Civil Engineering / İnşaat Mühendisliği

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

Browse

Filters

2009 - 200912010 - 201912020 - 20222

Settings

Author: search.filters.author.Ecemiş, NurhanSubject: search.filters.subject.Liquefaction

Search Results

Now showing 1 - 4 of 4
  • Article
    Citation - WoS: 13
    Citation - Scopus: 12
    Geotechnical Reconnaissance Findings of the October 30 2020, Mw7.0 Samos Island (aegean Sea) Earthquake
    (Springer, 2022) Ziotopoulou, Katerinaa; Pelekis, Panagiotis; Klimis, Nikolaos; Çetin, Kemal Önder; Altun, Selim; Sezer, Alper; Ecemiş, Nurhan
    On October 30, 2020 14:51 (UTC), a moment magnitude (Mw) of 7.0 (USGS, EMSC) earthquake occurred in the Aegean Sea north of the island of Samos, Greece. Turkish and Hellenic geotechnical reconnaissance teams were deployed immediately after the event and their findings are documented herein. The predominantly observed failure mechanism was that of earthquake-induced liquefaction and its associated impacts. Such failures are presented and discussed together with a preliminary assessment of the performance of building foundations, slopes and deep excavations, retaining structures and quay walls. On the Anatolian side (Turkey), and with the exception of the Izmir-Bayrakli region where significant site effects were observed, no major geotechnical effects were observed in the form of foundation failures, surface manifestation of liquefaction and lateral soil spreading, rock falls/landslides, failures of deep excavations, retaining structures, quay walls, and subway tunnels. In Samos (Greece), evidence of liquefaction, lateral spreading and damage to quay walls in ports were observed on the northern side of the island. Despite the proximity to the fault (about 10 km), the amplitude and the duration of shaking, the associated liquefaction phenomena were not pervasive. It is further unclear whether the damage to quay walls was due to liquefaction of the underlying soil, or merely due to the inertia of those structures, in conjunction with the presence of soft (yet not necessarily liquefied) foundation soil. A number of rockfalls/landslides were observed but the relevant phenomena were not particularly severe. Similar to the Anatolian side, no failures of engineered retaining structures and major infrastructure such as dams, bridges, viaducts, tunnels were observed in the island of Samos which can be mostly attributed to the lack of such infrastructure.
  • Article
    Citation - WoS: 36
    Citation - Scopus: 39
    Sand-Granulated Rubber Mixture To Prevent Liquefaction-Induced Uplift of Buried Pipes: a Shaking Table Study
    (Springer, 2021) Ecemiş, Nurhan; Valizadeh, Hadi; Karaman, Mustafa
    Buried pipelines in liquefiable soils are vulnerable and can float during earthquake excitation. The uplift forces due to pore-water-pressure generation relocate the pipelines in the soil. Therefore, it is essential to measure the liquefaction effects of the backfill materials on buried pipes and make an intelligent choice for the surrounding soil to reduce the applied forces on pipelines during liquefaction. Recently, scrap tire-soil mixtures have been used as a new geomaterial to decrease the adverse effects of liquefaction. This paper investigates the flotation of the buried pipe and the sand-granulated rubber mixture's effectiveness around the pipe by a series of shaking table tests. Dynamic tests were performed under 1 g conditions on a fully saturated sand-granulated rubber mixture with small-diameter buried pipes. Three different granulated-rubber dimensions of 2.5-5, 5-10, and 10-15 mm and granulated rubber ratios of 10, 20, and 30 percent were examined in the tests. The outcomes of excess pore water pressure, settlement, pipe uplift, and upward pressure during and after shaking were compared. The test results demonstrated that the sand-granulated rubber mixture reduces excess pore water pressure accumulation and prevents liquefaction. Moreover, the effect of pipe diameter, burial depth, consolidation coefficient of the mixture, and uplift initiation time on pore water pressure and load increment below the pipe were combined to predict the buried pipe's uplift probability.
  • Article
    Citation - WoS: 36
    Citation - Scopus: 38
    Simulation of Seismic Liquefaction: 1-G Model Testing System and Shaking Table Tests
    (Taylor and Francis Ltd., 2013) Ecemiş, Nurhan
    In this paper, we focus on the development and performance of the 1-g model testing system to monitor the liquefaction occurrence of saturated soils, under subsequent one-dimensional shake table tests. The system is composed of one-dimensional laminar box, cone penetration system, soil model, system for hydraulic soil pumping to achieve loose soil deposit, instrumentation and associated testing hardware. In order to simulate the free-field conditions in the laboratory, the laminates slide on each other using rollers placed between each laminate. The static calibration test results demonstrate that the friction effects between the laminates and the rollers are satisfactorily low. The loosest and the most liquefiable sand deposit is prepared inside the laminar box by hydraulic filling process and subjected to four subsequent shaking tests at different intensities. First, the laminar box and shake table performance is verified by using time-histories of acceleration and displacement test results. Then, the measured data inside the soil and on the laminates are compared with the numerical model. The previously calibrated numerical model UBCSAND which shows the seismic loading conditions in the free field is used in the simulations. Those shake table test results and the numerical simulations of the box and the soil indicate that the usefulness of the laminar box system for shaking table tests is satisfactory for dynamic model tests in 1-g gravity.
  • Article
    Citation - WoS: 48
    Citation - Scopus: 51
    Laminar Box System for 1-G Physical Modeling of Liquefaction and Lateral Spreading
    (American Society for Testing and Materials, 2009) Thevanayagam, S.; Kanagalingam, T.; Reinhorn, A.; Tharmendhira, R.; Dobry, R.; Abdoun, T.; Elgamal, A.; Zeghal, M.; Ecemiş, Nurhan; El Shamy, U.
    Details of a large scale modular 1-g laminar box system capable of simulating seismic induced liquefaction and lateral spreading response of level or gently sloping loose deposits of up to 6 m depth are presented. The internal dimensions of the largest module are 5 m in length and 2.75 m in width. The system includes a two dimensional laminar box made of 24 laminates stacked on top of each other supported by ball bearings, a base shaker resting on a strong floor, two computer controlled high speed actuators mounted on a strong wall, a dense array advanced instrumentation, and a novel system for laboratory hydraulic placement of loose sand deposit, which mimics underwater deposition in a narrow density range. The stacks of laminates slide on each other using a low-friction high-load capacity ball bearing system placed between each laminate. It could also be reconfigured into two smaller modules that are 2.5 m wide, 2.75 m long, and up to 3 m high. The maximum shear strain achievable in this system is 15 %. A limited set of instrumentation data is presented to highlight the capabilities of this equipment system. The reliability of the dense array sensor data is illustrated using cross comparison of accelerations and displacements measured by different types of sensors. Copyright © 2009 by ASTM International.