By Sonia B. Glover
The chances of an iceberg hitting the Hibernia gravity base structure are slim - but still possible. Everyone knows icebergs pose a hazard for structures built offshore, and, therefore, proper structural requirements are needed. And by now it's likely that everyone knows the GBS was uniquely designed to withstand iceberg impact.
But what most people don't know is that it took thousands of hours of research by several experts to produce the ice data that was used to design the Hibernia platform - and that a significant amount of the research work was conducted in St. John's.
So who were these experts? Look no further than Memorial University. The key players behind this major historical research project, involving ice mechanical strength testing, were all connected to the university - - either a faculty member, former faculty member, a student, or a graduate; in fact, one team member has since come to work at Memorial.
In the early 1980s, Mobil Oil recognized the possibility of impacts with icebergs and decided to fund research on the mechanical and physical properties of ice. The Hibernia partner had already done its homework on the size, shape, number and distribution of ice bergs on the Grand Banks, but still did not know the extent of an iceberg's force on a structure.
In order to estimate the forces that an iceberg could deliver, you need to know the mechanical properties of the ice; and this of course, translates into a lot of research.
Mobil awarded the project to the former Ice Engineering Limited of St. John's. The company president was Peter Benedict, who at the time was an associate professor of engineering at Memorial. The Memorial connection doesn't stop there.
The principle research person was Dr. Peter Gammon who also did his Masters and PhD at Memorial University; the senior project scientist was Dr. Bob Gagnon, who is a Memorial graduate, with a PhD and Masters in Physics; and the project consultant was Dr. John Lewis, who was and still is a Memorial physics professor.
Other team members included Gary Dinn and Dave White, who are both graduates from Memorial's Engineering Faculty; Chris Hammond, the project photographer, is now a photographer in Memorial's University Relations Division; and some Memorial work-term students also assisted with the project.
Dr. Gagnon, now a research officer with the National Research Council at the Institute for Marine Dynamics, said the research team's close Memorial connection is something to be proud of.
"This was very exciting work and ground-breaking work in terms of understanding the properties of iceberg ice. Clearly it had consequences as the information was going to be used in the real world to design something that was hopefully going to benefit the oil industry and our province. Just about every person involved in this had their training at Memorial and all of these people conducted a very significant piece of work," Dr. Gagnon told the Gazette.
This significant work was under a five-year embargo by Mobil and little was known about the data, outside of Mobil and the two levels of government. Following the proprietary period Dr. Gagnon initiated the idea to make the research findings public; Mobil and HMDC gave him permission to write a paper on the data and release the information.
Re-visiting the research data reminded Dr. Gagnon that there was a lot of information to decipher. In fact, there was so much information that he ended up writing three papers. The hard work paid off though - two of the papers were recently published in the Journal of Glaciology and the third paper is about to be published.
Dr. Gagnon said even though the project was carried out a long time ago, he still felt it was important to publish the data because of the growth of the offshore industry in our province.
"The data may be a bit old but it is still very valuable. When oil companies pay to get work like this done, they obviously want to keep it under wraps for a few years because they are paying for it and so on, but after the five-year period was up I realized that the data was just sitting there," he said.
"The offshore business was a big issue and I knew there were still more problems that needed to be dealt with like smaller pieces of glacial ice interacting with structures . . . and I knew it was important that we should do something about it, which was to make this data available to the general audience."
Dr. Gagnon added, "We are delighted that the work finally ended up being published. "It's an important data set, there's no doubt about it."
Making the information public was a wise move according to Dr. Gammon. "Mobil basically got the commercial benefit out of it and it was such good data of general interest that it made a lot of sense to make it available to the general community . . . so I wasn't surprised that they decided to take that route."
The project was the largest and most significant for Drs. Gammon and Gagnon - a project that they won't soon forget.
"Although it was 15 years ago, I still remember that the project involved a large number of assessments and tests done over a wide range of test parameters, so it was a very comprehensive program and that was the feature that made it stand out," said Dr. Gammon.
"We completed other small projects relating to characterization of ice and mechanical properties of ice, but this was the first large scale comprehensive test program that we had done in that area. It was very challenging and I guess it was hard to appreciate how much was involved at the outset."
So what exactly was involved in the ice mechanical strength testing for the Hibernia GBS?
Well, if you are going to do research on ice properties of iceberg ice the first thing you have to do is get ice from an iceberg. And that's exactly what the research team did; they headed to Labrador in search of a suitable iceberg. When the proper iceberg was located, seven and half tonnes of ice in 350 pound chunks were put into insulated boxes and transported by plane to St. John's.
Dr. Lewis, who also worked as a consultant for Ice Engineering Ltd., was involved in identifying a suitable iceberg in order to carry out the research. After a couple of weeks, he said the right specimen was discovered and the team quarried the ice.
