Journal: fib Symposium Proceedings

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Publisher

International Federation for Structural Concrete

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ISSN

2617-4820

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2020 - 202523
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Publications 1 - 10 of 23
  • Identifying Levers for Mass Market Penetration of Digital Fabrication
    Item type: Conference Paper
    Bischof, Patrick; Mata Falcón, Jaime; Kaufmann, Walter (2021)
    fib Symposium Proceedings ~ Concrete Structures: New Trends for Eco-Efficiency and Performance, Proceedings of the fib Symposium 2021
    The construction industry produces buildings and infrastructure and, hence, satisfies basic needs of modern society. It provides a considerable portion of total value added and worldwide jobs. At the same time, it is responsible for more than 11% of CO2 energy-related carbon dioxide (CO2) emis-sions worldwide. Digital concrete fabrication is a young, yet already broad research discipline which brings about potential for the necessary reduction of the ecological impact and for further industrial-isation of the construction industry, while being compatible with the specific requirements of flexi-bility and individuality. Still, it has not succeeded to penetrate the mass-market, largely due to lack-ing competiveness and compliance with structural integrity requirements. The present contribution comprehensively considers features of conventional construction processes to identify benefits when using digital concrete fabrication. Thereby, it addresses not only a complete substitution of conven-tional construction methods, but also solutions taking advantages of the synergic combination of traditional and novel technologies. It assesses traditional construction methods (in-situ construction and prefabricated construction) and clusters their features in order to elaborate their strengths and persistent challenges. Following a customised review on the digital fabrication methods, it identifies some new levers and opportunities for mass-market penetration of digital concrete fabrication tech-nologies in structural and civil engineering construction works.
  • Influence of pit geometry on the load-deformation behaviour of axisymmetrically corroded reinforcing bars
    Item type: Other Conference Item
    Haefliger, Severin; Thoma, Karel; Kaufmann, Walter (2023)
    fib Symposium Proceedings ~ Capacity Assessment of Corroded Reinforced Concrete Structures. Proceedings of the fib CACRCS 2023
    The results of tensile tests on locally corroded reinforcing bars conducted by several researchers indicate that the pit geometry strongly influences the residual load-carrying and deformation capacity. This paper presents the results of an experimental and theoretical study conducted on axisymmetrically damaged reinforcing bars with varying pit geometry. It reveals that short pits pronouncedly increase the apparent tensile strength of the residual cross-section and that the deformation capacity is significantly less impaired than predicted by conventional strain localisation models. Both effects are caused by a triaxial stress state near the pit, whose influence was comprehensively studied using non-linear finite element analyses.
  • Localised rebar corrosion morphology – Data collection on structures
    Item type: Conference Paper
    Yilmaz, Deniz; Angst, Ueli (2021)
    fib Symposium Proceedings ~ Capacity Assessment of Corroded Reinforced Concrete Structures. Proceedings of the fib CACRCS DAYS 2021
    One of the most important parameters for the modelling of the structural behavior and the service life of structures that are exposed to chloride-induced corrosion is the morphology of the corrosion attack. The depth of a corrosion pit, its extent along the circumference of the steel cross-section and in longitudinal direction greatly influence the load-deformation behaviour of a structure. Today, researchers are aware of the diverse shapes of corrosion pits, but there is no statistical data that could be used as an input parameter for their models. This results in large uncertainties in the analysis of the load-deformation behaviour of corroded structures. Therefore, we present a practical approach for the data collection on-site and the subsequent analysis.
  • Embodied structural ambivalence: a neurophysiological perspective on structural expression
    Item type: Conference Paper
    Wang, Shuaizhong; Kotnik, Toni (2021)
    fib Symposium Proceedings ~ Proceedings of the International fib Symposium on the Conceptual Design of Structures
    The paper attempts to provide a neuroscientific perspective on the discussion of structural expression. Taking human perception as the clue, this article starts with the notion of strong structures, take it asthe base to review and analyses the principles of structural perception under the neurophysiological perspective. Based on the findings from mirror neuron and embodied simulation, this article further reviewed the impact of embodied structural ambivalence on structural expression and human perceptionfrom the concrete example to the theoretical implication. Therefore provides a neuroscience-based scientific perspective on the research of structural expression.
