Many years ago I felt privileged to have an audience with Christian Menn, one of the world’s greatest architects based in Chur, Switzerland. A graduate of Switerland’s ETH (see Professor Vogel’s interview some months back), Menn is known for the Sunniberg and Ganter Bridges in Switzerland.
During our meeting, we spoke about the Bridge Museum itself and his philosophy of bridges. Below are a few excepts from his thoughts, accompanied by a few photos, which lays out his philosophy. Budding engineers, architects and others in the built environment will find his views important.
The aesthetic quality is one of the main components of architecture. It cannot be directly quantifiable, but one can estimate the monetary value of different aesthetics in comparing different projects. Bridge aesthetics consists in part of the relationship between the structure and environment and in part of the bridge’s design itself.
The balance between bridge and environment – the optimal insertion of the bridge in the wider environment – is visualized primarily by temporal and spatial aspects as well as the more or less strong emphasis on the symbolism of the appearance. The temporal aspects include history and tradition of local bridge construction and the current level of local building culture and bridge technique. The spatial aspects consist of character and scale of long-distance, authentic or urban landscape, the exposure of the bridge and its importance as a potential landmark. The insertion of the bridge in its immediate, local environment requires the optimal consideration of topography and geology, soil properties, local buildings, existing traffic conditions, clearance gauges, water characteristics and water course.
Structural aesthetics are the most important requirement for balance and harmony, derived from the design concept and spatial structure. It is not two-dimensional, drawn on a sheet of paper.
A slim, transparent, elegant structure should be sought, characterized by technical efficiency. The following aspects must also be considered: a holistic approach of the support system (i.e. interaction of as many structural parts), uniformity/consistency of structure (i.e., continuous rod or surface structure as well as formally similar cross-sectional shapes). The power flow must be visualized through careful inspection, the stress corresponding to the variation of the cross-sectional dimensions and emphasizing the space frame stability.
Overall, a model or a computer visualization helps to check a bridge’s aesthetics. As three-dimensional objects, models provide a good understanding of the spatial effect. However, models are mostly too small and are often seen and photographed from a perspective that is not real. This is especially true when bridge and environment are painted white (which is very common in architectural models) and loses contrast. Photographs are then hardly more useful.
Computer simulation of the bridge in its landscape reveals much more than models. The only downside is that it misses the three-dimensionality.
An important aspect in the assessment of a concept in this respect is the additionally required for the aesthetic quality cost compared to the simplest, most economical solution, which should not exceed about following limits:
- Large bridges about 5%,
- Medium bridges (length less than 500 m center span 100 m), about 15%
- Small bridges (length less than 100 m, center span 50 m) about 25%.
For pedestrian bridges even large additional costs are justifiable depending on the desired bridge experience.
The visualization and evaluation of the correlated with balance, i.e. balance and harmony with the natural bridge aesthetics is not simply a matter of taste; Although it requires a certain sense of form, it can be at least see defects with models and computer images.
One can – even without much sense of form – make an easy distinction between easy elegance and clunky awkwardness, between functionally suitable and unsuitable materials, between efficient and inefficient support systems, between necessary and unnecessary structural elements between design and decoration, and between conceptual approaches that are probably in the building construction, but are not suitable in bridge construction.
Bridges should, apart from small, nostalgic webs reflect (also with their looks) natural, mathematical physical beauty in the context of the current state of the art. The bridge is not a piece of art in the narrow, literal sense. Aesthetically wayward bridges characterised by visual incompatibility with their environment, poor design, improper support system or inexpedient building materials should not be glossed over and termed “modern art in a bridge”. The genuine bridge does not follow neither architectural trends nor fashions.
On Sunniberg, I made two decisions:
- the bridge should be long and thin;
- the pylons should not be built on top of each other.
The rest was about being built in the most efficient way, and so the bridge built itself.
On Architects and Engineers
Architecture is closer to art and engineering is closer to the natural sciences. Accordingly, architects prefer the creative decorative and engineers prefer the natural design aesthetic. This can lead to misunderstandings between architects and engineers. With the growing volume of standards, guidelines, technical requirements, qualifications and controls engineering has shifted in recent times increasingly to natural science, and architecture has shifted towards the pursuit of originality and creativity. This phenomenon hurts the mutual understanding of the two professions that formerly belonged together. Many engineers today are quite willing to allow architects to conceptually design bridges. In turn, architects expect that engineers count bizarre, absolutely deconstructive designed structures “healthy” from the point of view of physics with the resources available today.
It would be much more fruitful if engineers and architects approached each other again when the understanding of the architecture and the architect would promote understanding for the construction of the engineers. The engineer should develop with its overview of the design possibilities with the architect as a consultant, the concept, and with the progress of design development. Then the architect can refine the basic concept, with the engineer having an advisory role during that phase.
In an interview for an exhibition on Bridges in Switerzland, Menn was asked which of his bridges he would like to cross the most. His answer? “One that I have not yet built.”
Author's note - Christian Menn passed away 18 July 2018 at the age of 91.