Highway 17 (SFPR) Upgrades

[Klazu]

Originally Posted by Diegotheartist1

the new overpass appears to be very high compared to the old one.

Height is good but it looks like it won't be wide enough to facilitate 3+3 through lanes in the future.

[officedweller]

Originally Posted by madog222

A little update, pictures from November 16.

91 & Nordel

Reminder of the plan:

Originally Posted by gkz

Current plan in more detail:

[gkz]

the new overpass appears to be very high compared to the old one.

Originally Posted by Klazu

Height is good but it looks like it won't be wide enough to facilitate 3+3 through lanes in the future.

I bet this is just preload to squish down the bog. The actual overpass won’t be as tall or narrow.

[Diegotheartist1]

Originally Posted by gkz

I bet this is just preload to squish down the bog. The actual overpass won’t be as tall or narrow.

Oh, I see. The surface is not very solid. That explains why the soil looks taller..

[Bobert]

Was driving through there a few days ago and noticed the soil of the Nordel section is slowly being removed/deconstructed. It's no longer as tall as it was before or the way it looks in these pictures.

[c041v]

Originally Posted by gkz

I bet this is just preload to squish down the bog. The actual overpass won’t be as tall or narrow.

Correct. The clearance envelope will be ~5.5 m

[madog222]

Progress as of 14 April.







Images from BC Moti https://www.flickr.com/photos/tranbc/with/52066980414/

[montyhallgoat]

Highway 91 Connector is now on its final alignment west of the truck scale.
Also, at-grade Hwy 91C/Nordel Way intersection closed last Thursday and the replacement Nordel Way (west) interchange opened Monday morning.

[flipper316]

The stretch east of 136th street where that pipe is is complete. It actually looks pretty nice . Fresh pavement new cats eyes etc . If only they could redo the lane lines and cats eyes for the rest of the road .

[libtard]

For the overpass under construction in the last picture what’s the point of building the support piers right in front of the retaining wall? Could they make the bridge beams slightly longer to rest on the retaining wall? The budget engineering on this project is just crazy. So sad

[officedweller]

I don;t think the retaining walls would be strong enough and having the two separate may allow future widening by pulling the retaining walls back.

[libtard]

Originally Posted by officedweller

I don;t think the retaining walls would be strong enough and having the two separate may allow future widening by pulling the retaining walls back.

Seriously? You’ve never seen an overpass like this? This is in Pennsylvania


Image is not mine, posted by xzmattzx over at https://www.skyscrapercity.com/threads/u...ays-state-highways.605044/post-174275814

This type of set up is everywhere (except the lower mainland).

The overpass in the original post has actually eliminated any type of future expansion by having the support piers right up against the shoulder of the road. Trying to use the space between the retaining wall and the support piers would lead to a bizarre configuration of 2 lanes of traffic going each way and then an extra lane on either side of the support piers? The picture I posted has no support piers so expansion would be seamless by using the space between the shoulder and the retaining wall.

Just hilarious how value engineered this specific overpass is

[VancouverOfTheFuture]

Originally Posted by libtard

Seriously? You’ve never seen an overpass like this? This is in Pennsylvania


Image is not mine, posted by xzmattzx over at https://www.skyscrapercity.com/threads/u...ays-state-highways.605044/post-174275814

This type of set up is everywhere (except the lower mainland).

The overpass in the original post has actually eliminated any type of future expansion by having the support piers right up against the shoulder of the road. Trying to use the space between the retaining wall and the support piers would lead to a bizarre configuration of 2 lanes of traffic going each way and then an extra lane on either side of the support piers? The picture I posted has no support piers so expansion would be seamless by using the space between the shoulder and the retaining wall.

Just hilarious how value engineered this specific overpass is

wasnt this style installed on the improvements on the north shore just last year? isnt there one also on Knight St on the Richmond side?

my favourite overpass structure are the original steel ones for the Upper Levels Highway. they look so sleek.

[Marshal]

Nothing to do with this so called value engineering, nor is it an inferior design. The factor driving this engineering solution is SEISMIC. The main span is independent. The connecting (mini) spans allow movement and in extreme situations can fail, allowing the main structure to survive. The main span is isolated from the retaining system, which, with the fill, is designed for traffic load only. This is smart because because a rigid structural retaining wall design (like the Pennsylvania example) would fail from the lateral forces of a quake which would use the span's beams to shred it (unless it was massively over sized - but then the beams would get crushed). Also, soil berms are incredibly difficult to structure against seismic loads - it is best to design them for an isolated single purpose. Remember, seismic design must succeed across a range of loads and purposes. Life safety is obvious, but in the event that a structure fails you want it to do so in as minor a fashion as possible. If Vancouver is devastated, structures like this will allow for the quickest repair (even if temporary) to use-ability.

This design is 1) used on virtually all new overpasses over the region, and 2) is ingenious if not brilliant.

As for future expansions: in 50 years the whole thing will be demolished, just like the Pennsylvania example will be. What will be needed then is beyond even libtard's crystal ball. It ain't the structural system that will be the limiting factor. Get real.

[Changing City]

Originally Posted by Marshal

Nothing to do with this so called value engineering, nor is it an inferior design. The factor driving this engineering solution is SEISMIC. The main span is independent. The connecting (mini) spans allow movement and in extreme situations can fail, allowing the main structure to survive. The main span is isolated from the retaining system, which, with the fill, is designed for traffic load only. This is smart because because a rigid structural retaining wall design (like the Pennsylvania example) would fail from the lateral forces of a quake which would use the span's beams to shred it (unless it was massively over sized - but then the beams would get crushed). Also, soil berms are incredibly difficult to structure against seismic loads - it is best to design them for an isolated single purpose. Remember, seismic design must succeed across a range of loads and purposes. Life safety is obvious, but in the event that a structure fails you want it to do so in as minor a fashion as possible. If Vancouver is devastated, structures like this will allow for the quickest repair (even if temporary) to use-ability.

