Silver Line Dulles WMATA Metrorail progress/pictures

From Dulles Corridor Metrorail Project progress update e-mail 05 12 2010.


Truss erection at the Dulles Connector Road (Route 267) and Chain Bridge Road overpass.
Photo by Stephen Barna, Dulles Corridor Metrorail Project

Building Bridges for Rails in Tysons Corner

Aerial Superstructure Construction Begins

Construction will begin soon on what can best be described as "bridges" over Tysons.

One will begin this month on the Dulles Connector Road (Route 267) and cross over Route 123 to the northwest side of southbound Route 123. Another will cross I-495. Another will be built in the median of Route 7 from just west of Route 123 and into the median of the Dulles Airport Access Highway and the Dulles Toll Road.

These bridges are really guideways, or aerial foundations, to carry the tracks for the Dulles Corridor Metrorail Project.

Construction of the new rail line, an extension of existing Metrorail service from East Falls Church to Dulles Airport and eastern Loudoun County, is being built in two phases. Phase 1 work is well under way from I-66 to Wiehle Avenue in Reston. Four stations will serve Tysons Corner.

The first of those 366-ton trusses is now visible near the Dulles Connector Road and Route 123 where construction of piers that will support the aerial guideways have been built in recent months. Soon it will be used to build the spans of the aerial guideway between those piers. In a few months, other trusses will be assembled to erect guideways that cross I-495 and in the middle of Route 7.


Segments are manufactured off-site at a precast facility near Dulles Airport.
Photo by Dulles Corridor Metrorail Project

Here is a guide to the erection of the spans in Tysons Corner:

Q. What is a guideway?
A. A guideway is a structure that supports trains or other vehicles that ride over it. This project features both at-grade and aerial guideways.

Q. How many miles of this project are aerial guideway?
A. Of the entire Phase 1 alignment of 11.7 miles, three miles of inbound and outbound guideway will be aerial - or a total of six miles of aerial track.

Q. What is the average height of the guideway (from ground level to the base of the guideway)?
A. The average above-ground height is 35.7 feet.

Q. What is the tallest point of the guideway?
A. Approximately 55 feet above the southbound entrance from Route 123 to I-495.

Q. Where will aerial guideway be built?
A. Aerial guideway begins where the new line splits off from the existing WMATA Orange Line tracks just before the West Falls Church Metrorail Station and yard. It will fly over the westbound lanes of I-66 and descend to the median of the Dulles Connector Road (Route 267).

Aerial guideway resumes at the Connector Road near the Chain Bridge Road overpass, then crosses over the eastbound lanes of the Connector Road onto the northwest side of Route 123, and into the Tysons East Station. The rail will continue at elevated level, flying over I-495 and into the Tysons Central 123 Station where the rail line briefly goes underground.

The tunnel portion resurfaces in the median of Route 7, at the Tysons Central 7 Station. From there, the rail line goes aerial again along the median of Route 7 to the Dulles Toll Road. One more flyover takes the guideway westward from Route 7, and the guideway then begins its descent to the median of the Dulles International Airport Access Highway, reaching ground level well before Wolf Trap National Park for the Performing Arts.

Q. How will the aerial structure be built?
A. The guideway will be constructed by connecting more than 2,700 concrete segments, each weighing about 25 to 40 tons, using massive pieces of equipment called trusses. A truss is also known as a lifting gantry.

Q. What is a truss? How much do they weigh? How big are they?
A. A truss, or launching gantry, is a large, rigid structure that will erect and piece together the segments of the aerial guideway. The first truss that will be used has a total weight (structure and supports) of 366 tons.

Q. How many different trusses will be needed for this project?
A. Three.

Q. How and where are they being assembled? How will they be moved along the alignment?
A. Trusses are self-propelling mechanisms that erect spans between each pier. They will be assembled at the locations where the segment erection will begin.

Q. What is a segment? How big are they?
A. A "segment" is a large, unique piece of reinforced precast concrete designed to interlock with other segments to form a "span" between two piers. The segments are held together with steel cables, called post-tensioning strands. Spans make up the guideway.

Q. Where are the segments being made? How many are needed; what is the process?
A. The segments are all being fabricated off-site at a precast facility located in a remote area of Dulles Airport. More than 2,700 segments will be constructed and trucked to sites along the alignment. Each segment is custom engineered to fit a specific location along the alignment.

The casting plant is located on the site of the future Dulles Yard. The future Dulles Yard will be located in the 44300 block of Old Ox Road in Sterling, Virginia.

Q. How are they connected?
A. The truss' lifting mechanisms hoist the segments into place in the alignment, where they are sealed with epoxy, joined and aligned. The spans have steel tendons (post-tensioning strands) running through the interior of each segment that "string" the segments together into place.

