Most Expensive Construction Project Mistakes in the World. 2022-23
From horrible engineering flaws that led to tragic bridge collapses to windows crashing down from skyscrapers, here is our fourth part of the most expensive construction mistakes in the world. We begin with Number 4: The horrific Mississippi Bridge Collapse Bridge collapses can be the most devastating incidents of infrastructure failure.
They are often the result of engineering and construction flaws or lack of maintenance. In this case, both reasons probably played a big role in the disaster. On Aug. 1, 2007, the so-called I-35W Mississippi River bridge collapsed into the Mississippi after 40 years of operations.
More than a hundred cars and 18 construction workers plunged 40 meters into the river. The disaster that remains one of the biggest tragedies in Minnesota killed 13 people and injured another 145. The collapse started when the center span suddenly started to crumble followed by other sections of the bridge. In the aftermath of the incident, many issues about the bridge came to light.
The eight-lane structure had already been classified as structurally deficient meaning that it was in desperate need of repairs. However, it was found that the bridge could still have survived if not for one other critical design flaw.
The installed gusset plates, which join different beams and sections of the bridge, were found to be only half as thick as required. In addition, the investigation also found that nearly 300 tons of construction equipment were on the extension at the hour of breakdown.
This along with the rush hour traffic strained the structure further and the thin gusset plates could not hold the bridge together any longer. The findings of the investigation were followed by multiple lawsuits and $52 million was paid to the victims of the bridge collapse.
To make sure this tragic collapse doesn’t happen to other bridges, the Minnesota legislature raised $2.5 billion for a bridge improvement program. Close to 250 million dollars out of that fund was set aside for contracts to rebuild the bridge. Do you know of other massive construction mistakes in your country?
Number 3: AON Center skyscraper
Number 3: The skyscraper that almost caused a tragedy Constructed in the 1970s for around 120 million dollars the AON Center was the tallest building in Chicago.
But not only the height of 346 meters impressive at the time. Also, its facade consisting of Italian marble slabs gave the AON Center a unique appearance. However later on this unique marble proved to be a very costly and dangerous mistake.
It was soon found out that the marble slabs were too thin and started cracking right after they were attached to the facade. Just weeks after the tower’s opening, one of its shaky marble blocks loosened from the facade and fell.
The falling block weighed about 160 kilograms or the weight of a full-grown lion and crashed into the roof of a nearby skyscraper. Fortunately, it didn’t hit the street and no one was injured. Questions were raised over the structural stability of the tower itself. Most Expensive Construction Project Mistakes
However, the architects stressed that the problem was only with the facade, which they secured to avoid further blocks falling. Over the next few years, Chicago’s temperature swings caused the thin marble slabs to bow outward again and they started cracking. That’s why in 1985 they decided to attach steel straps to keep the blocks from falling.
But this only proved to be a temporary solution. 5 years later the whole exterior cladding had to be refaced. The marble slabs were replaced by much thicker granite panels for 80 million dollars, or almost a quarter of the total cost of the skyscraper when adjusted for inflation. But the AON Center wasn’t the only tower built in the 1970s that had objects falling out of its facade.
Other buildings were having similar problems like Chicago’s CNA Center which was completed a year earlier. The windows of the CNA Center started cracking due to thermal expansion and endangered the pedestrians below.
But in 1999 something really bad happened, a window on the 29th floor cracked and killed a 37-year-old woman. After the terrible incident, a lawsuit started, which was settled at 18 million dollars, and every one of the building’s windows was replaced. Most Expensive Construction Project Mistakes
Thermal Expansion caused similar problems for a Boston Skyscraper completed in 1976, as the windows of the famous John Hancock Tower started cracking as well. Some of the windows fell out and crashed onto the pavement. Most Expensive Construction Project Mistakes
That’s why the streets around the highrise were closed during high winds. Ultimately they had to replace over 10,000 windows to fix the problem. Most Expensive Construction Project Mistakes
Number 2: San Francisco’s Radioactive Problem
This shipyard was supposed to be the site of San Francisco’s biggest redevelopment project.
The former Navy Yard in the city’s bay housed the largest U.S. facility for nuclear research, and in 1945 components of the atomic bomb “Little Boy” were loaded onto a heavy cruiser from there.
In the 2000s, the U.S. Navy wanted to clean up the radioactive waste at the site, and plans to transform the former shipyard were made. These plans included over 12,000 new housing units, several parks, and offices. To put these plans in motion, a company named Tetra Tech was paid $250 million in cleanup contracts from 2006 to 2012.
