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Translation abstract A constitutive model for the determination of anchor bearing capacity based on distributed sensing in geotechnical engineeringFrom 2015 to 2017, as part of his work as head of research and development at Stump‐Franki Spezialtiefbau GmbH, the author devoted himself to the topic of pioneering measurement methods on the basis of Distributed Strain Sensing in geotechnics. One of the first developments was and is the monitoring of grouted bodies on strand grouted anchors. The new findings at that time were presented internationally at the DFI India, 2017 as well as nationally in construction technology, 2017 and locally at the 12th Hans Lorenz Symposium in Berlin, 2016. It was shown that the measurement results of the strain measurement using distributed strain sensing can be used to check over the following years whether the grouted anchors have been overloaded. The author already pointed out at the time that correct interpretation not only requires an understanding of the measuring process used, but also a certain wealth of experience in interpreting the measurement results in the direct context of geotechnics. As part of his work on the DIN standardization committee NA 005‐05‐17 AA Grouted anchors, accompanied by his practical experience, the author has dealt in depth with the question of what exactly is actually measured in the grout body using distributed strain sensing and what conclusions can be drawn about the load‐bearing capacity of grouted anchors on the basis of the measurement results. This article is intended to describe a constituent model on the basis of which further developments are possible for the interpretation of the measurement results with regard to their use as proof of economic efficiency and anchor load‐bearing capacity. [ABSTRACT FROM AUTHOR]

Translation abstract Contribution to determining the diameter of piles based on thermal integrity profilingWhen carrying out thermal integrity profiling (TIP), it is often said that the profiling serves, among other things, to determine the cubature of the pile created. In the relevant publications on TIP, Pile Dynamics, Inc., among others, points out that this is only an estimate of the concrete cover or excess concrete during pile production. In particular, in this case it is assumed that the installed concrete volume must also be monitored in order to contrast this with the measurement results. However, from the authors′ point of view, this alone is not enough to draw a well‐founded conclusion about the pile cubature from the temperature records. This approach appears to be problematic, particularly with special shapes. As part of the 17th Hans Lorenz Symposium 2023 at the Technical University of Berlin, the first “New findings on Thermal Integrity Profiling (TIP) on deep piles with special shapes” were presented. These findings were expanded upon as part of further investigations using the commercial software COMSOL Multiphysics and are presented in more detail below. The result is that the influencing factors are so diverse that even if they are taken into account, no conclusions can be drawn about the diameter. This is clearly presented by the authors below. [ABSTRACT FROM AUTHOR]

Geostatic considerations for the verification of pile base expansions As part of a current construction project, large bored piles with pile base expansions were carried out in Germany for the first time in many years. In this context, questions arose regarding the required evidence for the expansions. According to the current status of the design standards DIN EN 1992‐1 and DIN EN 1997‐1, the relevant verifications for punching shear and/or bracket failure cannot be carried out in a targeted manner. Based on this finding, the author researched old literature sources regarding the widening of the pile base. In the end, the research led to theoretical soil mechanics as the limit of earth statics and thus to the forefathers of modern soil mechanics. This article is intended to represent a contribution to possible theoretical solutions for the verification of pile base expansions. On the one hand, he shows what a deeper understanding of earth statics can give the working engineer and on the other hand, that some things remain open and that the in‐situ execution might bring the solution if we start thinking the problem from the end. [ABSTRACT FROM AUTHOR]

Long‐term crack monitoring of prestressed concrete structures by means of distributed fiber‐optic strain sensing In the ceiling area of a connecting subway tunnel in Munich, Germany, fiber‐optic sensor cables were installed for continuous long‐term crack monitoring. According to the measurement concept, continuous monitoring of the total deformations as well as several reference date measurements are planned with regard to the actual crack monitoring of the prestressed concrete construction. The aim of the measurements is the fiber‐optic crack monitoring of a pre‐damaged prestressed concrete structure from the 1970s, which was refurbished in the course of the fiber‐optic installation. The structure is exposed to high traffic loads from road traffic as well as temperature impact. The prestressed concrete structure is a single span slab construction with straight and parabolic tendons. The original ceiling had an increased potential for damage on the underside of the slab (crack pattern) as well as severe damages associated with the existing prestressing steel structure. During the renovation of the prestressed concrete slab, shotcrete with supplementary reinforcement was applied to achieve an announcement behavior in case of tendon failure. The following paper reports on the first results of crack monitoring based on continuous fiber optic measurements along the embedded fiber‐optic sensing cables. The measurements are based on the technology of distributed Brillouin sensing. [ABSTRACT FROM AUTHOR]