İnşaat Mühendisliği Bölümü Koleksiyonu
Permanent URI for this collectionhttps://hdl.handle.net/20.500.11779/1943
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Article Citation - WoS: 1Citation - Scopus: 2Probabilistic Seismic Microzonation for Ground Shaking Intensity, a Case Study in Türkiye(Springer, 2023-10-01) Tönük, Gökçe; Ansal, AtillaThe purpose of seismic microzonation is to estimate earthquake characteristics on the ground surface based on a probabilistic approach to mitigate earthquake damage in the foreseeable future for the new buildings, as well as for the existing building stock. The probabilistic analysis and related results are very important from an engineering perspective since the nature of the problem can only be dealt with in a probabilistic manner. The uncertainties associated with these analyses may be large due to the uncertainties in source characteristics, soil profile, soil properties, and building inventory. At this stage, the probability distribution of the related earthquake parameters on the ground surface may be determined based on hazard-compatible input acceleration-time histories, site profiles, and dynamic soil properties. One option, the variability in earthquake source and path effects may be considered using a large number of acceleration records compatible with the site-dependent earthquake hazard. Likewise, large numbers of soil profiles may be used to account for the site-condition variability. The seismic microzonation methodology is proposed based on the probabilistic assessment of these factors involved in site response analysis. The second important issue in seismic microzonation procedure is the selection of microzonation parameters. The purpose being mitigation of structural damage, it is possible to adopt earthquake parameters like cumulative average velocity (CAV) or Housner intensity (HI) that was observed to have better correlation with building damage after earthquakes. A seismic microzonation procedure will be developed with respect to ground shaking intensity considering probabilistic values of the cumulative average velocity (CAV) or Housner intensity (HI).Article Citation - WoS: 5Citation - Scopus: 8Factors Affecting Site-Specific Response Analysis(Taylor and Francis, 2022-01-18) Tönük, Gökçe; Ansal, Atilla M.The engineering purpose of a site-specific response analysis is to estimate the uniform hazard acceleration spectrum on the ground surface for a selected hazard level. One of the mandatory components for site response analyses is one or more representative acceleration time histories that need to be scaled with respect to the calculated seismic hazard level for the selected site. The selection and scaling procedures of earthquake acceleration records play an important role in this approach. The effects and differences in using two different scaling approaches are studied: scaling with respect to ground motion parameters and response spectrum scaling. A set of homogeneous ground motion prediction relationships are developed for peak ground acceleration, peak ground velocity, root-mean-square acceleration, Arias intensity, cumulative absolute velocity, maximum spectral acceleration, response spectrum intensity, and acceleration spectrum intensity based on a uniform set of acceleration records for ground motion parameter scaling.The uncertainties associated with site response analysis are considered as epistemic and aleatory uncertainties in source characteristics, soil profile, and soil properties. Aleatory variability is due to the intrinsic randomness of natural systems; it cannot be reduced with additional data (Passeri et al. 2020), however; its variability may be modeled by probability distribution functions. Thus, one possibility is to determine the probability distribution of the acceleration spectrum calculated on the ground surface for all possible input acceleration records, site profiles, and dynamic soil properties. The variability in the earthquake source and path effects are considered using a large number of acceleration records compatible with the site-dependent earthquake hazard in terms of fault mechanism, magnitude, and distance range recorded on stiff site conditions. Likewise, a large number of soil profiles may be considered to account for the site condition variability. The uncertainties related to dynamic soil properties may be considered as possible variability of maximum dynamic shear modulus in site response analyses. A methodology is proposed to estimate a uniform hazard acceleration spectrum on the ground surface based on the probabilistic assessment of the factors involved in site response analysis. The uniform hazard acceleration spectra obtained from a case study are compared with the spectra calculated by probabilistic models proposed in the literature.Article Citation - WoS: 5Citation - Scopus: 6Gis-Based Assessment of Seismic Vulnerability Information of Old Masonry Buildings Using a Mobile Data Validation System(American Society of Civil Engineers (ASCE), 2021-06-01) Özsoy Özbay, Ayşe Elif; Ünen, Hüseyin Can; Karapınar, Işıl Sanrı; Ozbay, Ayse Elif ozsoy; Sanrl Karaplnar, Işll; Sanri Karapinar, IsilThis study proposes a geographic information system (GIS)–based rapid visual screening approach for seismic vulnerability assessment of masonry buildings in culturally and architecturally important historical regions. Through the application of the proposed methodology, a prioritization strategy for seismic vulnerability assessment of the heritage masonry buildings in Galata, a historical center of Istanbul, Turkey, was performed. This approach is based on an integrated methodology including a data collection process conducted through visual inspections and standard survey forms filled on site, generation of a georeferenced building database enabling the calculations and mapping of the vulnerability scores, and camera-based data validation process. The validation process provides an online collaborative mobile mapping system through georeferenced images gathered from the field. By the updatable data validation process, the reliability and efficiency of the GIS-based building database are enhanced by minimizing the errors during the visual screening and the cost of data correction due to reinspection is reduced.Article Citation - WoS: 4Citation - Scopus: 7Modal Identification of the First Bosporus Bridge During Hanger Replacement(Taylor & Francis, 2020-01-30) Dikmen, Seyyit Ümit; Aytulun, Emre; Luş, Hilmi; Safak, Erdal; Soyöz, Serdar; Apaydın, NurdanAs the oldest of the three suspension bridges spanning the Bosporus, the (First) Bosporus Bridge wascommissioned in 1973. Its main span of 1074 m was originally designed to be suspended by inclinedhangers; in 2015, the original inclined hangers were replaced by vertical ones. In-situ ambient vibra-tion measurements were taken at different stages of this operation to gain an understanding of theeffects of the hanger cable orientation on the overall dynamic behaviour of the bridge. Measurementswere also recorded for various periods spanning several weeks to observe operational variations onthe modal frequencies of vibration. Measurements were made on the tower, the deck and the hang-ers. It was observed that, as a result of the hanger replacement, frequencies of the modes involvingpredominant deck motion decreased on the order of 6 to 16% while the frequencies of the modesinvolving predominant tower motion showed almost no change. A finite element model of the Bridgewas also developed to further investigate the physical reasons behind the observed changes in modalfrequencies and similar trends were observed in the modal frequencies yielded by the finite elementmodels developed for the inclined and the vertical hanger configurations.