Lehrstuhl und Inst. für Massivbau [u.a]
Zum Tragverhalten von Betonbauteilen mit Faserverbundkunststoff-Bewehrung
Abstract
dc:descriptionThis thesis deals with experimental and theoretical investigations on the load carrying behaviour of concrete members with Fibre Reinforced Polymers (FRP). Besides a detailed description of the FRP bars, which are used as non-prestressed reinforcement in concrete structures, this thesis contains the state of the art related to the experiments conducted within its scope. The experimental programme includes tests on the bond behaviour, the structural design under bending and shear loading and the limitation of the crack width of FRP reinforced concrete (FRPRC) members. To allow a general statement concerning the load carrying behaviour of FRPRC, three different types of reinforcement were investigated within the tests. A total of 33 pull-out tests, nine tensile tests on concrete members with FRP reinforcement, eight tests to determine the tensile strength of the FRP shear reinforcement itself and ten shear tests were performed. Own test results and databases with more than 230 shear tests and over 300 crack widths are the basis to derive design models for the bending and shear carrying capacity as well as the limitation of crack width. To simplify the design of concrete members under bending and normal forces, a general design concept for FRP reinforced concrete sections is derived. The comparison with the results of 20 bending tests from the literature reveals a good agreement of the experimental and theoretical load carrying capacity. By a modification of an empirical approach for the shear carrying capacity of steel reinforced concrete members without shear reinforcement, a design model for members with longitudinal FRP reinforcement is derived. Moreover, from a methodical evaluation of the database as well as an analysis of the own tests, an additive approach for concrete members with FRP shear reinforcement is developed. For concrete members with FRP shear reinforcement the shear capacity generated by truss action is limited by the tensile stress of the FRP reinforcement and not displayed by exceeding the yield strength as it is for steel reinforcement. Therefore, it is not possible to measure shear compression failure indirectly by yield strains. Thus, a yield limit depending on the stiffness of the concrete member is set up which enables to predict the shear failure in the concrete compressive zone due to high strains of the shear reinforcement. Because of the high strains of the FRP reinforcement in the ultimate limit state and the resulting wide crack openings for FRPRC members, the applicable concrete stresses for failure of the struts is reduced. By a comparison with shear tests it is shown that the own approach complies in the best way with the test results, better than other international approaches described in this thesis. In order to limit the crack width in FRPRC elements, an approach is presented which is based on a continuous crack theory. This approach is applicable to all FRP reinforcements with different extensional stiffness and bond characteristics. Instead of a complex calibration by means of full scale tests for common approaches, only the Young's Modulus and the bond-slip behaviour gained from pull-out tests have to be determined to calculate the crack width. The own approach for the determination of the crack width in FRP reinforced concrete members shows better agreement with the test results than other models from literature and features nearly the same accuracy as the approaches for steel reinforced concrete members.
Degree
thesis:*- Grantor dc:publisher
- Lehrstuhl und Inst. für Massivbau [u.a]
- Year dc:date
- 2009
Author and committee
dc:creator, dc:contributor.*- Author dc:creator
-
- Niewels, Jörg
- Contributors dc:contributor
-
- Hegger, Josef
Subjects
dc:subject × 16Rights
dc:rights- Statement dc:rights
-
- info:eu-repo/semantics/openAccess
- Language dc:language
- ger