Sumit Singhal loves modern architecture. He comes from a family of builders who have built more than 20 projects in the last ten years near Delhi in India. He has recently started writing about the architectural projects that catch his imagination.
The Great Rock in Budapest Zoo, Hungary by Peter Kis Atelier
March 6th, 2011 by Sumit Singhal
Magic Mountain in the Great Rock
Pursuant to the government decision of 23 September, major development projects will be implemented at the Budapest Zoo and Botanical Garden. As part of the project called ‘Magic Mountain’, a complex exhibition and event space will be created inside the Great Rock; at the same time, the Bison House and Giraffe House will be restored according to the original plans. The project allows the facility, which has difficulties owing to limitations of space, to create an interactive exhibition on an area of 3,000 square metres, previously not accessible to visitors, that provides a unique experience. The construction of the interior of the Great Rock, the largest building of the garden, as an exhibition and event space has been planned since 1912 but has not been implemented to date. The utilisation of the interior of the Great Rock will provide the Zoo with a venue worthy of housing a number of cultural events, while it will also enhance the range of experiences and programmes that can be offered in winter, which could result in increased visiting times.
The Magic Mountain exhibition to be constructed in the Great Rock aims to demonstrate, in a unique and spectacular way, the extraordinary forms of existence that ever appeared on the stage of life, and the development and compelling richness of life, to present the public with “wonderful rarities”. The diversity of the forms of life and of organic and inorganic systems will be the guiding principle, where diversity is interpreted as a response to the challenges of the environment and problems to be solved, and presented in a true-to-life manner using an extremely wide variety of exhibition equipment that exploits the advantages of the space available. We are planning a system of exhibitions, richly equipped with interactive and adventurous games, shows of living animals, models of giant animals, projection microscopes providing an insight into the micro-world, and exploration and presentation rooms, which is unparalleled in Central Europe.
In addition to the construction of the exhibition space of the Great Rock, the listed monuments of the Bison House and the Giraffe House will also be restored as part of the project, according to the original plans of Károly Kós and Dezső Zrumetzky. The details of the listed monuments will be complemented by indoor housing designed and equipped to today’s standards, and a set of reconstructed paddocks. The buildings will be heated in part by using renewable energy.
The Budapest Zoo has twice changed dramatically during the past hundred years: first between 1907 and 1912, when the totally obsolete Zoo underwent a profound reconstruction, and for the second time between 1996 and 2008, when after nearly 90 years of “use” it was completely renovated and modernised, in line with the requirements of modern animal zoos. In the second stage of the reconstruction works between 2006 and 2008, in addition to the creation and modernisation of numerous new animal housing facilities, amongst them the largest enclosure of the Zoo, the Savannah, the area around the Great Rock was also renovated.
The new developments such as the promenades of the Great Rock which have been closed to visitors for almost 50 years were opened to the public in the spring of 2008. It was the first time since World War II that visitors could walk these paths, admiring the exceptional panorama that they open up. The Tejcsarnok (Dairy), designed by Károly Kós and Dezső Zrumeczky in the side of the Great Rock has also been re-built as part of the reconstruction programme.
The History of the Construction of the Great Rock
In June 1909, 43 years after the Állat- és Növényhonosító Társaság (Animal and Plant Naturalization Society) was founded, the capital took possession of the Zoo with the aim of establishing new animal demonstration areas and buildings- a modern zoo in line with the thinking of the time, the popularity of which had declined over the previous decade.
The general assembly of the municipal board of the Capital voted to offer 1,212,000 then later 1,788,000 kroner for the developments, electing a committee at the same time for directing the works. Dr Adolf Lendl was appointed for reviewing and inspecting the zoological work and Dr Kornél Neuschloss for the construction and technical works. The engineering work for the transforming the area of the garden was carried out by the engineer Gyula Végh, who with Károly Kós and Dezső Zrumeczky had the new buildings designed by several participating young architects. Ilsemann Keresztély, the Director of the Garden took a role in the transformation of the park and in the establishment of the long desired Pálmaház (Palm House).
In order for the area to appear larger and to show the animals in an environment similar to that of their natural habitat, the construction of two artificial rocks, at the time named Hill “A” and Hill “B”, were also included in the ideas.
Hill “A” is in the shape of a limestone range with a dolomite peak; its area is 4,700 square meters with an internal space of 38,850 m3.
“… we erect a high rocky hill… and it will be built in the characteristic grey limestone shapes of karst areas. It large area will provide a varied appearance and if we insert small grassy meadows and water-washed gullies between the steep rock walls and the ragged blocks leading down with a wide valley, it will thus naturally connect the rocky eminence. There will be animals all over it and in the deeper sections trees and bushes can develop.” (Lendl)
Two 1:200 scale models were made of the rocks for the planning and design phase, and for the construction work further models in more detail on a1:25 meter scale. In order to find the correct ratio, a scale model was also made for the whole of the planned garden.
The shape of the hill defined the reinforced concrete frame holding up the shell. The task was to connect the points in space and to create statically purposeful shapes that fitted onto these. Amongst the different structural solutions, the dome and the spatial trusses suggest the wooden frame form solution applied by Karl Hagenbeck, previously director of the Berlin Zoo, and the constructions of the different supporting walls as well as the curved supports suggest an enthusiastic experimenting mood.
In addition the structure had to be scaled for the public that conquered the ridge and also the snow load, as well as the soil that was used on the plateau between the two peaks (20 m and 34 m). The central inner space with a 31.80 m tension length and the suspended dome above it was unique in its own right at the time. Its height at the protective collar reached 16.80 m. The form of the eight curved main girders followed the thrust line; therefore the load on the rings holding them together was minimal. The basal ring was even omitted with the foundations sufficiently reinforced instead. The staggered design of the external surfaces of the supports enabled the joining of the posts and beams of the spatial trusses.
