 Using concrete is as old as recorded history, albeit in different forms. Nevertheless, it is the building material responsible for some of history's most iconic structures. Its prevalence has never really reduced. Liquid stone is essential in almost any construction project, from shed bases to today's subject power stations. Concrete is most definitely vital. And misjudgments in the process can have catastrophic results. Today I'm looking at the Willow Island disaster. My name is John and welcome to Plainly Difficult. Our story starts and pretty much ends in the 1970s in Willow Island, West Virginia. The region is getting a new coal power station called the Pleasants Power Station. The new plant was to have two electrical generators producing a name plate capacity of 1300 megawatts. The new power station would require two cooling towers. The first would be built during 1977, being completed in August of the same year. Soon after the second tower started to rise into the sky. Each tower had a base diameter of 358 feet with a height of 430 above ground level. They were of the natural draft variety. Now coal power plants are all about making steam to drive turbines, just like in nuclear powered power plants. As such, once turned into steam, you want to recover your coolant. This is where the towers come in. The ones at the Pleasants plant took the hot water from the system and cooled it through direct contact with fresh air. To increase surface area for the coolant, the water is sprayed into the tower via nozzles. Cooling towers are a pretty interesting type of structure as it has a wider base than its top and has different thicknesses as well as being circular. Because of this, concrete is really the only feasible construction material, although brick chimneys and towers exist, brick laying takes time and requires a certain skill and this costs money. If you're interested in brick towers, check out Fred Dibner's life and career. He spent most of his life maintaining and ultimately dismantling these types of structures. Or just ignore my side tension altogether. Anyway, how were these towers at Pleasants Power Station built? The construction method. The builders had to use a complex combination of formwork and scaffolding throughout the project. This would follow the construction all the way from bottom to top. To accommodate this, the scaffolds would be physically attached to the rising building. This is different compared to other building methods, where a scaffold is just mounted to the ground and rises up with the tower. To create each section's lift, the forms were placed. Then the concrete would be poured and once cured, the next section could be built. After each lift, formwork and scaffolding would be removed and placed above for the next lift. To raise up the concrete, cranes were used, but rather being fixed to the ground, they were also mounted to the newly made lift, by the scaffolding. Now this seems like a lot of weight relying on fresh concrete, but I'm no expert. I'm just a faceless voice, and yeah you don't want to see my face. The concrete would be reinforced with steel, both horizontally and vertically. Now with over 400 feet to build, it's no surprise the method for building the towers would need to be quick. This building method would rise at roughly 1.5 metres a day, or roughly 4 feet. The method, although in theory cheaper than a massive pile of scaffolding, relies on the previous lift's concrete to be as strong as it can be. It also vitally relied on correct geometry of the cranes and scaffolding for the whole system to have strength, and any weak link of the method's chain would yield not enough strength. But clearly it worked, the first tower was built using this method after all. The contractors used for the project were very well known in the industry at the time, New Jersey based research cultural. Safe hands you might think, and until the 27th of April 1978, you'd have no reason for concern. The Collapse. It is the morning of the 27th of April 1978, and the builders are planning to undertake another day of concrete work. So far 28 lifts have been successfully completed, with the scaffolding working its way up the structure. Cooling tower, number two, is roughly 166 feet or 51 metres tall. At 6.30 in the morning carpenters began removing wedges holding up the formwork. Some of the wood was discarded and new dimension wood was cut and set in place. This took place on the second level of the four level scaffolding. An hour later the iron mungers arrived and started hoisting the reinforced steel to the top of the tower. Around the same time the field engineer would arrive, and at 8.30 in the morning the scaffolding was jacked up to its new position. The formwork was being removed from the previous day's lift and being repositioned for that day's lift, number 29. Before 10 am, two buckets of concrete had been craned up to the top of the fourth level of scaffolding, which was now anchored to the previous day's work. Cracking was heard from the tower as the second bucket was