• engineering disasters

    These disasters were not because of the engineer

    Here’s a quick look at a number of engineering disasters that were caused by factors other than poor engineering. In many of these cases, the elements – weather, unexpected pressures – caused the failure. In other cases, it was poor workmanship, inferior materials, construction shortcuts, or human mismanagement.

  • engineering disasters

    Steamboat Sultana (1865)

    On the night of April 26, 1865, the passenger steamboat Sultana exploded on the Mississippi River seven miles north of Memphis. The resulting maritime disaster is categorized as the worst in US history. The explosion killed 1,547 people, surpassing the total number of deaths caused by the sinking of the Titanic. The Sultana was overcrowded due to a soldier prisoner exchange towards the end of the Civil War. The overcrowding contributed significantly to the high death toll.

    Another reason for the high number of deaths is that the steamer was made mostly of wood, which was documented to have been completely engulfed in flames approximately seven minutes after the explosion. The explosion happened around midnight which was when the Mississippi River was at flood stage. The single metal lifeboat on board was thrown from the upper-deck, landing on several people swimming from the steamer, resulting in further deaths.

    The disaster was believed to be the result of an explosion on a repaired boiler that led to the explosion of two of the three other boilers. The boiler had been found to have had a leak and was improperly repaired by a boilermaker due to orders from Captain J. Cass Mason who insisted the boiler repairs be made quickly because of time constraints. While the chief engineer approved the repaired boiler, the boilermaker stated that the boiler could not be considered safe since the boiler appeared to be burned from being worked on with too little water. Traveling along the Mississippi River, the boiler exploded causing fire to spread throughout the steamer. The fire on board led to the collapse of both of the Sultana’s smokestacks, killing even more passengers. (Image source: Wikipedia)

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    The Johnstown Flood (1889)

    The Johnstown Flood occurred in 1889 when a dam located on the south fork of the Little Conemaugh River, 14 miles upstream of the town of Johnstown, Pa., gave way. The dam broke after several days of extremely heavy rainfall. With a volumetric flow rate that temporarily equaled the average flow rate of the Mississippi River, the flood killed more than 2,200 people. This catastrophe almost completely destroyed Johnstown. Maintenance – not design – was the issue. Investigators found that the South Fork Dam was poorly maintained and when there was a tremendous amount of pressure from Lake Conemaugh, the dam crumbled. (Image source: Wikipedia)

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    Quintinshill rail disaster (1915)

    The Quintinshill rail disaster was a multi-train rail crash which occurred in 1915 outside the Quintinshill signal box near Gretna Green in Dumfriesshire, Scotland. It resulted in the deaths of over 200 people. It’s the worst rail disaster in British history. After an investigation, it was found that the disaster was caused by human error. The sequence of events leading up to the collisions featured multiple breaches of the railway’s regulations, which formed the basis of the later prosecution of those involved with the signaling. (Image source: Wikipedia)

  • engineering disasters

    Great Molasses Flood (1919)

    The Boston Molasses Disaster, occurred when a storage tank burst, releasing a wave of molasses through the streets of Boston. The tank itself was poorly constructed, with rising temperatures during the previous day believed to have caused the build-up of pressure within the tank, resulting in a fatigue crack. The fatal problem was that the steel that made up the tank was less than half as thick as required to withstand the pressure. The steel also lacked manganese – a cost-saving omission – which made the steel brittle. Many people believe that on a hot day on Boston you can still smell the molasses. (Image source: Wikipedia)

  • engineering disasters

    Tacoma Narrows Bridge (1940)

    The collapse of the Tacoma Narrows Bridge was due to the never-before-seen phenomenon of torsional vibration mode. This effect caused the two halves of the bridge to twist in opposite directions while the center remained motionless. Over time, the force produced by the fluttering movements surpassed the strength of the suspender cables, snapping them one by one until the remainder were unable to support the mass of the bridge. The bridge received its nickname Galloping Gertie because of its wild movements.

