Magazine 1 02 En

The Magazine

www.hilti.com

Spring / Summer 2002

Yokohama

• Belgium: Double capacity • Japan: Origami in steel on Yokohama Pier

• Reliable fastenings for dynamic loads • Career training programme

Page 4

Worldwide

CONQUERING THE OGRE More than 25 expeditions had attempted in vain to conquer the Ogre. Since the first ascent in 1977, no man or woman had set foot on the summit of the Ogre again. This is the English name give to a 7,285-meter mass of snow , ice and rock in Pakistan. But then, along came 28-year-old Swiss engineer Iwan Wolf, a professional German mountaineer Thomas Huber (34) and Swiss physics student Urs Stöcker (24) to challenge the mountain. Last summer, after extreme rock climbing and tremendous physical as well as mental effort they stood on the Ogre’s peak – the second rope team to claim such an achievement.

Hilti engineer Iwan Wolf: Peak performance in rock and ice with a Hilti nail as talisman

This peak mountaineering performance also went hand in hand with a first ascent: Twenty days before the three climbers set foot on the Ogre's summit, they had reached the peak of Ogre III at an altitude of 6,900 metres. Since then, a special Hilti powder-actuated nail, made of titanium, marks the highest point of Ogre III. Iwan

Wolf, a Hilti development engineer, received the nail as a talisman from company colleagues. Not having a powder-actuated tool, he drove in the nail with his ice pick – breaking a record for Hilti, as no Hilti DX nail has ever been placed at a higher altitude.

After his mountaineering achievement, Iwan Wolf returned to Hilti: “Going for the limits of what’s possible and pushing them to new heights”, he says, “is what drives people on in all fields.” ■

At 7,285 metres on the Ogre in Pakistan, Iwan Wolf, heavily loaded, climbs the fixed ropes he had put in place the days before.

WATER AGAINST WATER Water can become a major threat in the Netherlands. At Ramspol, specialists have installed three giant rubber (caoutchouc) sleeves. If a flood warning is given, they fill with air and water in no time, form a dam and thus contain the risk.

Although the principle of holding back water with an inflatable dam had been tried in other countries, it had never been employed in an emergency to avoid flooding. It has benefits: Installed under water, a dam of this kind doesn’t spoil the countryside or impair shipping and it costs relatively little. At Ramspol, three interlinked, inflatable dams 15 metres wide have been put in place over a to-

tal stretch of about 350 metres. When filled with water and air, they reach a height of up to 8.35 metres. Once the water exceeds a predetermined danger level, the caoutchouc-and-nylon dams automatically inflate. As soon as the situation normalises again, they deflate automatically, gradually folding together, within three hours. The entire system is computer controlled. Rollers, which are fastened to steel piers, support the caoutchouc dams. These steel piers are reliably secured to concrete foundations with Hilti HVU HAS-R M 30 anchors. Bearing in mind the significance of the dams from the human safety, scenic and

Stainless steel fastenings for steel supports for rollers carrying the dams.

economic points of view, their builders have used only products of the highest reliability. They estimate that the dams will probably come in-

to possibly life-saving action at least once a year. ■

Page 5

Worldwide

BENEFIT FOR PROFESSIONALS The Hilti Annual Report 2001, published a few weeks ago, gives, on the one hand, insights into the company’s economic standing and shows, on the other hand, how construction professionals all over the world benefit directly from Hilti products and services. Anyone interested can find the Annual Report, either in English or German, on the Internet under www.hilti. com or request a printed copy from Hilti corporate communications, telephone no. +423 234 27 10, telefax no. +423 234 29 56, [email protected] ■

Geschäftsbericht 2001

THE BRIDGE AND THE ANCHOR FASTENING ACADEMY At St. Petersburg, people are talking about the Hilti HSL-G-TZ heavy-duty anchor. It is being used for the first time there to repair a bridge.

Wide and sluggish, the Neva passes through the Russian city of several million before flowing into the Finnish Gulf. At the east end of St. Petersburg’s most famous street, the Nevskiy Prospekt, Nevskiy Bridge crosses the river. Under the burden of increasing traffic, it has sagged. The concrete is cracked, moisture has infiltrated and the reinforcement has corroded. Now, the bridge is under repair and being strengthened from the outside. Beneath the bridge sections, workers from Rizalit, a St. Petersburg construction company, are stretching some 100 steel cables from pier to

pier. As a result of post-tensioning them, the box-girder structure is lifting and the cracks in the concrete are closing. The bridge is regaining its strong and stable shape. The Hilti HSL-G-TZ heavy-duty anchor with its sleeve is ideal for taking up high shear loads. Each HSL-G-TZ of the M20 size takes up an imposed shear load of max. 5.5 tons at the cable ends where the loads are transferred to the bridge structure. These cables are embedded in steel beams, additionally reinforcing Nevskiy Bridge, where they are also fastened with Hilti HSL-G-TZ heavy-duty anchors. When rehabilitation of Nevskiy Bridge has been completed, the bridge sections, each with a span load of 4,200 tons, will have been secured between the piers. ■

The Hilti HSL-G-TZ heavy-duty anchor has a high shear resistance. On Nevskiy bridge, it supports steel beams with cables embedded in them.

Engineers, architects and general contractors as well as scientists all over the world are discovering the Hilti fastening academy as a platform for an exchange of know-how. Following the first event in Hilti’s headquarters at Schaan in Liechtenstein, this meeting has been held around the globe, always with new fastening subjects on the agenda. Innsbruck, Zurich, Seoul, Shanghai, Milan, Tokyo, Rome and Delft have been venues along the way. The number of participants has risen

to more than 600 since the fastening academy was founded three years ago. Hilti Great Britain continues the event by organising it in co-operation with the Imperial College in London. Taking place on August 21st., the next fastening academy will update participants on the current status of fastening and joining technology for structures in civil engineering. If you would like further information, please contact Sean Bonnes, bonnsea@ hilti.com ■

ENTHUSIASM One of the youngest Hilti fans in the world is a little girl who lives in South America. On finding a Hilti flag in father Josue Lopez’ car, three-year-old Zue made a noble robe out of the red cloth. Her proud father, who works for Hilti, grabbed his camera for a snapshot. An early brand preference sometime lasts a lifetime. ■

It doesn’t always have to be a hammer drill: Zue Lopez shows what a three-year-old Hilti fan should wear.

Antwerp’s venerable central station is being renovated and enlarged. Alberic Gregoor, a specialist in cutting and drilling concrete, first worked with pneumatic tools until he discovered the Hilti DD EC-1 diamond coring system: “I purchased it to make things easier for my staff.”

