Trailblazer in Geotechnics

July 12, 2008

By Fourie, Lorraine

He has been labelled idiosyncratic, demanding, impatient, at times downright bloody-minded – exacting qualities that spring from an imaginative and inquisitive mind tirelessly searching for practical solutions to engineering problems. But he is also known as a thorough gentleman, courteous and fair, a friend and confidante who takes time to listen and who cares deeply about humankind. Throughout Dr Ross Parry-Davies’life, his muse has been his wife, Renee, who has shared his every success and setback. Lorraine Fourie met the couple at their home in Hout Bay in the Cape, where, on observing their energetic lifestyle, one hesitates to say that they live in retirement GUTSY FROM THE START

R P-D showed a keen interest in science from a very young age. Growing up in Queenstown, he remembers setting up his own ‘laboratory’ in an old stable.

‘Once, I made my own Bunsen burner by installing a tube through the lid of a Lyles Golden Syrup tin, half-filling it with methylated spirits, pressurising the tin with a bicycle pump and lighting the jet of meths emerging from the end of the tube.’ Needless to say, he lost all his eyelashes and eyebrows in the resulting explosion.

This was nothing compared to the day that he built a cannon with a 1/2-inch barrel, charged it with gunpowder and match heads, and stuffed lead shot down the barrel as the projectiles. He aimed for the top of his father’s garage door and fired, expecting only that the wood would be peppered with tiny holes from the shot. However, it resulted in the door lurching crazily and falling to the ground. For this experiment he was rewarded with ‘four of the best’ and had to cool his bum in a basin of cold water.

The premature death of his father, who was the headmaster at Queens College, left the 15-year-old R P-D the male head of the family. Money was tight and he changed his career plans from a six- year medical course to a four-year civil engineering course. Even so, university fees were not cheap and R P-D set his sights on winning the Sir Abe Bailey Bursary for the best matric results in the Border area. This he achieved, giving up all sport activities for the last semester of school to concentrate on Latin, which he considered his Achilles heel. He started his BSc Civil Engineering studies at the University of Cape Town in 1942 and was deeply disappointed at failing his medical when he wanted to join the army at the end of that year.

After graduating, R P-D joined MacNicol Construction on the Churchill pipeline, which was being built for Port Elizabeth Municipality. ‘The pipeline job was a great training ground as it involved survey, concrete works, timbering, under and over river crossings and excavations ranging from sand to rock to clays requiring support.’ From a shrewd Scot he learned about cost- accounting. ‘My family have had to put up with my crossing Ts and dotting Is ever since.’


Next step was to become site agent on the construction of a composite dam in the Zuurberg mountains in the Eastern Cape. Although still pretty green, R P-D showed his depth of thought, a trait for which he became renowned: According to the design, the left flank earth dam section was to be founded on a natural clay blanket, resting on top of some 8 m of alluvium. This clay blanket was viewed as sufficiently impervious to make it unnecessary to excavate a cut-off down to rock. This worried R P-D and he excavated trial pits downstream of the dam and pumped in water. ‘To my consternation I found that, at 40 000 gallons per hour, I could not fill the hole as the water just seeped away into the alluvial material.’ When he told MacNicol about his concerns, the MD called a meeting. Although the inspecting engineer thought that the ‘youngster’ was right, construction went ahead according to design. In the end his fears proved accurate: ‘Water saturated the alluvium below the clay blanket, which settled, shearing the contact with the concrete spillway and cutting a channel 30 ft wide and 30 ft deep right down to the rock, virtually emptying the dam. Not many civil engineers can claim to have built a dam that failed, in the anticipation that it was likely to fail.’ Fortunately R P-D insisted on getting a signature every day that the work had been carried out strictly in accordance with the specs.

It was then that he started to court Renee Ella, a girl whom he had admired ‘from afar’ since school days, and whom he married in 1952. Soon afterwards, the newly-weds set off for the construction site of the Keerom Dam in a gorge in the Matroosberg mountains, near Worcester. The valley was so remote and isolated that it was nicknamed ‘Wegkruip’, the only means of communication to the outside world being by radio. R P-D felt that the site, a narrow gorge, was perfect for a blondin (cableway), so designed and built a home-made one that worked perfectly.

