Chapter Two - Pre-stressed Concrete Post-Tensioning System

The following accounts are my efforts in bringing new engineering technologies to Malaysia and their effectiveness in improving the engineering services in Malaysia during the two and a half decades when I was active in my professional career. The first is the world renowned pre-stressed concrete post-tensioning system – Freyssinet system.

After Malaya gained its independence from the British Empire in 1957, it started the process of "Malayanisation" in which British officers serving in Malaya were slowly being replaced by Malayans.

By the time I joined the PWD in 1967, most, if not all the British engineers had been replaced. Ostensibly, what the British had left behind in PWD was the legacy of an administrative system that was most appropriate at the material time but unfortunately it also left a conservative mentality amongst the engineering professionals who were doggedly reluctant to accept new engineering technologies.

As a young and enthusiastic engineer I was rather frustrated for not been given the encouragement to make innovations and changes in the design of bridges.

When the original Bota Bridge, designed by PWD's expatriate engineers in the mid 60s using 40ft pretension girdles, was destroyed by flood in 1970, I was working as a time-scale design engineer in Airport Section of the Design & Research (D&R) Department in PWD headquarters. Though D&R Department then had a Bridge Design Section, for some unknown reasons, the redesign of the washed-away Bota Bridge ended up in Airport Section! Also, during this period, Muar Bridge and Batu Pahat Bridge were under construction. These two bridges were designed by a local Consulting Engineering firm, appointed by PWD Headquarters. If this firm could undertake the designs of these two bridges, why the redesign of Bota Bridge was not given to this firm?

In the redesign of Bota Bridge in Perak, I was assigned to determine the cause of its collapse and come out with a viable proposal. I was left completely on my own to carry out hydrological and subsurface investigations. From these investigations and further studies carried out by me, it was indisputable that the original design of the bridge was totally inadequate to even cater for a flood frequency of 1-in-5-year. (Note: the flood frequency of 1970 was estimated as 1-in-50-year.) The bridge was totally submerged during the 1970 flood, its pier spans of 40 ft was insufficient to provide for the free flow for debris brought down by the flood from upstream and the piled-foundation was too shadow to cater for the riverbed scour during the food. And this is the sole reason why the bridge collapsed.

My proposal was to construct a bridge with a minimum pier span of 140ft. with its deck arising at its abutments above the 1-in-50-year flood to above that at its mid span and a foundation supported by piles with an imbedded length of 40 ft or more. The total length of the bridge would be about 1,400ft. But it was only after a long and tedious effort of convincing the high-ups in PWD before my concept of the design was reluctantly accepted.

I was responsible for the design of the substructure and my colleague, the late KD Chang, the superstructure. Based on the geotechnical information from the subsurface investigations carried out earlier, bored piling was the most appropriate for the bridge’s foundation because the substrata consisted mainly of dense granular materials. But unfortunately bored piling was something new then and not a single piling contractor had the appropriate equipment to do it! The only option was to use open-ended steel piles. I proposed two types of steel piles; a welded piped pile and a welded twin H-pile. The test piles were ordered from Hume Industries and a tender was called for driving and testing. The piles were designed to take a working load of 200 tons each and a test pile was to be tested to twice the working load, i.e. 400 tons. But at that time, the maximum capacity of hydraulic jacks available was 200 tons. Therefore a testing procedure had to be devised to take into account this limitation and the existing conditions at the site. I proposed to use a steel girder placed over the test pile forming a T structure. A 200-ton jack would be placed on one end of the cantilever to jack against a kentiledge of 200 tons and the other end would be propped against another kentiledge of 200 tons in order to impose a load of 400 tons on to the top of the test pile. To accommodate this testing procedure, it was important that the location of the test piles had to be selected so that part of the remaining bridge deck not washed away by the flood could be used not only as a platform for the piling machine but also to provide adequate kentiledge for the tests. The tests were successfully conducted and the piped pile was selected as it was more economical and could be locally fabricated.

After the completion of the pile tests, Chang and I proceeded to complete the design and tender documentation of the bridge. I was also assigned to compile all design calculations and drawings when the designs of the sub and super structures were completed. In the design of the superstructure, we were instructed to use the post-tensioned 102ft girdle.

When I first joined PWD in 1966, pre-stressed concrete construction was in its infancy. It was used mainly in precast pretension girdles for bridge construction with a maximum length of 40ft. The first precast post-tension bridge girdle was 102ft long designed by an engineering consulting firm in Kuala Lumpur, appointed to design two major bridges in Muar and Batu Pahat in Johor. Upon the completion of these two bridges, the 102ft post-tensioned girdle was adopted as a PWD's standard design.

