05.05.2025

Experimenta Square in Heilbronn

Building design

Heilbronn

With its unique look, the Experimenta Square in Heilbronn, designed by uniola AG and von K GmbH, connects the striking buildings and the parking areas of the Kraneninsel. Photo: von K GmbH

From a prestigious open space to a green urban oasis: the central square on the Kraneninsel in Heilbronn has been undergoing continuous development since 2019. With a fog system and climatic forest, it is now an urban place to take a deep breath. The offices of K GmbH and uniola AG report on its design in their project presentation.

With an area of around 25,000 square meters, the experimenta in Heilbronn, Baden-Württemberg, is the largest science center in Germany. Here, people of all ages have the opportunity to discover and understand science and technology. The learning and adventure world is located in the middle of Heilbronn’s city center on the Kraneninsel in the Neckaruferpark. The original knowledge exhibition in the historic Hagenbucher warehouse was expanded in 2019 for the Federal Garden Show (BUGA) to include a new building – also on the Neckar island.

Between the old and new experimenta buildings, there is now a space of around 7,000 square meters. The design of this prestigious area, which was completed for the opening of the 2019 Federal Horticultural Show, provides a visual link between the original building and the futuristic new building. Since then, the square has continued to develop both visually and in terms of its functionality, as the following description of the design stages shows – from the characteristic look to the climate-friendly greenery.

The first design plans for Experimenta Square were drawn up by the landscape architects at uniola AG based on the competition concept, which was then implemented by von K GmbH. Since its completion in 2019, the von K GmbH team has further developed the open spaces several times based on the original design. Visually, the square is recognizable: as a homogeneous carpet, it connects the parking areas of the Kraneninsel with the two striking buildings and establishes contact with the Neckar via terraced seating steps in the context of the adjacent water facilities. The small basanite stone paving was laid in a wild pattern (passe) and extends to the adjacent Kranenstrasse to the west, which was rededicated in close consultation with the city. In keeping with the shape of the building, pentagonal inlays of sandstone-like cast stone are integrated into the paved surface, giving the outdoor area an independent character with recognition value. Spread across the square are several tree islands with sparse trees. The polygonal edging, which also serves as seating, picks up on the architectural thread and continues it harmoniously. At night, the outdoor area is set in an atmospheric setting: pole-mounted luminaires of different heights illuminate the buildings and the entire square.

Even after BUGA 2019, the landscape architects at von K GmbH played a key role in the successive design development of the experimenta site and Kraneninsel. The office was commissioned to develop the new planting and maintenance concepts: the task was to convert the approximately 900 square meters of alternating flora on the heavily frequented square into a permanent installation and to coordinate the work. To this end, the von-K planners modified the arrangement of the beds and planted them with near-natural shrubs, perennials and early-flowering bulbs. They also redesigned the existing tree islands and restructured the paths. Thanks to its central location, the prestigious, ecologically high-quality site is a much frequented place in Heilbronn with a high quality of stay even after the BUGA.

In order to optimize the average maintenance effort, the vegetation areas on the Experimenta square are now watered using an intelligent system: the modern control system is not based on a conventional timer, but uses meteorological weather data. This means that the plants are only watered when it is really needed – for example, not when heavy rainfall is expected. This also minimizes water consumption.

Cities and municipalities – especially densely built-up inner cities – are increasingly becoming heat islands due to the rise in temperatures caused by climate change, particularly in the summer months. Sustainable and dynamic urban development therefore requires numerous well thought-out measures that focus on climate protection and climate resilience: More greenery, more water, less asphalt and concrete contribute to a better microclimate and thus ensure a better quality of life. The clients’ decision to erect an AI pavilion on Experimanta Square also made it possible to rethink the entire open space with a focus on climate resilient conditions. In a very short space of time, the proven collaboration between uniola AG and von K GmbH resulted in an unparalleled enhancement of the square. According to the motto “Experimenta Square should become greener”, the redesign takes into account the climatic and sustainable requirements and also contributes to improving the overall inner-city climate in Heilbronn. In the new AI pavilion, everything now revolves around the topic of artificial intelligence (AI). Visitors can gain an exciting insight into the technology and test AI applications on site.

The necessary redesign of the square is once again based on a concept by the landscape architects at uniola AG; Büro von K was responsible for the implementation of all service phases as part of a consortium. In order to sustainably improve the quality of life and air in the city center, the previous paved area was unsealed as far as possible to create space for green islands with a cooling forest character.

