Refurbishment and Reconstruction of the Academy of Arts M. Boehme

Refurbishment and reconstruction of the

Academy of Arts

M. Boehme

IPRO-Dresden, Schnorrstr. 70, 01194 Dresden, Germany

Abstract

The Academy of Arts is a striking part of the Dresden skyline. The building was completed in 1894 and suffered heavy damage in the bombing raid on Dresden on February 13*, 1945. Preliminary repairs and securing measures were carried out in the post-war years, so that teaching activities could be resumed. The building complex of the Academy of Arts with its exhibition has been undergoing renovation, reconstruction and modernization since 1992. The work, parts of which are very complex, will extend into the first years of the next century. In the following, the most important renovation and reconstruction work projects are portrayed and the adopted solutions are described.

1 History of the Academy of Arts

Precursors of the Academy of Arts can be found in Dresden dating from 1680. The "Kurfurstliche Akademie der Bildenden Kunste" (Electoral Academy of Graphic Arts) was founded in 1764. Subjects taught at the academy included the fields of painting, sculpture, copperplate engraving and architecture. The former "Briihlsche Bibliothek" was converted to house the academy and another storey was added to the building, which became the seat of the academy from 1790. The former "Briihlsche Gemaldegalerie" was used to house the art exhibitions of the Academy of Arts.

All buildings of the Academy on the "Briihlsche Terrasse" were conceived by the architect Christoph Knoffel and are an expression of a moderate baroque architecture, which gave the silhouette of the city by the Elbe river an unmistakable character for more than 150 years. Canaletto, but also other painters and artists, recorded this image in manifold ways in their paintings and drawings.

822 Structural Studies, Repairs and Maintenance of Historical Buildings

The government of Saxony handed down a decree to the Saxon orders in which the new construction of a building for the Academy of Arts and exhibition is justified, among other things, as follows: "The building on the Briihlsche Terasse, as well as the art exhibition building are dilapidated to a large extent. In addition to that, the premises are all together inadequate." The professor of architecture of the Royal Academy of Graphic Arts, Constantin Lipsius, was appointed to prepare the plans for a new academy of arts with an exhibition building. In the same year, he presented his initial concepts for the new buildings. Lipsius's plans met with serious protests from the association of Dresden architects. The concerns of the Dresden architects were predominantly directed against the height relations of the facade, which might spoil the beautiful cityscape with its huge dimensions. In the disputes that followed, however, Professor Lipsius design finally prevailed. The building was erected in the years between 1886 and 1893/94 at a cost of 4.08 million Reichsmark, of which 0.45 million Reichsmark were spent on sculptures. The Royal Academy of Graphic Arts was opened in 1894 and the Royal Art Exhibition building was opened in 1895. It wasn't long after their openings that the first remodelling and modernization work was begun on the complex of buildings. For instance, the connection to the district heating system in 1900. In 1904, the replacement of the gas lighting systems with electrical lighting was begun. In connection with the November revolution of 1918, all Royal insignias, such as crowns and inscriptions, were removed from the buildings.

This time at the Academy of Arts was substantially marked by the formative influence of dedicated artists, who helped to gain acceptance for new ideas in the arts in Dresden, as well: Oscar Zwintscher, Robert Sterl, Max Pechstein, Otto Dix, Oskar Kokoschka and many others. On January 30*, 1933, the time of fascist purging began at the Academy of Arts, as well. The dismissal of Otto Dix in April was followed by further purging actions concerning the so-called "degenerated art". In 1938 the former conference hall of the Academic Council of the Academy of Arts was refurbished with a "people's" design interior. The complex of buildings suffered heavy war damage on February 13* and 14* 1945, particularly the roof and the exhibition building, while nearly all buildings in the immediate vicinity were razed to the ground. In 1948, clearing of the rubble as well as emergency repairs were begun, which took until 1952 to be completed. With this accomplished, it was possible to resume teaching activities in the buildings of the Academy of Arts. The exhibition building remained standing as a ruin of war until 1990.

In the decades after the Fifties, efforts to renovate the building complex time and again didn't progress beyond the status of individual initiatives. It was not until 1990, when systematic activities for the refurbishment, modernization and reconstruction of the Academy of Arts were begun by the Free State of Saxony.

