Source: http://listosaur.com, May 15, 2012
We’ve all seen famous examples of “failed” engineering, from collapsed bridges and buildings to $300 million satellite launches that crash into the ocean. What seemed like a good idea during the design phase didn’t work as expected under stress or even normal conditions. In most cases, someone cleans up the mess and another project is started to replace the failed one. But some failed projects are left to stand, and have become renowned as “successful failures.” Here are 5 examples of failed engineering projects still standing today, in some cases a thousand years after they were first built.

5. Beauvais Cathedral

An incomplete Roman Catholic cathedral in northern France, Beauvais Cathedral was first commissioned in 1225. With spires originally 43 meters in height, an extra 5 meters was specifically added to make it the tallest cathedral of its time, surpassing the better-known Notre Dame cathedral by several meters. There was intense competition to build the “biggest, tallest and most ornate” cathedral in the Middle Ages. This ambition may also have caused the collapse of the vaulting in 1284 that brought construction to a halt. Through the centuries, many funders and architects had a go at the structure, but another collapse during an attempt to add a 153-meter-high central tower in the 16th century essentially halted construction for good. It has been said that the famous vaulting collapse precipitated the turn away from the Gothic style of architecture, and marked the decline of France into the quagmire of the Hundred Years War. Today, the cathedral, though unfinished, stands as a testament to the aspirations of Gothic architecture as well as a defining moment in medieval history where dreams gave way to reality.

4. Siena Cathedral

The city of Siena, Italy, hosted numerous high-profile construction projects throughout the Middle Ages. The centerpiece of the city is the massive cathedral built in the 13th century. Work began in 1339 on an even larger addition that would have rivaled the famous Duomo in Florence. An outbreak of the Bubonic plague a few years later halted work, and the entire project became an on-and-off affair due to sporadic Medici funding (they were also busy financing popes and funding wars). Construction finally halted for good when basic structural flaws became apparent. Almost 900 years later, the extension remains unfinished, and today, uncompleted sections accommodate parking, a museum and gift shops.

3. The New Orleans Levee and Canal System

The world watched in horror in late August 2005 after Hurricane Katrina hit southern Louisiana. A Category 3 hurricane at landfall, the high winds and storm surge were devastating enough to the city of New Orleans, but the disaster was compounded by the failure of the antiquated levee and canal system protecting the city. The resultant flooding covered some 80 percent of New Orleans, and killed more than 1,000 people, more than half the fatalities attributed to the storm. The flood control system’s failure has been characterized as the worst civil engineering failure in U.S. history. In March 2012, a U.S. Court of Appeals upheld a 2009 federal court decision that held the U.S. Army Corps of Engineers liable for the disaster; the federal government has estimated the cost of settling Katrina-related suits at up to $100 billion. In the years since Katrina, the U.S. has spent more than $15 billion upgrading the system, but critics say the federal government is inviting yet another disaster by only designing the new system to withstand a “once-a-century-event.” It should be noted that other levee projects in areas such as the Netherlands are built to a 1,250-year standard, although it could also be argued that protecting the Gulf Coast is a much tougher proposition.

2. The “Bent” Pyramid of Egypt

Many tourists gaze in wonder at the famous pyramids that dot the plains of Giza just outside of Cairo, but few visit the earlier attempts that the ancient architects made at pyramid building. One of the most famous examples is the “Bent” Pyramid of Dahshur, located just south of Cairo. Built around the 26th century B.C., this 344-foot pyramid shows the difficulty architects had in transitioning from the step-pyramid style seen in earlier structures such as the Pyramid of Djoser to the famous works of Cheops and Chefren in the Giza necropolis. The base of the pyramid begins with a 54-degree inclination, and then tapers to a shallower 43-degree slant. The builders likely did this to prevent the possibility of collapse after they realized the initial angle was unstable. Interestingly, most of the limestone cast encasing the pyramid is intact; that’s in contrast to the pyramids of Giza, which have been almost entirely stripped by the elements, with the exception of the peak of Chefren. It’s strange to think that the pyramids were flat-faced and some archaeologists believe they may have been painted when they where fresh from the builders.

1. The Leaning Tower of Pisa

One of Italy’s most famous symbols is a construction project that went bad. In 1173, construction began on the bell tower that would accompany the baptistry and cathedral in Pisa Square. About five years into the project, the tower began to sink into the unstable subsoil underneath. This was also due to the substandard foundation that had been laid, only 3 meters thick. Construction was finally completed over a century later, and today the tower leans nearly 4 degrees from true vertical. The tower doesn’t hold the greatest unintended slant of any structure in the world; that “honor” goes to Germany’s Leaning Tower of Suurhusen, with a cant of more than 5 degrees. The Leaning Tower of Pisa’s tilt increased alarmingly through the 20th century, closing it to interior visitors from 1990 to 2001. To solve the problem, engineers added cables to stabilize the structure, then excavated under the tower and added trusses and counterweights. Today, the tower is thought to be stable for at least the next 200 to 300 years. Of course, correcting it to vertical is out of the question, as it would then be just “another bell tower.”

One More: Boston’s “Big Dig”

In 2007, Boston officials declared the official completion of the city’s infamous “Big Dig” project. Officially known as the Central Artery/Third Harbor Tunnel (CA/T) Project, from the start the project was plagued with construction accidents, poor design and accusations of corruption. The problems didn’t end with the Big Dig’s completion, as families of victims killed in crashes in Big Dig tunnels have filed a number of lawsuits faulting the Big Dig’s engineering. In the most notorious case, a woman died in July 2006 when part of the ceiling collapsed in the I-90 connector tunnel. At least eight other victims have been killed in gruesome fashion in motorcycle and vehicle crashes, decapitated or dismembered by the tunnels’ so-called “Ginsu guardrails.” The U.S. DOT had warned Big Dig officials in 1992 about the potential dangers posed by those guardrails. Such shoddy engineering and work didn’t come cheap; with an initial cost estimate of around $2.6 billion, the Boston Globe estimates the final cost of the Big Dig at $22 billion, and says it won’t be paid off by taxpayers until 2038.