Q. How big are the piers that will support the guideway?
A. Piers vary in height; most piers are 6'x7', 7'x7' or 7'x9' rectangular columns.

Q. Who is the subcontractor? Describe their experience building guideways for other transit systems.
A. Rizzani de Eccher, headquartered in Italy, is the subcontractor that is fabricating the precast segments. The aerial team consists of leadership from Dulles Transit Partners (design/build contractor) and Rizzani's U.S. division. This team brings a combined experience of 50-plus years working on worldwide aerial and bridge projects.

Q. Will the work be done at night or during daylight hours?
A. For safety reasons, most of the work will be done during daylight hours, but some work may have to take place at night.

Q. The aerial guideway is being built in a densely populated area where cars and pedestrians are constantly present. What happens when construction is above roads and sidewalks? Will it be safe for cars and pedestrians? What are the safety procedures?
A. Traffic will be stopped momentarily when the truss moves over a roadway in between piers, and when the truss lifts segments from a truck onto its portion of the alignment. In some cases, to ensure everyone's safety, support work will require overnight closures of some main roadways. Contractors must adhere to a formal and extensive safety program while executing this work.

Q. When does the first work begin and where?
A. Construction of caissons, piers and pier caps to support the aerial guideway have been under way for several months and are very visible in the median of the Dulles Connector Road. The superstructure will begin at the Tysons East guideway, at the Dulles Connector Road and Route 123 and move across I-495. Expected completion: Late 2011.

Q. What is the schedule for Route 7 guideway construction?
A. Once the road shift on Route 7 occurs this summer, drilling of caissons (the underground foundations for piers that support the guideway) will follow. Expected completion: Mid-2011.

Q. Cost of the aerial guideway construction?
A. $170 million.


Piers on the Dulles Connector Road. The truss will connect the piers with the aerial guideway.
Photo by Dulles Corridor Metrorail Project

###

PDF version click here (268 KB)

Sand Box John wrote:From Dulles Corridor Metrorail Project progress update e-mail 05 15 2010.

This is the handout we got on Tuesday related to the trusses .

"JackRussell"
This is the handout we got on Tuesday related to the trusses.

You got a hard copy of the monthly update e-mail and PDF before it hit the web. You also posted your response before I corrected the publishing date of the update e-mail and PDF.

I went by today to see what was new. There are now 7 sections lined up on the ground (the 7th isn't in the picture frame).

Sorry for the poor quality - the wife has the "good" camera, so this one was from my phone. Click to enlarge.



A traffic advisory was released:

http://www.dullesmetro.com/pdfs/10MAY14 ... sories.pdf

Conspicuous by its absence is any discussion of lane shifts for westbound Rt 7. I suspect that nothing will happen there in the next few weeks.

VDOT has put the mobile traffic camera back on the westbound shoulder of VA I-66 at Haycock Road. Provided it stays there, one will be able to observe progress in real time the construction of the VA I-66 fly over. If one does a right click > view image (Firefox) one will be able to see a 640 X 480 image. IE users will have to save it.

VDOT also has a camera overlooking the Tyson Central 7 (Pike Seven Plaza) station construction site.

The first span between the piers is up, but it isn't at all where you expected it to be (click to enlarge):



This is along the westbound side of the access road in the area near I-66.

I went by the truss yesterday, and believe it or not there were no noticeable changes since last week.

The Washington Post had a story about the trusses this morning:

Story: http://www.washingtonpost.com/wp-dyn/co ... d=newswell
Graphics: http://www.washingtonpost.com/wp-dyn/co ... 0052203587

A few other random notes:

• I saw them pouring concrete into the cut-and-cover trenches again the other day.
• The preparations for the lane shifts along Rt 7 are still underway. It will probably be at least a few days before they shift however.
• The steel beams over Macgarity Road are up.
• Along westbound I-66, the pier foundations are evidently complete - I see rebar sticking out of the ground now.
• Along eastbound I-66, the pier foundation work is still underway.

Cool.

The precast concrete beam is located between the west abutment and the first column on outbound track N2. It appears that there will be a cast in place trackbed deck poured on top of the precast concrete beam.

This beam is a variation of post-tension type construction. Instead of assembling multiple segments and passing cables through them and applying tension, the cables are placed under tension before the concrete is poured in the casting mold.

The attached graph is an excellent graphic depiction of how the whole process works. There is however an error is the inset map. The inset map does not show the actual location of the where the truss gantry is as described in the Post article.

"JackRussell"
The first span between the piers is up, but it isn't at all where you expected it to be (click to enlarge):




This is along the westbound side of the access road in the area near I-66.[/b]

The precast concrete beam is located between the west abutment and the first column on outbound track N2. It appears that there will be a cast in place trackbed deck poured on top of the precast concrete beam.

