montréal REM (ligne A) - Discussion générale

[Decel]

Pas d’impact pour Québec, persiste la Caisse de dépôt

https://www.lapresse.ca/affaires/2021-06-10/depassements-de-couts-du-rem/pas-d-impact-pour-quebec-persiste-la-caisse-de-depot.php

Citation

Une batterie de tests a déjà eu lieu sur le segment représentatif de la Rive-Sud, et CDPQ Infra vise à reproduire l’exercice d’ici six mois entre Brossard et le centre-ville, jusqu’à la gare Centrale. « Ce sera fait d’ici la fin de l’année ou le début de la prochaine. Notre but, c’est de faire plusieurs tests dans différentes conditions », ajoute Jean-Vincent Lacroix.

 

Citation

Jean-Vincent Lacroix utilise d’ailleurs l’exemple du Canadien de Montréal pour démontrer l’importance de l’automatisation. « Si un match termine tard le soir, et que soudainement plein de gens sortent du Centre Bell, c’est sûr que la fréquence à 22 h, un jeudi soir, elle ne sera pas suffisante. Mais en amont de ça, on va pouvoir augmenter la fréquence des trains, et passer par exemple de cinq minutes à deux minutes 30, voire moins, pour répondre à l’achalandage », illustre-t-il.

 

[champdemars]

Le 2021-06-03 à 21:59, Né entre les rapides a dit :

mais je peux raisonnablement présumer qu'ils étaient (auraient été) constitués de l'un ou l'autre des modes suivants (ou d'une combinaison de ces derniers):

1) automobile personnelle;

2) métro et/ou autobus de la STM et des autres sociétés de transport; 

3) trains de banlieue.

Ou encore, le REM va entraîner une densification urbaine et donc une possibilité d’avoir plus de résidents près du centre et des stations.

Ces résidents peuvent aussi provenir de l’immigration intérieure ou extérieure. Dans ces cas ce n’est pas un transfert modal mais quand même une bonne chose. Le REM aura permis un ralentissement de l’étalement urbain axé sur l’auto. Il pourrait causer un certain étalement urbain mais si cela se fait autour du transport en commun, ça devrait être plutôt positif.

 

[Né entre les rapides]

il y a 7 minutes, champdemars a dit :

Le REM aura permis un ralentissement de l’étalement urbain axé sur l’auto. Il pourrait cause un certain étalement urbain mais si cela se fait autour du transport en commun, ça devrait être plutôt positif.

C'est un argument fort intéressant, dont on constate déjà la validité dans des développements immobiliers denses qui anticipent la mise en service du REM, en particulier à Brossard, et c'est aussi vrai pour certaines stations terminales du métro, notamment Montmorency.  Ces développements denses en banlieue constituent une méthode économique de bénéficier de certains (pas tous) avantages de la vie en ville sans auto.

Par ailleurs, même si ça peut sembler paradoxal que ces stations facilitent aussi la vie des banlieusards des deuxièmes et troisièmes couronnes, il demeure que ces gens n'ont plus/n'auront  plus besoin de venir à Montréal en automobile: ils le feront en TEC à partir d'une station terminale "extérieure".   Pour éviter que cela n'attire d'autres développements dispersés et peu denses, d'autres restrictions, par exemple le zonage agricole, sont susceptibles de les rendre moins attrayants, la rareté des terrains constructibles entraînant un renchérissement de leurs prix.  

 

[Julpyz]

https://montreal.ctvnews.ca/video?clipId=2219536&binId=1.1332485&playlistPageNum=1

 

The chime is just a boring duuuu-doooo.. 

[geraldshaw]

27 minutes ago, Julpyz said:

https://montreal.ctvnews.ca/video?clipId=2219536&binId=1.1332485&playlistPageNum=1

 

The chime is just a boring duuuu-doooo.. 

6 hours ago, Decel said:

Pas d’impact pour Québec, persiste la Caisse de dépôt

https://www.lapresse.ca/affaires/2021-06-10/depassements-de-couts-du-rem/pas-d-impact-pour-quebec-persiste-la-caisse-de-depot.php

 

 

4 hours ago, champdemars said:

Ou encore, le REM va entraîner une densification urbaine et donc une possibilité d’avoir plus de résidents près du centre et des stations.

Ces résidents peuvent aussi provenir de l’immigration intérieure ou extérieure. Dans ces cas ce n’est pas un transfert modal mais quand même une bonne chose. Le REM aura permis un ralentissement de l’étalement urbain axé sur l’auto. Il pourrait causer un certain étalement urbain mais si cela se fait autour du transport en commun, ça devrait être plutôt positif.

 

Breadcrumb Trail Links

Opinion 

 

Columnists

Quebec's misplaced loyalty to concrete, a rigid sponge

Author of the article:

Peter F. Trent  •  Special to Montreal Gazette

Publishing date:

Jun 10, 2021  •  10 hours ago  •  3 minute read  •   Join the conversation

Construction of the REM at Highway 40 in Dollard-des-Ormeaux continues on Thursday March 25, 2021. PHOTO BY DAVE SIDAWAY /Montreal Gazette

Article content

Thanks to the operation of neophilia — the love of novelty — in our society, the allure of newness often stifles caution. For example, when it comes to the Réseau express métropolitain (REM), there has been little public comment on the wisdom of choosing an elevated rail system. Aside from its ugliness, that is.