The following two years were spent in the consulting field with F E Kanthack & Partners (now Knight Piesold) on the design of the Kafue Hydroelectric Project in Northern Rhodesia (now Zambia). The couple had settled in Johannesburg with their first-born daughter, Janice (1953), who was soon followed by the second, Megan (1954).

In 1956 the Kafue project was suspended in favour of the Kariba Dam. R P-D, who had used his designs for Kafue to obtain his AMICE, moved back into contracting by accepting an offer to join the Cementation Company as contracts engineer on Kariba and other projects. Cementation had been subcontractors on Keerom, so knew of his home-made cableway. In his first week he was told to build a cableway within six weeks, capable of carrying a two-ton truck across the Zambezi. Working 36 hours non-stop, he staggered into the workshop on a Monday morning with his drawings, ready for them to start manufacturing the components. He had met the time limit with a day to spare.

Still at Cementation, he applied and improved techniques for the stressed strengthening of a series of concrete dams throughout South Africa. During the construction of what is now the Dap Naude Dam in Magoebaskloof, his design for large-capacity steel anchor heads worked excellently in prototype and for the first twelve anchors. He was blamed when some failed subsequently. Many years later he discovered by accident that the failures were because a much harder steel had been used for the heads instead of the softer mild steel he had specified. Cable heads, identical to his original design, were later patented by a Swiss company, but it was too late for R P- D to oppose the application.

In what was a world first at the time, he applied the same technique to the provision of lateral support for a deep basement excavation face in Port Elizabeth. ‘I had looked at a basement being excavated in Johannesburg and it was a mass of struts and shores – very difficult to build around – and I suggested to my MD that perhaps we could use anchors to replace this mess. He may have mentioned this to a consultant in Port Elizabeth. Shortly afterwards this consultant asked our Cape Town office whether Cementation thought that anchors could be used to support a basement excavation 15 m deep in PE. This concept is old hat nowadays, but in those days I was virtually standing alone as everyone said it was like trying to lift oneself by one’s shoelaces. At a depth of 12,5 ft we put in temporary struts, installed the anchors, tensioned them and removed the struts, all the while keeping our fingers crossed. The face stayed put.’ The procedure was repeated in phases all the way down the entire 50 ft. R P-D tried to patent his technique, but his attorney advised him that it was simply a modification of pre- stressing and non-patentable. He then fought off patent applications from all over the world. ‘If I had been better advised, I would have been a very rich man.’

By this time R P-D and Renee’s third child, David, had been born (1956) and they happily bore the brunt of friends’ jokes about having their family in rapid ‘concussion’. R P-D was also accepted into Freemasonry. Because he had been so privileged in life, he felt that he would like to help those less fortunate. His involvement in the movement, known for its support to the needy, is an indispensable part of his life.

Persistent and resourceful

In 1960 the family moved to Cape Town when R P-D was appointed manager of the Cape branch of Cementation. One of his first tasks was the construction of the Apostles water tunnel through Table Mountain, which would traverse a geological fault zone about 500 m from the Camps Bay portal. ‘Of all the tunnelling operations I had been involved with, this one was the most difficult and challenging.

‘One afternoon I was met with the news that the tunnel roof was collapsing, the sidewalls were caving in, and the tunnelling team were knee-deep in water.’ R P-D discovered that the team, who had successfully penetrated a smaller parallel fault zone, had assumed that they were through the major one. They had proceeded quickly, realising that they had reached the real fault zone only when they were 15 ft into it. By retreating about 18 ft and creating a sandbag bulkhead in sound rock with large pipes carrying the water through the bulkhead, then injecting a weak sand-cement grout into the collapsed zone, he got the water under control. He finally emerged after 48 hours in the tunnel. A cement-bentonite mix was then used to form a grout curtain and the tunnel continued through this material. It took six months to penetrate the fault, whereas tunnelling at this site had previously advanced at up to 30 ft per day. “The completed tunnel attracted huge interest nationally and internationally, also because of the “raise” at the Disa Gorge end. Nearly 1 500 ft was driven uphill at an inclination of 30″, an incredibly difficult operation.’ A technological achievement that R P-D regarded as simply a practical solution to an engineering problem was his technique of creating a gravity-type soil wall to keep boulders and cobbles from falling onto De Waal Drive. ‘After creating a ‘skin’ of mesh-reinforced gunite over the face above the road, I tied the skin back into the soil mass with bolts, which were anchored in cement grout and tensioned.’ He never gave this technique a name, but 20 years later it was ‘invented’ in Europe and called soil nailing. It was taken up by GeoFranki, who refer to it as geo-nailing.

