 It is the morning of the 5th of April 1987 and traffic is light across the School Harry Creek Bridge, New York State. Rain has been falling for a couple of days and the water level along the creek was rising. Without any real warning, a section of the bridge over the creek plunges into the flowing water below. The disaster would force a rethink of bridge design, maintenance and how water flow can cause a sudden and catastrophic disaster. Welcome to Plainly Difficult, my name is John and today we're looking at the School Harry Creek Bridge Collapse. Background. This video is prompted by recent events in Baltimore. Of course being the content hunter I am and giving me something to research in the meantime I started looking at other bridge-based tragedies. This leads us on to today's bridge, one of the spans over the School Harry Creek. The need to cross the creek has been one that dates back to the early 1820s, with the construction and operation of an aqueduct for the Erie Canal, with the original being replaced in the 1840s. This was a few miles away from today's disaster zone but it shows the creek was an obstruction that needed to be overcome. The creek had a nasty sting which would cause the demise of a few crossings and this was its propensity to flood on the odd occasion. Rainwater ran off into the roughly 83 mile long creek which in turn flowed into the River Mohawk. Further upstream the creek is dammed in two different places. The creek over the years would flood and in 1940 would take down the Erie Canal viaduct after a roughly 100 year lifespan. The canal had ceased operations and thus maintenance in 1917. Needless to say the creek will get you. Now this leads us on to our main focus for today's video, the School Harry Creek Bridge, designed in 1952 and constructed in 1954. It was originally meant to be a three-lane highway in each way, although in actual use it only had two wider lanes in each direction during its operation. The bridge carried the New York State throughway. It consisted of five spans of concrete reinforced decking. Sattertop steel supporting bars which were then themselves held up by reinforced concrete columns on top of concrete piers. Just a few years after opening four of the five concrete plimps were found to have cracks. This was in 1957. The remedy was to pour an additional layer of concrete over as a cap. Interestingly this was discovered two years after one of the creek's worst floods. The flood of 1955 was bad. Floods would happen in the area over the following decades but nothing would come close until 1987 and this time it would prove to be deadly. The disaster. The start of April 1987 was a wet one. Rain had been falling for the best part of a week, amassing over seven inches of rainfall. As such the creek had begun to fill up and the ground was sodden and saturated. And to add watery insult to injury the nearby Catskill Mountain snow had begun to melt which then also ran off into the creek. The water levels in the creek were becoming alarming so much so as said in a later NTSB report. The NWS issued at least seven flood statements and six flood warnings at through the 5th of April 1987 to advise the public of the rising water and flood conditions along the school-hury creek basing. Weather warnings were relayed by local news agencies to the public. People were made aware of the rising water levels and by the 5th of April most had decided that driving around in the terrible weather wasn't such an ideal plan. As such over the school-hury bridge traffic was light to moderate at around half 10 in the morning. Funnily enough morning the rain had been fairly light and not really affecting any issues with visibility. Witnesses would later say of the morning that apart from the higher creek waterline all else seemed pretty average. At 10 40 a.m. in the morning a police state trooper made the crossing and would later report that all seemed well. However just five minutes later a disaster would strike. Volunteers working nearby observing the water in the creek heard a loud bang. Peer three of the bridge had collapsed sending two spans plummeting into the water some 80 feet below. Two eastbound vehicles which was a car and a truck fell into the void. Two more eastbound and a westbound car would also drive off the edge. The cars now in the fast-flowing creek sunk beneath the water. Some of the luckier following cars managed to stop and drivers got out to start flagging down other vehicles in an effort to try and save more lives. The first calls came in to emergency services around 10 48 in the morning. This was from a toll booth operator and the volunteers watching the creek. Police were dispatched and arrived on scene at roughly 10 50 in the morning. They started clearing the bridge and police began searching the creek's banks. The emergency response was swift but of the 10 missing people inside the stricken vehicles none would be seen alive. Nine bodies were pulled out from the water leaving one more missing and presumed drowned. Around 90 minutes after the initial collapse Peer two also collapsed plunging another span into the water which rather fascinatingly was actually captured by local news reporters. Search efforts would continue along until the 12th of April and would include divers and around 40 emergency personnel. Now the bridge collapse would cause severe issues in the region with traffic needing to detour. The collapse was rather high profile due to in part of it being caught on TV. To add more disaster to the area another bridge further upstream also collapsed a few days later but thankfully it had been close to traffic as a precaution. So it being a road-based disaster our investigators today are the NTSB the investigation. Bridges collapsing aren't meant to be a regular occurrence. For some reason multiple structures had failed along the school Hurry Creek over the years. The three-way authority were commissioned its own investigation in addition to the NTSB. This would result in a physical model in order to undertake scale hydraulic experiments. Divers were employed to recover any debris of the bridge and addition to this cofferdams were constructed around the bridges columns. This allowed a rare view of the structure devoid of water. Investigators discovered that piers 2 and 3 had separated. They found the riverbed had eroded away from the base of the piers. After interviewing witnesses it was discovered that pier 3 had failed first. This in combination with the erosion around the upstream face of the lower part of the bridges support. This led the NTSB to set out and investigate a couple of failure modes including failure of the super structure first but the cause was most likely a scour. A scour is when sediment around a bridge abutment or pier is eroded away which after enough time and material loss would undermine the structures foundations. This problem is more common in an area that has strong fast-flowing currents like what the school Hurry Creek was known for. So what can be done to fix it? Well you can use this thing called riprap. It's man-deposited rocks or pebbles and acts as a rock shield against sediment erosion. The NTSB would summarize their findings in their 1988 report into the collapse. The National Transport Safety Board determines that the probable cause of the collapse of the school Hurry Creek bridge was the failure of the New York State Three Way Authority to maintain adequate riprap around the bridges piers which led to severe erosion in the soil beneath the spread footings. Contributing to the accident were ambiguous plans and specifications used for construction of the bridge an inadequate NYSTA bridge inspection program and inadequate oversight by the New York State Department of Transport and the Federal Highway Administration. Contributing to the severity of the accident was a lack of structural redundancy in the bridge. All pretty damning to everyone involved. It would seem that from the day the bridge was built the countdown to disaster had already begun with the creeks bed beginning to scour and this would be a 35-year journey of it wearing away to ultimate failure. The state would have to pay out on several lawsuits brought by the victims families which would result in various settlements totaling an estimated four million dollars. The state would then later file suit against the bridges designer for a six hundred thousand dollar settlement but it also sought to file against the contractor but the statute of limitations had already passed four point six million dollars for ten lives doesn't really seem like a great deal for the victims so it's scale time. It's going to be a free on my disaster scale and this is what I've got for my bingo card. Do you agree? Let me know in the comments below. This is a plain default production. All videos on the channel are creative commons that you should share like licensed. Plain default videos were used by me John and they're currently wet and windy corner of southern London UK. 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