt as a precaution?

Right, and look up the history and development of the Lion's Gate bridge. I never said suspension bridges were new, you're projecting that, I said there were new technologies. Deck construction, cable types, and tower construction have all seen changes an innovation.

https://www.pc.gc.ca/apps/dfhd/page_nhs_eng.aspx?id=11273

Regarding the Lion's Gate Bridge:

Despite its enormous size, the open steelwork of the twin towers and pioneering use of a thin deck gave the structure a light weightless quality that blend well with its picturesque setting. The bridge was remarkable because of its length and the technical innovations in cable use and construction.

As you noted, the MacDonald bridge was built on the same template... But I guess that doesn't count as new enough for you?

...Also keeping in mind that between Lion's Gate and the MacDonald bridges, you also had the Tacoma narrows bridge, which also tried something new to spectacularly horrible results... and caused a lot of re-evaluation and over engineering.

[Saul Goode]

Originally Posted by Phalanx

Found the article...
https://www.cbc.ca/news/canada/nova-scot...cdonald-mckay-plaza-tolls-toll-1.6814240



So take it up with HHB...



Right, and look up the history and development of the Lion's Gate bridge. I never said suspension bridges were new, you're projecting that, I said there were new technologies. Deck construction, cable types, and tower construction have all seen changes an innovation.

https://www.pc.gc.ca/apps/dfhd/page_nhs_eng.aspx?id=11273

Regarding the Lion's Gate Bridge:


As you noted, the MacDonald bridge was built on the same template... But I guess that doesn't count as new enough for you?

...Also keeping in mind that between Lion's Gate and the MacDonald bridges, you also had the Tacoma narrows bridge, which also tried something new to spectacularly horrible results... and caused a lot of re-evaluation and over engineering.

Wow, you're all over the place with this.

Look, you're the one who suggested that the replacement of the MacKay was necessary because of capacity limitations. Your words: "MacKay is at capacity and has no room to handle more because it was built exactly to spec. So yes, it does need to be replaced, it cannot be upgraded."

I responded that it wasn't a capacity problem, but a structural one - which your latest post only confirms. So why on earth would I have to "take it up with HHB"? They and I agree.

As for "new technology", I still haven't seen anything, anywhere (apart from your own assertion) confirming (or even suggesting) that the Macdonald was in any way "overbuilt". Sounds like urban lore to me.

The Tacoma Narrows example is a red herring. The Lion's Gate - of which the Macdonald is a virtual duplicate - preceded it.

[NorthernGreg]

During todays transportation standing committee meeting, Waye Mason asked David Reage about the status of updated fare payment system. As discussed here already, this is now in the hands of Halifax Transit and Masabi to get the project operational. Reage failed to provide an updated timeline for when the upgrade will be complete and said it will ultimately not be this summer as previously stated (who would have thought). Reage noted a meeting that will take place mid September, where he hopes to have an updated timeline to present to council. I smell a 2024 launch

Mason and Reage both mentioned they've been frustrated with the delays and have been receiving email/online complaints regularly. Reage seemed to deflect most of the blame onto Masabi and said he has escalated their case - implying Halifax Transit has done everything they need to do. Whether or not that is the case we don't really know.

[OldDartmouthMark]

Originally Posted by Phalanx

Found the article...
https://www.cbc.ca/news/canada/nova-scot...cdonald-mckay-plaza-tolls-toll-1.6814240


So take it up with HHB...

I posted that same article earlier in this thread, and the points quoted were the argument for replacement vs refurbishing. This is separate from the reason that it has to be done in the first place, which is:

Although still structurally safe, the 51-year-old suspension bridge is nearing the end of its life span.

HHB CEO Steve Snider said right now the orthotropic deck plate on the MacKay is only 9.5 mm thick, which doesn't meet the current minimum code requirement of 14 mm.

“My understanding is steel structures that have continuous loadings on them will experience fatigue and the MacKay Bridge fatigue life for the steel deck, it has a projected finish date,” he told NEWS 95.7 fill-in host Jordi Morgan.

“We will be maintaining that deck, but it gets to the point where it's no longer reasonable to maintain it … so the question is, do we do something like we did on the Macdonald Bridge? Do we replace that deck or do we consider replacing the entire bridge?”

