Chief William Commanda Bridge (former Prince of Wales Bridge)

[acottawa]

Originally Posted by roger1818

I figured it would be at least an order of magnitude more than repairing the existing bridge, which you said was in the tens of millions.

I on't think I would assume retrofitting old infrastructure is cheaper than building new infrastructure, particularly when changing the purpose.

[Acajack]

[QUOTE=lrt's friend;8092906]Maybe I have not used that crossing myself, but there were complaints about the delays in the early days of Rapibus and some of the buses now return to old Gatineau by Pont des Draveurs to reduce the number of bus conflicts at the railway bridge.

Here is a video which suggests a 2.5 to 3 minute crossing cycle, so my estimate of 8 minutes would not be far off expected reality with the POW bridge. https://www.youtube.com/watch?v=Dc6_Fi0qu_E

I think synchronization with bus schedules is being very optimistic. We all know buses don't operate that precisely. Even if we use sensors and cameras, traffic signals will still be used and being STO's main Ottawa terminus as suggested, there will be a lot of buses crossing especially during peak periods. Surely, you are not suggesting service frequency cuts here too to accommodate inadequate infrastructure. How does that benefit the transit rider?[/QUOT<script id="gpt-impl-0.5958016987667496" src="https://securepubads.g.doubleclick.net/gpt/pubads_impl_180.js"></script>E]


I've crossed on the Rapibus' Pont Noir over the Gatineau River numerous times. That video is pretty typical in terms of the wait to get across.

It's worth noting that the bus coming toward you in the video is out of service, and so in a sense this is actually a case of an empty bus delaying an oncoming in-service bus with passengers on it.

I am not aware if STO has a policy on this, though. Presumably out of service buses travelling in the non-peak direction could use the A-50 (Pont des Draveurs) or Alonzo-Wright to get across the river, and not clog up the Pont Noir. Though the west side of the Pont Noir Rapibus bridge is very close to the STO's Hull garage.

[roger1818]

Originally Posted by acottawa

There are two spans, both of which are longer than the Gatineau river.

True, but it wouldn't be that difficult to have the lights on spans synchronized in such a way that the light on the second span will turn green shortly after the bus crosses the first span. One simple way to do that is to have both bridges green for buses going onto the island at the same time and then green for buses going off the island at the same time, though there are probably even better algorithms.

[acottawa]

Originally Posted by roger1818

True, but it wouldn't be that difficult to have the lights on spans synchronized in such a way that the light on the second span will turn green shortly after the bus crosses the first span. One simple way to do that is to have both bridges green for buses going onto the island at the same time and then green for buses going off the island at the same time, though there are probably even better algorithms.

That sounds like the kind of thing that might work in theory, but once one bus is delayed unloading a stroller the whole system gets thrown out of sync. Certainly o-train operations have not been as smooth or fast as predicted by city staff and system you are proposing is way more complicated than that.

[roger1818]

Originally Posted by Acajack

It's worth noting that the bus coming toward you in the video is out of service, and so in a sense this is actually a case of an empty bus delaying an oncoming in-service bus with passengers on it.

I am not aware if STO has a policy on this, though. Presumably out of service buses travelling in the non-peak direction could use the A-50 (Pont des Draveurs) or Alonzo-Wright to get across the river, and not clog up the Pont Noir. Though the west side of the Pont Noir Rapibus bridge is very close to the STO's Hull garage.

It looks like there is lots of room for optimization. It seemed to take a long time for the light to turn green after the bus had cleared. Having bus counters on both sides of the bridge should be able to indicate when all of the buses are off.

Does STO have a GPS system? That could be used to prioritize the signals for buses in service over those out of service. Of course STO may not care as they have to pay both drivers so they won't financially benefit from giving priority to buses in service.

[roger1818]

Originally Posted by acottawa

That sounds like the kind of thing that might work in theory, but once one bus is delayed unloading a stroller the whole system gets thrown out of sync.

I wouldn't expect there to be a stop on Lemieux Island, so I don't know how a delay on either end of the bridge could affect how long it takes to cross the bridge.

[Kitchissippi]

Originally Posted by acottawa

I don't think I would assume retrofitting old infrastructure is cheaper than building new infrastructure, particularly when changing the purpose.

The most difficult thing about this type of bridge is the piers, especially with regards to environmental assessment because of their impact on the river. In the case of the PoW bridge, they already exist.

I think the comparable here was the widening of the Champlain Bridge which is similar in length if not longer. In the late 1990s the NCC replaced the steel girders with concrete spans and a deck twice as wide as the old one, using the same piers with some modifications. The cost was around $30 million then. I could see the same thing being done to the PoW, doing a 2-lane bus bridge + peds/bikes, which would be made suitable for LRT in the future but not necessarily heavy rail.

[Acajack]

Originally Posted by roger1818

It looks like there is lots of room for optimization. It seemed to take a long time for the light to turn green after the bus had cleared. Having bus counters on both sides of the bridge should be able to indicate when all of the buses are off.

Does STO have a GPS system? That could be used to prioritize the signals for buses in service over those out of service. Of course STO may not care as they have to pay both drivers so they won't financially benefit from giving priority to buses in service.

Yes, STO has a pretty good GPS system in fact.

You're quite right that this could be optimized.

[acottawa]

Originally Posted by Kitchissippi

The most difficult thing about this type of bridge is the piers, especially with regards to environmental assessment because of their impact on the river. In the case of the PoW bridge, they already exist.

I think the comparable here was the widening of the Champlain Bridge which is similar in length if not longer. In the late 1990s the NCC replaced the steel girders with concrete spans and a deck twice as wide as the old one, using the same piers with some modifications. The cost was around $30 million then. I could see the same thing being done to the PoW, doing a 2-lane bus bridge + peds/bikes, which would be made suitable for LRT in the future but not necessarily heavy rail.

