Journal: World Conference on Earthquake Engineering Online Proceedings

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International Association of Earthquake Engineering

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Publications 1 - 3 of 3
  • Low Aspect Ratio RC Shear Walls with Lap Splices: Seismic Performance and Design Implications
    Item type: Conference Paper
    Kovarbasic, Milan; Pizarro Pohl, Diego; Stojadinovic, Bozidar (2024)
    World Conference on Earthquake Engineering Online Proceedings ~ Proceedings of the 18th World Conference on Earthquake Engineering (WCEE 2024)
    Reinforced concrete (RC) shear walls are frequently used as lateral load-resisting elements in RC structures in seismic regions. Hence, reliable evaluation of the displacement capacity of these elements is essential for the performance-based seismic design. An experimental campaign on low aspect ratio RC shear walls with lap splices was conducted at ETH Zürich to investigate their seismic-performance and collect data for the development and validation of numerical models for the displacement-based seismic assessment. The campaign includes quasi-static cyclic (QSC) and hybrid simulation (HS) tests. It was found that the tension failure of the lap splices caused a progressive cyclic strength degradation of the walls and the transition from flexural to rocking mode of behaviour. Once the rocking occurred, the walls were able to sustain significant ductility demands showing at the same time no signs of additional damage or loss of the axial load bearing capacity. Further, the approaches for numerical modelling and assessment of RC shear walls with lap splices are presented and discussed.
  • The Chicken and Egg Problem In Empirical Fragility Modeling and the Approaches to Solve It
    Item type: Conference Paper
    Bodenmann, Lukas; Baker, Jack; Stojadinovic, Bozidar (2024)
    World Conference on Earthquake Engineering Online Proceedings ~ Proceedings of the 18th World Conference on Earthquake Engineering (WCEE 2024)
    Regional earthquake risk analyses employ fragility models to estimate shaking-induced damage to the built environment. Empirical fragility models are estimated from damage data gathered after past earthquakes and present a valuable resource to calibrate and validate models derived from physics-based computer simulations. Yet, empirical fragility modelling is challenging because it requires knowledge of the ground motion intensity the buildings were subjected to. The latter, however, is only known at locations of seismic network stations while its uncertainty increases for locations further away. Thus, if a group of damaged buildings is observed, we do not know, a-priori, whether they were damaged because they were particularly vulnerable or because the ground shaking was particularly strong or because of both. We refer to this as the chicken and egg problem in empirical fragility modelling. In this work, we present a Bayesian approach to quantify the joint posterior distribution of the fragility model parameters and the ground motion intensity. Using a simulated damage data set, we compare the Bayesian approach to the traditionally used approach that relies on fixed ground motion intensity estimates.
  • Large-scale experimental investigation of resilient timber-based energy dissipation systems
    Item type: Conference Paper
    Tsiavos, Anastasios; Kolyfetis, Dimitrios; Stojadinovic, Bozidar (2024)
    World Conference on Earthquake Engineering Online Proceedings ~ Proceedings of the 18th World Conference on Earthquake Engineering (WCEE 2024)
    This paper focuses on the demonstration of the efficiency of novel and resilient timber-based energy dissipation systems with recentering ability, which can be used as seismic isolation systems or tuned mass dampers for the sustainable seismic design and retrofitting of structures. Each of the novel systems, defined with the general term ‘Dovetail with SPrings (Dove-SP)’ comprises two timber slabs that are designed to slide against each other in a motion that is restrained by a dovetail sliding joint. The use of timber for the construction of the slabs leads to storage of CO2, thus providing a solution of much lower environmental impact compared to the existing energy dissipation systems: Two different energy dissipation systems are proposed and experimentally investigated according to the materials used for the sliding interface: An energy dissipation system based on a PVC sand-wich (PVC-s) sliding interface, comprising a thin layer of sand that is sand wiched between two PVC layers and an energy dissipation system based on a timber sand-wich sliding interface consisting of a thin layer of sand encapsulated between two beech timber surfaces. A set of low-cost steel springs is designed and installed on both sides of the dovetail joint to recenter the structure back to its original position after the end of an earthquake ground motion excitation. A novel and deformable wood material fabricated from delignified balsa wood is used to reduce the pounding effects before the activation of the steel springs. The performance of the novel timber-based energy dissipation systems subjected to an ensemble of recorded earthquake ground motion excitations is demonstrated through a large-scale shaking table investigation at ETH Zurich.
Publications 1 - 3 of 3