10 December 2019

Rotunda is impressive again

The symbol of Warsaw – Rotunda – implemented by NDI SA as the General Contractor for PKO Bank Polski as the Investor will gain new life. The investment was officially launched on November 29.

‘Rotunda is one of the symbols of Warsaw, so when we were entrusted with this project, we fully felt the burden of responsibility and expectations resting on us in connection with the undertaken work,’ says Małgorzata Winiarek-Gajewska, President of the Management Board of NDI SA. ‘We hope that we have managed to successfully fulfil the task entrusted to us, and that the facility will serve future users and residents of Warsaw for many decades to come.

Rotunda is a unique building on the map of the capital city, which is why its revitalisation was a huge challenge for us. Today, I can proudly say that we are opening a building that not only regained its splendour, but gained a completely new quality as well. A new PKO Rotunda has been created, which will play the role of a bank branch and at the same time a multifunctional space open to everyone,’ says Rafał Antczak, Vice President of PKO Bank Polski.

Rotunda, located at the junction of Marszałkowska St. and Jerozolimskie Av., has three storeys, including one underground. The building was divided into a technical and banking part. Due to the expanded function of the building, the technical part was separated from the original plan of the office building and is located outside the banking part – from the side of Widok Street, below ground level. These are the rooms in which devices and system elements that enable the functioning of this modern office building were placed. The banking part was divided into zones for the bank’s operational work – floor -1 and 0 – and a zone with public function – floor 1. The area around Rotunda has also been developed.

The construction of Rotunda was divided into several basic stages. During the first stage, the existing building was demolished and clashes with utilities were resolved along with reconstruction of the networks, including in particular: electricity, heating, sanitary, water and rain networks. It was not an easy task due to the fact that the construction was carried out in the downtown of Warsaw.

The next stage was the construction of the main building. Below the ground level, Rotunda has a reinforced concrete structure, for which approximately 230 tonnes of reinforcing steel were used, and above the ground level, a steel structure, for which approximately 500 tonnes of structural steel were used for construction.

‘All steel construction elements were welded in the production plant, while on the construction site bolted connections were applied in 99% of the cases. The steel structure for the ceiling of the upper floor has been bolted with around 2500 pieces of preloaded bolt connections. The roof is based on 48 perimeter columns and one so-called central column, which is actually located off-centre in relation to the centre of the building. All steel columns were attached to the reinforced concrete structure by plate anchors, positioned using surveying, which were prepared at the stage of pouring concrete,’ says Łukasz Czuchaj, NDI Project Director, and adds ‘All of the 492 anchors fitted perfectly to the openings in the columns prepared earlier a few hundred kilometres from Rotunda, in southern Poland. The precision of the steel structure execution made the subsequent construction stages easier.

Upon completion of construction works, equipping the building with systems and, simultaneously, facade works commenced. Rotunda has an internal and external facade with communication passage between. Access to natural light in office spaces below ground level has been resolved by installing glass ceilings at the ground floor level. The external facade was made using custom designed and manufactured elements. Due to its specificity, i.e. installation to a steel structure, displacements of that steel structure had to be taken into account, which at the stage of the workshop design became a real challenge for the engineers involved in this task.

Upon completion of facade works, the construction of partitions began, which are mainly made of glass. At this stage, stairs and glass ceilings were also installed on a previously prepared steel substructure. Approximately 4100m² of glass with various parameters was installed in Rotunda – from facade glass, which constitutes an acoustic and thermal barrier, through the glass partitions that perform mainly acoustic and decorative function, to glass with fire resistance in glass ceilings. The ratio of square metres of glass to the usable area of Rotunda (2,608.40 m²) is approximately 1.57. During this stage, decorative cladding mainly made of aluminium (solid aluminium and composite panels) as well as acrylic and mineral cladding was also installed. Due to the shape of Rotunda, almost each of the decorative cladding panels has unique dimensions, which at the stage of works forced the creation of many templates and high precision of execution.

Rotunda is equipped with all modern and functional systems, including electrical, teletechnical, sanitary and HVAC as well as fire protection systems which ensure the safety of people in the building. In particular, it should be noted that each room is protected by high-pressure water mist and the Fire Alarm System. In addition, all rooms of the bank section have modern lighting with the function of intensity control and lighting scenes, which improves the comfort of users of the facility. The interior of the building is protected against excessive sunlight by 82 blinds controlled by the building automation system. In the skylight on the roof, eight photovoltaic panels, which supply electrical sockets for charging portable devices, have been installed.

Upon finalising the installation works, suspended ceilings were mounted at each level. It is worth noting the characteristic shape of the ceiling spherical sector at the level of the upper floor in the part with public function made using plasterboards, which in the central part, under the skylight, turns into a slatted ceiling made of acrylic and mineral plates, shaped to be a continuation of the spherical sector.

An element worth describing is the roof of Rotunda with its characteristic wavy line (a symbol of general’s rank in the Polish military). The main structure of the roof consists of 48 pieces of structural steel plate girders. Thermal insulation, waterproofing and cladding of anodised aluminium sheets in the natural aluminium colour was applied on it, by mounting it to a custom-made steel substructure consisting of consoles and sections. Each of 1182 aluminium sheets has a unique dimension, which makes this project unique.

The final stage of implementation was the development of the area of Rotunda, along with the internal and external vegetation. From the side of Widok St., an urban patio was created, which is one of the elements of the designed public function. It is recessed below ground level. There is a fountain there in the form of a rain shower placed at the level of the ceiling of the ground floor, from which water will fall into the fountain basin made of granite slabs. Green walls have been placed around the entire urban patio, creating an interesting microclimate in this area. The entire Rotunda has about 1320 pots of different sizes both outside and inside the facility, together with about 15,000 plants of various sizes. The remaining part of the square at Rotunda was restored in accordance with the original land development together with one new element, which is a bench from the side of Marszałkowska St., attached to the wall surrounding the urban patio.

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