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This paper presents the newly established ACI‐DAfStb database of shear tests on slender prestressed concrete beams without stirrups subjected to point loads. From the 574 collected tests 214 tests remain for the comparison with shear design approaches after the control and selection procedures were applied. The main features of these tests are described. Subsequently, these tests are used to perform evaluations of the shear design procedures of EC2, fib Model Code 2010, and ACI 318‐14. [ABSTRACT FROM AUTHOR]

Copyright of Bautechnik is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Beton- Und Stahlbetonbau is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The risk of a fatigue failure has to be evaluated at coupling joints of older post-tensioned, concrete bridges in Germany, because weaknesses were identified in the design of these bridges. Because of the nonlinear bearing behaviour of post-tensioned, concrete structures, the results of this analysis strongly depend on the distribution of the permanent internal forces, which are uncertain due to time-dependent losses and redistributions. In this paper, a method to determine the bearing behaviour and the actual bending moment of the examined coupling joint, which is based on non-destructive, long-term measurements under service conditions, is shown. Therefore, the crack at the coupling joint, the temperatures and the traffic loading are observed. The results are used to calibrate a finite element simulation of the cross section. With this, a more realistic fatigue evaluation could be done as of the approaches in codes for the design of new bridges are used (e.g. DIN EN 1992, 2011,Eurocode 2. Bemessung und Konstruktion von Stahlbeton- und Spannbetontragwerken, Berlin: Beuth). [ABSTRACT FROM AUTHOR]

Copyright of Beton- Und Stahlbetonbau is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Slabs are one of the main load-bearing elements in nearly every structure. Because of additional live loads or modifications of the building structure these slabs often have to be strengthened. Using externally bonded carbon-fiber reinforced polymer (CFRP) strips to strengthen existing concrete structures has become common practice. One of the main failure modes is the loss of the composite action between the concrete and the CFRP strip making the bond force transfer very important. This bond force transfer depends on many parameters including the concrete strength, the ratio between shear force, and bending moment. A new parameter recently discovered by the Technische Universität München (TUM) is the deflection of the structural elements themselves. Because of this deflection self-inducted contact pressure occurs. This contact pressure affects a higher bond transfer. The lower effective depth of slabs compared to beams causes higher deflections. In this article, first a few principles on the strengthening with adhesive-bonded CFRP strips and the characteristics of the bond are explained. Then, the basics of the bond force transfer, at the end anchorage and in the rest of the element, are summarized. Based on these essentials, as well as numerous experiments, the change in the bond force transfer at the structural element caused by the curvature is then derived. With these findings, a complete verification concept is presented, which is ideal for computerized calculations. This verification concept is finally compared to several full-scale test results presented in pertinent literature. [ABSTRACT FROM AUTHOR]

This paper documents the results of a joint research project dealing with the loading of formwork systems used with highly flowable concretes. First calculation approaches concerning the pressure of fresh concrete on vertical formwork were developed on the basis of the investigations conducted on the material behaviour of highly flowable concretes. In doing so, construction management questions regarding, for instance, process design and quality assurance in the application of highly flowable concretes were also investigated. Different scientists from German research institutes collaborated in a research group to pool their knowledge in the field of the pressure of fresh concrete. Because of the extent and complexity of the tasks to be tackled, the joint research project was divided into five subprojects (A to E), which were performed by the research institutes according to their individual respective capacities. [ABSTRACT FROM AUTHOR]