DSpace-CRIS at TU Wienhttps://repositum.tuwien.atThe reposiTUm digital repository system captures, stores, indexes, preserves, and distributes digital research material.Fri, 15 Jan 2021 20:40:10 GMT2021-01-15T20:40:10Z5021Ultimate limits of reinforced concrete hingeshttp://hdl.handle.net/20.500.12708/15566Title: Ultimate limits of reinforced concrete hinges
Authors: Schlappal, Thomas; Kalliauer, Johannes; Vill, Markus; Mang, Herbert; Eberhardsteiner, Josef; Pichler, Bernhard
Abstract: This work is a further development of its predecessor, the topic of which was verification of serviceability limit states of reinforced concrete hinges. Herein, the same conceptual approach is used to derive analytical formulae, supporting verification of ultimate limit states. These formulae limit tolerable relative rotations as a function of the compressie normal force transmitted across the neck. The mechanical model is based on the Bernoulli-Euler hypothesis and on linear-elastic and ideally-plastic stress-strain relationships for both concrete in compression and steel in tension. The usefulness of the derived formulae and the corresponding dimensionless design dia-grams is assessed by means of experimental data from structural testing of reinforced concrete hinges, taken from the literature. This way, it is shown that the proposed mechanical model is suitable for describing ultimate limit states. Corresponding design recommendations are elaborated and exemplarily applied to verification of ultimate limit states of the reinforced concrete hinges of a recently built integral bridge. Since the reinforcement is explicitly accounted for, the tolerable relative rotations are larger than those according to existing guidelines. It is included that bending-induced tensile macrocracking beyond one half of the smallest cross-section of the neck is acceptable, because the tensile forces carried by the reinforcement ensure the required position stability of the hinges.
Tue, 01 Dec 2020 00:00:00 GMThttp://hdl.handle.net/20.500.12708/155662020-12-01T00:00:00ZBearing capacity of concrete hinges subjected to eccentric compression: multiscale structural analysis of experimentshttp://hdl.handle.net/20.500.12708/728Title: Bearing capacity of concrete hinges subjected to eccentric compression: multiscale structural analysis of experiments
Authors: Kalliauer, Johannes; Schlappal, Thomas; Vill, Markus; Mang, Herbert; Pichler, Bernhard; Pichler, Bernhard
Abstract: Existing design guidelines for concrete hinges are focusing on serviceability limit states. Lack of knowledge about ultimate limit states was the motivation for this work. Experimental data are taken from a testing series on reinforced concrete hinges subjected to eccentric compression up to their bearing capacity. These tests are simulated using the finite element (FE) software Atena science and a material model for concrete implemented therein. The first simulation is based on default input derived from measured values of Young’s modulus and of the cube compressive strength of the concrete. The numerical results overestimate the initial stiffness and the bearing capacity of the tested concrete hinges. Therefore, it is concluded that concrete was damaged already before the tests. A multiscale model for tensile failure of concrete is used to correlate the preexisting damage to corresponding values of Young’s modulus, the tensile strength, and the fracture energy of concrete. This allows for identifying the preexisting damage in the context of correlated structural sensitivity analyses, such that the simulated initial stiffness agrees well with experimental data. In order to simulate the bearing capacity adequately, the triaxial compressive strength of concrete is reduced to a level that is consistent with regulations according to Eurocode 2. Corresponding FE simulations suggest that the ductile structural failure of concrete hinges results from the ductile material failure of concrete at the surface of the compressed lateral notch. Finally, Eurocode-inspired interaction envelopes for concrete hinges subjected to compression and bending are derived. They agree well with the experimental data.
Mon, 01 Jan 2018 00:00:00 GMThttp://hdl.handle.net/20.500.12708/7282018-01-01T00:00:00Z