Hızal, Çağlayan
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Hızal, Ç.
Hizal, Caglayan
Hizal, Caglayan
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caglayanhizal@gmail.com
Main Affiliation
03.03. Department of Civil Engineering
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Former Staff
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Sustainable Development Goals
1NO POVERTY
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2ZERO HUNGER
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3GOOD HEALTH AND WELL-BEING
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4QUALITY EDUCATION
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5GENDER EQUALITY
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6CLEAN WATER AND SANITATION
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7AFFORDABLE AND CLEAN ENERGY
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8DECENT WORK AND ECONOMIC GROWTH
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9INDUSTRY, INNOVATION AND INFRASTRUCTURE
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10REDUCED INEQUALITIES
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11SUSTAINABLE CITIES AND COMMUNITIES
2
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12RESPONSIBLE CONSUMPTION AND PRODUCTION
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13CLIMATE ACTION
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14LIFE BELOW WATER
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15LIFE ON LAND
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16PEACE, JUSTICE AND STRONG INSTITUTIONS
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17PARTNERSHIPS FOR THE GOALS
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Scholarly Output
16
Articles
14
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31704/6713
Supervised MSc Theses
0
Supervised PhD Theses
2
WoS Citation Count
109
Scopus Citation Count
122
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0
WoS Citations per Publication
6.81
Scopus Citations per Publication
7.63
Open Access Source
10
Supervised Theses
2
| Journal | Count |
|---|---|
| Teknik Dergi | 3 |
| Experimental Techniques | 1 |
| International Journal of Disaster Risk Reduction | 1 |
| Journal of Bridge Engineering | 1 |
| Journal of Sound and Vibration | 1 |
Current Page: 1 / 3
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16 results
Scholarly Output Search Results
Now showing 1 - 10 of 16
Article Citation - WoS: 5Citation - Scopus: 8Comparative Dynamic Analysis of Axially Loaded Beams on Modified Vlasov Foundation(Techno Press, 2016) Hızal, Çağlayan; Çatal, Hikmet HüseyinVibration analysis of the beams on elastic foundation has gained the great interest of many researchers. In the literature, there are many studies that focus on the free vibration analysis of the beams on one or two parameter elastic foundations. On the other hand, there are no sufficient studies especially focus on the comparison of dynamic response including the bending moment and shear force of the beams resting on Winkler and two parameter foundations. In this study, dynamic response of the axially loaded Timoshenko beams resting on modified Vlasov type elastic soil was investigated by using the separation of variables method. Governing equations were obtained by assuming that the material had linear elastic behaviour and mass of the beam was distributed along its length. Numerical analysis were provided and presented in figures to find out the differences between the modified Vlasov model and conventional Winkler type foundation. Furthermore, the effect of shear deformation of elastic soil on the dynamic response of the beam was investigated.Doctoral Thesis Modal Identification of Structures by Using Bayesian Statistics(Izmir Institute of Technology, 2019) Hızal, Çağlayan; Hızal, Çağlayan; Turan, Gürsoy; Turan, GürsoyBayesian Probabilistic approaches in the health monitoring of civil engineering structures has gained remarkable interest during past decades. When compared to the available Operational Modal Analysis (OMA) methods, Bayesian Operational Modal Analysis (BAYOMA) determines a probabilistic range with a most probable value and uncertainty instead of a certain result. For this reason, the most important difference of BAYOMA lies in its capability of uncertainty quantification. Therefore, the modal parameters of a measured structure can be determined based on a probabilistic logic according to various cases (for example single measurement setup, well separated and/or closely spaced modes, multiple measurement setups). Further, the finite element model of the investigated structure can also be updated by a Bayesian approach incorporated with modal identification procedure. Some efficient BAYOMA methods such as Bayesian Spectral Density Approach (BSDA) and Bayesian Fast Fourier Transform Approach (BFFTA) have been presented by various researchers during the past two decades. Despite their efficient and fast solution procedure, the available methods have some critical issues that need to be solved. Most of these problems especially lie in the quantification of posterior uncertainties and some special cases arise in closely spaced modes and/or multiple setup measurement cases. In the literature, solutions for the aforementioned problems have been also presented by various researchers. In the light of the accumulated knowledge in the literature, this study presents a computational framework for BAYOMA and Bayesian Model Updating (BMU). In addition to some improvements to the available methods, new and alternative approaches are presented for BAYOMA and BMU. According to the results, it is seen that the quality of identified modal parameters and updated finite element models increases significantly by the proposed computational procedure.Article Mesnetlerinden Farklı Yer Hareketlerine Maruz Çok Katlı Çerçevelerin Deplasman Yüklemesine Göre Analizi(Turkish Chamber of Civil Engineers, 2019) Hızal, Çağlayan; Turan, GürsoyIn seismic analysis of structures, generally it is assumed that all supports are subjected to identical ground motions. This approach is assumed to be realistic when the foundation of the structure is formed as a rigid plate, but it cannot consider the dynamic effects of the earthquake wave propagation if the supports are able to move independently. In this study, the multi-support