As a young and inquisitive engineer, I wanted to know more about the prestressed concrete design and requested the head of the Bridge Section (KC Lee) for the design calculations and drawing of the 102ft post-tensioned girdle. But I was pointedly told to use the drawing without question as I was told the design had gone through a thorough check by some experts in PWD.

Not satisfied, I carried out on my own a detailed design calculation of the 102ft girdle and discovered that it was under-designed based on a more stringent loading condition as specified in the relevant British Standard, used in the design of bridges in Malaysia. And I also noticed that the girdle was designed using a specific pre-stressing system (BBRV)!

I reported my findings to my superiors and submitted to them all my detailed calculations. Again, it was after a long and tedious explanation, especially with KC Lee, that the higher-ups in PWD HQ, including the DG (LT Thian) finally accepted my exertion that the existing 102ft post-tensioned girdle was under-designed. I was then told to rectify the deficiency of the existing drawing of the 102ft post-tensioned girdle.

It was a simple matter; what I did was, maintaining the cross-section of the girdle, just increased its bottom flange by a few inches! Two sets of steel moulds for the 102ft girdle were in the procession of PWD after the completion of two bridges in Johor. With the simple amendment to the design, the moulds could also be easily modified. In the meantime, while redesigning the girdle, I did a bit of research on other pre-stressing systems available in the world then. I discovered that there were, besides BBRV, other established systems like Freyssinet, VSL and CCL were widely used in many developed countries. Not to favor any system, the redesign carried out by me did not specify a system to be used, but the profile of the resultant tensioning tendon and force required for the girder were specified. A sub-contract tender document for the supply and implementation of the post-tensioning work was prepared.

When all the designs, drawings and tender documentations were completed I felt it was a good opportunity for me to get involved in the site supervision and contract administration of the construction of the bridge. For nearly five years working as an engineer after graduation, I had spent most of my time in the design office. It was time now to get some solid experience in the construction site to make me a better all-round engineer. With this in mind, I approached the DG of PWD who had shown great interest in the re-design of Bota Bridge, and requested for his permission to appoint me as the resident engineer (RE) for the construction of the bridge. I further asked him to transfer me back to the HQ after the completion of the bridge as I would then be an asset to the D&R Department. He agreed to appoint me as the RE but told me pointedly that he could not transfer me back to the HQ after the completion of the bridge because as a RE, I would have to be transferred to the State of Perak as a state officer and thereafter I would be under the State’s jurisdiction to be transferred anywhere they thought fit. It was obvious that for what I had done, he was not even prepared to lift a finger to help but instead took pleasure in pouring cold water over my good intention.

For this reason I decided to quit PWD. But to quit was not a simple matter because I was already married and had a family to feed. I pondered over what I wanted to do for my future, and I had a choice to be a consulting engineer or a contractor. Also, with my experience I could easily find employment in a consulting engineering firm or a contracting company. But after being employed for over five years, I thought I should try to venture into something on my own and to stand on my own two feet. And that was exactly what I finally decided to do – one foot in operating a consulting engineering practice and the other in a specialist contracting outfit!

There would be no problem to start a new consulting engineering practice as there were not many in existence then. But to venture into a specialist contracting business, I needed to have in my possession something that was new and had room for expansion. That was something that I had in my hand before I decided to quit PWD.

From my limited research on the various patented pre-stressing systems available, I found that Freyssinet system was the first to be introduced in the early 1940s and was widely used throughout the world. It was developed by the French, but a British company, PSC Equipment Ltd. had the exclusive right to manufacture the Freyssinet products in the UK and market them all over the world.

Freyssinet system was introduced by the French Engineer Freyssinet and it was the first method to be introduced in the world.  

When I was re-designing the 102ft pre-stressed girdle I wrote to PSC Equipment Ltd. making enquiries about their products and informing them about the recent application of pre-stressed concrete in bridge construction in Malaysia. They were positive in their response and were prepared to establish their presence in Malaysia. I was invited to visit them in the UK to discuss the matter further.

Confident that my coming meeting and discussion with PSC Equipment would be successful in bringing the Freyssinet post-tensioning system to Malaysia, I set up, without any hesitation, a company called Prestressed Concrete Structures Sdn Bhd (PCS) in September 1970. This company would hold the exclusive agency for the Freysinnet system and undertake post-tensioning works in Malaysia. I left the composition of the shareholders in the company to be decided later as I had to take time to look for suitable partner/s.