Now, while elevated rail is new to Montreal, the material selected — reinforced concrete — is certainly not.

Quebec’s civil engineers have bestowed upon concrete a loyalty that, despite a succession of failures, often outlasted the object of their affections. For aboveground road structures, engineers kept returning to their main mistress of materials no matter how often it let them — and taxpayers — down:

The Champlain Bridge was opened in 1962. The deck and its supporting girders used reinforced concrete. Fifty years later, it was clear a new bridge had to be built.

In 1971, Laval’s De la Concorde concrete overpass was completed. It collapsed in 2006, killing five.

Some uses were plain weird. Take concrete sunshades. To help drivers emerging from tunnels adjust to the sun, hundreds of concrete grilles, weighing a tonne each, were suspended over the roadway and held up by 30-tonne concrete beams, one of which collapsed in 2011.

The elevated concrete Turcot Interchange, built in 1967, was riddled with holes, patches and exposed reinforcing when the project to replace it began in 2015. Turcot was sensibly rebuilt on terra firma, using (gasp!) steel beams for overpasses.

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Quebec is littered with such examples. Concrete failure was deemed to be caused by human error (is there any other kind?). Insufficient or misplaced reinforcing was usually blamed.

While concrete is superb in resisting compressive (downward) forces, it is weak when used — as in the above projects — as a solid beam. This is where reinforcing steel comes in: buried in the concrete, it serves as its secret source of strength.

But reinforcing steel has its own vulnerability: it mustn’t be exposed to air or water. Small problem: concrete, which serves as its protective sheath, is permeable. It is a rigid sponge.

Concrete is made by mixing cement powder, sand, gravel and water. Now, to make concrete placeable, a greater quantity of water is needed than the amount needed to react with the cement to make the whole mass harden. This excess water eventually migrates through the concrete and evaporates. The passages the water creates to make good its exit become permanent two-way avenues within the concrete.

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In mild or non-coastal climates, these pores present little difficulty. But freezing cycles can cause sodden pores to burst and concrete to spall. Visiting water (often laced with de-icing salt) can make its way to, and start corroding, the reinforcing steel, which then expands. The concrete fissures from this inside job. In elevated structures, truck (or train) vibrations aggravate matters when things get cracking.

This is how, during Quebec winters, water has the power to weaken concrete and its reinforcing.

Now on to the REM project. While today’s inexplicable infatuation with mid-century modern fashions has yet to die, mimicking elevated concrete expressways when building new rail lines is retrograde. They should be buried.

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That said, the REM’s quality control is exceptional. The reinforced concrete supports for the tracks are made up of a series of hollow shapes called segmental box girders, all of which are made in a factory. Elevated expressways generally used cast-in-place concrete, causing inevitable job-site goof-ups. REM is also using superior concrete. But concrete is still permeable, still a rigid sponge.

While I don’t agree with the claim that the REM elevated structures will last 100 years, I am not suggesting they could self-destruct. I am saying that, with all the staining, patching and repairs of the concrete becoming eventually necessary, if you think they look ugly now — just wait.

Peter F. Trent is a former mayor of Westmount. From 1971 to 1989, he was co-founder and CEO of Plastibeton Inc, a worldwide pioneer in polymer concrete technology.

[andre md]

Le 2021-06-03 à 21:36, crosbyshow a dit :

It is exactly the problem when you start digging...you know when you start but...

$$$$ and timeline is the unknown.

 

Reason when digging under René Levesque would be ..a disaster..

In fact Rem b project could have a lot of problems because there will a tunnel north-south of 8km

The construction industry need a reform. Not enough workers to do the job. We have to get foreign workers . No choice or cost gonna explose for any infrastructure project.

[jesseps]

40 minutes ago, andre md said:

The construction industry need a reform. Not enough workers to do the job. We have to get foreign workers . No choice or cost gonna explose for any infrastructure project.

I was thinking the same thing. More workers, things should go faster. True more hands, means more money to pay out, but I think that is better, compared to having less hands on deck. With less hands on deck, things take more time and inflation kicks in for material.

[trainsforever8]

11 hours ago, Julpyz said:

https://montreal.ctvnews.ca/video?clipId=2219536&binId=1.1332485&playlistPageNum=1

 

The chime is just a boring duuuu-doooo.. 

This is the most underwhelming chime I have ever heard..

[lma13]

On 2021-06-03 at 6:03 PM, SameGuy said:

😳

That’s really not a lot. After they work out the kinks, it should be able to bore 10-30 metres per day. They’re averaging less than 2 m per day.

thats crazy its gonna be already a year since the tbm arrived. What kinks do they still need to work out after a year. At 2m per day thats worse than an haveuse

[lma13]

1 hour ago, andre md said:

The construction industry need a reform. Not enough workers to do the job. We have to get foreign workers . No choice or cost gonna explose for any infrastructure project.

I was working on a major project in montreal and we had significant delays due to labor shortages. We couldnt even get additional workers from ontario because of the rules and laws here.