  • Non-linear finite element analyses to study the effects of local corrosion on reinforced concrete slabs and shells
    Item type: Other Conference Item
    Reckinger, Nathalie; Haefliger, Severin; Thoma, Karel; et al. (2023)
    fib Symposium Proceedings ~ Capacity Assessment of Corroded Reinforced Concrete Structures. Proceedings of the fib CACRCS 2023
    Local corrosion due to the ingress of chlorides is an issue for many existing structures, and assessing affected structures is an essential task in practice. However, few models for the assessment are mechanically consistent and practically applicable to entire structures. The Corroded Tension Chord Model (CTCM) is an analytical model that predicts the mechanical behaviour of concrete elements, capturing the effects caused by local corrosion. It is well-suited for continuum models because it relates the local effects to a reference volume with a length equal to the crack spacing. This paper presents the implementation of the CTCM into a commercial finite element software as a user-defined material for plate and shell elements. The load-deformation behaviour of a bridge deck cantilever with local corrosion is modelled with non-linear finite elements, and the results are presented and discussed.
  • Fatigue of Bond: Experimental Investigation using Pull-out Tests with Distributed Fibre Optical Sensors
    Item type: Conference Paper
    Lemcherreq, Yasmin; Kaufmann, Walter; Vogel, Thomas (2020)
    fib Symposium Proceedings ~ Concrete Structures for Resilient Society
    Research on reinforced concrete (RC) structures under repeated loading has shown that not only the integrity of the two materials deteriorates, but also the bond between them. Bond is crucial for the functionality of RC structures as it enables the force transfer between concrete and steel, and must be ensured throughout the service life of structures. This paper presents initial results of an experimental campaign aimed at investigating the deterioration of bond under high cycle fatigue. The experiments are carried out on standard pull-out tests according to RILEM with small bonded lengths lb = 5 ds, in which the reinforcement is additionally instrumented with distributed fibre optical sensors. The technique allows an almost continuous measurement of the strains over the instrumented length of the bar with minimal disturbance of the bond properties. The steel and bond stress distribution could subsequently be derived from the strain measurements. The specimens were subjected to cyclic axial tensile loading with constant amplitude. After reaching 106 cycles, the specimens were loaded up to failure. The results indicate that the repeated loads led to an increase in the global slip. The bond strength obtained after 106 cycles, however, was not adversely affected, while the continuous strain measurements revealed a redistribution of bond stresses with increasing load cycles. With an increasing number of load cycles, the peak of bond stress tends to increase, and its location shifts toward the unloaded end of the reinforcing bar.
  • New conceptual approach combining the probabilistic nature of localised rebar corrosion and the load-deformation behaviour
    Item type: Conference Paper
    Yilmaz, Deniz; Häfliger, Severin; Kaufmann, Walter; et al. (2021)
    fib Symposium Proceedings ~ Capacity Assessment of Corroded Reinforced Concrete Structures
    There is a need for sound engineering models and concepts taking into account the damage mechanisms of chloride-induced corrosion with respect to the load-bearing behaviour of reinforced concrete structures. In this paper, we present a novel conceptual approach combining the physical-electrochemical processes of chloride-induced corrosion initiation/propagation with the mechanical aspects of load-deformation behaviour. A particular focus lies on the stochastic nature of localised corrosion and the relevance of the location of corrosion for the load-bearing behaviour, which is considered with the Corroded Tension Chord Model (CTCM). We present a numerical implementation of this concept, applied to a case study of a bridge deck cantilever slab.
  • Proceedings of the International fib Symposium on the Conceptual Design of Structures
    Item type: Conference Proceedings
    (2021)
    fib Symposium Proceedings
  • Determination of the effective concrete area in tension relevant for modelling tension stiffening in SLS and ULS design
    Item type: Conference Paper
    Galkovski, Tena; Mata Falcón, Jaime; Kaufmann, Walter (2021)
    fib Symposium Proceedings ~ Concrete Structures: New Trends for Eco-Efficiency and Performance, Proceedings of the fib Symposium 2021
  • Sustainable seismic design of bridges inspired by ancient temples
    Item type: Conference Paper
    Reggiani Manzo, Natalia; Vassiliou, Michalis F. (2021)
    fib Symposium Proceedings ~ Proceedings of the International fib Symposium on the Conceptual Design of Structures
Publications 1 - 10 of 23