Vibroflotation was also unknown in South Africa at that time. R P- D watched this process in the UK and realised its potential as a ground improvement technique, so he imported a vibroflot from Cementation UK. The first major contract was for the foundation treatment of the sugar silos in Durban, under the supervision of my colleague Duncan McColl, who, I believe, subsequently put vibroflotation on the map in South Africa.’

In 1963 R P-D was called back to Johannesburg to take control of all Cementation’s geotechnical work in southern Africa. He and his wife were in the prime of their lives and did a great deal of the work themselves, on the property they had acquired in Bryanston, teaching their children the lesson of dignity in labour. RPD had more time to become involved with Queens College Old Boys’ Association and to move up the Freemason ranks, while Renee, who had a background in teaching, privately taught pupils with learning problems.

His work in the use of ground anchors for lateral support of basement excavations was widely applied in and around Johannesburg, the major sites being the Rand Daily Mail building at the Standard Bank Centre, the Star basement, and at least a dozen others.

Assertive and daring

On the Star excavation, which went down to 22 m, R P-D differed from the specialist consultant – then the doyen in geotechnics in South Africa – who believed that the top two rows of anchors were sufficient. R P-D believed that anchoring should be carried all the way to the bottom. At a depth of 18,3 m a huge wedge of weathered rock fell out from below the top anchors and a massive crack developed halfway across President Street. Had only the top two rows of anchors been installed, the collapse would have extended to the surface, and would have swallowed cars and pedestrians. After this, anchors were always taken all the way down to the bottom.

With the Trust Bank – at 31 m it was the deepest sheer basement in the world at the time – a different approach was adopted. He recounts the background: “The City Engineer temporarily forbade the use of anchors. He said, “Since you brought this technology of ground anchoring to Johannesburg, people are putting down basements where they never previously thought of it; that means extra cars during peak times, and my streets just can’t cope.” Ruben Stander proposed a circular structure, but this was rejected by the architect as a waste of space. The concept of a ‘squashed circle’ then emerged – that is, four flat arches tangential to the sides of the city block and joined by four small arches at the corners. ‘However, there was the risk of the flat arches buckling under the earth pressures, and Ruben and I developed the concept of creating four huge flat jacks behind the corners and pressurising these with cement grout to induce an inward thrust at the corners and a corresponding outward thrust behind the flat arches.’

When putting theory into practice, R P-D admits to having had butterflies in his stomach each time they carried out the grouting operation. Before the job started, his friend Professor Jere Jennings phoned him, saying: ‘Ross, don’t do it, you’ll lose your reputation completely,’ but it worked. At a conference in Mexico in 1969 Ralph Peck expressed interest in the technique, and at a conference in Tokyo in the early 1990s the Trust Bank was described as being 25 years ahead of its time.

During this period R P-D carried out the foundation grouting of at least 20 dams throughout southern Africa. In the civil engineering field up north he became known as ‘Mr Cementation’ and was recognised as being among the top experts on grouting technology and ground anchors locally and internationally.

He also patented what he called the ‘porcupine’ technique for consolidating old goldmine workings without man-entry into the workings. The concept was to drill holes from the surface to intersect the stope at depth in competent rock and insert the ‘porcupines’ into these holes. These were made from a central tube with ‘quills’ attached. When they were inserted, the quills folded back. On entering the stope, they sprang out again to create an entanglement of wires across the stope. Concrete heavily ‘doped’ with fibre was then dumped through vertical holes on to the porcupines to form a bulkhead and the void filled with a cheap lean sand-cement-bentonite grout. When a section of Main Reef Road in Langlaagte collapsed over one of the old workings, the technique was used successfully and the road was re-opened.

In 1970 R P-D resigned from Cementation to become a shareholder and executive director of Westcott & Associates. ‘In some respects I was sorry to leave, because the work I did was stimulating and stretched me technically, but there were new possibilities in the move.

Six months later he founded Ground Engineering Ltd (GEL), with very limited capital. He made his first grout pump from pipe fittings, and the grout mixer was fabricated from a 44 gallon oil drum. Within two years GEL was becoming ‘a thorn in the flesh’ of the big geotechnical contractors, and in 1974 the Westcott Group accepted an offer from LTA to buy GEL, on condition that R P-D continued to run it. As CEO of LTA’s geotechnical arm, he widened the disciplines of GEL to include pipejacking, guniting, horizontal collector wells, ground freezing and diaphragm walling.

