Analysis of Beams Strengthened with CFRP Laminates 1 International PhD Symposium in Civil Engineering, Vienna, October 5-7, 2000. ANALYTICAL ANALYSIS OF SIMPLY SUPPORTED AND CONTINUOUS BEAMS STRENGTHENED WITH CFRP LAMINATES 7RPDå8ODJD EMPA Ueberlandstrasse 129 8600 Duebendorf Switzerland Phone: +41-1-823 40 33 Fax: +41-1-823 40 14 E-Mail: [email protected] Supervisors: Prof. T. Vogel, IBK, ETH Zurich, Switzerland Prof. U. Meier, EMPA Duebendorf, Switzerland Abstract The analysis of a reinforced concrete beam strengthened with externally bonded CFRP (carbon fibre reinforced plastic) laminates and subjected to flexural loading can be performed analogously to the analysis of an unstrengthened beam. Equilibrium of forces, deformation compatibility and stress-strain relations of the materials are the tools that permit a reliable determination of the system’s response to any support and load configuration. A simply supported beam is considered that way. The analytically found results correspond closely to experimental data. A two-span continuous beam with various strengthening arrangements is similarly analysed. According to those findings, continuous girders should be strengthened by application of CFRP laminates in the spans only. Keywords: Carbon fibre reinforced plastic (CFRP) laminates, continuous girder, reinforced concrete, strengthening, structural analysis, flexure 1. Introduction The first application of CFRP laminates to strengthen a concrete structure was the repair of the Ibach bridge in Switzerland in 1991 (Meier [1]). The dimensioning and detailing was based on the pioneering works of Kaiser [2] and Deuring [3]. Since then, research and application activities have grown constantly, and today many publications and strengthened structures can be found (Meier [4]). While the use of CFRP products for flexural strengthening of beams or wrapping of columns is already well established, other possible uses (e.g. externally bonded shear reinforcement) are becoming increasingly common. Several gaps in knowledge have been recognized and systematically investigated. While some of the problems were treated successfully and suitable explanations have been found (e.g. the anchorage length, Holzenkämpfer [5]), other aspects require further research (e.g. the failure criterion, Raoof [6]). There are many experimental and theoretical investigations on simply supported beams (Meier [4]), but it is not obvious how to apply the conclusions of these studies to real structures with different support systems and arbitrary loads. Since there are virtually no studies on statically indeterminate structures (Rabinovitch [7]), questions regarding the performance of strengthened continuous girders can hardly be answered satisfactorily. This report aims to treat such problems theoretically. First, a simply supported beam is analysed. The analytical treatment is fairly simple and the findings correspond closely to experimental results. Second, a two-span continuous girder is analysed. The method of analysis used for the simply supported beam can be applied analogously and conclusions are drawn on the ultimate load for different strengthening arrangements. 1.1 Research Significance The analytical analysis of a CFRP strengthened concrete beam presented here is easily comprehensible because it is derived from well-known reinforced concrete principles. It provides excellent results and is much more transparent than often used finite element approaches. After consideration of a few basic examples, conclusions are drawn that justify simplified analysis for some cases and therefore make it even more useful for practical dimensioning problems.
ANALYTICAL ANALYSIS OF SIMPLY SUPPORTED AND CONTINUOUS BEAMS STRENGTHENED WITH CFRP LAMINATES
Jun 30, 2023
Welcome message from author
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Related Documents