Structural Studies, Repairs and Maintenance of Historical Buildings 823

Figure 1: Refurbishment and reconstruction of the Academy of Arts Dresden, architect's sketch of the entire building complex viewed from the north

2 The building

The building of the Academy of Arts of Saxony, today known as Hochschule fur Bildende Kiinste Dresden (Dresden College for Graphic Arts), is a group of nine interconnected wings located at Bruhlsche Terrasse. The entire grounds consist of a multifarious complex, having completely different elevations to four sides of a pentagon. The overall appearance is characterized by a uniform, richly ornamented sandstone architecture (clinker facades are used in the inner courtyards only), by a roofscape with many folds and creases, covered throughout with zinc sheets and inset glass panels and with, in part richly ornamented, zinc roof enhancements, by, in part, unusually large windows with finely chiselled, narrow bars and finally, by a large number of free-standing figures (sandstone, gold-plated copper) and acroteria.

3 The structure

The entire building rests on 150 individual foundation pillars of different sizes, which consist of lime concrete in the lower area and sandstone in the upper area. All walls are brick masonry. The exterior facades consists of differently profiled sandstone elements, while the inner courtyards are finished with a clinker facade. The lower storey is built with brick vaulted ceilings throughout, while the ceilings in the upper storeys consist of steel

824 Structural Studies, Repairs and Maintenance of Historical Buildings

girders with reinforced concrete slabs. The roof areas consist of structural steel, covered in part with glass (cupolas, skylights) and in part with reinforced concrete covered with zinc roofing material. The extensive use of reinforced concrete, steel and glass should be emphasized, because it represents state-of-the-art building techniques for the late 19* century. Builders in the old Roman empire already knew about concrete as a building material. But this building material wasn't rediscovered until the 19* century. With advanced development of concrete and the invention of reinforced concrete by Monier a new age began in the building industry. Since that time, reinforced concrete has profoundly changed the building industry. Thus, the use of reinforced concrete ceilings in the construction of the

Academy of Arts of Dresden represented the most advanced technology at the time. Chief Government Building Surveyor Temper explained the use of this new building material in the building complex on the Bruhlsche Terrasse in 1896 with the following words: "As far as design is concerned, it should be emphasized that the architect has stipulated to ban any flammable materials from the building to the greatest possible extent. All ceilings above the lower storey are vaulted brick ceilings, the upper stories are built with reinforced concrete ceilings, the roof consists of structural steel with reinforced concrete slabs instead of rafters.

In the second half of the 19* century, new advanced methods in the production of glass made it possible to produce large panes of glass. The formerly very expensive glass became much more affordable due to the new production processes, so that glass was used in much larger quantities in building projects.

Constantin Lipsius took advantage of the advanced developments in the steel and glass production by making extensive use of structural steel and sheet steel, riveted and bolted girders or framework in the new construction of the building complex, particularly in the roof and cupola construction. Lipsius used extensive glass areas as skylights in the exhibition rooms and the studios windows as well as for the dust-ceilings made from glazed structural steel constructions located below. Particularly in case of the large windows of the studios and the nearly 10 m high windows on the east and south sides of the building complex, the structural steel construction was thinned out to the permissible minimum with regard to static considerations, in order to let the steel frames appear as filigree as possible in the facades. Glass was used in many varied ways, such as cylindrically curved glass in segments of circles and bent spherically in both directions in the small cupola. Even though iron had been used for a long time in the building trade, it wasn't until the late 18* and early 19* century that the preconditions were created for its application on a large scale. The growing steel industry supplied iron in the form of steel profiles, sheets and reinforcing steel in various dimensions in order to meet the new and changing requirements of the building industry.

Structural Studies, Repairs and Maintenance of Historical Buildings 825

4 The artistic ornamentation on the building

At the time the Academy of Arts was built, the philosophy of historicism had a decisive formative influence on the thinking and behavioural patterns of the people, in particular the architects of the late 19* century. The art-historical term HISTORICISM refers to the use of art forms that were already historic

in the fields of architecture and applied arts.

The building complex, erected in the neo-renaissance style, is embellished with countless figures and other artistic works. Outstanding works of Johannes and Robert Henze, both professors at the Academy of Arts, can be

still be seen today in the original beauty. Allegoric reliefs on the characteristics of the artists, statues, medallions of artistic models in architecture, graphic arts as well as literature of the ancient world, the middle ages and German classic era, sculptures and "putti" of different fields of teaching at the Academy of Arts alternate with allegoric reliefs and sculptures

having their origin in ancient Greece.