Source

Originally Posted by Phalanx

Right, and look up the history and development of the Lion's Gate bridge. I never said suspension bridges were new, you're projecting that, I said there were new technologies. Deck construction, cable types, and tower construction have all seen changes an innovation.

https://www.pc.gc.ca/apps/dfhd/page_nhs_eng.aspx?id=11273

Regarding the Lion's Gate Bridge:


As you noted, the MacDonald bridge was built on the same template... But I guess that doesn't count as new enough for you?

There was approx 17 years between the Lion's Gate and the Macdonald. Sufficient time to hone the craft of suspension bridge design, if that had been an issue.

FWIW, all engineered structures are designed with a safety factor, i.e. they are "overbuilt" to ensure the safety of the users in the event of unforeseen circumstances. One would have to be privy to the details of the design process and meetings with government officials to determine whether it was built with additional safety factor over and above minimum (which would obviously have a cost associated with it) - but this goes beyond my knowledge of the history and specifics of the Macdonald bridge and engineering standards of the time.

Anecdotally, I was told by an engineering prof many years ago that the loading spec upon which the Macdonald was designed was the equivalent of large, heavy trucks, 3 lanes wide, filling the entire bridge... but it's just anecdotal as I'm not sure if he really knew or was just trying to give us a tangible example of the practical application of safety factors.

Then there are also other factors other than pure static loading. Dynamic factors such as wind speed, varying loading concentrations, etc. all factor into the final design.

Originally Posted by Phalanx

...Also keeping in mind that between Lion's Gate and the MacDonald bridges, you also had the Tacoma narrows bridge, which also tried something new to spectacularly horrible results... and caused a lot of re-evaluation and over engineering.

The failure of the Tacoma Narrows bridge was caused by a natural harmonic resonance that was unwittingly designed into the bridge. When the wind speed was exactly 68 km/h, it set up a resonance that caused the bridge to flutter and ultimately fail with spectacular results. This is very different than 'simply' "overbuilding" as you are suggesting.

Interesting discussion, but it would be nice to get back on the topic of transit...

[Phalanx]

Originally Posted by Saul Goode

Wow, you're all over the place with this.

Look, you're the one who suggested that the replacement of the MacKay was necessary because of capacity limitations. Your words: "MacKay is at capacity and has no room to handle more because it was built exactly to spec. So yes, it does need to be replaced, it cannot be upgraded."

Yes, capacity. As in weight capacity. As in it could not handle additional lanes/structures/etc without effectively rebuilding the whole thing.

Originally Posted by Saul Goode

I responded that it wasn't a capacity problem, but a structural one - which your latest post only confirms. So why on earth would I have to "take it up with HHB"? They and I agree.

And no, you didn't say it was structural, you just said it was a 'lifespan' issue, which is even more open to interpretation.

Originally Posted by Saul Goode

The need to replace the MacKay is not a capacity matter. It has to do with the limited lifespan of the structure.

Originally Posted by Saul Goode

As for "new technology", I still haven't seen anything, anywhere (apart from your own assertion) stating that the Macdonald was in any way "overbuilt". Sounds like urban lore to me.

The implication being that the MacDonald was able to take a 'Big Lift' style project in addition to the pedestrian and bike lanes and suicide prevention fence where the MacKay couldn't without an even more extensive rebuild.

Anyway, I've wasted enough time and I've provided the source for my original assertion. Not going to waste any more time lawyering this with you.

[swimmer_spe]

Originally Posted by Phalanx

Adding more lanes to the same geographic location will inevitably lead to more congestion in and around the area. If you want more crossing points, then spread it out a bit, too. Completing the circumferential highway with a tunnel at the south end or similar makes more sense if you want to go to three crossings. All that said, an even better solution is just to give people alternatives to driving in with better/more reliable transit like BRT or even better, rail.

Well, if a freeway was built from it to the 102, there would not be a problem. And then build a freeway to connect to the future tunnel and finally, Halifax would have done something right with its transportation.

[Empire]

Originally Posted by swimmer_spe

Simple,as init could remain open while the work was being undertaken, and only closed for the actual work. That is quite easy.



So, why not build a new bridge beside it, then redo the current bridge. Have 8 lanes? Kind of like the Burlington Bay Bridge in Hamilton.

Building a new bridge would mean locating it on the north side of the MacKay. The bridge in this location would require stanchions and exit ramps in Africville Park. If you look at the exit ramps for the MacKay they look like they occupy some of the former Africville location so this would be a very difficult sell.