raised. After roughly one cubic yard had been poured, the next bucket was sent up. As this went up to the platform, the 28th lift began to fail. The crane pulling the bucket of concrete fell into the cooling tower's centre. The previous day's lifts peeled away from the tower, sending scaffolding and workers on top plummeting down into the hollow of the building. That morning there were 51 workers on the scaffolding and none survived the fall. Immediately other builders on site rushed to dig out anyone they could find. At the same time calls went to 911 and ambulances and firetrucks from Belmont, Parkersburg, Vienna and St Mary's in West Virginia and Marietta in Ohio arrived to assist. Co-workers who had helped to drag the victims out of the rubble were there to assist in identification. Sadly due to the damage many were only identified by the contents of their pockets. OSHA was on the accident site pretty quick to begin the process of investigation. They even turned up on the same day of the disaster, with another team from the National Bureau of Standards arriving a couple of days later. These two organisations sought to find what caused tower number 2 to fail, especially when the other had been so successful in its construction using the same methods. The investigation Investigators scoured the disaster site and found not much left of the 28th lift. It was thought that it had been pulverised upon contact with the ground. Reinforcement bars were found to be bent, hinting that they hadn't fractured, kind of ruling them out as a potential cause. They also found that the scaffolding hadn't failed, causing the collapse. Neither did they find issues with the hoist cables. During the investigation, they found that the concrete was not strong enough to support the scaffolding. This was the official theory and was published in the 1979 report and the Bureau of Standards summed up in its conclusions. The imposition of construction loads before the concrete of lift 28 had gained adequate strength to support these loads. The imposition of concrete loads before the concrete of lift 28 had gained adequate strength to support these loads. Long story short, the concrete hadn't been given enough time to cure. But that wasn't the whole story. Our good old friend corner cutting reared his ugly penny pinching head. OSHA found that rather than following the carefully planned positioning of the cranes for rating the buckets, different positions were used to allow more buckets to be lifted and thus pulled the concrete more quickly. They also found a worrying lack of field tests of the concrete they were making, allowing inconsistencies in each lift. The anchoring for the scaffolding was also found to be lacking, with some bolts missing and in other cases made of an incorrect grade. It was also found that there was only one escape ladder, which would have hindered any escape. On the 8th of June 1978 OSHA sighted the Willow Island contractors with 10 willful and 10 series violations, which would result in a settlement of $85,500, a measly $1,700 per victim. But the verdict on the case of the disaster wasn't agreed upon by everyone. The power plant's main contractor hired a private engineering firm to investigate the failure. They were a bit more doubtful for the concrete theory, instead pointing the finger of blame at the feat of the unique scaffolding method. The consultants, Lev Zetlin Associates said, problems originated due to lack of understanding of the scaffold system by the workers and also due to its systematic misuse. Lack of technical and management supervision was also an underlying pause to this collapse. OSHA was aware of the problems with the scaffolding method, even as early as 1977. Lawyer Ralph Nader began researching OSHA reports soon after the collapse and he found some worrying concerns. An OSHA inspector had seen that the scaffolding used in the first tower's construction needed repairs and that they had been modified without any knowledge of the engineers. OSHA rejected the Nader report, still upholding the concrete theory. The disaster would improve concrete and masonry standards across the industry, which can only be seen as a good thing, but we all know this still was not enough. Now I'm going to rate this disaster as a free. Oh balls, people will remember this. And 5 on my legacy scale. This is a plain difficult production. All videos on the channel are creative commons that we should share like licensed. Plain difficult videos are produced by me, John, in the currently wet and windy corner of southern London, UK. I have YouTube members and Patreons who support the channel financially. I'd like to thank you, as well as all the rest of you who tune in every week to watch my disaster videos. I have Twitter and Instagram, if you fancy checking out some random photographs I post up there. And if you're enjoying this outro song, please feel free to go to my second channel, made by John, to check out the full video. And all that's left to say is thank you for watching, and Mr Music, play us out please.