The first major contract with LTA was the stressed strengthening of the Laing Dam for the East London Municipality, where 600 tonne anchors were specified. ‘I had previously done anchors of 350 tonnes, but for 600 tonners I was uncertain of the fixed anchorage length. I made a 36-strand anchor with a 2 metre fixed anchorage length. Because there was no jack in South Africa to test this size of anchor, I tensioned each strand individually up to 80 % of its ultimate strength – a total of 900 tonnes. This satisfied me that a 4 metre fixed anchorage length would be OK. I once again used a blondin for the job, which went like clockwork. We had only one problem with the consulting engineer. He wanted to anchor the cables in the dry.’ Remembering the early experience of anchoring in the dry at Dap Naude Dam, R P-D argued that if he anchored the consultant’s way, the consultant would have to accept responsibility for the efficacy of the anchors, but if it were done his way, he would accept full responsibility. ‘We anchored all the cables “wet” and had not a single problem.’

An extremely taxing project at this time was the Huguenot pilot tunnel. It was constructed to explore the geology of the proposed road tunnel between Worcester and Paarl and to drive cross-cuts from the road tunnel to the pilot tunnel, so that in the event of a disaster in the tunnel, there would be an escape route. The rock tunnelling on the east side gave no problems, but the Paarl side gave plenty. The worst possible material for tunnelling was encountered – completely saturated residual granitic talus. ‘When tunnelling started on this end, we used spiling, but had mud rushes. Next we tried jacking “knives” ahead of the face. Again we had mud rushes. It was like trying to dig a hole next to the sea, as the material simply liquefied and came at us.’ Grouting ahead of the face using the tube-a-manchette system as an experiment for about 6 m worked perfectly, but this pilot tunnel was only about 3 m diameter, and part of the objective of the pilot tunnel was to establish methods for the first road tunnel, which would be 13 m in diameter. ‘We were not confident of taking a 13 m tunnel through this material under cover of a grout curtain, so decided with the consultants that freezing offered a better solution. We built our own freezing plant with the assistance of Deilmann of Germany. We froze the water around the tunnel, creating an ice-wall within which we could drive the tunnel, put in concrete support, and then allowed the ice to thaw. When the consultants called for tenders for freezing the first 160 m of the road tunnel on the Paarl end, we tendered with Foraki of the UK and won the tender. Once again the job went like clockwork.’


As a challenge to his engineers, R P-D put together teams consisting of a young and an older engineer, and got them to look for new geotechnical technologies that could be used in South Africa. Duncan McColl as the senior engineer, with Bernie Krone the young engineer, came up with dynamic consolidation (DC), which was developed by the French Menard Group.

Bernie, now CEO of Esor, says: ‘What can I say about a man who has had such a profound and varied influence on my life? Boss, mentor, colleague, and friend.’ He remembers his first impressions of R P-D: ‘I thought he was rather stiff, formal, a stickler for detail, a man with his eye on the time. These attributes haven’t changed and he still has an eye for time as he continues to make every second of his 84 years count. But he also had patience and tolerance. I left his office one day in a huff because of some minor criticism that I couldn’t bear and slammed the door so hard that his pictures fell off the wall. I apologised later and he forgave me instead of firing me. He always gave me the benefit of his considerable experience and knowledge, and this became even more obvious after I had left GEL and he had retired to the Cape. Ross introduced me to Freemasonry and we became friends – I am often privileged to have him stay over at my home when he is in Johannesburg.’ Following the recommendation from Duncan and Bernie to look at DC, R P-D obtained an exclusive licence from Menard to use the process in South Africa. On a contract involving a 2,1 km length of road that would carry the Johannesburg Western bypass over marshy ground, they found that the underlying material did not respond to conventional DC. ‘We therefore carried out a modification of DC, called dynamic substitution. This involved pounding mine waste rock through the marsh down to competent material, and carrying the road on a similar rock mattress – also consolidated by DC spanning between the columns. We used a 40 tonne pounder dropped from a height of 30 metres and built a Menard tripod to handle it. Certainly no pounder of this size had been used in South Africa before, and probably hasn’t been used here since. This was apparently the forerunner of many dynamic substitution jobs in other parts of the world.’

