Because Heft 240 is considered a "standard work" in German engineering, physical copies are often worn from use. The demand for digital versions remains high. However, engineers searching for these

In the complex world of civil engineering and concrete construction, certain documents stand the test of time, becoming foundational pillars for professionals. Among these, DAfStb Heft 240 (Schriftenreihe des Deutschen Ausschusses für Stahlbeton, Heft 240) holds a legendary status. Often searched for with technical query markers like "--39-LINK--39-" in database archives, this publication is more than just a booklet; it is the definitive guide to the strut-and-tie method (Fachwerkmodell) in structural concrete design.

This article explores the history, the technical content, and the enduring legacy of Heft 240, explaining why it remains a critical resource for structural engineers navigating the transition from standard formulas to the analysis of complex structural details. Published by the German Committee for Reinforced Concrete (Deutscher Ausschuss für Stahlbeton - DAfStb), Heft 240 is titled "Hilfsmittel zur Berechnung der Schnittgrößen und Formänderungen von Stahlbetonbauwerken" (Aids for the calculation of internal forces and deformations of reinforced concrete structures). However, its reputation was solidified by its focus on the Discontinuity Regions (D-Bereiche) .

For decades, engineering education focused heavily on "B-regions" (Bernoulli regions), where plane sections remain plane, and standard beam theory applies. Heft 240 was the watershed moment that brought the analysis of "D-regions"—areas where strain distributions are non-linear, such as corbels, deep beams, and node points—into mainstream practice through the use of strut-and-tie models. Before the widespread adoption of the principles outlined in Heft 240, engineers often relied on empirical formulas or overly simplified mechanics to design details like pile caps or frame corners. This often led to either unsafe structures (due to a lack of understanding flow of forces) or uneconomical designs (due to excessive safety margins).