Silver Line Dulles WMATA Metrorail progress/pictures

[JackRussell]

A couple of pictures (click on them for full-sized images). First at Wiehle Ave:



Sorry for the poor quality of this one - I got all the way out there to discover that the battery on the camera was dead. So I had to take this one with my phone . You can see the concrete posts that I believe will be the supports for the roof over the platform. It doesn't look like they have poured any concrete for the platform yet.

At Chain Bridge Rd and the Toll Road Extension (Chain Bridge Rd != Rt 123 here), I saw this structure having been constructed that is described as a truss. I went back today with a fully-charged camera to take this picture:



From last month's status report:

A large truss will be assembled at the Dulles Connector Road bridge over Old Chain Bridge Road. This is a very large, rigid structure that will be used to build the elevated track. It will start at the abutment and piers that are under construction where the Dulles Connector Road runs over Old Chain Bridge Road.

When they said the thing was very large, it didn't really dawn on my exactly how large they meant - I would call them huge, really. When I first saw the things it was a sort of "Holy C**p moment".

There are concrete piers appearing up and down the length of Rt 123 now in various stages of construction. Some of them just have the foundation and nothing sticking out of the ground yet. Others are nearly complete and ready for elevated track. I haven't yet found a good place to take a picture that lets you see the whole thing.

At the site of the cut-and-cover tunnel, I have seen concrete pumpers on-site for the first time. I looked around for a good spot to take a picture, but I couldn't find anything really suitable - it still looks like a pair of trenches.

Along I-66 they are starting work on the piers that will be needed to get the track up-and-over the west-bound lanes. Mostly foundations at this point as there weren't any piers sticking out of the ground yet, but there is a large rebar cage lying on the ground that will presumably be used soon. This photo also came from my phone:

[JackRussell]

I was curious as to how exactly this truss is to be used, and I found an online reference which explains how it all works:

http://www.arema.org/eseries/scriptcont ... s/0022.pdf

See photos starting on page 17. Some of the photos are for WMATA construction over Suitland Parkway. The elevated rail sections would be hoisted by crane and set on top of the two long bars - they would then be fastened together (post-tensioned), and when the entire span is complete, evidently the truss would be lowered a bit to set the section on top of the piers, and then the truss would be moved so that the next section can be assembled.

Edit: Here are a couple more photos of the truss assembly. This thing seems significant enough that it was worth posting the other pictures..

[Sand Box John]

"JackRussell"
A couple of pictures (click on them for full-sized images). First at Wiehle Ave:



Sorry for the poor quality of this one - I got all the way out there to discover that the battery on the camera was dead. So I had to take this one with my phone :( . You can see the concrete posts that I believe will be the supports for the roof over the platform. It doesn't look like they have poured any concrete for the platform yet.

Actually those columns will support the mezzanine above the platform. 2 rows of 7, 14 columns total. The east end of the platform will be 33' 4" east of the center line of the pair of finished columns nearest the camera.

At Chain Bridge Rd and the Toll Road Extension (Chain Bridge Rd != Rt 123 here), I saw this structure having been constructed that is described as a truss. I went back today with a fully-charged camera to take this picture:



From last month's status report:

A large truss will be assembled at the Dulles Connector Road bridge over Old Chain Bridge Road. This is a very large, rigid structure that will be used to build the elevated track. It will start at the abutment and piers that are under construction where the Dulles Connector Road runs over Old Chain Bridge Road.

When they said the thing was very large, it didn't really dawn on my exactly how large they meant - I would call them huge, really. When I first saw the things it was a sort of "Holy C**p moment".

There are concrete piers appearing up and down the length of Rt 123 now in various stages of construction. Some of them just have the foundation and nothing sticking out of the ground yet. Others are nearly complete and ready for elevated track. I haven't yet found a good place to take a picture that lets you see the whole thing.

The Jig Is Up !!

I watched the contractor build the postension spans along the Suitland Parkway when I lived in Calvert County. The truss as you call it, in the case of the southern F Route Green line, had the postension segments resting on top of a box truss. The ends of the truss were supported by a temporary scaffolding surrounding the columns. When the span was completed the truss was moved to the temporary scaffolding surrounding the next column. Each span took about two weeks to assemble.