This design is 1) used on virtually all new overpasses over the region, and 2) is ingenious if not brilliant.

As for future expansions: in 50 years the whole thing will be demolished, just like the Pennsylvania example will be. What will be needed then is beyond even libtard's crystal ball. It ain't the structural system that will be the limiting factor. Get real.

Thanks for this explanation. I couldn't be bothered to reply because pointing out that having 'extra' columns is one of the strangest definitions of 'value engineering' seemed too obvious. I checked on the seismic risk in Pennsylvania. There isn't much, they don't really have them. (It's the square blue state, top right).


[source NIST]

[officedweller]

Thanks for the explanation Marshal.
That also makes sense as Delta isn't on stable soil.

Originally Posted by VancouverOfTheFuture

my favourite overpass structure are the original steel ones for the Upper Levels Highway. they look so sleek.

Love those!

[libtard]

Originally Posted by Changing City

Thanks for this explanation. I couldn't be bothered to reply because pointing out that having 'extra' columns is one of the strangest definitions of 'value engineering' seemed too obvious. I checked on the seismic risk in Pennsylvania. There isn't much, they don't really have them. (It's the square blue state, top right).


[source NIST]

You can't be serious?

So looking at that drawing, Seattle it seems to be in an even higher hazard zone than the lower mainland.

And this is a recently completed overpass between I-5 and the port of Tacoma. As you can see the quality of the overpass is much higher and its much more aesthetically pleasing. Why didn't they go with the support column garbage on the SFPR? Did they go with a less seismically safe design? Of course not. The retaining wall is engineered strong enough to support those massive beams spanning the entire highway. Which costs more money, hence why the overpass on the SFPR is value engineered. Don't be so foolish
SR 99 roundabout and Wapato Way East Bridge by Washington State Dept of Transportation, on Flickr
SR 99 roundabout and Wapato Way East Bridge by Washington State Dept of Transportation, on Flickr

[chowhou]

Originally Posted by libtard

And this is a recently completed overpass between I-5 and the port of Tacoma. As you can see the quality of the overpass is much higher and its much more aesthetically pleasing. Why didn't they go with the support column garbage on the SFPR? Did they go with a less seismically safe design? Of course not. The retaining wall is engineered strong enough to support those massive beams spanning the entire highway. Which costs more money, hence why the overpass on the SFPR is value engineered. Don't be so foolish

My brother in Christ, the overpass you're putting on a pedestal is constructed in the exact same way. The only difference is the load bearing girders have their fixture points on top of a concrete support pier rather than piles, which is arguably more value engineered than ours considering the surrounding area seems boggy.

You can look and see with your own eyes in your pictures that the bridge surface ends as soon as the girders end on the support piers.

https://www.youtube.com/watch?v=0QBagvwGbt0

[libtard]

Originally Posted by chowhou

My brother in Christ, the overpass you're putting on a pedestal is constructed in the exact same way. The only difference is the load bearing girders have their fixture points on top of a concrete support pier rather than piles, which is arguably more value engineered than ours considering the surrounding area seems boggy.

You can look and see with your own eyes in your pictures that the bridge surface ends as soon as the girders end on the support piers.

https://www.youtube.com/watch?v=0QBagvwGbt0

How is it value engineered when the fit and finish is literally better in every way? The lack of piers right next to the retaining wall and the longer girders. That costs money. If the original overpass in question were built to these standards, so no ugly piers, just girders on reinforced retaining walls, it would have costed more. There is no disputing that. That’s what I mean by value engineering. Shorter girders and exposed piers was the cheaper option. They went the value engineering route. The first response for why they went that route was because “the retaining walls couldn’t support the weight”. Then someone else tried to justify it because we’re in a higher danger zone for earthquakes even though Seattle is in an even worse location. Just stop. Look at the 2 different overpasses in question, one clearly looks better engineered and more aesthetically pleasing. And that one costed more money to build

[Changing City]

Originally Posted by libtard

How is it value engineered when the fit and finish is literally better in every way? The lack of piers right next to the retaining wall and the longer girders. That costs money. If the original overpass in question were built to these standards, so no ugly piers, just girders on reinforced retaining walls, it would have costed more. There is no disputing that. That’s what I mean by value engineering. Shorter girders and exposed piers was the cheaper option. They went the value engineering route. The first response for why they went that route was because “the retaining walls couldn’t support the weight”. Then someone else tried to justify it because we’re in a higher danger zone for earthquakes even though Seattle is in an even worse location. Just stop. Look at the 2 different overpasses in question, one clearly looks better engineered and more aesthetically pleasing. And that one costed more money to build

Er no - you offered an example in Pennsylvania, which clearly has a lower seismic risk and can be designed differently. So you dug around to find an example in Tacoma that had the aesthetics you like (straight retaining walls) rather than the design here (columns, with a retaining wall behind). Now you're arguing that columns must be cheaper than a reinforced retaining wall, with no evidence except your strong conviction, and an innate dislike of columns, it would seem. The column solution may well be related to the soil conditions - the hint is in the name Delta. Either way, if this is what really bothers you, keep hammering the keyboard, if it makes things better to have vented.