Page 7

Construction

DOUBLE CAPACITY The capacity of Antwerp Central Station in Belgium is being doubled. High-speed trains will run through it, beginning 2006. Speed – with top quality – is also what Alberic Gregoor wants when working. By Ursula Trunz

s it quiet envy or sad forlornness? With stoic calm, the venerable building of the Diamond Exchange on Pelikaan Street stands opposite Antwerp Central Station silently “watching” it being modernised and enlarged. In 2006, trains will arrive and depart on three levels, and the capacity of the station will have doubled. A cathedral-like building, built by architect Louis De la Censerie from Brugge between 1898 and 1905, this station is protected as a historic building and monument. It will soon lose its reputation as a traffic bottleneck and its oppressing gloominess of past years.

I

Strongly built with a weathered face and wide-awake eyes, Alberic Gregoor stands beneath the glass-covered steel structure of the railway station. As a sub-contractor, specialising in cutting and coring concrete, he works for one of the construction companies that have formed various joint ventures to tackle this major project. Not long ago, he drilled holes 30 mm in diameter in shaft walls lined with concrete slabs

using pneumatic tools. He did this until he recently discovered the new Hilti DD EC-1 diamond coring system for his purposes: “I purchased this unit to make things easier for my staff.”, he says. “You have to work anyway,” states Alberic Gregoor laconically, but “if you can make things easier when doing so, all the better.” In Antwerp Central Station, he and his employees have already cored thousands of holes, learning to appreciate the Hilti DD EC-1 while doing so. This hand-held diamond coring system is ready for use in no time and can produce holes from 8 to 35 mm in diameter with hardly any noise or vibration. A slightly eccentric movement (wobble) of the core bit causes more pressure to be applied to certain points of the diamond cutting face of the core bit. As a result, the diamonds cut deeper into the material being cored. This slight, hardly discernible wobble, combined with an exceptional high speed of up to 800 r.p.m., ensures rapid coring with excellent results. In this way, reinforcing bars can be cut

through in half the time previously required. Supporting this Hilti innovation, known by the name of TopSpin, is a portable water treatment module. It feeds cooling water to the core bit through a hose, draws of coring slurry, filters out the water and pumps it back to the core bit. This closed water circuit makes the DD EC 1 largely independent of an external water supply so that the user can work more freely and, consequently, more efficiently. Alberic Gregoor ventures to make a prediction: “The thousands of holes we’ve already drilled won’t be the last. We’ll carry on drilling thousands more.” In these holes, his employees will set anchor rods using the new Hilti HIT-RE 500 injection adhesive – an adhesive that is particularly suitable for large-diameter and deep holes. Afterwards, the strong bond between anchor rods and adhesive will reliably connect concrete floors and other structural members. Up till now, Antwerp Central Station had ten dead-end tracks. At the be- 3

Page 8

Construction ginning of 2006, it will have fourteen, four being on each of the two new subterranean levels. In addition, the platforms are being lengthened to 425 metres. As a result, not only the capacity but also the length of the station will be doubled. This, in turn, will call for a second entrance or, to be more precise, a second station building. At the back, the Louis De la Censeries Station will be given a modern structural finish with a ticket counter hall, a station restaurant and a parking facility for 600 cars. Both buildings will be joined by a pedes-

trian zone on an additional fourth floor. Overall, the construction site is 710 metres long. Antwerp Central Station, however, can look forward to even greater things: On the lowest of the three levels, the track will run into a 3.8-kilometres tunnel which has been under construction since May 1998. Passing beneath the city of Antwerp, it will form part of the high-speed network planned by the Société Nationale des Chemins de Fer Belges (SNCB). On completion of construction, the

stretch to the west will extend from Brussels to the French border and that to the east up to the German border. Finally, in the north, the line will run from Brussels to Amsterdam via Antwerp. Currently, it takes a passenger a little more than two hours to travel from Antwerp to Amsterdam. As of 2006, the journey will take only an hour and eight minutes. Unerringly, Chris Decock, in the excavation pit in front of the old station building, points his index finger at a concrete wall and says: “That’s the

From 2006 onwards, trains will arrive and depart on three levels one above the other in Antwerp Central Station. Chris Decock, co-ordinator with Hilti Benelux, is providing advice for his customers throughout the project and construction phase.

way to Amsterdam.” Chris Decock is Hilti’s project co-ordinator on the site. The next day, he will hold a meeting with those responsible for construction of this section of the tunnel. As he says, “It’s to ask questions and to discover.” Where and how can Hilti fastening systems and other Hilti products make the work of the tunnel builders easier? Chris Decock’s queries and discoveries will later become recommendations and advice. After all, they constitute an integral part of the services Hilti provides, even before construction work begins.

Page 9

Construction Chris Decock knows what is needed in project co-ordination: “I have to be in the right place at the right time.” He knows the managers of the various joint ventures and, at the same time, he maintains contact with workers on the construction site. He brings the engineers of ordering parties into contact with our specialists and ensures that Hilti sales representatives follow up with customer service. On the east stretch alone of the Belgian high-speed network, which runs towards Germany, he serves 20 to 25 construction sites, among them a

large one at Liege where a completely new station is being built. To serve customers, Chris Decock travels some 80,000 kilometres a year in Belgium alone, one of smallest countries in Europe. Nevertheless, he gives all his customers the assuring feeling that he is there for them alone. Turning through 180°, from the finger pointing towards Amsterdam to the view southwards towards Brussels, the historic building of Antwerp Central Station has already been given a new foundation. Beneath

it, a tunnel 80 metres long has been excavated manually with a tremendous physical effort. To drill the conduits for the concrete foundation, metal plates were fastened on the endfaces to secure the drilling machines. The metal plates are fastened to the base material with anchor rods and Hilti HIT HY 150 injection adhesive. The holes were cored in to the base material with the Hilti DD 100 diamond coring system. Chris Decock continues. He could relate something avout Hilti wherever he stops. ■

Adhesive and anchor rods for connecting new concrete floors are inserted into the holes cored by Alberic Gregoor.

ORIGAMI IN

STEEL

Origami is the Japanese art of paper folding. It’s what springs to mind at the sight of the terminal on Yokohama Pier where passengers from ships – the first this summer heading for the Soccer World Championships – will set their eyes on a new fastening technology. By Ursula Trunz

The special stainless-steel Hilti X-CR20 DP10 nail is also galvanised (top left). It made the structure built of folded, fireresistant steel on Yokohama Pier possible. For the first time, a powder-actuated nail ensured the loading capacity of the entire structure.

Page 13

Engineering piece of paper is transformed into a bird. Pointing to a writing pad, Tomoshige Fujiyama explains that the piece of paper doesn’t have to be very big. A quarter of an A4-sheet is quite adequate. And then he begins folding – skilfully and without having to think about it. Origami is something he learned at school. A tiny paper bird in the engineer’s hand in this 500 metre long, 100 metre wide terminal hall on the pier at Yokohama: an extraordinary story of inventiveness and perseverance. It could add a new dimension to construction.

