Print Email Facebook Twitter Dwarskrachtsterkte van verticaal voorgespannen tandopleggingen / Shear capacity of vertically prestressed half joints Title Dwarskrachtsterkte van verticaal voorgespannen tandopleggingen / Shear capacity of vertically prestressed half joints Author Kranenburg, M.C. Contributor Hordijk, D.A. (mentor) Van der Veen, C. (mentor) Hendriks, M.A.N. (mentor) De Boer, A. (mentor) Houben, L.J.M. (mentor) Faculty Civil Engineering and Geosciences Department Structural Engineering Programme Concrete Structures Date 2014-07-29 Abstract The application of prefabricated and usually prestressed concrete elements has increased since mid-20th century. These elements are at the point of reaching the end of their life span, are subjected to damages or a change in functionality. Therefore, it is necessary to evaluate their structural safety. In many cases, existing structures do not meet the minimum level of structural safety according to the current building codes. If it is possible to improve the verification of the minimum level of structural safety of existing structures, it is not necessary to take expensive measures like reconstruction or strengthening these structures. For concrete beam elements the structural safety appeared to be in most cases governed by shear resistance. This study specifically investigates the shear resistance of vertically prestressed dapped end beams. An analytical study is performed in order to evaluate the influence of vertically prestressing on the failure mechanism and the shear resistance of vertically prestressed dapped end beams. Next, an analytical calculation procedure based on the equilibrium of the “torn-off” section is used to determine the bearing reaction of several prestressed dapped end beams. Additionally, a Case Study is performed to verify if the results of a nonlinear finite element analysis (NLFEA) using a highly simplified model are in accordance with the results described in CUR-report 40. In this report the results are described of a full size test on a prestressed dapped end beam. Determining the design shear resistance of vertically prestressed dapped end beams using the equilibrium calculation procedure will give very conservative results. This is caused by the unknown locations of reinforcements and possibly by omitting the concrete contribution to the shear resistance caused by the compressive zone, aggregate interlock and dowel action. Furthermore, in case of correct detailing of reinforcement, the equilibrium calculation procedure will in all cases lead to a safe, lower limit of the shear resistance. It should be noted, that in the experiments in case of a limited amount of reinforcement the concrete contributes to the shear resistance significantly. It is of great importance that proper detailing of reinforcement is carried out to prevent sudden failure of dapped ends by shear. In case of improper detailing the failure mechanism assumed to be governing can mostly not develop. In accordance with the results described in the experiments, this will probably cause early failure. The finite element model (FEM) used is highly simplified. Only the prestressing cables and Dywidag bars are included in the model and loads are not distributed over multiple nodes. Overall it can be concluded that initiation as well as the direction of crack propagation are simulated quite well. However, it is not possible to make realistic statements about crack propagation, crack width and realistic crack strains at different load steps. More important, the calculated bearing reaction is a safe lower limit of the shear resistance. During the NLFEA it became clear that obtaining a realistic model of a prestressed dapped end beam is strongly depended on the input parameters used. It is expected that modelling of all reinforcement bars will result in a less conservative shear resistance. Further research is required to verify the statement above. Subject shear capacityhalf jointsdapped end beamsvertically prestressedFEMDIANA To reference this document use: http://resolver.tudelft.nl/uuid:5227795e-4147-4d20-b058-cc3650956556 Part of collection Student theses Document type master thesis Rights (c) 2014 Kranenburg, M.C. Files PDF Thesis_MCKranenburg_final.pdf 6.53 MB Close viewer /islandora/object/uuid:5227795e-4147-4d20-b058-cc3650956556/datastream/OBJ/view