A Roof with a Wave: Zagreb International Airport
Client: Zagreb International Airport d.d.
Architect: Kincl + Neidhardt
Structural framework: Institut IGH
Location: Ulica Rudolfa Fizira 1, 10410 Velika Gorica (HR)
The new terminal of Zagreb Airport is part of a development area at the southern edge of the Croatian capital. It consists of two building portions: a main structure with four levels and a nearly square floor plan measuring 137.5 x 131.1 metres, and a pier that juts to the left and right on the front side. The departure hall and arrival halls as well as the airport’s security zone are found in the main volume. The other wing is home to shops and the waiting area. Passengers reach the planes via steel bridges; there are eight of these.
The two-part edifice is spanned by a shared steel roof built as a Mero construction. The architects created the undulating shape of the roof as a reminder of the surrounding mountains. The twice-curved framework structure measures 152.3 x 151.2 metres in its main area and consists of 26,000 steel rods and 6,100 nodes. Like a breaking wave, it ends at the gates in an inward curl. Along with the clear supporting structure, large-format glazing on the lateral façades creates a high spatial transparency.
The supporting roof structure above the main volume is constructed as follows: the base and the height of the basic triangle each measure 3.6 metres, while the axial height of the spatial triangle is 3.0 metres. The entire roof area rests on 18 supports arranged in a grid measuring 43.2 metres (parallel to the wing) by 28.8 metres. The highest vertex of the structure lies between +20.0 and +34.0 metres. Above the wing, the roof is cylindrical, with heights ranging from 1.4 to 3.0 metres at the transition to the main roof. The vertex measures 20.50 metres at the ends and 24.7 metres where it joins onto the main roof.
The supporting structure of the main building consists of reinforced or prestressed concrete (levels 0 to 3). The resulting loads are transferred over supports in a grid of 7.2 x 14.4 or 14.4 x 14.4 metres. The levels of the wing are also made of reinforced concrete.
Altogether 2,000 tonnes of construction steel, 35,000 cubic metres of concrete and 5,000 tonnes of reinforcing steel were used to build the airport.