Page - 283 - in Frühe Brücken - Zug- oder druckbeanspruchte Konstruktionen, kreative, innovative und interessante Brücken

283 summAry Summary There are very different ways of thinking. For linguists thinking is the use of words and sentences using the ap- propriate grammar. But a thinking in pictures, a pictorial thinking, also exists. Architects and structural engineers should have the most distinct three-dimensional, spatial thinking that is possible. In addition, there is a construc- tive way of thinking that is strongly influenced by prac- tical life experience and often influenced by external parameters. Certainly, this also concerns bridges. But it also pertains to nearly every other field of daily life. In constructive thinking, it is important to distinguish bet- ween at least two different types of constructive thinking. There are cultures and ethnic groups in which thinking in structures subject to tension clearly predominates, and those in which thinking in structures subject to pressure is dominant. Using the examples and phenomena already mentioned in this work, it could be shown that this thin- king in constructive categories permeates the entire li- ving space and can support or hinder innovative cons- tructive ideas. Suspension bridges of perishable material, for exam- ple, were built in Asia in pre-Christian times and the first documented forged chain bridge in China was span- ned over a valley at the beginning of our era. Over the centuries, travelers from Europe gave repeated ac- counts of these ingenious suspension bridge constructi- ons. However, since Roman times at the latest, Europe has been so strongly influenced by a way of thinking in terms of pressure-stressed constructions that this inge- nious idea of stretching suspension bridges over wider obstacles did not emerge until the beginning of the 19th century, almost 2000 years after the first forged chain suspension bridge was constructed in China. After the great wave of European suspension bridges after 1800, many of them were soon exchanged for other construc- tions. The triumphant advance of suspension bridges in the 20th and 21st centuries was only continued using forged iron cables and later steel cables, which were significantly more capable of absorbing tension and the new dimensions that could be spanned in bridge cons- truction. These suspension bridges were first construc- ted in Switzerland starting in Geneva in 1832. Conversely, the Maya in Mesoamerica had already constructed the first documented barrel vaults in the 1st century AD. Even later, barrel vaults and true arches were constructed sporadically in the whole of pre-Co- lumbian Amerika. Despite the many great possibilities of this equally ingenious construction method, it did not prevail anywhere in America and remained the excep- tion. Here, too, the pronounced thinking in tensile cons- tructions stood in the way. Only the conquerors from Europe brought the change from 1492 onwards. Since then, the traditional suspen- sion bridges have continued to be stretched over valleys only in remote areas. Otherwise it was true arch bridges for short distances or ship bridges over wide rivers and steel cable suspension bridges have been constructed increasingly since the second half of the 19th century. The big bridges in New York in the USA were of course a model for Latin America. Here, however, it was alrea- dy Europe that had very soon replaced the chains with forged iron and then with steel ropes and brought the constructive idea of suspension bridges back to North America. Since then, there no longer seem to have been any culturally or ethnically related barriers either in thin- king categories or in bridge building.