For the planted oases, there was a desire for them to inspire with a varied and preferably flower-rich appearance all year round and to offer a wide variety of species. When selecting the trees and shrubs, it was also important to consider that they had to be able to cope with the extreme site factors: Parts of the Experimenta square are built under and therefore offer little root space. The sealing and reflective façade walls also ensure a high level of heat development, especially in the hot season. For this reason, the two forest oases have been raised (around 1.20 meters) on modelled terrain. A special lightweight substrate reliably supplies the planted greenery thanks to its high water retention capacity. When selecting the trees and shrubs, Büro von K had both the native flora and fauna and climate change in mind: So-called “future trees” were planted in the two tree areas of the square – i.e. those that can adapt to changing climate conditions or are known to cope well with extreme climates such as drought. Where possible, native plants were chosen. The result is a so-called “climate forest”, in which some of the original willows can be found, as well as Scots pines, Himalayan birch, serviceberry and red maple for colorful accents. Small shrubs such as copper rock pear and winter honeysuckle complement the planting, as do drought-resistant grasses. Evergreen shrubs such as the fragrant blossom also ensure attractiveness in winter.

In addition to the woodland planting, a flowering meadow was also created to preserve biodiversity. The colorful meadows – some with wildflowers as well as herbs and grasses from native seeds – provide insects and other microorganisms with much-needed nesting and living space as well as a wide range of food; at the same time, they are a feast for the eyes for walkers and passers-by. The partial unsealing of the square has also created more open areas that allow better rainwater infiltration.

Also with a view to improving climate resilience, a misting system now cools down passers-by on hot days. The humid air also has a positive effect on the environment: the timed water mist can lower the outside temperatures in the immediate vicinity by several degrees – the positive effect is particularly noticeable and useful near STEIN surfaces such as floors and facades.

As part of the redesign of the Experimenta square, von K also took on the traffic system planning for the Kraneninsel (load class 3.2): This included the planning of a traffic light system, the optimization of the road width as part of the unsealing measures and the creation of passing places for trucks. The von-K landscape architects also integrated a parking facility for autonomous buses into their concept and – in coordination with the fire department, the city of Heilbronn and the operators of experimenta – developed a safe access control system that only allows experimenta employees and the city administration to access the Kraneninsel. The use of bollards controls the access of delivery vehicles and allows them access to the square. Anyone wishing to access the area must authenticate themselves using a chip or ring the bell. Automatic vehicle license plate recognition is also possible.

Since the redesigned Experimenta Square was inaugurated in June 2024, visitors have shown that the local improvements to the climate have been successful and well received: On the hot days in summer, passers-by have stood in the spray mist to enjoy the cool refreshment. Those who need a short break to rest can now find a seat in the shade of a tree. A long-term measurement of the temperature and climate development on the square is also planned; in addition to the subjectively perceptible improvements, this will also provide measurable results on the cooling of the area.

Designing outdoor spaces sustainably, creating green and open spaces for well-being and planning individual gardens – this is what von K Landschaftsarchitektur does with passion and expertise. Founded in 2017 in Ostfildern, Baden-Württemberg, the young company is based on the Filder plain. From there and remotely, around 20 employees work on projects far beyond the Stuttgart metropolitan area; since 2024 also at the second location in Denkendorf, where von K has created space for a dynamically growing team.

The von K landscape architects have made a name for themselves with their high standards of quality, creativity and attention to detail. Their core values and way of working are also well received: Von K scores points for reliability, adherence to deadlines, professionalism and fairness. Private, commercial and municipal clients value the office as experienced consultants and planners of economically well thought-out and authentic landscape concepts. Major showcase projects are proof of this. These include, for example, the design of the educational campus and the square surrounding the experimenta learning and experience world in Heilbronn for the Dieter Schwarz Group.

07.12.2024

The corrected Rembrandt

Building design

Alongside other important works by Rembrandt (1606-1669), the Berlin Gemäldegalerie owns his masterpiece “Susanna and the Two Old Men” (1647). Recent studies of the painting have produced spectacular new findings. We spoke about the discoveries with Katja Kleinert, research assistant, and Claudia Laurenze-Landsberg, conservator at the Gemäldegalerie der Staatlichen Museen zu Berlin (SMB). The latest results of their […]

From March 3 to May 31, 2015, the Berlin Gemäldegalerie and the Kupferstichkabinett (SMB) are presenting the latest results of their examination of the Dutch artist Rembrandt Harmensz. van Rijn in the exhibition “Rembrandt’s Berlin Susanna and the Two Old Men. The creation of a masterpiece”. What exactly did you find out?