Figure 11 PDF Page 26 in the PDF file linked above is incorrectly labeled, (Greenbelt Parkway). The elavated in that photo is passing over Chillum Road in Hyattsville south of the West Hyattsville station.

[Sand Box John]

From Dulles Corridor Metrorail Project progress update e-mail 04 23 2010


Retaining walls on Route 7, necessary to build up the service roads to the same grade as Route 7 for lane shifting.
Photo by Stephen Barna, Dulles Corridor Metrorail Project

Visible Construction to Take Place Along Corridor

Major Rail Construction About to Take Place Along the Mile-Long Stretch of Route 7 Between Route 123 and the Dulles Toll Road

Residents and commuters must be constantly alert for changing traffic patterns and construction equipment.

Most of the service roads that had been on both sides of Route 7 have been closed. Most of the mid-block left turns have been or will soon be eliminated.

By the end of summer, both the Tysons Central 7 and the Tysons West Metrorail stations will be under construction.

Route 7 will be widened to accommodate those stations in its median.

Along portions of the eastbound lanes, crews are building retaining walls to support the elevations of the old service roads to the same levels as Route 7. This will create space to push those lanes to make room not only for the major shift in traffic lanes but to create construction staging areas for those stations. Rail officials have been working with owners of all affected properties for many months.

Construction of the westbound end of the tunnel that will carry trains from Route 123 to Route 7 is well under way next to Route 123 and on the north side of Route 7 near the landmark water and communications towers.

Throughout construction, entrances to all businesses will be maintained.

Rail project officials will continue to work with businesses to keep them informed as construction ramps up.


Route 7 retaining wall construction under way near the future Tysons Central 7 Metro Station.
Photo by Stephen Barna, Dulles Corridor Metrorail Project

Truss Moving Into Place for Erection of Aerial Guideway Spans Along Dulles Connector Road

Drivers in Tysons Corner will soon be looking up and seeing big equipment in the sky when crews begin construction of the aerial guideway that will carry Metrorail trains along portions of Routes 123 and 7 and the Dulles Connector Road (Route 267).

Huge pieces of equipment, known as trusses, will be used to lift large concrete segments into the air to create several miles of the aerial guideway spans in Tysons Corner.

The first truss is being put into place along the Dulles Connector Road overpass of Chain Bridge Road where the first part of the aerial system will be built. Not only will this work be eye-catching and create gawking, it requires closing one lane of Chain Bridge Road from time to time. Flagmen will be at the site to direct traffic. Drivers and pedestrians are encouraged to use extreme caution in this area during the coming months.

Aerial construction will soon take place at other locations along Routes 123 and 7


The first guideway span erection, taking place on the Dulles Connector Road at the Chain Bridge Road overpass.
Photo by Stephen Barna, Dulles Corridor Metrorail Project

Tysons Central 123 Station Under Construction

Foundations are now being built for the Tysons Central 123 Station. It will serve Tysons Corner Center and Tysons Galleria. This will be the busiest station in Phase 1 of the project.

The left-turn lane from northbound Route 123 to westbound Tysons Boulevard will be closed for approximately two months starting in the overnight hours of Friday, April 30 for caisson and pier installation. Traffic will be detoured to International and Galleria Drives. Southbound Route 123 traffic will continue to make right turns to Tysons Boulevard.


The Tysons Central 123 Metrorail Station construction is beginning, at the Route 123 and Tysons Boulevard intersection.
Photo by Dulles Corridor Metrorail Project

Wiehle Avenue Station Construction Begins

The Wiehle Avenue Station is in the median of the Dulles Toll Road and the Dulles International Airport Access Highway on the eastern edge of Reston. The station platform is being built with caissons.

Work will begin soon on the pedestrian bridges from the station to the north and south sides of the Dulles Toll Road.


