Schoellkopf Disaster
On the Collapse of the Schoellkopf Power Station
5:00 PM, June 7, 1956
The cause of the collapse of the Schoellkopf power generating plant has never been officially determined. A professor in Buffalo stated that it was caused by an earthquake, but it is more likely that it was the collapse that registered on his instruments as an earthquake. Therefore, this document was created for the purpose of presenting the possible contributing factors that ultimately resulted in the collapse and loss of a significant amount of generating capacity, 313,500 Hp from Schoellkopf 3B and 3C, not counting the damage done to 3A.
1. Management Actions
This section details management actions concerning the Schoellkopf Power Station, passed down through former employees who worked in the facility. To my knowledge, none of this sections information can be found in any documentation. I received this information from my Father, who was an operator in the facility, who received it from former employees.
Having spent my 40-year career in the engineering field, I am the personification of Scott Adam’s character Dilbert. Having had a plethora of incompetent “pointy haired bosses” and working with useless “Elbonean” consultants, I have seen more than my share of management-caused disasters. While the details of this section my seem unbelievable to the average person, they would be quite believable to a seasoned engineer.
A domestic analogy may help to understand the assertions of this section. On a visit to my in-laws home, I noted that water was leaking into a basement den from the shower above and suggested that my father in-law address the problem. On my next visit, my father in-law proudly showed me his repair to the ceiling. I immediately pointed out that this did not address the problem. The ceiling was wet, sagging, and about to collapse, which reminded me of the topic of this paper. Unlike Schoellkopf, on the following visit, my father in-law proudly displayed a row of holes drilled into the ceiling to let the water out, recreating the initial problem, but solving nothing. Finally, but unlike Schoellkopf, I caulked the track of the sling glass shower door, thus solving the root cause of the problem.
1.a) Initial Construction
The employees who worked in the Schoellkopf Power Station in the 1920’s passed down the story of its construction to an employee in the 1950’s, who then passed it on to me. It is not known if this pertains to Schoellkopf 3-B, 3-C, or both 3-B and 3-C.
The story claims that during construction, management took action to save money by not lining the penstocks with steel. The penstocks are the large pipes through which the water flows from the forebay above to the turbines below. At Schoellkopf, the penstocks are bored through the rock behind the wall of the gorge and exit at the base of the gorge, just behind the turbines.
Due to previous borings through rock, this area behind the face of the gorge was pretty much “swiss cheese.” Also, any rock formation has layers, cracks, and fissures. Without steel linings to restrict the water from entering the surrounding rock, a great amount of leakage would occur and a great amount of pressure would be created within the rock of the gorge.
If the above store is true, it would doom the Schoellkopf plant to a short life and disastrous demise. The is analogous to my father in-law not fixing the source of his leak, which was in the shower.
1.b) Ongoing Actions
Throughout my father’s many years working with the Schoellkopf, he frequently spoke of efforts to stop and seal all leaks out of the gorge face. This was accomplished by forcing what he called “grout or cement” under pressure into the fissures that were leaking. By doing this, they allowed the pressure to build up in the rock wall, rather than allow the leaks to relieve the pressure. This is analogous to my father in-law sealing up his basement ceiling, allowing the water accumulate in the ceiling.
On the morning of June 7, it was noticed that a rock was protruding from the wall of the gorge, a clear
sign that water pressure was pushing the rock outward. Still, the impossible attempts to seal the evergrowing leaks with grout continued to the final collapse.
Another effort to reduce the leaks was to install a “grout curtain or wall” behind the edge of the gorge.
While this might prevent leakage from the forebay into the rock wall area, it would not have helped the
case of posssibly the unlined penstocks.
While it is not exactly clear how much progress was made on the construction of the grout wall at the time of collapse, it is possible that this effort weakened the rock face of the gorge by mechanically and horizontally disconnecting the gorge face from the rock behind it. This created a narrow, free-standing column of rock, as shown below. In fact, looking at the only 8-mm, grainy movie of the collapse appears to show a section of the gorge face, several feet wide, separating from the rock behind it. This rectangular section of gorge face then tilted away from the rock to which it was formerly attached and then tilted sideways, as it collapsed under its own weight onto the Schoellkopf 3B and 3C buildings and severing the penstocks.
2. Conclusion
The Schoellkopf Power Plant collapse was probably a preventable event, caused by a series of poor management decisions from its construction to its destruction. It is no surprise that an “official cause” of the collapse was ever determined.
What they should have done and did not do: 1) Prevent water from entering the fissures in the rock behind the gorge wall to the maximum extent possible. 2) Provide a means for water that did get into the rock behind the wall of the gorge to drain out, eliminating the build-up of hydro-static pressure.
What they did and should not have done: 1) Nothing to prevent water from entering the fissures in the rock behind the gorge wall. 2) Compromised the horizontal strength of the upper rock layers by excavating a slot behind the gorge wall for the grout curtain. 3) Actively prevent water that did get into the rock behind the wall of the gorge from draining out. This resulted in the build-up of hydro-static pressure, around 90 psi, which eventually pushed the gorge wall outward, causing the collapse.