A

Flashback to the previous millennium. At the end of the eighties or beginning of the nineties, Kazunori Koshida, now technical director of Shimizu, one of Japan’s largest construction companies, held a Hilti powder-actuated tool in his hand for the first time. The advantages of this fastening method were quickly obvious to this “Master of Technology” and needed no long explanation. A nail is driven into steel by a piston, powerfully and at high speed. Trapezoidal profiled metal sheets or gratings can thus be fastened to steel structures extremely efficiently and, to give another example, the installation of drywall track is reduced to a few quick and simple operations. Rapid progress and great reliability are guaranteed, thus meeting the requirements for costconscious construction. Powder-actuated fastening is also a genuine alternative to the conventional welding of sheet metal and steel. Welding can usually only be carried out in dry weather and only on uncoated steel. Besides, welding is a skilled trade that requires the appropriate training. Powder-actuated fastening doesn’t face these restrictions. It works equally well in wet and windy conditions, is also suitable for coated steel and handling a powder-actuated fastening tool is quickly learned. Fastening quality is consistently high and doesn’t depend on the skill of the operator. Construction trades throughout the world have acknowledged the advantages of this fastening system.

From Japan we move to Canada, still in the last millennium. Professor Jeffrey A. Packer at Toronto University researched the possibility of developing a powder-actuated fastener for connecting steel tubes for electricity pylons. A nail of this kind had high theoretical requirements to meet, a fact also recognised by development engineer Hermann Beck. Across the Atlantic at Hilti’s headquarters in Liechtenstein, he worked together with Jeffrey Packer on the same subject. The nail had to be corrosion resistant but, at the same time, its surface required the ductility necessary to ensure penetration in the hard material. The answer was a galvanised stainless-steel nail – its galvanised finish providing the surface ductility required to ensure penetration. At this point in time, the concept existed only on paper. Neither Jeffrey Packer nor Hermann Beck were aware of the significance of their idea, an idea that was later to take on a new dimension. The Yokohama municipal authority comes into the story at this point. In 1994 they announced an international architecture competition – and received 660 entries. The passenger terminal to be built on the pier at Yokohama was to provide the infrastructure for arrivals and departures as well as a public multi-storey car park. Foreign Office Architects Ltd. of London came up with the winning

design. They proposed a long, low, two-storey building with a steel roof structure clad in steel plate. Each surface was to take the form of a triangle with an extremely pointed apex and each triangle was to be different, more than 700 of them. The triangles were to butt against each other as if created by folding – origami in steel – but on an infinitely larger scale than the bird folded from a piece of paper years later by engineer Tomoshige Fujiyama.

A NEW NAIL The question was, could this exceptional, challenging design be realised and, if so, when? Kunio Watanabe, director of the Structural Design Group, a Japanese structure engineering company consulted for advice, ruled out welding in this particular case. Welding could cause distortion of the relatively thin steel plates. Kazunori Koshida suggested an alternative – and powder-actuated fastening’s moment had arrived. However, it soon became clear that existing types of nails would not meet the requirements in terms of technology and design. Back in Liechtenstein, Hermann Beck pulled an old idea out of the drawer – the idea of the galvanised stainless-steel nail. Only Hilti X-CR stainless-steel nails could fulfil the demanding fire-resist- 3

WORLD CUP IN YOKOHAMA In Seoul, on May 31, at 20.30 local time, the referee’s whistle will sound to signal the start of the opening match of the Soccer World Cup 2002. Soccer fans in Europe or in South Africa will make themselves comfortable in front of their TV screens at 13.30 while those in New York, who don’t want to miss the opening game between France and Senegal, will have to be awake at 6.30. The Soccer World Cup is being hosted jointly by Korea and Japan. The matches will be played in ten stadiums in each country.

Japan vs. Russia in the stadium at Yokohama on June 9. On June 11, Saudi Arabia vs. Ireland and on June 13, Ecuador vs. Croatia. Yokohama will also be the scene of the final on June 30, at 20.00 local time. Those also interested architecture and building design, and arriving in Yokohama by ship, should take a look at the passenger terminal. It’s a fire-resistant, steel structure, incorporating Hilti fastening technology – the first of its kind in the world.

Page 14

Engineering ance requirements of the Yokohama passenger terminal project. The result was a special nail called the Hilti X-CR20 DP10, final development of which took little time thanks to the work already done on the subject. It was a world première. For the first time, nails driven by powder-actuated fastening tools were to connect loadbearing components of an entire structure. The use of new types of fire-resistant steel that maintain their strength even at temperatures up to 600 degrees had also led to a new fire-resistant fastening system. But, it was still too early to celebrate. This “world’s first” still had several hurdles to take.

project in Japan together with Tomoshige Fujiyama, accompanied the three gentlemen on their trip to Europe.

LARGE NAIL SPECIMEN

In March 2001, the assembly work finally began. As a consequence of its length of 500 metres, the passenger terminal construction site on the pier at Yokohama was divided into three, with the three general contractors Shimizu, Kajima and, first and foremost, Toda tackling this huge project as a joint venture. They had contacted possible subcontractors for the assembly work and drawn up contracts with them. Tomoshige Fujiyama still had no time to think about origami.With Kenji Arita and further colleagues from Hilti Japan, he was putting in overtime, helping to prepare the subcontractors for the assembly work. They were to nail the steel plates to the steel beams in their workshops throughout Japan.

The special nail had already passed the feasibility test. It was found to be suitable for the proposed structural design. Tests to determine its strength when subjected to heat, conducted at the Japanese Testing Center for Construction Materials and at the Swiss Federal Materials Testing Centre at Duebendorf in Switzerland, produced exceptionally good results. The Building Center of Japan basically approved the nail and the technology but demanded further detailed clarification following the successful first round of tests. A second feasibility test and a second static test at a temperature of 600 degrees centigrade under more realistic structural conditions as well as a dynamic test were called for. Hermann Beck and his team made preparations for the dynamic test at the powder-actuated fastening development centre at Hilti’s headquarters in Liechtenstein. Meanwhile, three men were packing their suitcases in Japan: Kunio Watanabe of the Structural Design Group and Kazunori Koshida and Yoichi Obi who, like Kazunori Koshida, work for Shimizu. They travelled to Liechtenstein, wishing to witness the tests for themselves. Hilti engineer Kosuke Hirase, who managed the

Irrespective of the fastening method employed, in a project such as this nothing is left to chance. But another surprise was waiting. Due to a design change, the steel plates had become too large and heavy to be nailed to the steel beams without additional support. Clips or clamps would not be strong enough and too difficult to install. It was therefore decided that the steel plates would be brought into position and tacked by welding at a few points spaced at 250 to 500 millimetres.

CLEVER LOGISTICS The distances involved were also a challenge to logistics. The major Japanese cities lie hundreds of kilometres apart and logistics between Europe and Asia also had to function. Months before the first serial fastenings were made with the special Hilti X-CR20 DP10 nail in Japan, Hilti began mass production of the nail in Europe. It also had to be ensured that an adequate number of Hilti DX 750 G powder-actuated fastening tools would be available for use.

