16km (10 mile) England High Speed 2 (HS2) Chiltern Hills Tunnel

North Portal: (Satellite, nothing shows on the map accessed in May 2024)

South Portal: (Satellite)

This is the longest tunnel on the HS2 route between London and Crewe. "The two TBMs that are being used to create the ‘twin bore’ Chiltern Tunnel were launched in the summer of 2021. TBM Florence completed her drive in February 2024 and TBM Cecilia completed her drive shortly after in March 2024." [hs2]

The tunnel boring began at the south portal, so that is where the TBM's were assembled, the tunnel lining segments were built, and the slurry was processed into chalk cakes. The chalk cakes will be used to create a new chalk grassland.

1:11 video @ 0:07 

Look at all of the rebar it broke through.

1:06 video @ 0:12

The TBM's bored 5.6m (18') diameter tunnels at an average pace of 16m (52') per day with a maximum depth of 80m (262'). The geology varies and includes chalk and flints. [BornToEngineer]

This source specifies a significantly larger diameter.

h2

Mammoet posted three photos with the comment:

🚄 Move3D software makes HS2 tunnel boring machine dismantling more efficient 🚄 

Digital twin proves that a lower capacity crane could do the job just as effectively, despite unknown center of gravity of the cutter head.

Read more: https://mmoet.me/44Ph41L

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Much of the chalk from the spoils is going to be used to transform the construction land scar into a chalk grassland.

Satellite

h2_green_corridor
"Chalk grassland – a type of calcareous grassland – is a habitat of international conservation importance mainly found on limestone and chalk valleys of south-east England and the Isle of Wight. As part of the ambitious scheme, 90 hectares of chalk grassland will be seeded into re-profiled soil layers using the nutrient poor subsoils on the site and mixing these soils with chalk from the tunnelling and recycled concrete and aggregates from construction works. This will sit alongside new areas of woodland, wood pasture and wetlands, including almost 65,000 trees and shrubs of 32 species and nearly 3.5km (nearly 2 miles) of new hedgerows on the western slopes of the valley of River Colne. Lime-rich, but low in nutrients, the thin soil holds little water and heats up quickly. These conditions encourage a huge variety of smaller herbs and wildflowers and over 40 species can be found in one square metre of grassland, including some of the UK’s rarest orchids and invertebrates. Only 700 hectares of chalk grassland exist across the whole of the Chilterns AONB."

A 4:27 video showing not only the inside of the TBM, but also the machine that lays the concrete at the bottom of the tunnel.

Oct 2024 Update: the TBMs are done and they plan to finish the excavation and concrete work "by the end of this year."

0:32 Video

New Video 🎥

Six months on since the historic breakthroughs for HS2’s longest tunnel.

Following the tunnel breakthroughs earlier this year, both Tunnel Boring Machines (TBMs), Florence and Cecilia, have been dismantled to allow for the construction of the north porous portal. This is the part of the tunnel's end that features openings to the outside air along its length.

In addition, teams have been hard at work inside the tunnel, building cross passages, constructing five headhouses above the tunnel shafts, and completing the porous portals at the South Portal.

Watch now 👉 https://youtu.be/FGaUWYZ001o

Black Bayou Bridge and Calcasieu Lock near Lake Charles, LA

Bridge: (Satellite, this is not the one in the photo that was jumped.)

Lock: (Satellite)

I could not find this bridge.

safe_image (source) for 2 Men Dead After Trying To Jump Over Drawbridge With Car: Police
"Black Bayou Bridge in Calcasieu Parish, Louisiana, was closed off to traffic to let a boat sail by, but the passenger left the car and “pushed the gate arm up,” according to a witness. The other person allegedly drove the vehicle under the gate, picked up the passenger and went toward the ramp at the end of the bridge. “After stopping briefly, the driver placed the vehicle in reverse then accelerated forward in an attempt to ‘jump’ the ramp of the bridge,” the statement said. “The vehicle became airborne, landed in the waterway, and sank to the bottom.”"

But the one I did find is noteworthy because it is a swinging pontoon bridge. A street view shows that it has a floating dock at both sides of the navigation channel. So the span must be a floating pontoon bridge.

Street View, Apr 2014

Given that the control tower is north of the floating span, this photo shows that the span swings into the northeast quadrant.

Capt. Hayes, Jan 2018

This satellite image shows the notch into which the span swings and the control arm that swings the span.