Caissons under construction for the foundations of the Wiehle Avenue Metro Station site.
Photo by Dulles Corridor Metrorail Project

Free Mid-Day Shuttle Buses Provide Easy Way to Move In and Around Tysons

The weather outside is delightful for taking a bus ride! Especially if the ride is free and gets you through mid-day traffic without having to drive.

The Tysons Connector buses, clad in orange and blue, provide that opportunity to those who work and live in the core of Tysons Corner on weekdays.

Funded by the Dulles Corridor Metrorail Project and operated by the Fairfax County Connector, the free buses run every 10 minutes weekdays from 10 a.m. to 2:30 p.m. and stop at key locations throughout the heart of Tysons Corner, including Tysons Corner Center and Tysons Galleria. For information about stops, click here.

In addition, in June, the Rail Project is paying for new express buses from Loudoun County to several locations near major businesses in Tysons Corner. Details can be found here.

These services are part of the Rail Project's efforts to ease congestion in Tysons Corner.


Free buses run every 10 minutes in the core of Tysons during mid-day hours.
Photo courtesy of Fairfax County DOT

[Sand Box John]

Went out to check the progress and take pictures 05 08 2010. Pictures to come later.

Footers and pier caps for the columns that will be in the VA I-66 median are well under way. Looks like they are utilizing at least some of the the pier caps that were put in when VA I-66 was originally built in late 1970s.

The column stub between tracks K1 and K3 shows evidence that is has been load tested.

Shoring for the Falls Church Yard lead tunnel is evident in the median of the Dulles Connector Road VA-267.

The trackbed slab has been poured in the outbound track N2 cut and cover tunnel at Leesburg Pike and Dolly Madison Boulevard, the invert slab has been poured that will be under the trackbed slab in the adjacent inbound track N1 cut and cover tunnel. Looks like there will be a fan shaft with an emergence exit at the east end of the cut and cover tunnel.

JackRussell,
The truss to assemble for the concrete postension segment spans at Chain Bridge Road is fully complete. The first concrete segment was attached to the hoist on the traveling crane mounted on top of the two parallel trusses. The completed rig is bigger then what was shown in the photo you posted. This thing is ginormous. The $64.00 question is, will the contractor[s] use other similar rigs at the same time at other locations along the line or will this one rig be used to do the whole project.

Still a lot of prep work taking place along Leesburg Pike.

Mezzanine columns up at Wiehle Avenue are up.

[JackRussell]

Went out to check the progress and take pictures 05 08 2010. Pictures to come later.

I was driving around Saturday morning, and I saw someone with a camera peering into the cut-and-cover trenches around 11:30AM. Was that you by any chance? I wasn't in a good place to stop/park and walk over, and at the time I was thinking to myself "Naah, can't be".

The truss to assemble for the concrete postension segment spans at Chain Bridge Road is fully complete. The first concrete segment was attached to the hoist on the traveling crane mounted on top of the two parallel trusses. The completed rig is bigger then what was shown in the photo you posted. This thing is ginormous. The $64.00 question is, will the contractor[s] use other similar rigs at the same time at other locations along the line or will this one rig be used to do the whole project.

Yes, I usually swing past the thing on Saturday mornings to see what if anything is new. They finished assembling the thing about a week after I took the previous pictures, and my quick impression yesterday was that nothing had changed - I didn't notice the concrete segment attached to the hoist however, if I had pulled off onto the shoulder I certainly would have seen it. The truss is large enough that it is actually kind of tough for me to photograph from the side - I would want to back up a ways so I could get the whole thing in the frame. It isn't obvious to me how they will use this - they are still working on some of the piers just to the west, and the track ought to be at ground level to the east.

They hung new temporary traffic signals at Rt 7 and Gosnell Rd this week. They are temporary in that that they are attached to wooden utility poles, and the cabling for the signals is attached to the utility poles with duct-tape. The curbs over there are in, but no asphalt yet - lane shifts could come within weeks, I suppose. My *guess* is that they will also shift the westbound lanes which will let them extend the cut-and-cover tunnels a bit further out, but that's just a guess..

DTP is having an info meeting for locals this coming week, and I can ask some of these other questions. Hopefully there will be someone with some engineering knowledge .