The exhibition building on the Bruhlsche Terrasse was arranged in the shape of a Greek temple. The portal carries an allegoric portrayal of an art exhibition in its gable triangle. The leading German-speaking art centres of

the time, Berlin, Munich, Duesseldorf and Vienna, look down from its gable in the form of personified female sculptures. The gold-plated copper sculptures Phantasos and Eros on the north wing and the Fama on top of the cupola of the south-east wing, the "lemon squeezer", crown the building complex and are supposed to proclaim Dresden's renewed claim as a centre

of fine arts. Finally, three gold-plated crowns and two Saxon coats of arms on the building complex bore witness of the fact that this was indeed a Royal Academy of Graphic Arts.

5 The refurbishment of the building complex

After a comprehensive status analysis of the building's condition in the years 1991 and 1992 and the determination of the condition of the foundation, facade, roofs, interior rooms, ornamental sculptures, planning activities were

initiated for a multi-phase refurbishment.

Planning task

The main planning task for the refurbishment of the outer skin of the building

included essentially: refurbishment of the foundation, including securing the foundation of the ruin with regard to static-constructive considerations, refurbishment of the entire facades, including doors and windows, and including new construction of missing and worn out, no longer functional

826 Structural Studies, Repairs and Maintenance of Historical Buildings

doors, including refurbishment or replacement of the eaves mouldings and the attica, refurbishment of all roof and attic surfaces, including roof structures and glass roofs, refurbishment of the sculptural and ornamental embellishments in the area of the facade and the roof, static-constructive shell refurbishment and reconstruction of the ruin parts as a prerequisite for the refurbishment of the external building shell, including prior salvage and dismantling of protected elements of the building.

The concerns of preservationists were given particular consideration in accordance with the objectives of the office for the preservation of historic buildings and monuments.

Further to that, the ongoing teaching activities of the Academy of Arts had to be taken into consideration.

The following section deals with some distinctive areas of the external refurbishment:

6 Refurbishment of the foundations

In the course of the analysis of the building's condition vertical cracks in the exterior walls were discovered throughout the building. These cracks were particularly obvious in the area of the spiral staircases, leading to a shift of the stair's axis of about 10 cm.

This was essentially caused by the foundations. A contemporary record of the description of the foundation reads as follows: "The entire foundation consists of 150 individual pillars of different sizes, which are brought down to the undisturbed gravel below the zero level of the Elbe river and which consist of lime concrete from a depth of 3.30 to 6.00 m, on which sandstone pillars, reaching up to the floor of the lower storey, are erected. The lime concrete used for the pillars was made up of one part lime, two parts Elbe gravel and three parts broken sandstone."

Boreholes in individual lime concrete foundations showed that a large number of the lime concrete foundations were destabilized, indicating that the building complex rested, to a large extent, on desolate foundations. The cause for this lies in the choice of lime, which hardens very slowly and thus tends to be susceptible to wash-outs as well as to the formation of gypsum with its associated swelling phenomena. This faulty choice of material, combined with the fluctuations of the groundwater influenced by the high-water of the

Elbe river as well as its direction of flow towards the river, accelerated the destabilization process of the foundations.

Structural Studies, Repairs and Maintenance of Historical Buildings 827

The jet injection process (also known as high-pressure injection) was used in the refurbishment. In this process, a concrete suspension is injected under high pressure into artificially created hollow spaces, thus forming new foundation pillars.

Over a period of 24 months of construction time the lime concrete foundations were replaced by a total of approximately 1,300 high-pressure injection pillars with a total volume of 5,500 m\

7 Refurbishment of the sandstone facades

Three varieties of sandstone were used in building the Academy of Arts: sandstone type "Posta coarse grained" was used for the ashlars of the facade, particularly for the pedestal areas as well as for pilasters and columns. It patinates in a dark-brown, almost black tone, even though it has a yellowish- brown colour whenfirs tcut . The "Cottser" sandstone was used as ashlars in the facades, for recessed smooth wall surfaces, mouldings as well as for the area of the attica. The third type was the Postelwitz sandstone of the type "Posta fine grained" which turns black with patinization. This sandstone is a high-quality sculptor's sandstone, which was used for sculpture works on the building complex.