Satellite

Charles Reeser, May 2018

Street View, Apr 2014

I wonder how often the lock is used because this satellite image shows that the sector gates are open on both ends of the lock.

Satellite

I noticed the lock wasn't being used when I tried to figure out which direction the Intracoastal Waterway flows here to see if I should label the Grand Lake Swing Bridge as upstream or downstream from the Black Bayou Bridge. Even though the sector gates are open, we can tell that this other pontoon bridge is downstream from the Black Bayou Bridge.

$1.5b Midtown Tunnel Expansion under Elizabeth River between Norfolk and Portsmouth

(Satellite)

7:12 video @ 1:34

1949+2021 Replacement of Bayfield River Bridge in Bayfield, ON

1949: (Historic Bridges)

2021: (Satellite)

This is a rendentaton of the new bridge. Unlike many steel arch bridges that are tied arches, this bridge is a true-arch bridge.

The anchorages are socketed 4m into bedrock. [McIntoshPerry]

11:02 video @ 1:23

The 1949 deck-truss bridge replaced this through-truss bridge.

HistoricBridges

A temporary (a few years) bridge was shoved over the river.

@ 1:42

I thought we lost just a UCEB (Ugly Concrete Eyesore Bridge), but I see the old bridge was a deck truss.

@ 2:08

A big lattice-boom mobile crane was used to lift each of the 120-ton arches into place.

@ 4:03

@ 6:00

Normally, concrete is poured from one end to the other. In this case, they poured from both ends to keep the load on the arches balanced. Note the use of two concrete pump trucks.

@ 8:28

A comment on the video questioned the expense of a temporary bridge. That question makes sense to me given that they had to acquire the land for an alternate route anyhow.

Satellite

The temporary bridge was rented. [ellisdon]

1911-2016 Wagon Wheel Bridge over Des Moines River west of Boone, IA

(Archived Bridge Hunter returned 503; Historic Bridges; HAER; Satellite, the bridge was destroyed by an ice flow in 2016)

The Abandoned Iowa Project posted

The Wagon Wheel Bridge stretched over 700 feet across the Des Moines River west of the city of Boone.

Its construction and design were unique when it was erected in 1909.  Four spans representing two distinctive truss styles imbued the bridge with a distinctive style and unique quality unmatched by other Des Moines River crossings. The Wagon Wheel Bridge was added to the National Register of Historic Places in 1998. Its four spans remained open to traffic until its closure due to damage from the devastating 2008 floods.

 Sadly, the Wagon Wheel Bridge met its demise in Winter of 2016. An ice jam in February caused significant damage to a vital support pillar causing a center span to twist, contort, and collapse downstream later that March. 

The collapse inflicted significant damage to the connecting spans. Renovation became impossible.

The Wagon Wheel Bridge was demolished following a century of service to the surrounding communities. The remaining spans were removed in their entirety that following June.

[There are several comments noting that the wood planks made a lot of noise when a car crossed the bridge.]

Dawn Reitz commented on the above post
My dad on the Wagon Wheel bridge.

Tony Jones commented on the above post
I took this pic on the Ogden side in 2012.

This Flickr photo shows the metal column piers.

"Significance: This bridge is one of the few remaining large-scale wagon trusses in Iowa. A locally important crossing of a major river, it is one of the few multiple span pin-connected Pratt trusses remaining in the state. One of its four spans is a long-span Pennsylvania through truss, an important sub-type of the Pratt truss." [HAER_data]

The bridge in the background was the original C&NW High Level (Kate Shelly) Bridge.

HAER IOWA,8-BOONE.V,2--7
7. ELEVATION, FROM NORTH - Wagon Bridge, Spanning Des Moines River, Boone, Boone County, IA

The middle diagonal members in the middle panel are smaller because they carry a lighter load. And this photo easily confirms that the truss is pin connected.

HAER IOWA,8-BOONE.V,2--5
5. DETAIL OF CONNECTIONS, WEST TRUSS, FROM SOUTHEAST

This view shows how the middle pier got shoved by an ice flow in Feb 2016 and caused a span to fall into the river on Mar 10, 2016.