The dome would have provided a home for the water storage, which would have been filled from the drilled wells of the Garden providing a water supply to the area. However by the time the rock was completed, the town’s water supply had reached the Városliget, therefore it became unnecessary. The tank that can be seen today was initially planned as storage in case of fire but due to a lack of funds the idea did not actually come to fruition and the tank has never been filled. During construction the dimensions of the hill at the lion house was altered, thus creating another new large inner space. The former are connected by a structure that is made up of 8 curved supports between 9 and 13 m long. The supports for the passages everywhere are reinforced concrete plates that rest on a beam frame.
“… and the largest cats, the lions and tigers (no doubt we can expect many specimens, as these are the more common species available) according to the Stellingen method are under an open sky on the southern side of the hill erected from limestone, with sloping yards surrounded by a wide ditch and enclosed at the back by high stone walls.
The large bears will be located similarly at the northern base of the same hill. With all certainty we will have many specimens in 3 to 4 species…
Several paths lead through the heights of the hill. We bridge the gorges and turn walking around the peaks: from the highest points of the hill beautiful views open up to the fresh and green areas below… and as we cross to this side of the hill, another view opens up to us; there are different animals amongst the rocks and in the valley that leads downwards. In places caprine and ovine animals are grazing freely in the small meadows inserted between the naked boulders; wild goat species from Asia and Africa and moufflon climb to the ridges to jump from there as we have seen in the Stellingen Zoo. The grids and the fences are not visible to the visitors amongst the rocks and bushes, for that reason the animals appear as if they lived free in the wild. The environment around them is developed in a masterful way; the animal houses are also hidden or at least their view does not disturb the audience.” (Lendl)
The construction commenced in 1909. The work was awarded in a tender to György Pohl’s company. The rock was continuously built by 150-220 people for 3 years, fifty of them alone carried out the shuttering works, with eight thousand cubic meters of concrete being used. The progress of the support was continuously followed by the construction of the outer shell. Cantilever beams and steels that projected from the reinforced concrete scaffolding were used for supporting the hill’s covering shell. This was made of 6-12 centimetres of a Portland cement wire lattice structure (3.5 parts Danube sand, 1 part Portland cement) covering nineteen thousand m2 with pig hair mixed into the mortar to achieve better plasticity. Fine particle concrete was applied to the scaffolding.
The drainage for the rock was developed with great care, applying impermeable concrete to the sensitive areas. In order to prevent cracking in the rocks, expansion joints were included in many places in a way that they would appear to the external observer as natural formations. The foundation, due to the high water table, was from compacted concrete with the walls and floors of the pens of reinforced concrete to prevent the animals from scraping their way through it.
Leaks, internal condensation and damage from World War II together with their poor restoration, as well as the erosion and the corrosive effect of the air pollution of several decades all damaged the support and crustal structure of the rock. On the surface of the crumbling concrete pitting and cracks appeared as well as corrosion of the reinforced steel surfaces. Despite all this the support structure remained in adequate condition until the 21st century. However the shell structure became largely carbonated and full renovation became unavoidable by the turn of the millennia. During the wide ranging renovation works that were carried out between 2006 and 2008, care had to be taken to ensure the external surface remained waterproof and to provide for ventilation of the inner spaces.
The rocks were the most modern animal display spaces of their time
The story of the use of the artificial rocks in the zoo, as animal enclosures started in Zürich. Urs Eggenschwiler, a sculptor who befriended the animals in Zürich designed an artificial rock for the Zürich Zoo. The plan was not implemented there, however the idea appealed to Karl Hagenbeck, the director of the Hamburg Zoo and so the first zoo artificial rocks were built in the Hamburg-Stellingen Zoo with the application of the “panorama-display”. The idea then was taken up by several zoos at the time, and was also the case in Budapest. This was supported by a visit of the members of the “Zoo Building Committee” prior to the great reconstructions of 1909-1912, to Hamburg as part of a study tour.
In those few places, where the artificial rocks still survive today, they are treasured as the specialities of previous times from Hamburg to Antwerp and from Barcelona to Buenos Aires. However artificial rock hills of similar size to the ones in Budapest are only found in the Vincennes Zoo in Paris. These were made two decades later and were opened in 1931 with the highest peak; their “Great Rock” at 72 m. In the inside however there are no really usable spaces; neither does the finish of its surface show such details as those in Budapest. Its reconstruction was completed in 1997.
The Magyar Királyi Földtani Intézet (Hungarian Royal Institute of Geology) provided expert guidelines for the preparation of the patterns of the artificial rock and for shaping the granite, gneiss, limestone, dolomite, sandstone, basalt and trachyte stones. A geologist and a sculptor was said to have directed the foremen at the construction and in order for the work to resemble a natural cliff as much as possible, photos and surveys of the “Egyeskő” peak in Transylvania served as a model.
In the Budapest Zoo the role of the rocks was partially to create an aesthetic, nature like display of the animals, as well as to develop exhibition spaces that were considered most modern at the time. Their most important function however was to optically divide the area that was already constrained and to provide an extended walkway. Everybody is surprised that it is only 10 hectares that can be viewed by visitors in Budapest (both amongst the zoos of European capitals and of larger Hungarian towns the zoo at Budapest is one of the smallest). The Gardens are perceived as a much larger space when walking around than in reality, thanks to the artificial rocks and successful landscaping.
Contact Peter Kis Atelier
Category: Artificial Rock