This beam is a variation of post-tension type construction. Instead of assembling multiple segments and passing cables through them and applying tension, the cables are placed under tension before the concrete is poured in the casting mold.

The Washington Post had a story about the trusses this morning:

Story: http://www.washingtonpost.com/wp-dyn/co ... d=newswell

Read it.

The article didn't go in very much detail on how this engineering method works. What it did tell us, is the exact amount of segment that will be used (2,763 segments). The monthly up date e-mail said "more than 2,700 concrete segments".

Here are the two photos that are in Post article:


This massive, self-propelled mechanism will be used to assemble hundreds of concrete segments into a rail bridge over the Capital Beltway.
(Jahi Chikwendiu/the Washington Post)


Ivan Nealy, left, and Dick Hanson are among the many workers engaged in rail and highway projects at Tysons Corner, where a bridge, or aerial guideway, is being built to carry Metrorail over the Capital Beltway. The congestion adds complexity and risk to the projects.
(Jahi Chikwendiu The Washington Post)

Both of the above photos were taken during the process of assembling the truss gantry. The truss gantry in the in the first photo is sitting on a temporary scaffolding (end nearest the camera) and the west abutment.

The fully assembled truss gantry was then advanced to the bearing structure seen in the back ground in the second photo.

Graphics: http://www.washingtonpost.com/wp-dyn/co ... 0052203587

The attached graph is an excellent graphic depiction of how the whole process works. There is however an error is the inset map. The inset map does not show the actual location of the where the truss gantry is, as described in the Post article.

A few other random notes:

• I saw them pouring concrete into the cut-and-cover trenches again the other day.
• The preparations for the lane shifts along Rt 7 are still underway. It will probably be at least a few days before they shift however.
• The steel beams over Macgarity Road are up.

Read about that in the e-mail alart.

• Along westbound I-66, the pier foundations are evidently complete - I see rebar sticking out of the ground now.
• Along eastbound I-66, the pier foundation work is still underway.

Saw that when I took pictures on 05 07 2010. Some of that work appear in the photos I took.

The form shown in this photos is scheduled to be set over the eastbound lanes of the Dulles Access Road on the evening of 05 25 2010.

The assembly of the segments has begun. Here is the first section (my camera doesn't do sufficient wide-angle to let me do this in just one picture). There are 14 segments in all that are glued together.







I presume that once this is done, they will shift the truss over and perform the same procedure with the outbound segment.

Over at West Falls Church, they are busy with a number of things. They were driving piles in the foreground (preparing a footing for a pier), and working on the old pier that is in between the orange line tracks.. Also note additional piers that are under construction just to the north of I-66.



Here is a closeup of the activity on the old pier that they are going to use:



I previously had a picture of a pre-cast beam near the West Falls Church station. I had incorrectly stated that it was on the outbound segment - I looked at it again today and it was on the *inbound* segment. There were no noticeable changes since last week however, so I didn't bother to take pictures.

I got a traffic advisory from DTP - the lane shifts along Rt 7 are now scheduled for the evening of June 4 (alternate dates are the evening June 11-12). They have been doing lots of paving, but still have a bit more to do before they will be done.

Cool pictures.

Dulles Corridor metrorail Project added a couple of picture to the server that hosts the images in the e-mail traffic-advisories and updates:


Similar to your pictures above.


Magarity Road span beam installation.

I am going to be out of town for the next couple of weekends, so it might be a few weeks before I get any more pix.

Paving for the Rt 7 lane shifts is essentially complete, and the pavement is striped. As long as it doesn't rain tonight they will do the shifts, and the VDOT camera that Sand Box John pointed out should show the new traffic patterns.

Over at the truss they are now in the process of putting together the outbound segment.

"JackRussell"
Paving for the Rt 7 lane shifts is essentially complete, and the pavement is striped. As long as it doesn't rain tonight they will do the shifts, and the VDOT camera that Sand Box John pointed out should show the new traffic patterns.

The lane shift was done in the early AM Saturday 06 05 2010. Checked the Tyson Central 7 (Pike Seven Plaza) VDOT traffic camera around 2300 Friday night, lane shift had not happened yet.

Stations, Aerial Bridges for Track Under Construction

Truss Building Spans on Dulles Connector Road Toward Route 123


The truss located on the Dulles Connector Road is now in action as it lifts the segments to build the aerial guideway tracks.
Photo by Stephen Barna, Dulles Corridor Metrorail Project

For weeks, a giant yellow and blue truss has been in place along the Dulles Connector Road (Route 267) near Route 123 where the trains will move from the Connector Road to the northwest side of Route 123. That truss weighs about 366 tons and is now being used to lift huge concrete segments into place to make the spans between piers that will create the aerial bridges for support tracks across Tysons Corner. Those piers have been built along Route 123 and in the middle of the Dulles Connector Road.

