In the project entitled ‘Performance of comprehensive design tasks within the reconstruction of the Castle Garden Bazaar and the development of related public transport’, in addition to the complete design of the access ramp of the underground event space behind the Castle Garden Bazaar from Aradi utca, Főmterv was responsible for the traffic engineering design of the underground car park, the design of the temporary shoring of the pit of the event space with a pile wall, the preparation of a geotechnical expert’s report for the underground structure behind the Castle Garden Bazaar, and the design of external utilities.

A back-anchored spaced pile wall on the side of the Castle Hill (piles with a diameter of 1.0 m at a spacing of 1.4 m), a spaced pile wall on the north side (piles with a diameter of 0.80 m at a spacing of 1.20 m), and elsewhere soil nailing (if necessary, supplemented with jet grouting) were used for shoring the pit.

In the case of the back-anchored spaced pile walls, grout was injected into the part between the piles in the area of the underground parking garage and in a certain section of the access ramp up to the expected water level in order to keep off the quantity of water collecting in the pit during construction.

The undersground structure behind the Castle Garden Bazaar has several functions. It is suitable primarily for organising various events and conferences and as such, it also has a car park with a 298-car capacity. At the same time, it is also possible to allow access for lorries delivering goods to a confectionery, a buffet and a restaurant.

Road access to and exit from the underground parking garage are provided from Apród utca with a 78 m long curved ramp, which is quite steep in its section turning behind the Semmelweis Medical History Museum and its deepest point is at –10 to –12 m. Its average width is 8.0 m, its headroom is 4.60 m, and it has a closed reinforced concrete frame structure.

The entrance part is open in a length of about 17 m, becomes significantly wider between the delimiting retaining walls towards the street, safely separating the outgoing and incoming traffic also with a raised kerb.

There was a cellar system with partially known branches, connected to the Medical History Museum, in the area of the access ramp, which had to be removed before the start of construction and walled up towards the cellar of the Museum.