[Sand Box John]

Pictures of postension assemble truss rig 05 08 2010:

The assemble truss rig can move laterally to allow the assemble of segments for each of the parallel spans. The truss rig is presently located above where the inbound track N1 span will be.


The near end is the sitting on the abutment.


First segment attach to hoist.


This one gives you a sense of scale.








This one was taken from Chain Bridge Road.

The reason why I did not post pictures with the earlier post is because I inadvertently removed the memory card from my camera before turning the camera off. Was able to recover all of the images from the card but one.

Reminder do not remove memory card from camera when camera is still turned on.

More to come.

[JackRussell]

Grab yourself a cuppa coffee - this is going to be a long one. DTP had a meeting tonight for locals who are interested - mainly to fill us in on current progress. Marcia McAllister was the presenter.

Let's start with the tunnels. They are currently about 830 feet into the westbound tunnel, and about 630 feet into the inbound tunnel. They don't plan to do any lining of the tunnel until the mining phase of the project is complete. I asked about completion of the tunnels, and they are looking at a 2013 completion date, so there is a lot of stuff that still needs to happen once they have the basic tunnel cavity complete. It is actually important that the two tunnels be staggered like this - there would be a greater risk of subsidence if the two tunnels were not staggered like this.

As has been noted before, they are fabricating the aerial segments at a site somewhere out near Dulles Airport. There will be a total of about 2700 segments that will be needed for this project - 375 have now been fabricated.

The truss. The one that they now have up is 244 ft long, and weights 366 tons. They will actually start raising segments next week (earlier they had suggested that after truss assembly some amount of testing would need to be completed, and evidently the one segment that is in Sand Box John's photo was there for them to test the cranes). The Washington Post will have a story with some graphics in a few weeks that shows how all it all works.

They will ultimately use 3 different trusses for construction. The 2nd truss will be used to build the aerial segment over the beltway, and the 3rd truss will be used along Rt 7. The aerial segment that crosses Rt 66 will be built using a different construction technique that doesn't involve a truss - much more like traditional bridge building. I don't know why they are using a different construction technique there.

I have a handout related to the trusses - it looks like the sort of thing that you ought to be able to find on the website, but I don't see it there yet.

This led to an important point. Metro will be closing the Orange Line between East and West Falls Church stations over Memorial Day weekend, and the 1st 2 weekends in June:

http://www.wmata.com/about_metro/news/P ... aseID=4424

During the three-day project, the Dulles Corridor Metrorail Project will perform construction on a pier located east of the West Falls Church-VT/UVA Metrorail station, drive piles outside of the right-of-way fence along the I-66 west and eastbound lanes and replace ties on the tracks. All of this work is necessary to connect the new rail line to the Orange Line.

Sometime between May 21 and May 27, the lanes will shift on Rt 7 near where the cut-and-cover tunnel comes out. As soon as this happens, construction of the "Tysons Central 7" station will begin. In early August, the lanes will shift on Rt 7 in the Tysons West area, and station construction will begin there immediately afterwards. In the August/September timeframe, we will see piers appear in the middle of Rt 7.

In the May/June/July timeframe (possibly slipped a few weeks from this), piers will be constructed in the DIAAH median. There may be some pile driving during this phase of construction, which obviously is going to be a concern for some people. They are clearly constrained by Fairfax County noise ordinances (7AM to sundown), but they are also someone constrained in that they cannot drive piles while performances at WolfTrap are taking place (WolfTrap asked that construction stop by 2PM on days of performances - but it didn't sound like they were willing to go that far).

The next 18 months are going to be the period of greatest construction activity.

Phase II (from Wiehle to the Airport and beyond) is in the preliminary engineering phase - that will conclude in March 2011. Planned completion is still 2016, so this thread still has lots of life in it.

That's as much as I can remember, and as much as I wrote down. If there is something else you want to know, feel free to ask me. I might have the answer .

[strench707]

Does it sound like when they shut down the orange line they will add the switches on the exsisting mainline to provide access to the silver line or will that be at a later date. I only ask because they say they will be doing "tie replacement" which is concerned with the process of adding a switch to some effect.