A different truss will be put into place to build the spans across I-495 starting this fall, and a third truss will be used for aerial spans to be built in the middle of Route 7 in Tysons Corner.


Inside the connected segments being built as part of the aerial guideway.
Photo by Dulles Corridor Metrorail Project

Connecting with Metro's Orange Line

Trains on the Dulles Corridor Metrorail extension will merge with Metro's existing Orange Line just east of the West Falls Church Metrorail Station and use the existing Metrorail tracks to carry passengers all the way to the Stadium Armory Metro Station. That means passengers boarding future trains in Tysons Corner, Reston, Washington Dulles International Airport and Ashburn will not need to transfer to get into downtown Washington.

Building the track connections to make this system work is not easy. For many months crews have been building caissons and piers that will carry the tracks from the new line to the existing Orange Line near I-66 and the Dulles Connector Road. Metro service was disrupted for several weeks so additional piers could be built adjacent to the existing tracks.

Now the construction of the aerial guideway is taking place in that area.


* Precast concrete span beam on aerial guideway in media of Dulles Connector Road north of I-66. (inbound track N1)
Photo by Dulles Corridor Metrorail Project


* Pear construction in median of westbound I-66.
Photo by Dulles Corridor Metrorail Project


Construction at the I-66/Dulles Connector Road interchange, where the new line will merge with the existing Orange Line.
Photo by Dulles Corridor Metrorail Project

Work Beginning on all Five Phase 1 Stations


Construction of the Wiehle Avenue Station in the median of the Dulles Toll Road and Dulles International Airport Access Highway.
Photo by John Odorisio

Construction is now beginning on the Tysons Central 7 Metrorail Station along Route 7 just west of the Route 123 overpass.

The station is being built in the median of Route 7 between SAIC on the north side of the road and the Marshalls Shopping Center on the south. The eastbound lanes of Route 7 from just east of Spring Hill Road to Koons was shifted about 40 feet south in early June to make way for station construction.

In late summer, a similar lane shift will take place on Route 7 between Spring Hill and Tyco Roads to make room for construction of the Tysons West Metrorail Station, also in the median of Route 7.

Construction is already under way on the Tysons East Station on the northwest side of Route 123 at Scotts Crossing Road/Colshire Drive and at the Tysons Central 123 Station, also on the north side of Route 123, near Tysons Galleria and Tysons Corner Center.


Tysons East Station construction progressing on Route 123 near the Colshire Drive intersection.
Photo by Stephen Barna, Dulles Corridor Metrorail Project

Construction of the platform for the Wiehle Avenue Station, the fifth station in Phase 1 of the Dulles Rail Project, has started in the median of the Dulles International Airport Access Highway, just west of the Wiehle Avenue overpass.

By fall, construction of all five of the Phase 1 rail stations will be taking place.

Piers, Piers, Piers

Piers will soon be built in the median of Route 7 and along the median of the Dulles International Airport Access Highway and the Dulles Toll Road just west of Route 7, using the same processes that are being used from I-66 and the Dulles Connector Road and along Route 123.

Utility Relocations Almost Completed in Tysons

During the past several years, crews have relocated and undergrounded 21 different utilities along Routes 7 and 123.

Those relocations are 95 percent complete, and most of the old brown utility poles that lined Route 7 are gone. In place below ground are room-sized manholes and ductbanks where utility operators have pulled and spliced cable that support the demands of the businesses and residents of Tysons Corner. When future expansions and repairs are needed, crews can do that work inside the new manholes without digging up the new roadway.

Moving Along Far Below Tysons Corner

Construction of the outbound and inbound tunnels that will carry tracks to and from Routes 123 and 7 is on schedule.

Miners using the New Austrian Tunneling Method (NATM) have completed more than 1,000 feet of the outbound tunnel and more than 750 feet of the inbound tunnel. Both tunnels are completed below International Drive, one of the busiest thoroughfares in Tysons Corner.

###

* Photo not in newsletter.

June 2010 Newsletter (317 KB PDF file) Text and pictures same as above with the exception of the two picture.

What are those tall skinny poles for in the construction of the Wiehle Station?

Cool update!

Davis

strench707 wrote:What are those tall skinny poles for in the construction of the Wiehle Station?

I believe it to be supports for the mezzanine level. It looks quite a bit different than the picture now - I am not 100% sure what they are doing, but I suspect they may be preparing to pour pieces of the platform proper. Lots of rebar and conduit all over the place.

Many of the DTP pictures seem slightly old to me - I will be back in town this coming weekend, and will try and take some pictures of my own that will show whatever seems to be new and changed.