Seventh International Congress on Construction History, Lisbon 12 - 16 July 2021

Meltem Çavdar

Who built the timber formwork for reinforced concrete?

Keywords: knowledge transfer, timber formwork, fairfaced concrete, reinforced concrete, 20^th century

Abstract

Fairfaced concrete structures from the middle of the 20^th century, like the impressive brutalist buildings of the post-war period, are mostly considered the product of a totally industrialized process, planned in detail by engineers and realized according to plan by unskilled labor. However, the construction of necessary formwork in timber was an accomplishment of carpentry craftsmanship well until the 1970s.

Until the early 20^th century, concrete was mainly used in unreinforced rammed form. The formwork structures for stamped concrete buildings were of minor importance compared to the permanent structure. Adding iron to the concrete created a major challenge for formwork construction. The amount of water in the concrete mix was increased to enhance the concrete flow and the molding of bigger volumes of concrete became possible. The formwork required for reinforced concrete depended on specific carpentry skills. Initially there were no trained concrete builders, thus experienced carpenters were assigned the task.

In Germany, the first reference guide for timber formwork construction for reinforced concrete arose from the carpentry trade. Master carpenter Fritz Kreß, the eminent author of technical textbooks for carpenters and founder of a vocational school for carpentry in Tübingen-Lustnau, dedicated a long chapter to formwork carpentry in the first edition of his seminal publication Der Jungzimmerer in 1926. At about the same time, the German concrete association established the first concrete builder vocational construction site in Essen, resulting in similar concrete builder training workshops throughout Germany. With a first manual for concrete builders (Lehrgang für Betonbauer) published in 1930 in form of worksheets, it was not before 1938 that Carl Kupfer, a civil engineer, published Der Betonbauer, the first comprehensive technical textbook on concrete construction. Contentwise, as an extensive study has shown, all these textbooks and training workshops strongly focused on formwork construction, thereby relying on older publications on carpentry. In the post-war period, questions of timber formwork construction were still widely represented in vocational publications for concrete builders until prefabricated formwork panel systems gradually replaced timber formwork until the 1970s.

Discussing on the interconnected transfer of technology, knowledge and workforce, the proposed paper will examine the transmission of traditional know-how in carpentry to timber formwork construction in the post-war period. Through analyzing both longstanding technical texts and the archive documents relating to timber formwork, the characteristics of the mostly unrecognized means of timber formwork constructions will be assessed.