With the use of sandstone qualities showing differences in colour after ageing for the facade Lipsius followed the design principle, in which lighter wall surfaces and window frames are offset from a massive, darker base made of "Teichstein" and, in some areas, of granite. The figured embellishment on the facades and the sculptures in the area of the eaves were intended to provide a clear contrast against the sky.

With regard to the refurbishment of the facades it became apparent that the Cottser sandstone used in the area of the attica and the upper sections of the eaves showed considerable weathering damages, which could only be repaired by replacement with new sandstone ashlars. A replacement sandstone with the same geological origin was located in Koniggratz. By very accurate mapping of the damages it was determined precisely in which areas the sandstone was to be replaced or supplemented by applying layers of stone mortar.

Planning and execution were implemented accordingly. Stone supplements were retouched only in part, as far as they were executed in stone mortar. Stone supplements remained fresh and will only take on a similar patinated appearance to the original stones in the course of ageing. Parallel to the refurbishment the sandstone and clinker facades were cleaned with warm water jets without any chemical or mechanical additives, in order not to strip the sandstone of its natural patinated "skin" and to guarantee the preservation of the detailed facade profiles.

828 Structural Studies, Repairs and Maintenance of Historical Buildings

Figure 2: Refurbishment and reconstruction of the Academy of Arts Dresden, portal with main entrance to the exhibition building

8 Restoration of the artistic ornaments

The free-standing sandstone sculptures and the ornaments on the facades of the Academy of Arts and the exhibition buildings were predominantly made from Postelwitz sandstone "Posta fine-grained". This is a high-quality sculptor's sandstone, on which no weathering damage could be found. The damages of the sculptures were caused by the war and by air pollution. The sculptures were cleaned and any deposits were removed mechanically. After that they were desalted and cleaned. After that, larger damages were repaired by quadratures of similar sandstone material, smaller damages were

Structural Studies, Repairs and Maintenance of Historical Buildings 829

repaired by supplementation with a mineral sandstone mortar. Finally, the were retouched using mineral colours. Some sculptures missing large parts were inspected intermediately by the state office for the preservation of historic buildings and monument before commencing restoration work. The sculpture "Kupferstecherkunst" (art of copperplate engraving) was the only one that could not be restored in original due to the extent of the damage. A copy was produced using a Silesian sandstone material.

A special feature of the building are the three sculptures "Eros" and "Phantastos" on the attica of the side projection of the north wing as well as the sculpture of "Fama" on the cupola of the south-east wing of the exhibition building, which are embossed from copper sheet and gold-plated.

All three sculptures were made according to a design by Robert Eduard Henze in Brunswick.

After rough cleaning the layer of corrosion was removed from the copper sheet. Bronze castings were used as connecting parts between the support frame and the exterior skin. The support frame was reused in part. Finally, gold-plating with leaf gold was carried out on-site.

Finally we would like to mention the glazing work in the refurbishment of the cupola on the center projection of the north wing.

Aside from the restoration of the structural steel construction and the annular anchors and the complicated zinc covering work, the manufacture of new glazing was proceeding at the same time. The reason that this was so complicated is that the centre cupola is built on an elliptical layout and is also curved towards the top. For that reason, the originally installed panes were curved spherically (in two planes). Due to the shape of the cupola there are only two identical panes on opposite sides. For that reason, a template had to be made on site for each pane in order to set up the manufacture.

The above descriptions can only convey a small portion of the entire range of planning and refurbishment work done on the building of the Academy of Arts. The co-ordination of all works and the cultivation of trade skills in the sense of preservation represented a big challenge to all participants in the refurbishment of a historic building.

Not only the external appearance, but also the building in its historic environment and the conditions prevailing at the time with the way of thinking and the technological and constructive possibilities should be taken into consideration when evaluating the building complex of the Academy of Arts, which occupies a dominating place in the silhouette of Dresden. Only the entirety of all these factors permits an objective assessment and appreciation of the noteworthy achievements of 100 year ago, the care and preservation of which must be our aim.

830 Structural Studies, Repairs and Maintenance of Historical Buildings

Figure 3: Refurbishment and reconstruction of the Academy of Arts

Dresden, main entrance at the centre projection of the north wing with small cupola