In 1976 tenders were called for the Drakensberg pump storage hydroelectric project – at over R100 million this was a major project by any standard. R P-D headed up the tendering team, a joint venture between LTA and Shaft Sinkers, and they won the contract. During construction R P-D was part of the management committee of Drakon, the joint venture formed to carry out the construction.

In the 1970s, while on a game drive at Londolozi, R P-D received a radio message from Jere Jennings to go to Zebediela immediately. On arrival, Jennings took him to Magoto Dam, which was piping badly. ‘The discharge was being caught in a 44 gallon oil drum and every hour the water was decanted and the sediment weighed. The rate of increase was frightening. Jere had already alerted the police to stand by to evacuate the valley at short notice if needed. He asked me how long I thought we had before the dam failed. I estimated seven days and he thought four. Nobody will ever know who was right because I managed to choke the piping by grouting in four days using some very unusual ‘additives’. Jere and I often disagreed on geotechnical issues, but our friendship always survived. This was no exception. He wanted me to drill just upstream of the leak, but I had spotted a small unusual feature in the foundation records about 50 metres away. I drilled the first hole where I wanted to, and injected fluorescene dye. Within 20 minutes the dye-discoloured water came out at the leak. It was then a case of using every trick in the trade to choke the piping. “We were lucky, but as Gary Player has said, ‘The more I practise, the luckier I get.”

In those years he became involved with Chapman’s Peak Drive. On viewing a major rockslide in 1977, Professor Tony Brink, who had been called down by Basil Kantey, said immediately: ‘This is a Ross job.’ Basil replied that he knew it was a ‘rush’ job. R P-D was called in and used what was considered the latest technology in anchoring at the time, but is not acceptable by today’s standards. Those anchors served their purpose for 25 years until they were replaced during the reconstruction in 2003.

In Cape Town, on a site just behind the City Hall, Ground Engineering carried out the largest diaphragm-walling project ever tackled in the country at the time. ‘Being reasonably close to the sea, the basement went well below the water table, and the object was to retain the sides and stop water inflow.’

Forming a joint venture with British geotechnical contractor Colerete, he became involved in the grouting ahead of the Island Line, then under construction in Hong Kong. “The problem was that the tunnels were all below sea level, and some very sophisticated drilling and grouting was carried out, using cements, bentonites and chemicals.’

One of R P-D’s senior representatives in Hong Kong was Ernst Friedlaender. Ernst, who now lives in Sydney, Australia, commented: ‘Working for South Africa’s leading geotechnical contracting company, under Ross’s inspirational guidance, was a dream position to be in. He was always at the forefront of technology and innovation, driven by his passion for geotechnical contracting and carried by his ability to attract and inspire the people that worked for him. The words ‘can’t be done’ didn’t exist in his vocabulary. Many of the key players in our industry today have been groomed by or exposed to Ross in some form or other during their career. Ross’s success can be measured in many ways, but possibly is best represented by the network of people around the world that have been positively influenced by him. There are not many countries in the world where someone of influence does not know Ross Parry-Davies.’

A person who remembers him well is Helen Parker, R PD’s former secretary. Demanding though he was – she recalls having to retype a 55-page report five times – R P-D was the most courteous and fair man she ever had the pleasure of working with. ‘I never

heard him raise his voice or use derogatory language to any of his staff, no matter the seriousness of the matter, or who was responsible. He would always sit one down in his office and discuss the matter to the point of a cordial resolution.”

This attitude was an offshoot of the culture of quality and integrity that prevailed in GEL. ‘It was an unwritten law that we simply did not lie to clients and consultants,’ R P-D commented. ‘It is so easy for an operator to make a foundation investigation look better than it really is. The whole staff knew that if anyone lied, he would be fired immediately. We eventually acquired the reputation of being quasi-consultants, because civil consultants would ask us for our advice on solutions for difficult geotechnical problems.’


He retired from the LTA Group in 1987 and ‘to keep out of mischief he formed R Parry-Davies & Associates, a small consuiting practice that provided a problem-solving and troubleshooting service within the civil engineering and geotechnical fields. From the start, he was as busy as ever, the monitoring of all the anchored structures on the national road network being one of his commissions.

