Bearing capacity of concrete hinges subjected to eccentric compression: multiscale structural analysis of experiments

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.

On a nonlinear hybrid method for multiscale analysis of a bearing‐capacity test of a real‐scale segmental tunnel ring

“…Some of them even became plastic hinges. This has provided the motivation to compute M-N interaction diagrams, analogous to the strategy proposed for concrete hinges by Kalliauer et al 35 The present analysis is based on the following two types of failure envelopes:…”

“…Some of them even became plastic hinges. This has provided the motivation to compute M ‐ N interaction diagrams, analogous to the strategy proposed for concrete hinges by Kalliauer et al The present analysis is based on the following two types of failure envelopes: The first failure envelope is calculated based on the initial contact area of the segments (see Figure ). The initial full‐face contact is lost because of the bending moments transmitted across the joints.…”

Application-oriented fundamental research on concrete and reinforced concrete structures: selected findings from an Austro-Chinese research project

“…Combined experimental and theoretical research was carried out in order to study the structural behavior of reinforced concrete hinges [51,52]. The experiments included material tests of plain concrete and structural tests of three nominally identical reinforced concrete hinges.…”

“…Structural creep Fig. 20 a Schematic illustration of the tested concrete hinges, and b comparison of measurements from eccentric compression tests with numerical results from three-dimensional FE simulations, see [51,52] under eccentric compression, however, has turned out to be significantly larger. This is a consequence of the strong interaction between this form of creep and cracking [51].…”

“…This was the motivation for a detailed numerical analysis of the bearing capacity tests. They were simulated using the state-of-the-art FE software "Atena science" and a nonlinear material model for concrete implemented therein [52]. Numerical simulations were carried out in order to gain quantitative insight into the stress states activated in the neck region and to find out why reinforced concrete hinges fail in such a ductile fashion.…”