Davis

[JackRussell]

Does it sound like when they shut down the orange line they will add the switches on the exsisting mainline to provide access to the silver line or will that be at a later date. I only ask because they say they will be doing "tie replacement" which is concerned with the process of adding a switch to some effect.

Davis

They didn't say, and I didn't think to ask. That's only a few weeks away, and when they are done it will be obvious if they did or not.

The old pier between the two tracks is something else that they could be working on - I suspect the need for that is sooner rather than later.

[Sand Box John]

"JackRussell"
Sometime between May 21 and May 27, the lanes will shift on Rt 7 near where the cut-and-cover tunnel comes out. As soon as this happens, construction of the "Tysons Central 7" station will begin. In early August, the lanes will shift on Rt 7 in the Tysons West area, and station construction will begin there immediately afterwards. In the August/September timeframe, we will see piers appear in the middle of Rt 7.

Does this entail moving the westbound lanes of Leesburg Pike over the back filled cut and cover trenches to allow excavation of the remainder of the cut and cover tunnels to the east end of the Tysons Central 7 (Pike Seven Plaza) station? The construction of the tunnel boxes should happen pretty quickly as the inverts slabs are poured along the length of both trenches.


Trackbed slab outbound track N2. The dark area at the far end trench is the shadow of the forms for the walls and roof of the tunnel.


Invert slab under trackbed slab inbound track N1.

In the May/June/July timeframe (possibly slipped a few weeks from this), piers will be constructed in the DIAAH median. There may be some pile driving during this phase of construction, which obviously is going to be a concern for some people. They are clearly constrained by Fairfax County noise ordinances (7AM to sundown), but they are also someone constrained in that they cannot drive piles while performances at WolfTrap are taking place (WolfTrap asked that construction stop by 2PM on days of performances - but it didn't sound like they were willing to go that far).

I don't see noise being an issue as Wolf Trap is some distance from the Leesburg Pike VA-7 Dulles Access Road / Dulles Toll Road VA-267 interchange.

"strench707"
Does it sound like when they shut down the orange line they will add the switches on the exsisting mainline to provide access to the silver line or will that be at a later date. I only ask because they say they will be doing "tie replacement" which is concerned with the process of adding a switch to some effect.

No. The work on the three weekends is related to the construction of the columns that will carry the inbound track N1 over the existing K route tracks.

There is a lot of ground work at the future location of the junction that need to be done before 'switches' turnouts can be installed. None of that ground work has been done, as a matter of a fact the ground work has not even begun.

The ground work intails the instalation of third rail conduits between the existing Great Falls Street traction power substation and the future junction turnouts, third rail conduits at the future double crossover east of junction, Instalation of communacation conduits between the future train control room that will be built adjcent to the Great Falls Street traction power substation and the new double crossover and junction.


The bump outs in the security fence under Haycock Road is where the original N route junction was planed to be built. As stated above the the Junction will be under Great Fall Street.

[JackRussell]

Does this entail moving the westbound lanes of Leesburg Pike over the back filled cut and cover trenches to allow excavation of the remainder of the cut and cover tunnels to the east end of the Tysons Central 7 (Pike Seven Plaza) station? The construction of the tunnel boxes should happen pretty quickly as the inverts slabs are poured along the length of both trenches.

I asked and I didn't get a clear answer. She started to answer, and then an engineer present correctly noted that I was asking about whether there would be a lane shift during the construction process and that I wasn't inquiring about the final alignment of the road. I was then told the lane shifts would happen all at one time.

If they planned to cover the tunnels and then pave, they still have a lot of work to do, and I have trouble seeing how they can get it all done in time. Not only do they need the walls and roof, but imagine they then need to remove all of the shoring and timbers that they had in place to dig the trench in the first place (or do they just leave those and cover them over??). Then they need to bring in fill dirt and properly compact it, and finally pave (assuming there are no storm drains that need to be installed).

Still, it seems logical that they would eventually need to make such a shift, and sooner would be better than later. When I go out this coming weekend, I will take a close look to see if it looks like they are preparing to cover the tunnels that they have so far.