QUICK FASTENING With assembly only just begun, it became apparent that the final hurdle had yet to be taken. The fire-resistant steel was causing excessive wear. Drilling holes provided a simple solution to the problem. Although this meant an additional operation for the subcontractors, driving the nails became quicker and easier. The thicker the steel plate, the closer the spacing between the 4.5 millimetre diameter nails. Fire-resistant steel 2.3 millimetres thick required the nails to be spaced 150 millimetres apart. At a thickness of 3.2 millimetres, nails were spaced at 100 millimetres and for 4.5 millimetre thickness, spacing was reduced to only 50 millimetres. The base material had a uniform thickness of 9 millimetres. In areas where fire-resistance requirements were less critical, the subcontractors used Hilti EDSH22P10 nails instead of the special Hilti X-CR20 DP10 nails. The fully assembled units were transported to Yokohama and brought into position. In the fire-resistant areas of the building, the steel plates and nails are not only of architectural significance, they also have a load-bearing function. The steel plates increase the rigidity of the underlying steel structure and the nails take up shear loads, which are greatest along the central longitudinal axis of this hall which is entirely free from supporting columns. Concrete was cast in place on the floor structures for the upper levels. This building, the true greatness of which only becomes apparent when seen from inside, will welcome visitors to the Soccer World Cup 2002. It is the largest project ever tackled by Hilti Japan. And it is the first building in the world to incorporate fire-resistant, powder-actuated fastenings. Tomoshige Fujiyama can now finish folding his paper bird.

More about this subject on page 16.

The passenger terminal on Yokohama pier is 500 metres long: and 100 metres wide. All over Japan, sub-contractors fastened steel plate to steel beams with Hilti powder-actuated nails. Completed components were then transported to and erected on the site. A public park will be provided on the concrete roof (large photo).

Page 16

Engineering

AMAZING THE E Kazunori Koshida manages the construction technology department of the large Japanese construction company Shimizu Corporation. He gave us his views on the significance of powder-actuated fastening as applied to construction technology and indicated some possibilities for the future. By Ursula Trunz

Kazunori Koshida: “The reliability of the Hilti powder-actuated fastening system can be compared with that of high-strength bolts.”

Something you experienced more than ten years ago obviously made a big impression on you. Kazunori Koshida: That was when the people from Hilti came to my office and introduced me to powder-actuated fastening. I tried out the tool for myself right away, driving the first studs into steel behind our headquarters here in the middle of Tokyo. The sound of the tool in use brought a few complaints, but the system convinced me on the spot. At that time, welding was the only method in use in Japan for fastening trapezoidal profiled metal sheets to steel structures. I had already given some thought to the subject of welding, and the extent to which the welds could negatively affect the load-bearing capacity of steel structures. Then, along came Hilti – at exactly the right moment. One of the advantages of powder-actuated fastening was obvious to me immediately: In contrast to welding, it doesn’t depend on the weather. Rain or wind don’t delay progress. And, Japans Business Construction Society now approves three methods for fastening trapezoidal metal sheets: Spot welding, stud welding – and the efficient powder-actuated fastening system. More efficient than other methods? Kazunori Koshida: The reliability of the Hilti fastening system can be compared with high-strength bolts. On the Yokohama Passenger Terminal, for example, it cuts the work involved by half. A workman can place 200 to 300 high-strength bolts in a day, but with the Hilti powder-actuated system, he can drive up to 600 nails. This cost-efficient method, however, also has its limits. The nails presently available do not penetrate very thick steel deeply enough. Although they are quite suitable for normal con-

Page 17

Engineering

XPERTS struction steel, they reach their application limits in high-strength molybdenum steel. The question here is whether Hilti intends to continue to invest in the further development of powder-actuated fastening and how large the market potential in this highperformance area would be. Nevertheless, Hilti powder-actuated fastening has been used on fire-resistant steel, on the Yokohama Pier, for the first time . . . Kazunori Koshida: . . . it amazes me – like the entire project amazes me! The system works! The structural design of the passenger terminal tends to

suggest a ship or a bridge rather than a building. For the first time in Japan, the Hilti powder-actuated fastening system has been used to connect loadbearing components. This method of construction is unconventional, but possibly points to the future. What was it that led to it being selected? The public authorities usually keep their projects under lock and key until tenders for the work have been received. But as a suitable method of construction for this exceptional project still had to be found, the city of Yokohama called in structural design-

ers at an early stage in order to check the feasibility of the architectural plans produced in London by Foreign Office Architects Ltd. Kunio Watanabe, president of Japan’s Structural Design Group, ruled out the use of welding, as it could not have achieved the necessary quality. High-strength bolts were also out of the question because there would not have been the necessary size to meet durability requirements. In addition to quality and durability, two other aspects had to be considered: Costs and safety on the construction site. Structural designers were looking for a method that takes productivity into consideration. After the contracts

had been awarded, Hilti powder-actuated fastening was recommended, because it takes all requirements into account. After work had started, my team in design technology brought the architects’creative vision into line with engineers the technical know-how. Architects primarily pay attention to shape, proportions and appearance. They have every right to do so. For the Yokohama passenger terminal, we also came to an agreement with Foreign Office Architects Ltd., ensuring that their plans would allow for design aspects. ■

THE THIRD DIMENSION

Yoichi Obi, project manager for Shimizu. Admirers of the Yokohama Passenger Terminal quickly forget the idea of flat, twodimensional surfaces. The steel sheets take on a third dimension and the corners of the building, normally expected to be at right-angles, are either obtuse or acute. How each of the surfaces of varying size meet is quite imperceptible to the human eye. There seems no system to it. Yoichi Obi, in charge of the construction work for Shimizu, reckons he has seen bigger jobs, but nothing more complex.

Conventional CAD systems are hardly capable of producing the plans for this architectural creation. The Shimizu technicians therefore adapted VRML (Virtual Reality Modeling Language), a system normally used on the internet, to suit their own needs. VRML permits views of the passenger terminal’s steel structure to be pivoted and rotated as desired. It simulates and checks approaches to the work, so that steel beams and components required for interior finishing fit together optimally, and also shows where pipes and cables can be installed. “The human brain has great difficulty, for example, with the design calculations for a fastening point on a convex or concave surface. But that’s child’s play for VRML”, explains Yoichi Obi. Thanks to the advanced VAD (Visual Advanced Design) system, which was developed by technicians in the Shimizu Corporation, the data from calculations can be presented in formats suitable for use with other applications. A supplier, for example, can thus be given an Excel spreadsheet showing a precise listing of material requirements.

Sophisticated software for construction: The drafted passenger terminal can be rotated, turned and calculated, as desired, on a screen. As is always the case when a project is realised, Yoichi Obi will be relieved to see the passenger terminal reach completion. But in this particular case, his feelings also reflect an additional dimension: “I will feel privileged to have worked on this demanding project.”