    An engineering solution that was considered sound was devised, but one more storm hit the bridge before the repair could be put into place. Now one was hurt in the collapse. In 1950 a new bridge was opened to replace the failed enterprise, using the original pedestals and cable anchorages but a different design. (Image source: Wikipedia)

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    Cleveland East Ohio Gas explosion (1944)

    In 1944, an above-ground storage tank containing liquefied natural gas at the East Ohio Gas Company started leaking. The gas drained into the sewers via street gutters. It mixed with the air and ignited. An estimated 130 people were killed by the resultant explosions, with an entire square mile of the east side of the city of Cleveland destroyed. The event drew public attention to the inherent dangers of the above-ground storage of natural gas that was used as fuel for homes as well as factories. The disaster contributed to the relocation of these units below ground to prevent a recurrence. (Image source: Wikipedia)

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    The Banqiao Dam flood (1975)

    The Banqiao Dam on the River Ru in Zhumadian City, China, was completed in 1952 to manage regional flooding and generate hydroelectric power. The dam functioned successfully until 1975, when the dam was unable to hold back record rainfalls. The resulting collapse and flood caused a wave 6.2 miles wide and 10 to 20 feet high as it rushed onto the plains below at 30 mph, almost wiping out an area 34 miles long and 10 miles wide, killing an estimated 171,000 people.

    The government blamed weather conditions, but the dam’s failure was mostly due to structural faults which exacerbated the dramatic increase in water capacity. Soon after the project’s completion, cracks appeared in both the dam and the sluice gates. While these were repaired, it is believed that they were never returned to full strength. The sluice gates on the night of the incident were rendered ineffective due to sediment blockage. The real culprit was likely the cost cutting measures that resulted in only five sluice gates. Engineers lobbied for a minimum of twelve but were overruled by management. (Image source: Wikipedia)

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    Hyatt Regency Hotel walkway collapse (1981)

    In 1981, in Kansas City, two suspended walkways of the Hyatt Regency Hotel collapsed, killing 114 people and injuring 200 more. During this calamity, the hotel was hosting a dance competition. There were numerous competition attendants and observers standing and dancing on the suspended walkways when connections supporting the ceiling rods that hoisted both the second and fourth floor walkways across the atrium failed and collapsed onto the crowded first floor atrium below.

    During the resulting investigation, architectural engineer Wayne G. Lischka noticed a substantial alteration of the original design. The fabricator constructed a double-rod support system rather than the originally designed single-rod system without approval of the engineering design team. In doing so, the created support beams doubled the loading on the connector which resulted in the failure of the walkway. (Image Source Wikipedia)

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    Chernobyl disaster (1986)

    The accident, which occurred in 1986, resulted when operators took actions in violation of the plant’s technical specifications. Operators ran the plant at very low power, without adequate safety precautions and without properly coordinating or communicating the procedure with safety personnel. 

    The four Chernobyl reactors were pressurized water reactors of the Soviet RBMK, which were designed to produce both plutonium and electric power, they were very different from standard commercial designs, employing a unique combination of a graphite moderator and water coolant. The reactors also were highly unstable at low power, primarily owing to control rod design and positive-void-coefficient factors that accelerated nuclear chain reaction and power output if the reactors lost cooling water. These factors all contributed to an uncontrollable power surge that led to Chernobyl 4’s destruction. The power surge caused a sudden increase in heat, which ruptured some of the pressure tubes containing fuel.

    The hot fuel particles reacted with water and caused a steam explosion, which lifted the 1,000-metric-ton cover off the top of the reactor, rupturing the rest of the 1,660 pressure tubes, causing a second explosion and exposing the reactor core to the environment. The fire burned for 10 days, releasing a large amount of radiation into the atmosphere. 

    The Chernobyl plant did not have the massive containment structure common to most nuclear power plants elsewhere in the world. Without this protection, radioactive material escaped into the environment. The accident cause 44 immediate death and 9,000 to 16,000 cancer deaths in the following years from radiation exposure. (Image source: Wikipedia)

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    Walnut Street Bridge, Harrisburg, Pa. (1996)

    In January 1996, as a result of rising flood waters from the North American blizzard of 1996, the Walnut Street bridge lost two of its seven western spans when high floodwaters and a large ice floe lifted the spans off their foundations and swept them down the river. A third span was damaged and later collapsed into the river. Shortly after the loss of the three western spans, the People’s Bridge Coalition was formed to support the restoration of the bridge. Public surveys show overwhelming support for the restoration of the western spans. It is estimated that restoring the western span of the bridge will cost between $12–15 million in December 2005. In this case, engineers could not have anticipated the unusual weather conditions that lifted and destroyed the bridge. (Image source Wikipedia)