Test of strength for PERI formwork and scaffolding

9:25 pm UTC June 3, 2014 Jun 3, 2014 | by: Peri | Civil engineering

(Photo by: Peri)

The Energy Financing Team (EFT) is currently constructing the Stanari coal powered power plant near Doboj. For this project, the contractors have been tasked to realize a particularly large scale, massive structure whilst, at the same time, complying with small dimensional tolerances. PERI supplies two of the building contractors involved with a customized formwork and scaffolding solution. In addition to the materials, it is the technical preparation done by PERI engineers that provides extremely helpful support thus ensuring efficient project execution.

Massive components with a high degree of reinforcement and weight as well as great heights – these are normally the challenges faced for the construction of power plants. Consequently, the requirements for formwork and scaffolding are maximum loading capacity, a high level of flexibility in the application, and the availability of large amounts of material – usually within the shortest construction time. At the same time, all formwork and scaffolding constructions required for realizing power plants have to be individually developed and dimensioned. This is also the case for the Stanari coal‑fired power plant in Bosnia‑Herzegovina – the first power station in this region which complies with environmental policies of the EU. PERI has planned and is supplying the formwork and scaffolding systems for two areas of the structure: a climbing formwork solution for the piers of the platform for the condenser as well as a combination consisting of stable shoring and complex arched slab formwork for the turbine building of the power plant.

26 metre high massive platform

The MD Perić Company is building a massive platform designed to carry the air‑cooled condenser for the power plant. A steel construction will be subsequently positioned on a total of 9 circular concrete piers with external diameters of 3.60 m and with a wall thickness of 40 cm. Each pier is formed by means of 9 concreting cycles respectively, each cycle 3.00 m high. The massive, 2 m thick pier heads are constructed with the last cycle.

On each pier, 12 brackets of the CB 240 climbing system support the project‑specific VARIO GT 24 wall formwork elements. The finishing platforms are equipped with ladders which ensure quick access to the wall itself. The fact that the climbing brackets and formwork can be moved as a single unit by crane from concreting cycle to concreting cycle accelerates the construction progress.

On the inside of the piers, the BR Shaft Platform provides tailor‑made support for the wall formwork. For supporting the platform by means of gravity pivot plates, bearing boxes are mounted on the walls accordingly which simply remain in the wall after the platform beams have been moved.

The turbine house – a heavyweight structure comprised of approximately 2,300 m³ concrete

With a base area of 30.50 m x 12.00 m and a total height of 16.90 m, a very substantial structure is being realized which will subsequently house the turbines. GP Gradip AD is responsible for the construction and was faced with meeting the challenge of processing up to 950 m³ of material in a single concreting operation. The entire turbine structure is characterized by impressive dimensions: the columns required have cross‑sections reaching up to 1.40 m x 2.10 m whilst the beams measure up to 2.10 m x 5.30 m. The up to 5.30 m thick slab also features arched sections in some areas. Last but not least, only 5 months was made available for the GP Gradip AD construction team to complete the concreting work.

For the execution, PERI engineers from Serbia and Weissenhorn developed a shoring solution on the basis of the PERI UP modular scaffold that is designed to support the project‑specific formwork. The leg spacings of the 11.60 m high shoring vary between 25 cm and 150 cm – in this way the supporting structure is optimally adapted to suit the load requirements found in the different areas. For the flat slabs, MULTIFLEX girder slab formwork provides the necessary versatility to accommodate the high loads generated in the construction. With GT 24 formwork girder spacings of 30 cm, the construction can comfortably carry the high concreting loads.

For the arched construction, PERI design engineers developed a supporting structure comprised of rentable system components: the construction features SLS heavy‑duty spindles, RCS rails and tubular steel slab props, covered with proven GT 24 formwork girders – and thus provides sufficient stability for the more than 5.00 m thick slab.

PERI´s contribution for realizing the turbine house is a project specific overall concept – consisting of formwork, scaffolding and engineering from a single source. In addition to the materials, PERI has compiled detailed plans along with the static calculations for the complex design. Furthermore, PERI engineers have been continuously providing on‑site support for the implementation, thus ensuring that the short construction schedule is maintained.

The power station

The Energy Financing Team (EFT) company is investing around € 600 million in the new Stanari thermal power plant near Doboj in Bosnia-Herzegovina. Approx. 3,000 people are involved in the construction of the power plant over a time frame of 45 months; when operational, the power station will provide 200 people with full‑time jobs.

With an installed capacity of 300 MW, the Stanari power plant will generate in the region of 2 million megawatt hours (MWh) of electricity annually. It is the first power station in Bosnia‑Herzegovina which fully complies with European Union environmental standards, explained the investor. Among other things, continuous waste gas treatment including a flue gas desulfurization system and dust extraction is planned.