Page 18

Engineering

TRIED AND Powder-actuated nails now serve as structural connections in a folded-plate structure – that’s a world première. For the first time, nails instead of fillet welds were used to connect steel plates for a building. In close co-operation with customers, Hilti carried out a comprehensive testing programme. Afterwards, the results served the engineering office responsible to verify the fastening design. By Hermann Beck*

or decades, powder-actuated fasteners have been well established means of fastening in the construction industry. Extensive experimental research has provided the fundamentals for the approval of powder-actuated systems for fastening applications, such as the "classical" installation of profiled metal

F

sheets for roofing and siding in steel construction. Sound technical experience of this kind is a pre-requisite if new, challenging fastening tasks are to be tackled quickly, like those presented by the folded plate structure project. Nevertheless, a final check of the suitability of new fasteners for applications is still neces-

sary when safety is at stake and, thus, the performance capability is verified experimentally.

EXCEPTIONAL DEMANDS Right from the start, the specified high shear resistance of 7 kN per nail at a temperature of 600° centigrade

The folded-plate structure where, for the first time, Hilti powder-actuated nails act as connectors within the main structure.

presented the greatest challenge. Each fastening had to meet such high requirements because a new type of fire-resistant structural steel was being used and its good high-temperature strength had to be utilised. At 600° C, a standard carbon-steel, powder-actuated nail 4.5 mm in diameter has a shear resistance of 2.5 kN which, of course, is far less than the specified 7 kN. Theoretically, special stainless-steel Hilti X-CR powder-actuated nails could have been regarded as a promising alternative to satisfy the stiff requirements. It was clear from the start, however, neither the thickness nor the strength would permit standard Hilti X-CR nails to reliably penetrate the fire-resistant steel. Once before, some time ago, Hilti had developed special stainless-steel and additionally galvanised nails for a research project being carried out by Professor Jeffrey A. Packer from the University of Toronto. His research work investigated whether powderactuated nails could be used for fastening thick sheet metal as an alternative to the conventional screws, bolts or welds. At that time, a nailed tubular joint proved to be reliable and its loading capacity predictable under

Page 19

Engineering

TESTED both static and fatigue loading [1]. In the case in question, making tubular connections to have the highest possible strength was of paramount importance. It was just this requirement that led to nails already resistant to corrosion being zinc plated additionally. The zinc layer acts like a lubricant, making it easier for a nail to penetrate steel.

FEATURES OF HILTI X-CR20 DP10 NAIL With its shank diameter of 4.5 mm over a length of 20 mm, the stainlesssteel, additionally galvanised Hilti X-CR20 DP10 nail has a high shear strength. The ultimate tensile strength of the X-CR material exceeds 1,850 N/mm2. On the nail, the zinc plating is 10 microns thick which facilitates reliable fastening of the fire-resistant plates. These can be up to 9 mm thick and have an ultimate tensile strength of 610 N/mm2. Two plastic washers on the nail shank, each 10 mm in diameter, permit use of the heavy-duty Hilti DX 750 tool which has the requisite high driving power. These washers centre the nail while it is being driven in.

INFLUENCE OF HIGH TEMPERATURES Shear tests at elevated temperatures were carried out in Japan and also in Europe. During the tests in Japan, the performance of the complete, nailed plate fastening was studied. Specimens were subjected to temperatures up to a maximum of 600° C in increments of 100° C and then subjected to shear loading until failure.

At the same time, fastened plates of various thicknesses were studied. During the tests in Europe, on the other hand, pure shear loading was applied only to the nail subjected to temperatures of up to max. 700° C. After the tests, the results verified the excellent resistance of Hilti X-CR nails when exposed to high temperatures. Fig. 1 shows that the specified resistance of 7 kN at 600° C was exceeded by far. Furthermore, it can be seen in fig. 2 that, at 9 kN, the resistance of the nail remained at an exceptionally high level even at a temperature of 700° C. Also, a very long period of exposure to heat had no effect whatsoever on the shear resistance.

BEHAVIOUR IN SHEAR During a series of tests carried out in the laboratory at Hilti's technical centre, the influence of plate thickness, pre-drilling the plate before fastening and preliminary dynamic loading of the fastening was studied. During this test series, two million harmonic shear loading cycles with a max. upper dynamic load of 5 kN were applied to the specimens before they were subsequently subjected to static loading until failure. The main conclusions drawn from these tests were as follows: • Cyclic loading causes neither fatigue failure nor visible damage to the nailed fastening. • Cyclic loading has no detrimental effect on the resistance under static loading: Neither the mode of failure nor the overall load-displacement

The Hilti X-CR20 DP10 nail has a shank length of 20 mm and is made of additionally galvanised stainless steel. Plastic washers centre the nail while it is being driven in.

Page 20

Engineering characteristics changed because of dynamic pre-loading. • Shear resistance (loading capacity) of the fastening is governed by fracturing of the nail. The resistance in this respect was more than 15 kN in the case of the 2.3 mm thick plate and more than 17 kN where the 4.5 mm thick plate was concerned. • Pre-drilling plates results in their yielding earlier where they bear on the nail. At the same time, however, the entire fastening develops greater ductility (deformation capability).

Figs. 3 and 4 provide examples of the load-displacement characteristics and thus permit a visual assessment of the described behaviour. Hilti documented all tests in English test reports and Japanese translations, which were then made available to the customer. All technical and formal pre-requisites were thus fulfilled for the Yokohama première to go ahead – Hilti powder-actuated nails used for structural fastenings in the wide-span main steel structure of

SHEAR RESISTANCE, V, [KN] OF NAILED PLATE CONNECTIONS WITH X-CR20 DP10

the new passenger terminal on Yokohama Pier. For further information, please contact Hermann Beck, [email protected] Reference literature: [1] Kosteski, N., Packer, J.A., Lecce, M., (2000): Nailed Tubular Connections under Fatigue Loading, Journal of Structural Engineering, Vol. 126, No. 11, November 2000

SHEAR RESISTANCE, V [KN] OF X-CR20 DP10 Level of shear resistance from control tests at room temperature: 18.3 kN

20

20

18

18

16

16

14

14

12

12

Test temperature [ºC]

10

10 8

8

Thickness of fastened plate

6

2.3 mm 4.5 mm

4 2

300 600 700

6

3.2 mm 6.0 mm

4 2

Structural steel thickness: 6 mm

0

0 0

100

200

300 400 Temperature [ºC]

500

600

5

Figure 1: The Hilti X-CR20 DP10 nail develops an exceptionally high shear capacity at high temperatures.

30

60 90 Duration of exposure to heat [min]

Figure 2: The duration of exposure to heat shows no influence on the shear resistance of the Hilti X-CR20 DP10 nail.