AmesTrib

American Airlines Flight 191 Disaster on May 25, 1979 at O'Hare

I remember this airline crash. I wonder if the 273-death total (2 on the ground) is still the worst airline accident in the US history. And it would have been a lot worse if it fell on the nearby tank farm or mobile home park. (A comment suggested that the flight crew deliberately brought it down in a vacant area. I don't know if they had enough control to do that.) An engine fell off a DC-10 and severed the hydraulic lines that controlled the flaps. If I remember correctly, there were three hydraulic lines, each for a redundant system. Unfortunately, the lines were next to each other. A lesson learned from this accident is that the different hydraulic lines for the different redundant systems should be routed through different parts of the wing. I remember that the engine fell off because a forklift was incorrectly used when putting the engine back on the plane during a maintenance procedure.

 

Janet Morrow posted
Janet Bausch posted
Remembering American Airlines FLT 191, May 25, 1979.

Andrea Mather four posted four images with the comment: "Today we remember the American Airlines Flight 191 disaster. The lives lost will forever be in our hearts. This was the worst aviation disaster in US history."

Paul Webb shared with the comment: "It was 45 years ago today.✈️😢"

Paul Webb shared with the comment: "It was 45 years ago today.✈️😢"

Paul Webb shared with the comment: "It was 45 years ago today.✈️😢"

Bohdan Gajecky: Years later the final report said that the engine mount was not designed to be removed from the wing, but that the engine was to be removed from the mount.

But, there were fewer bolts holding the mount to the wing than there were holding the engine to the mount, so the maintenance people did what was easier, though fatally wrong.

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1954+2002 I-95 Fuller Warren Bridge over St. Johns River in Jacksonville, FL

(Archived Bridge Hunter; Satellite)

This photo is over a couple of decades old. It looks like today's bridge replaced a trunnion bridge. I wonder how often the old bridge stopped traffic on I-95.

Gregg Welliver posted, cropped
Jacksonville, Florida back in the day, new bridge construction over the St.Johns river@ I-95 looking south, that’s quite a Boom Party going on with The American crane out in front. This is a picture taken from the Facebook Jacksonville history page. Looks like a drawbridge on 95 years ago.

Street View, Apr 2024

roadtraffic-technology
The new bridge is 1.4 mile (2.25km) long. "The main span over the shipping channel is 250ft [76m] with a vertical clearance of 75ft. [23m]"
"The haunched pier segments transition from 120ft [3m] deep at the piers to 80ft [2m] deep at the ends." [I think the units should have been inches instead of feet for the depth of the girders.]

It looks like the traffic was stopped for a sailboat.

roadtraffic-technology

Was the fixed spans of the old bridge a continuous or cantilever design?

roadtraffic-technology

A 12-foot (3.7m) "shared use path" opened in Apr 2023. [news4jax]

Holcim/Dundee Cement

(Satellite)

Street View, Oct 2022

Viv Rivera posted the comment: "Is there anything about the two silos that are there by calumet fisheries? I’d like to tell my kids more about them thanks in advance!"

Steve Malachinski: The silos belonged to a cement company. They received cement by railcar and transferred it into trucks.

[Several comments identified it as the Dundee Cement Company.]

Brian McCafferty: Believe Holcim/Skyway Cement (plant on 103rd Calumet River, west bank) recently owned them. Not sure if they still do.

Dennis DeBruler commented on Brian's comment
 Evidently Holcim does currently own it. That blue truck scale was added since I was last there.  wonder if they receive cement via lake freighter and/or barges because the rail service doesn't look intact. https://maps.app.goo.gl/SKXP5RxGHzbspRSo8

Dennis DeBruler commented on Brian's comment
An Oct 2022 street view caught a truck on that scale https://maps.app.goo.gl/nXVwmnxxGMVbvn6n9 According to other street views, the weeds were cleaned up and the scale added between Jul 2019 and Nov 2021.

1954 95mw Flatiron Power and Pumping Plant near Loveland, CO

(Satellite)

Commissioned in 1954, this 95mw plant has 3 turbines. [gem]

Two of the units generate power and the third unit is 8.5mw pumped storage to Carter Lake. It is part of the Colorado-Big Thompson Project that diverts water from the West Slope to the Colorado plains. It is one of over 100 structures that stretch over 250 miles. [power-technology]

I have not been able to determine the source of the water for the 2 main turbines.

Andy Michel posted 20 photos with the comment: "Got to tour Flatiron Power and Pumping Plant today [May 22, 2024] with our EPTC Class. Very cool tour and equipment."

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