Kleinert: Rembrandt worked on the Berlin “Susanna” for more than a decade and created three different versions of the depiction during this time. This was already known and documented by the Rembrandt Research Project. Now, however, it is possible to reconstruct the three versions in detail. In addition, in collaboration with the Kupferstichkabinett, it has now been possible to reassess the time when work on the painting began. The first composition must have been created around 1635 rather than 1638. What was previously completely unknown and truly spectacular is the discovery that the work was extensively reworked again in the 18th century.

How did you track down this sensation?

Kleinert : The decisive clue came from a reproduction engraving by Richard Earlom (1743-1822) from 1769. The original is kept in the Kupferstichkabinett (SMB). The sheet documents the version of the picture that Rembrandt left to posterity in the 17th century. A comparison with the present-day work reveals how much more differentiated the painterly execution of the painting must originally have been. As a result, it was possible to correlate existing art technological results, which proved that parts of the painting had clearly been reworked at a later date.

Laurenze-Landsberg: ” Earlom’s reproduction engraving was a relief for me. I had already examined the panel painting with a stereomicroscope before I became aware of it. The separation of the paint layers and chipped areas revealed beautiful, precisely executed details that had been very roughly painted over. At the time, however, I still assumed that Rembrandt had reworked the painting and was confused by the master’s superficial, less meticulous way of working.

What investigations did you then carry out to investigate the suspicion of a later intervention by a third party?

Laurenze-Landsberg: In addition to the neutron autoradiographs, we also analyzed the X-ray, infrared and grazing light images and examined the image stereoscopically. The image carrier is a sugar box wood which, contrary to previous assumptions, is not made of mahogany but amaranth. The sugar trade flourished in Amsterdam in the 17th century.

You assume that the later overpaintings are by the English painter Sir Joshua Reynolds (1723-1792). What supports this theory?

Kleinert : The provenance of Rembrandt’s Berlin “Susanna” is very well documented. Two painters had the panel in their possession. Sir Joshua Reynolds was one of them. He owned the painting for a particularly long time. We also know that Reynolds was interested in old painting techniques. And that he often worked on other people’s works and altered or corrected them to suit his own taste. He was also not afraid to remove paint in order to study the working methods and techniques of other artists. By looking at the original together with English colleagues from the Reynolds Research Project, the painting technique could then be clearly attributed to Reynolds.

Laurenze-Landsberg: The neutron autoradiography supports this thesis. It shows intense blackening caused by the antimony isotope SB-124. Since no tin can be detected at the same time, the antimony-containing pigment must be Naples yellow. It came into increasing use from the middle of the 18th century. Elsewhere, the paint layer is swollen, which indicates the use of copaiva balsam. This is a resin that was used to “freshen up” paintings. It is known that Reynolds used it as a binding agent.

How do you assess the reworkings today?

Kleinert: There are examples of even more far-reaching interventions that raise the question of the extent to which one can still speak of an original masterpiece. The Berlin “Susanna and the Two Old Men” is a painting that has been altered at a later date and must be declared accordingly. But it remains a Rembrandt.

The interview was conducted by Britta Grigull.

More on Rembrandt’s drawings, the biblical Susanna theme and the corresponding Berlin exhibition in RESTAURO 2/2015.

21.12.2024

Event

Architects in snow fever

Building design

At the beginning of February 2015, the tenth open German Architects’ Championships in the disciplines of skiing and snowboarding took place in Mellau and Damüls, Austria. Around 120 participants took up the challenge. around 120 participants took up the sporting challenge. At the warm-up in Peter Zumthor’s “Werkraum” in Andelsbuch on Thursday evening, the early arrivals were able to get a first impression. In the exhibition “No Name Design” by Franco Clivio, the focus was on the inconspicuous things that accompany us in everyday life and yet rarely attract attention.

The following evening, the GAM open 2015 was officially opened by patron Lutz Heese (President of the Bavarian Chamber of Architects) in the Elsenalpstube in Damüls. After the subsequent ‘Kässspätzle’ meal, which was a culinary highlight, originally served in a wooden bowl, the 4 kilometer long and illuminated toboggan run into the valley could be tested. In bright sunshine and perfect conditions with 1.90 meters of snow, the starting signal for the 10th GAM open in the parallel slalom discipline for skiers and snowboarders was given on Saturday morning.

Jannis Merz (men’s skiing) with 22.420s, Armin Tittel (men’s snowboarding) with 27.360s, Birgit Keppler (women’s skiing) with 26.430s and Ulrike Schneider (women’s snowboarding) with 34.780s won the championships with best times. The office championship went to the team from the Reutlingen Chamber of Architects (Nightmare 2). The award ceremony took place in the evening, followed by a party at the four-star Design Hotel Sonne in Mellau.