LOAD-DISPLACEMENT CURVE

LOAD-DISPLACEMENT CURVE

of fastened 2.3 mm thick plate

of fastened 4.5 mm thick plate 20

20 18

18

earlier yield

16

16

14

14

12

12

10 8 6

Flat start due to slight bend in specimen

4 2

no preloading / predrilled 3 mm dia. dynamic preloading: 5 kN / predrilled 3 mm dia. no preloading / no predrilling dynamic preloading: 1,25 kN / no predrilling

V [kN]

V [kN]

120

10 no preloading / predrilled 3 mm dia. dynamic preloading: 5 kN / predrilled 3 mm dia. no preloading / no predrilling dynamic preloading: 5 kN / no predrilling

8 6 4 2 0

0 0

0,5

1

1,5

2 2,5 3 Displacement [mm]

3,5

4

4,5

Figure 3: The nailed connection reaches a resistance of more than 15 kN in the case of 2.3 mm thick plate. The static shear behaviour remains unaffected by dynamic pre-loading.

0

0,5

1

1,5

2 2,5 3 Displacement [mm]

3,5

4

4,5

Figure 4: In case of the 4.5 mm thick plate, a resistance beyond 17 kN develops corresponding to the pure shear capacity of the Hilti X-CR20 DP10 nail.

Page 21

Engineering

RELIABLE FASTENING OF DYNAMIC LOADS

Varying loads heavily stress anchors and the materials they are set in. To enable engineers to make allowance for dynamic loading as early as the planning phase of construction work, the University of Dortmund in Germany has developed a new anchor fastening design process. It quickly provides economical and reliable fastening solutions. Hilti offers a simple system to tackle the anchor fastening problems encountered in field practice. Please read Gerald Marxer’s article on this subject on the following double page.

Page 22

Engineering hen designing load-bearing structures and, in particular, anchor fastenings, engineers mostly concern themselves with only static or quasi-static loads. If, however, they underestimate the effects of dynamic loads, the result can be an undersized structural member or anchor fastening.

W

For the purposes of designing anchor fastenings, dynamic loads are put into three categories – seismic, shock and fatigue. Certain characteristics differentiate these categories, namely the probability and frequency of occurrence during the service life of a structure, the loading amplitude, the loading frequency and also the fundamentally different behaviour of an anchor (or other type of fastener). On Hilti’s initiative, especially in the field of anchor fatigue resistance, a major effort was made in research and development to fill the gaps in knowledge and thus make anchor fastening design work reliable. As a rule, reference is made to fatigue when loading cycles are very high during the service life of a structure, e.g. more than 10,000 times. A typical example is the vibration of fans or other rotating machines. This generates frequent, mostly narrow loading

amplitudes. On the other hand, frequent wide loading amplitudes are caused by varying loads set up when cranes, robots or other heavy machines are in operation. These loads can vary uniformly with respect to time and be sinusoidal, as, for example, in the case of rotating machines, or they might be completely stochastic like, for example, traffic loads.

DECREASING STRENGTH If the stress and strain set up in a material change frequently, the variable properties of concrete and steel have the greatest influence on the design of an anchor fastening. Material fatigue has long been known to occur with all normal grades of structural steel and is also allowed for in standard engineering practice when designing steel structures. The strength of steel decreases significantly between 10,000 and 2,000,000 load cycles. Steel then reaches its fatigue resistance (strength). Afterwards, an increase in the number of load cycles does not reduce its strength. Generally, the ultimate strength is only in the order of 25 to 35% of the original strength (under static loading). This dependency of the strength on the number of load cycles is often depicted in fatigue curves (S-N or Woehler curves).

Concrete also displays a similar although not quite so pronounced behaviour. Its ultimate strength, depending on the direction of loading and type of anchor, lies between 55 and 65% of the original strength.

SIMPLE DESIGN PROCESS In order to verify the behaviour under fatigue loading of the chemical Hilti HVZ adhesive anchor and mechanical Hilti HDA undercut anchor, the University of Dortmund and Hilti jointly carried out an extensive test programme. Specialists from Hilti and Dortmund University then derived a reliable design process from the results and, after submittal to the Deutsche Institut für Bautechnik (DIBt), succeeded in obtaining a general construction supervisory authority approval for both anchor systems. Users need a complete anchor system. To keep the design work as simple as possible , Hilti provides a PC program for users. It covers both the simplified design process according to the DIBt approval and also the full-scale design process. The latter is also easy to use, but takes not only the number of load cycles into account, but also a breakdown of static and fatigue-relevant loads, thus permitting a clearly

more efficient design and a less expensive anchor fastening. Further information about this subject can be found in the Hilti brochure “Dynamic design for anchors”*.

PROBLEMS IN PRACTICE . . . When anchors are pre-set prior to putting the fixture in place or when anchors are set through in-place fixtures, the holes in the fixture must always be larger in diameter than the anchors to facilitate the installation work. A gap thus exists between the hole wall and the anchor. If a static shear load is then applied, the fixture shifts slightly and the anchor bears most of its weight. This guarantees a more or less uniform load distribution (transfer). If, though, varying shear loads are applied, the fixture can move once friction has been overcome. As a rule, movement of this kind is not permissible and can have a negative effect on the fixture. It is thus absolutely necessary for the gap to be minimised or, even better, eliminated, if a varying shear load is involved. An anchor can never be placed perpendicular to the material it is set in for practical reasons. An inclination of up to 3° from the perpendicular is quite normal. In view of this, a considerable proportion of what might

ANCHOR 1/2 X 6 1/2” Thread Mean value

With original nut, pulsating tensile load of rod, no adnesive; Fu = 0.5 kN

Undamaged after test

* Fractile

60 *

Amplitude [kN]

50

* **

40 30

** *

*

** *

*

20 10 0 1000

10000

100000 1000000 No. of load cycles [LC]

10000000

How does the anchor behave under a frequently repeated load? The S-N (Wöhler) curve provides the answer. The values for the plot originate from anchor tests.

How can fatigue loads be allowed for when designing anchor fastenings? The PC program from Hilti offers users a practical solution.

Page 23

Engineering well be a pure tensile load on the fixture is transferred to the anchor as a bending load. This bending load, however, is particularly detrimental to the anchor, reducing, among other things, its failure load. Yet another effect, which occurs above all under vibration, is that nuts are successively shaken loose so that the fixture lifts away from the anchor base material.

Construction, Institute of Construction Research, Dr. Klaus Block, 2000 2. Various reports “Untersuchung zur Eignung ... HDA ... HVZ ... bei ermüdungsrelevanten Einwirkungen” (Investigation into the suitability of... HDA ... HVZ ... when subjected to fatigue actions), University of Dortmund, Germany, Faculty of Construction, Institute for Construction Research, Dr. Klaus Block, 2001 3. General construction supervisory authority approval, Z-21.3-1962, Hilti HVZ adhesive

anchor, dynamic, Deutsches Institut für Bautechnik, 2001 4. General construction supervisory authority approval, Z-21.1-1963, Hilti HDA undercut anchor, dynamic, Deutsches Institut für Bautechnik, 2001 5. Dynamic design for anchors, Hilti Corporation, Schaan, 2000 * 6. Fastening technology manual, Hilti Corporation, Schaan, 2000 *

country. The telephone numbers are given on the fourth cover page.