You certainly don't need water-based piers on any bridge crossing the Ottawa river, bridge technology has improved somewhat since the 1880s. Even if you do require piers in the water, the extra cost for the environmental assessment is not in the hundreds of millions.

[acottawa]

Originally Posted by roger1818

I wouldn't expect there to be a stop on Lemieux Island, so I don't know how a delay on either end of the bridge could affect how long it takes to cross the bridge.

The system you are proposing requires something like this:

Bus A, Bus B and Bus C leave bayview station. These buses have green lights going Northbound. At the same time southbound red light goes on on the Quebec entrance to the bridge area. Southbound buses D, E and F would time their departure from Taché so that they arrive at the bridge say two minutes after A, B and C leave the station. If Bus B is late departing because of stroller problems, it has to wait for A and C (assuming C can get around B) to finish their Northbound trip, then DEF to finish their southbound trip, so B is 4 minutes behind schedule (despite only having a 30 second delay) and no longer in sync for the return trip. This keeps going on and these delays and disruptions multiply until the buses are all out of sync.

[Uhuniau]

Originally Posted by acottawa

You certainly don't need water-based piers on any bridge crossing the Ottawa river, bridge technology has improved somewhat since the 1880s. Even if you do require piers in the water, the extra cost for the environmental assessment is not in the hundreds of millions.

If you want a cost-effective and level bridge crossing the river, you're going to need piers, yes: the channel south of Lemieux Island is 260m wide, and the north channel is 370m.

[acottawa]

Originally Posted by Uhuniau

If you want a cost-effective and level bridge crossing the river, you're going to need piers, yes: the channel south of Lemieux Island is 260m wide, and the north channel is 370m.

If you look at any of the longest bridge articles on wikipedia, the longest spans are well over 370m with various bridge technologies.

[Radster]

So why don't the busses travelling in opposing directions use Lemieux island for passing?

[roger1818]

Originally Posted by acottawa

If you look at any of the longest bridge articles on wikipedia, the longest spans are well over 370m with various bridge technologies.

Yes, it can be done, but engineering costs go way up when you do that. Normally it would be done either as a showcase bridge or when the terrain makes installing piers impractical (or both).

Then of course there is the question of where can we build a new bridge. I can't think of any places downtown for a new bridge unless the line is tunnelled and comes out of the cliff (which would also add to the cost). The would the NCC accept it?

A better option might be to use a different existing crossing (potentially widening or replacing it) that is more centrally located.

[Uhuniau]

Originally Posted by acottawa

If you look at any of the longest bridge articles on wikipedia, the longest spans are well over 370m with various bridge technologies.

Are they level and cheap?

[acottawa]

Originally Posted by Uhuniau

Are they level and cheap?

Hard to tell, so few bridges are built in North America anymore it is hard to get a sense of construction costs. I agree that piers are probably cheaper, I was just making the point that they are not mandatory. They managed to build the Adawe bridge with piers in the water without creating a crisis for the critters in the river.

[acottawa]

Originally Posted by roger1818

Yes, it can be done, but engineering costs go way up when you do that. Normally it would be done either as a showcase bridge or when the terrain makes installing piers impractical (or both).

Then of course there is the question of where can we build a new bridge. I can't think of any places downtown for a new bridge unless the line is tunnelled and comes out of the cliff (which would also add to the cost). The would the NCC accept it?

A better option might be to use a different existing crossing (potentially widening or replacing it) that is more centrally located.

I don't think a new bridge is needed at all. The fundamental problem with inter-provincial transit is not a bridge capacity problem (the bus lanes on the Portage bridge are nowhere near capacity) is that the two cities do not agree on what form rapid transit should take. The push to try to convert a derelict old bridge into a bus bridge or rail bridge seems to be driven more by the fact that it is there rather than any particular need to move passengers at that location.

If the problem you want to address is getting STO buses off of downtown streets (and I am not convinced this is a big problem that needs addressing) then to me some sort of Maisonneuve/Portage/Wellington/Lyon surface LRT would be more in line with where transit users want to go.

If the problem you want to address is the unfilled demand for a link between the Rapibus and Trillium Line (and as I have already stated I am not convinced this demand exists) then building a new bridge (even at the same location) would probably cheaper and would certainly be more beneficial then trying to set up some complicated system of bus timing.

[Kitchissippi]

Originally Posted by acottawa

You certainly don't need water-based piers on any bridge crossing the Ottawa river, bridge technology has improved somewhat since the 1880s. Even if you do require piers in the water, the extra cost for the environmental assessment is not in the hundreds of millions.

My point is that it would be far easier to build a bridge using those existing piers. Even the removal of piers requires environmental consideration since doing so would likely disturb the riverbed, which is why they often leave old piers in place

[Uhuniau]

Originally Posted by acottawa

If the problem you want to address is the unfilled demand for a link between the Rapibus and Trillium Line (and as I have already stated I am not convinced this demand exists) then building a new bridge (even at the same location) would probably cheaper and would certainly be more beneficial then trying to set up some complicated system of bus timing.

The demand for the 2000 O-Train line, the demand for the Corkstown Bridge, and the demand for Adawe, didn't exist, either.

[acottawa]

Originally Posted by Kitchissippi

My point is that it would be far easier to build a bridge using those existing piers. Even the removal of piers requires environmental consideration since doing so would likely disturb the riverbed, which is why they often leave old piers in place

Doesn't it depend on the condition of the piers? Are they structurally sound, do they meet modern standards for earthquakes, etc. If they require significant rehabilitation then it might not be easier.