Exploring the world's built environments and seeking sustainable solutions.

Thursday, July 28, 2011

Foot Fancy in Freiburg

Freiburg is a small university city but still has a lot of variety, not only in its architecture but in its streetscapes as well. As we walked around we noticed many different types of cobbled stones and other paving materials. The city additionally includes small details within the streetscape such as many small open canals for storm water runoff and river water, and has small bronze placards in the pavement to honor the Jews who were removed during WWII.
The most common type of pavement within the historic center is cobbled stones. These are not only consistent with the historic character but are also long lasting, attractive and permeable to rain water. However these can be uncomfortable to walk on and the variation in size and spacing makes it very easy to trip, roll an ankle, or catch your bike or stroller tire.

Tarring the gaps in between the cobbled stones is also relatively common, especially on the busier streets. Tarring has the added benefit of making the surface more even and easier to walk or bike on, but unfortunately detracts from the historic character. Sealing the gaps in between the cobbled stones also increases the amount of storm water runoff because it lessens the permeability of the street and thus directs more water into the canals.
An attractive variation on cobbled stones is the use of river rocks that are cut in half and placed vertically in sand. This provides greater visual stimulus in changing sizes, colors, and spacing. These river rocks provide excellent drainage because of the gaps and the sand. They are also more comfortable to walk on than traditional cobbled stones because they lessen the impact on feet and knees despite potentially being more unevenly spaced. In some areas where they use smaller river rocks, the rocks are spaced fairly uniformly and are used to create patterns and mosaics. The mosaics ae in front of historic buildings and depict the former use of the buildings. The use of these local materials in general is in character with the genus loci, the spirit of the place, because the river is an important motif within the city. A negative aspect of using river rocks is the labor intensity of laying them so precisely, which ultimately can make them an expensive sidewalk treatment.
Like any city, Freiburg also has traditional asphalt and concrete streets. The majority of these are outside of the historic center and do not enhance the aesthetics. Asphalt and concrete do provide better traction, are smoother to walk on and are more durable for heavier traffic such as trucks. One major con to using asphalt and concrete is the lack of permeability, which creates a lot of storm water runoff.
Pavers are a good compromise to many of the pros and cons previously discussed; they can easily combine durability with visual interest and permeability. They are generally seen in areas with less heavy automotive traffic, such as driveways (like the one leading to our hostel) and sidewalks along major roads. Pavers can be spaced in a particular pattern and can even allow for vegetation to grow in between the gaps which helps enhance drainage. Pavers are also easier to place than cobbled stones or river rocks due to their uniform dimensions. Although pavers are not always in tune with the historic character of the city, they do provide visual interest and charm in the vegetation and their patterning.
The more we explore Freiburg the more we appreciate the efforts the city has undergone to make walking a pleasurable experience. The city has done a lot to preserve historic character and provide visual stimulus, even to the extent of providing many different pavement types. Walking in Freiburg can be just as interesting looking at your feet as looking at the buildings.

–Chrissy Warner & Julia Mai Plotts

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