Civil Engineering / İnşaat Mühendisliği

Permanent URI for this collectionhttps://hdl.handle.net/11147/13

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Author: search.filters.author.Demirci, Hasan EmreCOAR Access Rights: search.filters.coarAccessRights.open access

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Now showing 1 - 3 of 3
  • Article
    Citation - WoS: 10
    Citation - Scopus: 10
    Usage of Tyre Derived Aggregates as Backfill Around Buried Pipelines Crossing Strike-Slip Faults; Model Tests
    (Springer, 2022) Karaman, Mustafa; Demirci, Hasan Emre; Ecemiş, Nurhan; Bhattacharya, Subhamoy
    Buried pipelines crossing active faults are exposed to excessive soil forces under fault movements due to large relative movement between pipes and the soil surrounding them. As a result, extreme longitudinal strains develop within pipelines under large fault movements and this leads to pipeline failures. Several seismic mitigation techniques were proposed to improve the performance of buried pipelines crossing active faults. In this study, the potential of using Tyre Derived Aggregates (TDA) as a backfill material for mitigating the effects of strike-slip faulting are investigated through physical model tests. First, the details of the physical model test setup and model configuration are presented. Then a comparative study is carried out to study the effect of TDA content in the backfill and trench configurations on TDA mitigation. Model tests revealed that using a sloped trench with 100% TDA content in the backfill can decrease peak axial pipe strains up to 62% and peak bending strains up to 19%. It is observed that enlarging the trench and using an inclined trench improve the performance of the TDA mitigation technique.
  • Article
    Citation - WoS: 13
    Citation - Scopus: 15
    A Survey of Damage Observed in Izmir Due To 2020 Samos-Izmir Earthquake
    (Springer, 2021) Demirci, Hasan Emre; Karaman, Mustafa; Bhattacharya, Subhamoy
    An earthquake of magnitude 6.9 hit the city of Izmir (Turkey) on 30 October 2020, resulting in 117 deaths (in Turkey) and considerable economic losses. The earthquake also triggered a tsunami. Following the earthquake, field surveys are being conducted in a Covid-secure way to study and document the damages caused. The earthquake caused significant damages to residential buildings mainly located in the district of Bayrakli and Bornova. However, no damages were observed in railway and roadway bridges or tunnels and that helped the rescue operations. The damages were mainly structural which included the so-called pancake collapse (where the entire building collapsed) and soft storey type collapse (weak storey characterised with weak columns collapsed), and in some cases, only the ground floor completely collapsed. Due to the proximity of the epicentre and the geology of the area, it seemed that the ground motions were amplified. This technical note provides a summary of the seismological and recorded ground characteristics of the earthquake together with the lessons learnt.
  • Article
    Citation - WoS: 34
    Citation - Scopus: 39
    Influence of Consolidation Properties on the Cyclic Re-Liquefaction Potential of Sands
    (Springer Verlag, 2015) Ecemiş, Nurhan; Demirci, Hasan Emre; Karaman, Mustafa
    The relative density can be used as the main indicator to assess the liquefaction resistance of clean sands. As relative density of the sand deposit increases significantly following the initial liquefaction, one should expect that the soil can improve its liquefaction resistance. However, earthquake records indicate that densified sand can be liquefied again (re-liquefied) at smaller cycles by the similar seismic loadings. This work aims to clarify the counterintuitive finding that, after the first liquefaction, the resulting significant increase in relative density (induced by settlements and variation of the water level) do not necessarily imply an increase in the number of loading cycles for re-liquefaction. In this paper, we present a series of experimental results concerning the cyclic liquefaction and the following re-liquefaction of clean sand deposits. The experimental setup is performed by a shaking table, transmitting one-degree of freedom transversal motion to the soil within the 1.5 m high laminar shear box. At four different seismic demands, the input excitation was imposed three times to examine the influence of the initial distributions of the relative density and the consolidation characteristics on the liquefaction potential of the sand. The re-liquefaction cycles of the sand, which previously experienced liquefaction under the same seismic loadings, show that post-liquefaction reconsolidation of the sand deposits affects the re-liquefaction resistance.