* These documents, in English, can be ordered from the Hilti organisation in your

. . . AND THEIR SOLUTIONS Standard anchor fastenings are not the answer to these three effects. One very simple but highly effective solution comes in the form of the socalled “Dynamic set”, specially developed by Hilti to tackle this problem. It consists of three components: • A special injection washer through which, after suitable adjustment of the fixture, the gap between anchor and fixture can be filled with Hilti HIT injection adhesive. • A spherical washer, adapted to suit the injection washer, which greatly reduces the amount of bending to which an anchor is subjected. • A conventional hexagon nut with which the fixture is clamped against the base material in the usual way. • A special locknut which, due to its small height, permits a larger fixture thickness and reliably prevents the hexagon nut from shaking loose, even when exposed to vibration.

IMPROVEMENT IN SHEAR LOADING The shear resistance (shear loading capacity) of anchors can be improved using the “Dynamic set”. When a multiple-anchor fastening is loaded at right angles towards the edge of a concrete member, the diameter of the clearance holes in the fixture play an important role. Clearance holes are always larger in diameter than anchors if the anchors are to be set without difficulty. As a result, on the other hand, the anchors making up the fastening are not loaded uniformly. As a careful assumption, all design methods, as for example the European Technical Approval Guideline (ETAG), Appendix C, take the approach that the row of anchors nearest to the member edge carries the load. The second row of anchors can only be brought into play if the fixture plate is shift-

ed a considerable amount. This, though, immediately causes the concrete edge to break and the multiple-anchor fastening fails completely. If, however, the Hilti “Dynamic set” (more on this page under “. . . solution”) is used for fastenings subjected to static loading, the shear resistance significantly improves. The unfavourable situation of only one row of anchors bearing the load no longer exists. Instead, the load is distributed uniformly among all anchors making up the fastening. Testing has also verified this. It was found that the second row of anchors set in the usual way only comes into play after the edge of the concrete member has broken away and a significant amount of displacement has taken place. If, on the other hand, the “Dynamic set” is used and the annular gap is filled with Hilti HIT injection adhesive, the load, once the ad-

hesive has cured, can be increased continually until the entire fastening fails. A rough estimate assumes that the overall resistance of a multiple-anchor fastening filled with this adhesive corresponds to the resistance of the row of anchors closest to the member edge multiplied by the number of rows. By injecting this adhesive, it is also possible to overcome several of the ETAG restrictions. Reference literature: 1. Influence of injection washer (Dynamic set) on shear resistance of two-anchor fastenings in a line, loaded towards a member edge, Hilti Corporation, Schaan, corporate research, TWU-IFF-07/01, 2001 2. Dynamic set for shear resistance, Hilti Corporation, Schaan, anchor business unit, 2001

By using the “Dynamic set”, fastenings subjected to fatigue loads can be reliably designed and installed. Furthermore, the anchor service life guarantees the serviceability state (fitness for the intended purpose). ■ Further information can be obtained from Gerald Marxer, [email protected]. Reference literature: 1. Grundlage eines vollständigen Bemessungsmodells (Fundamentals of a complete design model), University of Dortmund, Germany, Faculty for

The Hilti Dynamic Set improves the resistance of anchor fastenings subjected to dynamic loading. It consists of a washer, spherical washer, hexagon nut and locknut.

Page 24

Career

FINE TUNING FOR A

23-year-old Josep Martinez Parejo, studied to become a civil engineer in Barcelona, his home town. In London and with Hilti in Liechtenstein, he continued training for his professional career thanks to the Unitech International training and education alliance. Back in Madrid, he is now writing his dissertation to complete his studies.

Page 25

Career

CAREER The training and education alliance Unitech International fine tunes future engineers for their careers. Prior to completing their studies, they can develop management skills and accustom themselves to other cultures in foreign countries. Josep Martinez Parejo from Barcelona outlines his experience in London and Liechtenstein. By Josep Martinez Parejo My name is Josep and I am 23 years old. Thanks to the Unitech International training and education alliance, I spent a six-month period of practical training with Hilti in Liechtenstein. Eight renowned technical universities in Europe and 24 international companies take part in Unitech. Something makes this programme different from others – all participants commit themselves to achieving excellence. And the goal? By attending the Unitech programme, the intention is for up-andcoming engineers to acquire leadership skills, while learning to feel at home with various cultures and in today’s extremely dynamic world. I believe that my personal experience can illustrate this idea. I was born in Barcelona where I lived until the age of 21. While at the Universitat Politècnica de Catalunya, where I became a civil engineer, I attended a Unitech presentation. I didn’t hesitate for moment, submitted my application and, in no time, I was packing my suitcase. My destination: London. For twelve months, I studied company management and administration at the Imperial College of London. It was an unforgettable time in London. Apart from the academic knowledge I gained, I will remember my experi-

ence of people while living in a country like Great Britain, which is so different from my home country, Spain. For my period of practical training, I moved from London to the small country of Liechtenstein. With Hilti, I learned first hand how to solve daily problems facing a project manager. The support I received during this internship underscores the significance of Unitech for companies like Hilti. They need young managers who have been prepared for and feel at home in changing environments.

dreams will come true in the course of time. And they are multiplying due to the unlimited opportunities presented to me by a company like Hilti. Now that I have completed my internship in R & D, I am gaining experience in the commercial field as a technical sales representative with Hilti. At the same time, I am writing a dissertation to complete my studies. It concerns a subject I came across during my practical training with Hilti. ■

THE PARTNERS

The participating international companies actively promote development of the exceptional programme: ABB (Switzerland), Atofina, DaimlerChrysler, Degussa, F. Hoffman-La Roche, Gruppo Falck, Heidelberg Printing Machines, Hilti, IBM, J.M. Voith, L'Oreal, Mapei, Necso, PSA Peugot Citroen, Philips Electronics,

Unitech International’s offer goes beyond that of other exchange programmes. For one semester, students from participating universities attend engineering and management courses at a different Unitech university and then follow up for at least three more months in a partner company, gaining technically oriented, practical management experience. The leading positions of these companies and their commitment to the Unitech idea ensure that trainees find challenging work in a new cultural environment. At the beginning, in the middle and on completion of their exchange year in a foreign country, the Unitech students come together again for a one-week crash course. Not only is sound theoretical knowledge a prerequisite for participation in a Unitech International exchange programme, but a candidate’s personality is just as important. As scholars, they are also given the opportunity to build up and improve their social skills in greater depth, while involving themselves with various cultures, lifestyles and ways of thinking.

At the moment, my head is full of thousands of ideas and hundreds of dreams. I hope that these ideas and

The Unitech International training and education alliance was founded about two years ago on the initiative of the Swiss Federal College of Technology (ETH) and the Hilti Group.