I suppose it is possible that they could use steel beams to make a temporary cover over the tunnels which would accommodate a lane shift. But if they did this, they would eventually need to remove the temporary cover which would entail more lane shifts.

I don't see noise being an issue as Wolf Trap is some distance from the Leesburg Pike VA-7 Dulles Access Road / Dulles Toll Road VA-267 interchange.

The noise from pile driving carries a considerable distance. When I was a kid they were driving piles to build a nearby interstate, so I have some first hand knowledge about how annoying it is.

No. The work on the three weekends is related to the construction of the columns that will carry the inbound track N1 over the existing K route tracks.

That makes sense - any tie replacement would then be routine maintenance that they scheduled to be done at the same time that the work on the columns is taking place. In your photos, there are extra ties lying on the ground next to the rails - is it possible that these are the new ties that they have pre-positioned to be ready for the tie replacement?

[Sand Box John]

"JackRussell"
If they planned to cover the tunnels and then pave, they still have a lot of work to do, and I have trouble seeing how they can get it all done in time. Not only do they need the walls and roof, but imagine they then need to remove all of the shoring and timbers that they had in place to dig the trench in the first place (or do they just leave those and cover them over??). Then they need to bring in fill dirt and properly compact it, and finally pave (assuming there are no storm drains that need to be installed).

Common practice is, struts and whalers are removed shoring piles are cut off a couple feet below finished surface timbers are left in place. Any utility lines that cross the excavation are rebuilt if necessary.

Still, it seems logical that they would eventually need to make such a shift, and sooner would be better than later. When I go out this coming weekend, I will take a close look to see if it looks like they are preparing to cover the tunnels that they have so far.

I suppose it is possible that they could use steel beams to make a temporary cover over the tunnels which would accommodate a lane shift. But if they did this, they would eventually need to remove the temporary cover which would entail more lane shifts.

There is no way they can finish the tunnel boxes and back fill the excavation by May 21. I must have miss interpenetrated the purpose and location of the lane shifts. My guess is, they will the do short term closures of westbound Leesburg Pike VA-7 to allow the driving of shoring piles, deck over the excavation, and do the tunnel construction.

The noise from pile driving carries a considerable distance. When I was a kid they were driving piles to build a nearby interstate, so I have some first hand knowledge about how annoying it is.

My experience with pile driving is in an urban environment. Noise doesn't carry as far in the presents of buildings and urban background noise.

That makes sense - any tie replacement would then be routine maintenance that they scheduled to be done at the same time that the work on the columns is taking place. In your photos, there are extra ties lying on the ground next to the rails - is it possible that these are the new ties that they have pre-positioned to be ready for the tie replacement?

Hadn't noticed the ties, likely yes. When I was taking picture from Haycock Road I noticed the track was about 90% spikes and plates instead of the more modern E clips. The rail through area is likely 15 or more years old.

[JackRussell]

There is no way they can finish the tunnel boxes and back fill the excavation by May 21. I must have miss interpenetrated the purpose and location of the lane shifts. My guess is, they will the do short term closures of westbound Leesburg Pike VA-7 to allow the driving of shoring piles, deck over the excavation, and do the tunnel construction.

The main lane shifts they were discussing are in the East-bound lanes, and that should open up enough space for them to start station construction. The slides they showed leave the west-bound lanes in their original locations once the project is complete - the only question that we seem to have is how they are going to extend the cut-and-cover tunnels out into the median strip.

[Sand Box John]

"JackRussell"
The main lane shifts they were discussing are in the East-bound lanes, and that should open up enough space for them to start station construction. The slides they showed leave the west-bound lanes in their original locations once the project is complete - the only question that we seem to have is how they are going to extend the cut-and-cover tunnels out into the median strip.

"Sand Box John"
My guess is, they will the do short term closures of westbound Leesburg Pike VA-7 to allow the driving of shoring piles, deck over the excavation, and do the tunnel construction.

Two possible scenarios. Temporary shoe fly over tunnels that are presently under construction (lane shift to happen at a later date) or what I described above.