Engineering Disasters: Sinking Towers, Slippery Bridges, and Sinkholes

The Millennium Tower, a 58-story luxury building in San Francisco, is experiencing a serious engineering issue, causing residents to feel a distinct "sinking" sensation.
Residents, including former resident Frank Jernigan, who bought a 50th-floor apartment in 2011, reported strange occurrences, such as a marble rolling uphill on the floor.
The building's floor was found to be sloping, despite the Earth being round, indicating a significant engineering mistake.
The apartments in the Millennium Tower were sold for around $2 million, with the penthouse priced at $13 million.
San Francisco is known for its iconic landmarks, including the Golden Gate Bridge, street cars, and winding roads, and is often associated with the tech revolution, beaches, and trendy neighborhoods.
The city's engineering feats are often overlooked, but the Millennium Tower's issue is a notable example of a massive engineering mistake.• The Millennium Tower in San Francisco, a 200-meter-tall residential building, was completed in 2008 and has since sunk over 17 inches, with a predicted rate of 2 inches per year.

• The building's foundation consists of a giant reinforced concrete slab resting on around 900 long steel rods called friction piles, which only go down 25 meters, less than halfway to the solid bedrock.

• Engineer Gerald Cauthen explains that the friction between the soil and the steel pile is what holds the pile up, but the Millennium Tower's design may not be enough to counteract the weight of the building.

• The building's original design called for a steel foundation, but it was changed to concrete, which is heavier, and this may have contributed to the sinking.

• Residents have reported a tilting effect, with objects rolling towards the northwest, and some have even moved out due to concerns about the building's stability.

• The tilt is currently at 36 centimeters off kilter, which may not seem like much, but in an active earthquake zone, any imbalance could be disastrous.

• Geologist Dr. Ray Sullivan notes that the tower's location was originally a swamp, and the ground beneath it is not solid, which could also contribute to the sinking.

• Some speculate that a nearby construction project, the Trans Bay Transit Center, may have caused the building to sink and tilt, but experts are divided on the issue.

• Possible solutions to stop the sinking include freezing the ground beneath the building, lopping off 20 stories from the top, or adding longer piles to the foundation, but none of these options are confirmed or feasible.

• The Millennium Tower's problems are not going away anytime soon, and residents are left to wonder if a solution will be found.

• In Venice, Italy, an underwater construction project called MOSE (Modulo Sperimentale Elettromeccanico) is struggling to stay afloat, with a catalog of catastrophes including corrosion, wear, and environmental issues.

• MOSE is a tidal barrier designed to protect Venice from rising sea levels and flooding, but it has been plagued by problems since its conception in the 1980s.

• The project involves placing 78 mobile gates across three inlets, which can be raised to block tidal surges, but the gates have already shown signs of corrosion and wear.

• Environmental issues include the growth of muscles and other sea creatures on the gates, which can cause them to malfunction.

• The project has been delayed numerous times, and its estimated cost has ballooned to 5 billion euros, three times the original estimate.

• Residents are losing confidence in the project, and some argue that the money could be better spent on other solutions to protect Venice.

• In Bilbao, Spain, the Zubizuri Bridge, also known as the White Bridge, has become a construction calamity due to its slippery glass floor.

• The bridge was designed to connect the two halves of the city, but its slope and glass surface make it hazardous, especially when wet.

• Material scientist Gustavo Schwartz measured the slip resistance of the original glass floor and found it to be extremely slippery, with a reading of 205.

• The solution to the problem was to cover the entire surface with black mats, which reduced the slip resistance to 126, making it much safer for pedestrians.

• The Zubizuri Bridge is just one example of a construction project where style and design took precedence over safety and functionality.• A bridge's slippery surface was addressed with non-slip mats, but a glass manufacturing expert suggests using etched glass instead, which is rated for heavy use, has a design that works in all directions, and is scratch-resistant.

• The etched glass would maintain the bridge's beauty and address the slipperiness issue, making it a viable solution.

• In February 2016, a massive sinkhole appeared in the town of Nordhausen, Germany, causing a building to collapse into the ground without warning.

• Local journalist Angelo Glasshagel described the event as "scary and frightening" and "quite spectacular."

• The town of Nordhausen is over 1,000 years old and has a history of sinkholes, with over 10,000 registered cases in the state.

• Geologist Thomas Camera explains that the area is prone to sinkholes due to a seam of anhydrite beneath the hills, which absorbs groundwater and turns into gypsum, eventually dissolving and creating caves.

• The roofs of these caves can collapse, forming sinkholes, and the problem is exacerbated by the fact that the anhydrite is "thirsty" and absorbs water like a sponge.

• Sven Schmidt's engineering team investigates patterns in the area, but even they were surprised by the giant sinkhole, which did not occur in a known sinkhole cluster.

• It was revealed that a similar sinkhole had occurred in the same spot just six years prior, and it was filled in, but not properly addressed.

• The second sinkhole was a surprise, and predicting nature isn't easy, especially when building in a sinkhole hotspot.

• The unstable ground makes investigation and repair dangerous, and it's uncertain how to fix the sinkhole or even estimate the cost.

• The massive size of the sinkhole makes it difficult to fill in, and it may be left to stand as it is for a long time.