Before the end of Oct 1970, Chang and I completed all drawings and tender documentations for the construction of the piling and super-structural works of the bridge including the tender for the post-tensioning sub-contract. Immediately thereafter I took a 2-week leave to go to London to meet PSC Equipment Ltd to finalize the business of promoting the Freysinnet system in Malaysia. I flew by Aroflot, the cheapest airfare to London with a stopover in Moscow. It was my first ever trip oversea by air and with an over-night stop in Moscow, it was also my first time to see a snowfall. I arrived at London Heathrow on 26 Oct 1970 and the Sale’s Director of PSC Equipment, Tom Marquis, was at the airport to receive me.

I was brought to their office/factory in Iver, east of the town of Slough about 35km from west of central London, to meet the managing director, Gordon Wright  and other senior staff. I also visited their manufacturing unit and observed how the pre-stressing wedges were manufactured.

We discussed the new company I had recently set up in Malaysia to hold the exclusive agency for Freyssinet system, its main shareholders and its operation. At that period of time, Malaysia had just recovered from the May 13 aftermath of the racial riot in Kuala Lumpur. The racial riot resulted in the formation of the aggressive affirmative action policies, such as the New Economic policy (NEP) which targeted a 30% share of the economy for the Bumiputras. Under this new environment, 30% of the company would be reserved for a Bumiputra, 30% for PSC Equipment and the balance for me.

Returning home from my fruitful visit to the UK, I began to ponder the composition of the local shareholders of the company I had incorporated to take up the excusive agency for the Freyssinet system and undertake post-tensioning works in Malaysia. As I would also start an engineering consultancy company on my own, I need to source a person, with some engineering background, to operate the company. I contacted some friends, graduates from the University of Malaya whom I still kept in touch with and found one who was interested to pursue the matter further. He is YK Kwan who was my classmate in St John’s Institution, KL and also a couple of years together in the Engineering Faculty, University of Malaya. He was working in a one small company, Technical Structures, involved in timber building construction in Kuala Lumpur. I sold him 10% of my allotment in the company. The remaining 30% of my allotment was in my wife’s name.

For Buminputra share allotment, I managed to find a friend, Karim whose parents were very active in politics. He agreed to act as my proxy for 30% of the shares in the company. But officially, as a shareholder he was entitled to enjoy the company’s benefits, like annual Director’s Fees etc.

When the newly formed PCS was in operation, I left PWD in 1971. I was actively involved in the running of my engineering consulting form and let YK Kwan to run PCS.

Incidentally, the first contract awarded to PCS was the sub-contract for the supply and installation of pre-stressed pos-tensioning system for the 102ft pre-stressed girdles for Bota Bridge! Though all drawings and tender documentation were prepared by me while I was still in PWD, I was not involved in any hanky-panky deal in the tender and award of this sub-contract. But I did provide some technical inputs in its early stage of operation.

In 1976, PCS was renamed Pre-Stressed Concrete (M) Sdn. Bhd. (PSC) to reflect on the company’s new core business of pre-stressing along with related engineering products such as bridge bearings and expansion joints. By 1988 PSC was restructured to become a subsidiary of the Freyssinet International Group leading to the change in name in 1991 to the current Freyssinet PSC (M) Sdn. Bhd.

After my retirement from consultancy practice in 1994, I was contemplating whether I should be getting actively involved in Freyssinet PSC (M) Sdn. Bhd. I finally made up my mind not to do so. After a long deliberation and with the blessing of the other shareholders I have also decided to divest all my interests in that company. The rationale was that since I was not able to contribute to the growth of the company it would only be fair for me to let another party do it and bring it to greater heights. A suitable party was subsequently found (Muhibah Engineering) and the deal was soon concluded.

Since its inception in the early 70s, the company has progressively flourished in an environment of intense technical and commercial challenges. It is now well known and trusted in the construction sector in Malaysia for its experience, expertise and competence not only in its core business of pre-stressing but also with other related engineering products. Its MS ISO 9001:2000 certification is a testimony to its excellent quality of service and customer satisfaction. The overall achievement of the company is due to all the hard work and services provided by all its directors and staff and in particular, one of the founder members and the ex-Executive Director Mr Y K Kwan.

Before closing this chapter, allow me to show some of the outstanding projects where pre-stressed concrete construction were undertaken by Freyssinet PSC (M) Sdn Bhd.

• Putrajaya Bridge No. BR9
• Stay cable for Penag Bridge
• Telecom Tower
• Bangunan Boustead
• Permas Jaya Bridge
• HQ of MSC  

                                                                              End of Chapter Two                                             

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