"This was non-trivial as you can imagine . . . what was used to get the ice out of the iceberg was a long chain saw. You would go in and cut around the ice and dig in from behind, cuttting the gallery into the ice. So, you can imagine what it was like working at close quarters with chain saws; you needed rather cool nerves, but it was very interesting," Dr. Lewis told the Gazette.
Besides being important for the Hibernia GBS design, Dr. Lewis insisted that the project was also very significant for Memorial University.
"Very few people knew about what was involved or who was involved. I feel it was an amazing and important piece of work by a lot of people who were associated with Memorial. It shows that Memorial has a strong base of expertise and we can compete with anybody," Dr. Lewis said.
He described the amount of work involved in the project as 'nearly superhuman'.
The project did indeed involve a lot of work - collecting and transporting
the 350 pound blocks of ice to St. John's from Labrador was, as they say,
only the tip of the iceberg.
When the ice arrived in St. John's, experiments were conducted in Memorial's Engineering Building and the former Ice Engineering facility on Torbay Road.
Dr. Gagnon said the most basic type of experiment was the impact test on iceberg ice. Others were triaxial and beam-bending experiments.
"The impact test, which is also called a drop ball test, is most interesting. It is where you are dropping a heavy weight onto the ice surface. That was done at the Ice Engineering facility on Torbay Road.
"In the triaxial confinement experiments, which were carried out in Memorial's Engineering Building, you take a cylindrical shaped specimen and you push on the ends until it fails or breaks apart and you adjust the pressure around the sides as you are doing this by putting it in a confinement vessel and basically having a fluid of some sort that provides pressure around the sides as you are pushing on the ends," Dr. Gagnon explained.
He said this test was carried out to determine how ice behaves when the forces placed on it are not of a uniform nature.
"The beam-bending experiment is like a beam of wood that supports your house . . . you would make beam shaped objects from your material, in this case iceberg ice, and you support it on the ends and put a load in the middle to see how much load it can take before it fractures. That strength test was done in the facility on Torbay Road," added Dr. Gagnon.
Besides the lab experiments in St. John's, Dr. Gagnon said they were also involved in a set of field experiments at Pond Inlet on the northern tip of Baffin Island.
"In that case, work was done on a grounded iceberg and tunnels were put into the iceberg. These tunnels were about three metres high and went back about 15 metres and there were four of them. A big hydraulic indentor was put in the iceberg and it was pushed against the walls of the tunnels to cause the ice to fail or fracture," explained Dr. Gagnon.
"As an add-on to the big indentor tests, they (Mobil) wanted us to do drop ball tests in the tunnels, basically the same as we had done here in St. John's. Here I was up there with the same apparatus doing these drop ball tests in a tunnel, before the indentor experiment. The indentor tests used heavy-duty hydraulics and a lot of ice was flying around. It was exciting for sure," he added.
The experiments were also thrilling for photographer Chris Hammond, who told the Gazette it was the most said exciting time for him during his 18 years as a photographer.
"It was a wonderful experience for me and I am so delighted that I didn't miss out on it. I didn't know at that time the significance of the outcome of the research and it was only recently that I found out the impact of the data and that it was being published,"
Mr. Hammond added his trip to Labrador was an eye-opener and said he has many good memories of it.
"It was so interesting and great just to work with these people, Bob Gagnon, John Lewis and Peter Gammon. They were exciting professional people, who worked hard."
Dr. Gammon, meanwhile, said the scientific quality of the work was excellent.
"There was an emphasis on the volume of data which is good for that type of work. It wasn't just to do a couple of little measurements and infer from those everything you need to know about ice strength. Instead, the idea was to accumulate a large number of measurements and because of that the research was very statistically oriented and the result I feel was good quality data."
He said state-of-the-art equipment was used for the experiments, adding the research team was made up of very capable people.
"All of the people had a good ability to fit in with this type of work which was relatively novel in that there hadn't been much of this kind of work done around here. So all of a sudden the offshore business was moving, which meant a requirement for a whole new area of research, but we didn't have any trouble getting the expertise to get this project up and running," said Dr. Gammon.
"And the fact that this work was done here by people somehow related to Memorial just builds Memorial's reputation for arctic ocean expertise that the university has actually fostered through of number of its organizations like C-CORE. I think this project fits quite well with the university's general thrust in that area."
He added that the fact that this type of project was done in Newfoundland is also a credit to the local community.
"I really enjoyed this project. No doubt it was exciting and interesting. When I was doing it I was looking at it more as a scientist than just somebody who was trying to feed numbers to an offshore oil project," Dr. Gammon told the Gazette.
Dr. Gagnon agreed, stressing that prior to the experiments, very little was known about mechanical properties of ice berg ice.
"I feel quite happy about having been involved with this. There was a lot of very useful information, general information about glacial ice properties that came out of it . . . And the fact that we were able to publish three papers based on that information speaks for itself," he said proudly.