1 YEAR IN-DEPTH

Schindler Elevators, Schlumberger, Shell, Siemens, STMicroelectronics, Sulzer, TPC, Unaxis and ZF Friedrichshafen. The participating universities too, belong among the leading ones in Europe: the North-Rhine Westphalian Technical University (RWTH) Aachen, Universitat Politechnica de Catalunya Barcelona, Delft Technical University, Chalmers University of Technology Göteborg, Imperial College London, Politecnico di Milano, Ecole Polytechnique Paris and the Swiss Federal College of Technology (ETH) Zurich.

Interested students at participating universities can inform themselves under www.unitechint.org. The names of the local coordinators, who are available for further information, are given on the website of Unitech International.

Page 26

Efficiency

TIME SAVING Installation jobs of all kinds can be carried out easier than ever before with the new Hilti MQ System.

This new installation system consists of six product groups made up of components which cover a tremendously wide range of applications. Installation frames and structures, for example, can be built and pipe, air duct, electrical and process lines can be laid and fastened with it. The work involved is simple and time saving. The comprehensive programme is as follows: • Channels and brackets: A modular system, many intermediate sizes, reliable holding power, simple cutting to length, great flexibility, aesthetic appearance, thus, also ideal for installations that are seen • Pipe rings and pipe ring saddle: Revolutionary push connection, quick fitting without a tool, no

screws required, no deburring of threaded rods necessary • Pushbutton: Single-part, compact and convenient, quick installation due to easy positioning on a channel, no difficulty with removal and re-use, suitable for use with all channels • 3D system for innumerable connections: Four components, more are not needed, ready-to-use with prefitted bolt, very high installation rate, high system versatility owing to individual assembly on the site • Pre-assembled 90° angles: One part instead of the previous three, quick fitting, simplified stocking, no parts to be lost, simple positioning and removal, great stability from keying action with the channel • Angle, clamps, connectors, bases: Designed for various duty ranges, innumerable different structures quick and easy connection to channels of all cross-sections thanks to a “butterfly slot”

The Hilti MQ system covers a tremendous range of applications.

To go with this comprehensive programme of products there is a comprehensive range of services. It covers technical advice and assistance on sites and throughout an entire project. This includes such assistance as CAD drawings, bills of material, or-

dering lists and a channel cutting service. This package gives professional installers the assurance of always receiving the best solution to their installation task. ■

KEYLESS SAW BLADE CHANGES A tool is not needed to change the blades of Hilti’s new hand-held WSC 255-KE or WSC 265-KE circular saws.

In the past, changing a saw blade was complicated and laborious: A clamping bolt had to be released, the saw blade removed, a new one put in and everything re-tightened. Rather than do this, users often preferred to keep going with the saw blade already in place, no matter what material they were sawing. As a consequence, the sawing performance and cut quality suffered. All this has now become a thing of the past.

Unbelievably simple: Keyless saw blade changes with the hand-held Hilti WSC 255-KE and WSC 265-KE circular saws

Users can now fit a saw blade suitable for the application at any time. Changing saw blades in the latest hand-held circular saws in the KE

range is unbelievably quick and easy. All that’s needed is to shift an integrated clamping lever, release a clamping nut and simply change the saw blade. Not only does this revolutionary method save time and annoyance, but it also permits the user to forget any auxiliary tool. Often enough, it will not be in the tool bag or might already have been lost somewhere. Using the right saw blade for a job is no longer a complication. The user can work more efficiently and achieve the best sawing results. Where saw blades are concerned, new ones, optimised for each application with an innovative, narrow-kerf design, make their contribution to users always being a cut above others. ■

Page 27

Efficiency

DRILL AND DRIVE. High performance and a user-friendly design: The Hilti SF 121-A and Hilti SF 150-A battery drill-drivers are “bundles of energy” for sustained operation. Two batteries and a rapid charger are supplied, as standard.

The batteries, in particular, are really special: Two are offered for both tools, one rated at 2.0 and one at 3.0 ampere-hours. This gives the SF 121-A a performance of up to 36 watt-hours and a torque of 21 Newton-metres. With its speed of 1,450 r.p.m., the SF 150 not only leaves many a corded tool behind it, but also recommends itself for extensive serial fastenings with its battery capability of 46.8 watt-hours. Rubber padding for the entire grip section was developed bearing this in mind too. Vibration damping of this kind, the tool’s excellent balance and its low weight greatly ease the strain on an operator’s wrist and permit effortless drilling and screwdriving even over long periods. An adjustable side handle helps the operator to keep the SF 150-A’s power under control. And there’s reason to do so for the torque of this new drill-driver can be increased in 15 settings up to a remarkable 29 Newtonmetres.

KNOWING WHAT’S BEHIND IT.

Also supplied with the two new cordless drill-drivers is their “power station” – the Hilti SFC 7/18 rapid charger. In very little time, it recharges nickel-cadmium batteries (NiCd) and the more powerful batteries with metal-hydride cells (Ni-MH). As this charging is controlled electronically, overcharging is not possible and maximum battery efficiency is always ensured. As a result, both new cordless drill-drivers can be kept in non-stop use. And, there's a conditioning function to “revive” old batteries. Weighing 1.95 kg and rated at 12 Volts, the SF 121-A is an extremely convenient all-rounder that weighs only 2.18 kilograms. It is particularly suitable for making screw fastenings in tight spaces and corners, but also for light-duty drilling into timber and sheet steel. Even 8-mm-diameter Spax screws, 100-mm-diameter recesses in wood or drilling through sheet steel and masonry are no problem for the SF 150-A. Its power of 15.6 Volts with extremely high battery reserves take care of that. ■

SF 150-A stands for power and long use. More than 46 watthours make even sustained drilling into sheet steel no problem.

Anyone using the new Hilti PS 20 detector has full insight.

Virtually everyone who drills holes knows the problem: Suddenly, you come up against a rebar, hit a copper pipe or crush an electric cable. The outcome: Delayed work schedules and high repair costs. But now, the Hilti PS 20 detector puts an end to these problems. It permits a base material to be examined quickly and easily. If this instrument is passed over a concrete surface, a clear display automatically shows where a hole may be drilled or an anchor set without any trouble being experienced. But, that’s not all: The Hilti PS 20 detector identifies what it “sees” as a rebar, a copper pipe or a live cable. It not only provides this important information, but the detector also shows its user the exact depth of the object with an ac-

curacy previously considered impossible. If, for example, a rebar is about 75 millimetres beneath the surface, drilling an anchor hole 60 millimetres deep is not, of course, a problem. With a detection capability up to a depth of 100 millimetres, the Hilti PS 20 is ideal to cope with all normal situations arising on construction sites. This robust detector with its userfriendly design, now enables its operator to easily find all metal objects which could get in the way when drilling. Coming up against a rebar, hitting a copper pipe or crushing an electric cable have become things unknown to users in construction trades who own the Hilti PS 20. ■

The Hilti PS 20 detector shows what’s inside concrete and where drilling a hole or setting an anchor can be carried out safely.