Meanwhile, two different contractors were tasked with building homes while the clean-up work was done. However, the shipyard’s future was thrown into uncertainty after allegations of cleanup fraud. Starting from 2012, multiple whistleblowers came forward with accusations that Tetra Tech faked the cleanup process to speed things up. According to the allegations, workers from the company falsified data by using soil samples from clean areas and passing them off as soil from contaminated areas. 2 years later Tetra Tech admitted to falsifying soil samples and blamed the problem on individual employees. Most Expensive Construction Project Mistakes
The U.S Navy agreed to a revised plan to get rid of the still-existing contamination. And at the same time, the first portion of land was handed over to property developers to start building houses in the area. By 2016, more than 200 homes had been developed and even transferred to residents. Land transfers continued and new residents kept moving in.
However, an independent review of Tetra Tech’s data showed that they had faked more soil tests than previously thought. The review found that almost half of the previous clean-up work was based on false information. A further review by the U.S Environment Protection Agency in 2018, found that the Navy had understated the scope of the problem. Most Expensive Construction Project Mistakes
Based on these results, the development was put on indefinite hold. By that time at least 1 billion dollars had been spent on cleaning the shipyard and more than 350 housing units had been sold for about a million dollars each. As the project was put on hold many lawsuits followed seeking up to 30 Billion Dollars. Most Expensive Construction Project Mistakes
The Homeowners sued the developers, who then sued Tetra Tech, while Tetra Tech sued the U.S. Navy and the Environmental Protection Agency for lack of evidence. And it gets even worse than previously thought. Most Expensive Construction Project Mistakes
In 2022 a San Francisco grand jury reported that the shipyard will face a new problem. Previous cleanups might no longer be effective because of rising groundwater caused by climate change. The strategies of the past were premised on the idea that the dry areas of the shipyard will stay dry.
However, rising groundwater has the potential to mobilize inactive contaminants in the soil. Overall the project faces a massive delay. Most of the housing units at the former shipyard were supposed to be delivered to homeowners by 2020. Most Expensive Construction Project Mistakes
However, a majority of these transfers won’t happen until at least 2026. The project’s future remains uncertain for now and the clean-up mistakes mean that at least a billion dollars spent on it have gone to waste. For this video’s last project, we take a look at another bridge collapse, which is one of the most devastating in the world. Most Expensive Construction Project Mistakes
Number 1: South Korea’s Horrible Bridge Disaster
South Korea’s Horrible Bridge Disaster Constructed in 1977, the Seongsu Bridge was built over the Han River and connected the Seongdong and Gangnam districts of South Korea’s Capital. Repeated overloading resulted in one of the biggest disasters in Seoul’s history as the Seongsu Bridge collapsed on October 21, 1994.
One complete slab between the fifth and the sixth leg of the Bridge came crashing down more than 50 meters and landed on the water. One car, a van, and a bus were in the middle of the slab as it collapsed. In addition, some cars fell off the edge and sank into the river. 32 people died in this accident, and 29 of them were passengers on the bus. Most Expensive Construction Project Mistakes
Investigation to find out how this could happen was immediately ordered. Originally the bridge was designed for vehicles under 36 tons. However, over the years, traffic increased during Seoul’s rapidly increasing urban sprawl, and loads of over 47 tonnes per vehicle was allowed.
The biggest cause was found to be lacking welding work on the steel trusses of the suspension structure. The bridge supports had begun to rust and the overall condition was deteriorating. In addition, the structure wasn’t maintained accordingly despite multiple warnings. All these reasons combined resulted in this tragic collapse. Most Expensive Construction Project Mistakes
In the aftermath of the accident, seven city officials responsible for maintaining the bridge were arrested. Meanwhile, the City Mayor was forced to step down. While the collapse of the Seongsu bridge was the biggest in Seoul, it wasn’t the first accident involving the collapse of a bridge in South Korea. Similar collapses had occurred at least 8 times since the 1970s including 3 on the Han River.
Under immense public pressure, the Government started an emergency inspection program for bridges all over South Korea. Meanwhile, a plan to repair the Seongsu Bridge was put into effect. However, it was soon found out that the structural weaknesses made it impossible to repair the damage.
The bridge eventually had to be demolished and rebuilt. The new bridge was completed 3 years after the collapse and it was designed to maintain as much resemblance to the original bridge as possible.