Since the 1990s there has been an upsurge in high rise construction. After the Empire State Building (1931) and Sears Tower (1974, now Willis Tower) builds, their height records stood for decades. Since 1998 the cycle has been shortened to a matter of years. The “Year in Review: Tall Trends of 2017” study by the Council on Tall Buildings and Urban Habitat (CTBUH) reported that with 144 high rise structures (200 m or taller) built, a new record had been set. Most of these skyscrapers (53 %) are sited in China. At this time there are 1319 high rise buildings (200 m or taller) in the world. It is worth noting, too, that geographically 2017 was the most diverse year in history for tall-building construction. 69 cities in 23 countries completed new highrise builds, a huge increase of 54 cities and 18 countries compared to 2016.
The world’s tallest building and structure at this time is the Burj Khalifa in Dubai. It stands 830 metres tall and has 163 usable storeys. From the engineering point of view, the maximum viable height is about 1.5 to 2 km. Although buildable, taller structures are impractical because they could support little more than their own weight. New man-made materials and new technologies could push this limit higher in the future, however.
Doka is fit for the future. For any set of requirements, the company offers custom formwork solutions for all CIP concrete components in high rise and super-high rise construction, from the foundations to the topmost storey. No matter how different, no matter how unique every individual high rise project might be, Doka always aims at the overall project solution to make construction optimised, fast and safe.
Broad range of applications for climbing systems
For a little more than 40 years now (since 1977, to be precise), Doka has used climbing formwork on high rise projects. Automatic climbing formwork has been available since 1989. An 'automatic climbing system' is a combination of wall formwork and scaffold (or working platform) that is able to climb by itself from one pouring section to the next. Whatever the set of requirements, Doka offers automatic climbing formwork for the building core and building facade.
In terms of method of operation/type, three different systems with hydraulic drive have established themselves on the market.
- Profile-guided climbing systems
Structure-guided by climbing profiles, these systems are climbed from storey to storey by a fully integral or mobile hydraulic system. Climbing is safe and fast, even in high-velocity wind conditions.
- Platform systems
Platform systems are formwork machines optimised specifically for the construction of high rise building cores. The main component is a pouring and reinforcement platform. It is climbed in a single lift by a small number of long-stroke hydraulic cylinders.
- Protection screen systems
Safety is immensely important when construction work has to be carried out at dizzy heights. In high rise construction, protection screen systems offer all-round protection for the topmost levels of the structure. They boost productivity, particularly when work has to be carried out close to the edge of the structure.
Optimising construction progress
From planning stage through to project completion, Doka experts provide help with professional consultation in case of any questions. Safe use of formwork systems is achieved not only by the system, but even more so by using the system components correctly. Factors such as cycle time, construction method, type of reinforcement, site equipment and concrete placement have to be taken into consideration in the planning phase so that the ideal formwork solution can be developed. The 3D planning of structures and structural members is an important contributor in this respect. Animations and photo-realistic images make complicated structures easier to understand and make project progress forecasts more transparent. The boundary conditions are brought together in a holistic model. A network of highrise specialists worldwide and the Global Expertise Center High Rise in Amstetten support consulting, planning and successful implementation.
At Doka, work on technical innovations and product developments is ongoing all the time. The overview below shows the milestones in automatic climbing formwork from 1989 to the present day.
SKE – the beginnings of automatic climbing formwork
1989 marks the start of self-climbing formwork with the SKE 30 system, which was used for the first time on the Thai Wah Tower build in Bangkok, Thailand.
SCP – self-climbing formwork and working platform for any high rise core
22 years ago, Platform SCP debuted on the Zurich Toren project in The Hague, Netherlands. Long-stroke hydraulic cylinders, rated at 40 metric tons, quickly climb the fully enclosed working platform to the next pouring section. In 2010 the Super Climber SCP was developed for the requirements of the North American market. That same year it was used on the 2550 North Lakeview project in Chicago, USA.
Burj Khalifa – currently the world’s tallest building
In 2005 Doka formwork was used in Dubai, United Arab Emirates, to help construct the world’s tallest building. Doka supplied the formwork solution for the entire structure core. The shape of the 830-metre tower meant that the formwork needed to be highly adaptable. In addition, the extremely tight construction schedule necessitated an ingenious utilisation plan for the SKE 100 climbers and the versatile Large-area formwork Top 50.
Protection screen Xclimb 60 – applied variety of design
Protection screen Xclimb 60, used for the very first time on the Burj Khalifa build, offers safety all the way up. Framed enclosure Xbright, first used in 2011 on the European Central Bank (ECB) project in Frankfurt, Germany, fully encloses the topmost levels on the build. Short assembly times are another advantage, because the enclosure panels are frame-based and the panel connectors simple and easy to use. Protection screen Xclimb 60 has also been used since 2012 for structure renovation and demolition. The protection screen climbs downward as demolition work progresses. This dispenses with the need for costly and time-consuming erection of a full-height, scaffold-mounted enclosure. On the No. 1 Nine Elms project in London, England, a protection screen was built to enclose 3.5 floors of the structure. A radically new feature was incorporated for the Aurora Melbourne Central build in 2017. A monorail system integrated into the protection screen enabled the facade panels to be installed quickly and in absolute safety.
From GCS to Automatic climbing formwork Xclimb 60
The product line started in 2003 with the Guided climbing formwork system GCS. Back then, the climbing platforms had to be crane-lifted into position. Automatic climbing formwork Xclimb 60 is the next generation of guided climbing formwork with the addition of a mobile hydraulic system. It was used for the first time on construction of the Timelkam combined-cycle power plant in Austria in 2007.
Table Lifting System TLS – the ideal shifting device for tableform projects
With the Table Lifting System TLS, tableforms and construction materials can be vertically shifted from one floor to the next with no need for a crane.
SKE plus – crane-independent climbing formwork for structures of any shape and height
An extensive modular system with integrated hydraulics for a very wide range of applications. The SKEplus 50 system variant is rated at 5 metric tons per lifting unit and is ideal for the majority of applications on the core and on the building facade. Even stronger and rating 10 metric tons per lifting unit, bigger brother SKEplus 100 is built for elevated requirements such as severe influencing conditions, additional working platforms or extra-heavy live loads.
Xclimb 60 Short track – for formed/poured in advance cores of low to medium-tall structures
A compact climbing system with a short, one-piece vertical profile (hence the “Short track” suffix) that has been in use since last year and was designed specifically for the markets in Asia and the Near and Middle East. This system is Doka’s latest product innovation in the automatic climbing sector.