A customized PERI climbing formwork solution has been supporting the rapid construction progress on the ISET Tower in Yekaterinburg. The formwork concept has taken into account the high wind loads as well as the variable number of elevator shafts with varying dimensions. The climbing formwork for the walls along with the climbing protection panel on the outer edges of the building can be adapted to suit the circular ground plan without requiring any special components.
After its scheduled completion in summer 2014, the ISET tower will reach a height of 209 metres above sea level. The 52 floors have been designed to provide space for around 250 private apartments and a range of service facilities. The parking garage for the future residents is accommodated in four underground levels. While the external architecture is characterized in particular by its rounded shape, the elevator shafts inside the building provided the main challenges during the formwork planning. In addition, high wind loads had to be taken into account.
In the lower storeys, there are six centrally-arranged elevator shafts in the circular building with minimum internal dimensions of 2.30 m x 3.00 m. For this, the construction crew has used the self-climbing ACS S shaft formwork which was specially developed for this area of application – this was the first use of the system in Russia.
With this self-climbing version, the ACS 100 climbing unit is arranged centrally in the shaft; it lifts the climbing frame together with the suspended TRIO panel formwork and trailing working platform to the next casting section. The climbing rail is placed here on the bottom working platform, and vertically offset roller bearings guide the internally positioned shoring tower upwards on the building. As the formwork only slightly moves away from the wall during the climbing procedure, the available working space for operating the formwork is therefore not additionally reduced. Thus, the system facilitates the cost-effective use of self-climbing technology also for relatively small elevator shafts or stairwells.
From floor 28 onwards, the geometries change in the core of the building – six smaller elevator shafts merge into four larger ones. At this point, the shaft formwork is quickly coupled together and a multi-unit aggregate simultaneously lifts the complete sets of formwork upwards.
For constructing the internal wall of the building core with its circular ground plan, PERI engineers combined the ACS P (P = platform) and ACS G (G = gallows) versions. The required platform openings for the placing boom as well as the crane could easily be integrated in both solutions.
The external walls of the circular building core have also been realised without use of a crane with the RCS rail climbing system demonstrating its advantages to good effect. The RCS system allows rail-guided climbing with a very high level of safety. The scaffolding climbs the ISET Tower crane-independently by means of mobile self-climbing devices and aggregates to the next respective concreting section. This reduces costs and results in an extremely economical solution. The PERI climbing shoe that can be pivoted on the vertical axis +/- 15° is used for safe anchoring to the building.
During the development of the formwork concept, the varying floor heights were also taken into consideration. The planning thus included the increase in the height of the wall formwork for the top ten floors from 3.60 m to 4.50 m. In so doing, all wall formwork was designed for a maximum concrete pressure of up to 80 kN/m².
For forming the circular walls, the construction crew used special elements on the basis of the VARIO GT 24 girder wall formwork. The detailed planning and creation of assembly plans was carried out by the PERI design engineers in Germany whilst the cut-to-size timber formers were realized at the PERI facility in Moscow. After the individual components had been delivered, site personnel assembled the formwork units just in time on the jobsite. This optimally coordinated task allocation allows the efficient and cost-effective execution of the circular core wall.
In addition to the technically faultless solution, the concept also provides a high level of safety for the user. This is ensured not least by the RCS climbing protection panel which protects site personnel against falling at all times when working at the outer edges of the building as well as against strong winds at great heights. The enclosure serves simultaneously as advertising space and transforms the structure during construction into a landmark which can be seen from afar.
All working steps along with any required modification measures were consistently well thought-out and clearly coordinated in advance in close cooperation with the site management. In particular, the PERI planning attached great importance on creating site-compliant solutions for the necessary adaptations at various levels. After only a short training period, the construction crew were able to concrete up to 3 floors per month.