4 results for Akguzel, U.

  • Seismic Upgrading of 3-D Exterior R.C. Beam Column Joints Subjected To Bi-Directional Cyclic Loading Using GFP Composites,

    Pampanin, S.; Akguzel, U.; Attanasi, G. (2007)

    Conference Contributions - Published
    University of Canterbury Library

    In this contribution, as part of a more extensive research program on seismic retrofit solutions for reinforced concrete buildings, the effects of bi-directional loading on the assessment and design of the retrofit intervention using FRP composite materials will be discussed. Based on experimental evidences on the performance of exterior 3D (corner) under-designed beam-column joints, the limits and drawbacks of standard assessment methodologies when evaluate the hierarchy of strength and expected sequence of events prior to define the retrofit intervention, will be discussed. In addition, the preliminary results of an on-going experimental campaign to further investigate and address this issue will be presented, based on the quasi-static tests under bi-directional loading on two 3D exterior (corner) joint specimens, comprising of a pre-1970s as-built specimen (benchmark) and a “minimum” retrofitted configuration using GFRP sheets. The feasibility and efficiency of the adopted retrofit strategy and solution, aiming at controlling the hierarchy of strength within the beam-column joint system by protecting the panel zone and relocating the plastic hinge in the beam, will be discussed. Considerations and suggestions on the additional design criteria to account for the actual 3-D response under bi-directional loading will be also given.

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  • Considerations on the seismic performance of pre-1970s RC buildings in the Christchurch CBD during the 4th Sept 2010 Canterbury earthquake: was that really a big one?

    Pampanin, S.; Kam, W.Y.; Tasligedik, A. S.; Akguzel, U.; Quintana-Gallo, P. (2011)

    Conference Contributions - Published
    University of Canterbury Library

    The 4th of September 2010 Mw 7.1 Darfield (Canterbury) earthquake had generated significant ground shaking within the Christchurch Central Business District (CBD). Despite the apparently significant shaking, the observed structural damage for pre-1970s reinforced concrete (RC) buildings was indeed limited and lower than what was expected for such typology of buildings. This paper explores analytically and qualitatively the different aspects of the "apparent‟ good seismic performance of the pre-1970s RC buildings in the Christchurch CBD, following the earthquake reconnaissance survey by the authors. Damage and building parameters survey result, based on a previously established inventory of building stock of these non-ductile RC buildings, is briefly reported. From an inventory of 75 buildings, one building was selected as a numerical case-study to correlate the observed damage with the non-linear analyses. The result shows that the pre-1970s RC frame buildings performed as expected given the intensity of the ground motion shaking during the Canterbury earthquake. Given the brittle nature of this type of structure, it was demonstrated that more significant structural damage and higher probability of collapse could occur when the buildings were subjected to alternative input signals with different frequency content and duration characteristics and still compatible to the seismicity hazard for Christchurch CBD.

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  • Experimental Investigations On High-Performance Jointed Ductile Connections For Precast Frame Systems

    Pampanin, S.; Amaris, A.; Akguzel, U.; Palermo, A. (2006)

    Conference Contributions - Published
    University of Canterbury Library

    Recent developments on high performance seismic resisting precast concrete frame systems, based on the use of unbonded post-tensioned tendons with self-centring capabilities in combination, when required, with additional sources of energy dissipation, are herein presented. Alternative arrangements for jointed ductile connections to accommodate different structural or architectural needs have been implemented and validated through quasi-static cyclic tests on a series of exterior beam-column subassemblies under uni- or bi-directional loading regime. The results confirmed the unique flexibility and efficiency of these systems for the development of the next generation of seismic resisting structures, able to undergo high inelastic displacement with limited level of damage and negligible residual displacement when compared to traditional monolithic (cast-insitu) ductile solutions. In order to further emphasize the enhanced performance of these systems, a comparison with the experimental response and observed damage of 2-D and 3-D monolithic beam-column benchmark specimens designed according to the NZ3101:1995 seismic code provisions is carried out. The reliability and simplicity of recently implemented special code provisions for the design and analysis of jointed ductile systems is also confirmed by satisfactory results of analyticalexperimental comparison. In addition, the practical feasibility and efficiency of simple technical solutions to connect precast floor systems and lateral resisting frame systems, without incurring in damage due to displacement incompatibilities are experimentally demonstrated. The reliability of recently implemented special code provisions for the design and analysis of jointed ductile hybrid systems is also confirmed.

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  • Influence of slab on the seismic response of sub-standard detailed exterior reinforced concrete beam column joints

    Kam, W.Y.; Quintana Gallo, P.; Akguzel, U.; Pampanin, S. (2010)

    Conference Contributions - Published
    University of Canterbury Library

    For the seismic performance assessment of existing sub-standard detailed exterior beam-column joints, it is critical to accurately establish the hierarchy of strength of each element and therefore the likely failure mechanism. However, in current practice, the influence of cast-in-situ slab and transverse beams is typically neglected or calculated based on equations that were derived from modern detailed beam-column joint subassembly tests. In literature, experimental studies for non-ductile beam-column joints constructed prior to the 1970s, thus before the introduction of capacity design principles, explicitly considering the influence of slabs are scarce. This paper presents the experimental results of comprehensively instrumented four 2/3-scaled one-way (two-dimensional, 2D) and two-way (threedimensional, 3D) exterior beam-column joints with and without slabs. Tests were conducted under uni-directional and bi-directional quasi-static lateral loading with concurrent varying axial loading. Comparison in terms of global and local behavior between specimens show the influence of the floor slab and the transverse beam in the resistance mechanism of the beam-column-joint subassembly elements in different ways, depending on the type of frame and the loading protocol. Preliminary recommendations for assessment are tentatively provided as closure.

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