Yesterday I went to the 35th year anniversary celebration of the founding in Vancouver of SRK. It was a grand affair in a fancy hotel overlooking the harbor. Andy Robertson and Jim Robertson (no relation) who were the two originals were both there.
Today the firm is a major consulting success story. Maybe one day the promised book on the history of those time will appear–it has been five years in the writing.
My tribute is to Professor Jennings about whom I once wrote:
It all started with Professor Jennings. He taught us soil mechanics and foundation engineering. He was proud to be head of the Civil Engineering Department and Professor of Soil Mechanics and Foundation Engineering at the University of Witwatersrand. He fought against the introduction of what he called “that new-fangled French-sounding term ‘geotechnical.’”
Yet we became geotechnical engineers and SRK became a leading geotechnical consulting firm.
Professor Jennings was tall and imposing. His wife was small and gentle. She would serve us from that never-ending pot of soup that bubbled on the home stove, as Professor Jennings served us gin and orange juice. That was the standard lunch you got if you went home with Professor Jennings to eat and discuss some aspect of soil mechanics for your thesis.
The De Beers diamond mine is an open pit in Kimberly. Bomvu Ridge is a mine in Swaziland. Professor Jennings was a consultant to both on the question of the stability of the rock slopes. From his work on those pits, he formulated the issues that Oscar and Andy solved in their PhD theses. For me he defined a master’s thesis: analyze the flow net in a jointed rock mass.
He lured Oscar into lecturing soil mechanics. He lured me into lecturing fluid flow in soils and structures to the architects. He was amazingly persuasive. The magic of his personality was his ability to see a problem and find and encourage a student to solve the problem. He always seemed to be able to find a sponsor willing to pay the student enough to enjoy life in Braamfontein, the area surrounding the university.
He was a great engineer in the sense that he could grasp the theory and put enough of it to work to formulate a practical engineering solution. It was he who started the study of collapsing soils and heaving clays. He was a great exponent of the application of “judgment” to soil mechanics. He had studied in the United States under Ralph B. Peck and made us read Terzaghi and Peck as our primary text.
His favorite task for post-graduate soil mechanics students was to give them his ninety-page calculation of the horizontal pressures on the piles that formed part of a vast ring-beam constructed to support the excavation of the basement of the Carlton Center in downtown Johannesburg. He had earned enough as a consultant on that job to buy a beautiful brown Mercedes that nobody but himself was allowed to drive.
He asked the post-graduate students to read his Carlton Center calculations and to return the following week to critique them. The first time I read the calculations, I was baffled. Recall this was the days before calculators or computers. Over 89 pages, he had, in a neat hand, listed every theory and equation he could find to quantify horizontal soil pressures on a vertical surface. Then using a slide-rule and sometimes Vega’s seven-figure logs, he calculated the pressures.
Every equation yielded a different answer. It was frustrating.
“Is there no correct answer?” I wondered.
On the final page of the calculation set was a brief statement to this effect: “On the basis of judgment, we select the following as the design earth pressures for the piles and the associated recta-grid system.” And the numbers that followed were somewhere in the middle of the range calculated in the preceding 89 pages.
In class the next day, we attacked this arbitrary choice. But he defended the choice on the basis that engineering judgment involves assembling all the facts you can, doing all the calculations you can, and then, on the basis of a good bottle of brandy and a good night’s sleep, making your decision.
Professor Jennings taught us to respect the people who build what we engineers design. In his lectures on the practice of civil engineering he emphasized the need to talk to the construction foreman and learn from him. He never tired of a story he claimed to have heard from Terzaghi.
Apparently Terzaghi had been called in to deal with seepage from an unstable slope. Terzaghi walked the site once with the construction foreman. Then he walked the site a second time with the construction foreman.
“Tell me, Mr. Foreman,” he asked, “what do the think should be done. The foreman expanded on his own solutions.
“A good idea,” said Terzaghi, “Let us walk the site again and see how we can apply it.”
They walked the site a third time. Then back to the office where Terzaghi sat with the client and the foreman. Complimenting the foreman for his insight, Terzaghi proceeded to recommend a solution that incorporated the best of the foreman’s practical wisdom and Terzaghi’s theoretical knowledge. The slope was drained and stabilized.
I saw Jennings apply this approach in Welcome, a mining town in the Orange Free State of South Africa. Jennings had been retained as the consultant to design the foundations for a new shaft for a new mine. He took me to do the clerical work. He took Tony Brink, a lecturer in engineering geology to define the geology. For Jennings also taught us never to go to site without a good geologist; his theory was that a soil mechanics engineer should know and understand the geology of the site and a good geologist was indispensible. Tony Brink was such a person, and my one regret it that I never got to know him.
We had planned to auger 36-inch diameter holes and descend these in a chair suspended from a tripod. The rig bit into the soil and the hole stayed open for the first ten or fifteen feet. Then we hit sand. The water and the sand flowed into the hole, and the auger could not keep it open. We gingerly peered down this collapsing mess of sand and water, and backed off.
There was no way we were going down that hole. Jennings was silent, and then announced that negative information is as valuable as positive information and the only way to get a shaft through that flowing sand was by constructing a caisson.
A caisson was constructed. Mike Gowan stayed to supervise its construction. All went well until just before the caisson was all the way through the sand, it tilted and stuck. Nothing could make it move. Jennings took me down again to inspect. We walked the site three times with the construction foreman. Just near the end of our third turn, Jennings turned to the foreman and said: “I do not know how to get this thing moving again. I must return to Jo’burg and think about it. But there is one thing that it is a pity we cannot do: that is let off a large blast at the side that is stuck.”
We returned on the evening flight to Johannesburg. The next day, Jennings collared me and said: “The caisson moved overnight and is sinking nicely. I do not know what made it move, although there is a report that the construction foreman let of a bit of dynamite overnight.”
Many who came into contact with and who were influenced by Jennings were far smarter than he was. I grieve to think of the arrogance as his kindness, tinted admittedly by self-interest, was rejected and those on whom he sought to bestow opportunities rejected him, went to foreign universities, or took up the study of structures or hydraulics.
He could be frustrating it is true. He worked so much on the basis of judgment when he could not understand the theories and equations. He got an idea in his head and hammered away at it until he saw results that felt good. However much we were frustrated by that, I have noticed as age creeps on us, that too many of us, his students, now display the same tendencies.
There were many others who influenced the many SRK folk who have advanced the company. But this is not their story and not all SRK came from Wits, so we leave their stories for another day.