By this time he was a qualified arbitrator and a fellow of the South African Association of Arbitrators, having passed the association’s exams in third place and outshining the younger members on the course. Eventually he acted as mediator, conciliator and arbitrator, as well as chief witness in several major disputes, and had the satisfaction of seeing these settled just before or during hearings.

He also heeded the call by his professional peers to commit his extensive knowledge to paper by registering for doctoral studies at the University of Pretoria. Repeating the rigorous routine he followed in his arbitration studies, he got up at five every morning to put in a few hours of work before going to the office. As usual, Renee was at his side, proofreading the 520page dissertation. His thesis, ‘Grouting in Southern Africa’, was submitted in 1991, gaining him his PhD in Civil Engineering.

Using an unconventional modification of the jet grouting system in bouldery material – initially testing his theory in a glass- fronted container filled with rocks and sand – R P-D solved the problems engineers had encountered over a pier foundation of a jetty at Hobie Beach, Port Elizabeth. At a conference in New Orleans, where he presented a paper on this work, the eminent American geotechnical engineer Emilio D’Appolonia lauded it as ‘an inspiration of how revolutionary work should be done by experiment followed by execution’. ‘Of course, jet grouting in bouldery material is now commonplace,’ R P-D remarks.

As the geotechnical member on the panel of experts overseeing the construction of the Letsibogo Dam in Botswana, he directed the grouting, which was carried out by an international contractor. ‘These people had never previously come across my system of recording grout takes that enabled one to see the whole picture at a glance.’

In 1997 R P-D and Renee bade farewell to Johannesburg and moved to Hout Bay in the Cape. ‘I thought that my workload would dry up, but that just didn’t happen.’ He continued his work for the Department of Transport, monitoring anchors throughout the country, and investigating anchored structures and cuttings for the South Peninsula Municipality throughout its region.

He still commuted regularly to Johannesburg, inter alia to discharge his masonic obligations to the chapters in his district. By this time the highest honour in Freemasonry, the 33rd degree, had been conferred on him.

Having become involved with the Hout Bay and Llandudno Heritage Trust, he cut his way through loads of red tape to have a replica of Thomas Bain’s tombstone placed in a prominent position on the rerouted Victoria Road above Llandudno. ‘It was unveiled on Heritage Day in 2000, and in deference to Bain’s Scottish ancestry, I arranged for a piper to liven up the proceedings.’

He was appointed specialist advisor for the stressed strengthening of two old reservoirs on Table Mountain, built in 1896 and 1906, a project that won the SAICE Western Cape Branch Award for Technical Excellence in 2001. In 2003 he was appointed specialist geotechnical advisor on the restoration of Chapman’s Peak Drive, with the emphasis on ground anchoring to support the half-tunnel and to tie back the concrete structures. The project won the SAICE Civil Engineering Award for technical excellence that year. At the awards presentation ceremony in 2004, R P-D was elected an honorary fellow of SAICE. ‘This is the highest honour that can be bestowed on a civil engineer in South Africa. Mike Shand said it was the only time that he saw me stunned into silence.’ Although he has slowed down in retirement, he still makes every second of his life count. He is currently documenting some of the professional developments he has pioneered, and is passionate about the conservation of our planet that is so much at risk because of man’s avarice. ‘If I could express a wish, it would be to be remembered as one who cared for our fragile planet, a competent geotechnical civil engineer, and a humanist.’

R P-D in 1978 as national president of the Queen’s College Old Boys Association

In 1960 the family moved to Cape Town when R P-D was appointed manager of the Cape branch of Cementation. One of his first tasks was the construction of the Apostles water tunnel through Table Mountain, which would traverse a geological fault zone about 500 m from the Camps Bay portal. ‘Of all the tunnelling operations I had been involved, with, this one was the most difficult and challenging

He was appointed specialist advisor for the stressed strengthening of two old reservoirs on Table Mountain, built in 1896 and 1906, a project that won the SAICE Western Cape Branch Award for Technical Excellence in 2001. At the awards presentation ceremony in 2004, R P-D was elected an honorary fellow of SAICE. ‘This is the highest honour that can be bestowed on a civil engineer in South Africa. Mike Shand said it was the only time that he saw me stunned into silence’

Copyright The South African Institution of Civil Engineers May 2008

(c) 2008 Civil Engineering : Magazine of the South African Institution of Civil Engineering. Provided by ProQuest Information and Learning. All rights Reserved.

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