excitation analysis of multi-story, multi bay frames is performed by using displacement loading which defines the seismic load depending on the ground displacement. The modal analysis procedure of the structures subjected to multi-support excitations is given in detail and the effect of pseudo-static displacement on the dynamic response of the structure is highlighted. A static correction approach is implemented with a numerical example to reflect the higher mode effects which are a natural result of displacement loading.Article Citation - WoS: 2Citation - Scopus: 2Effect of Seismic Wave Velocity on the Dynamic Response of Multi-Story Structures on Elastic Foundation(Elsevier Ltd., 2018) Hızal, Çağlayan; Turan, GürsoyTraveling wave effects are generally considered with three main cases: (i) Wave passage effect that results with time delay in earthquake motion. (ii) incoherence effect which is defined as loss of coherency in the ground motion due to the reflection and refraction of waves, and (iii) local site effects. For multi-story structures whose supports are close to each other, the incoherence and local site effect may be omitted. In this case, traveling waves result only in a pure time delay in the earthquake motion (wave passage effect). Due to the wave passage effect of vertical and/or horizontal ground motion, the superstructure needs to be analyzed by multi-support excitation. Raft foundations cannot constrain vertical deformations and/or rotations, but they cause a diaphragm effect in the horizontal direction which results in uniform excitation. In this study, the effect of vertical earthquake motions onto multi-story buildings on elastic soil is investigated. Multi support excitation is considered by using displacement loading, which defines the equivalent seismic loads in terms of the ground displacement. According to the performed simulations of the selected structures, it is shown that structural height has a direct influence that results in member force magnifications with slow traveling wave effect. Among these, the ground floor column axial forces are most affected.Article Citation - WoS: 4Citation - Scopus: 5Pre-Identification Data Merging for Multiple Setup Measurements With Roving References(Springer Verlag, 2020) Ceylan, Hasan; Turan, Gürsoy; Hızal, ÇağlayanOne-time operational modal analysis (OMA) of large civil structures requires measurements of the vibrations, which, according to the number of channels to be measured, are generally expensive and arduous to obtain. In this study, identification of modal parameters of civil structures has been investigated by using multiple setups with a roving reference channel. In this manner, a limited amount of equipment becomes sufficient for OMA of structures. The procedure consists of a transformation function between measurement setups, which transforms all measured data to the time frame of a selected reference setup. To illustrate the procedure, an existing 10 story laboratory shear frame model is considered. A numerical and an experimental investigation have been carried out to identify its modal characteristics. The validity of the procedure has been explained in detail by making use of a coherence function in-between the multi-setup measurements. According to the results, OMA by using only a few sensors with the performed procedure can be equivalent to OMA by using a full measurement setup. Against a common believe, the results of this study reveal that synchronization among the setups does not prominently affect the identification results.Article Citation - WoS: 18Citation - Scopus: 19Modified Frequency and Spatial Domain Decomposition Method Based on Maximum Likelihood Estimation(Elsevier, 2020) Hızal, ÇağlayanIn this study, a Modified Frequency and Spatial Domain Decomposition (MFSDD) technique is developed for modal parameter identification, using output-only response measurements. According to the presented procedure, the most probable power spectral density matrix of the measured response (output PSD) is updated by a maximum likelihood estimation based on the observed data. Different from the available Frequency Domain Decomposition (FDD) techniques, a prediction error term which is associated with the measurement noise and modelling errors is included in the proposed methodology. In this context, a detailed discussion is provided from various aspects for the effect of measurement noise and modelling errors on the parameter estimation quality. Two numerical and two experimental analysis are conducted in order to demonstrate the effectiveness and accuracy of the proposed methodology under some extreme effects. The obtained results indicate that the proposed method shows very good performance in modal parameter estimation in case of noisy measurements.Article Sonlu Eleman Modellerinin Maksimum Olasılık Tahmini ile Güncellenmesi(Turkish Chamber of Civil Engineers, 2021) Hızal, ÇağlayanMatematiksel yapı modellerinin titreşim verileri kullanılarak güncellenmesi konusu, son yıllarda giderek artan bir şekilde araştırmacıların ilgisini çekmektedir. Bu hususta literatüre sunulan yöntemler genel olarak deterministik ve olasılıksal olarak sınıflandırılmaktadır. Bu bağlamda hem deterministik hem de olasılıksal model güncelleme yöntemlerinin birçok varyasyonu yer almaktadır. Bu çalışmada ise maksimum olasılık tahminine dayalı alternatif bir yaklaşım sunulmaktadır. Önerilen yöntemde, modal tanılama sırasında öngörülen ölçüm hatalarının yanı sıra model hatası da boyutsuz bir Rayleigh oranı üzerinden dikkate alınmaktadır. Sisteme ait model parametreler, ölçüm ve modelleme hatalarının normal dağılım göstereceği kabulüyle oluşturulan bir olasılık yoğunluk fonksiyonu üzerinden hesaplanmaktadır. Sunulan yöntemin güvenirliği bir sayısal ve bir deneysel uygulama üzerinden değerlendirilmiştir. Elde edilen verilere göre önerilen yöntemin oldukça makul sonuçlar verdiği gözlemlenmektedir.Article Citation - WoS: 1Citation - Scopus: 1Reliability Assessment of Structures With Bayesian Model Updating Accelerated Via Polynomial-Chaos Metamodeling(Taylor & Francis Ltd, 2025) Uzun, Ertugrul Turker; Hizal, Caglayan; Aktas, EnginFinite element models are often preferred in numerical modeling of structures, but model assumptions lead to inaccuracies and uncertainties. Measuring these is necessary to determine the reliability and accuracy of the numerical model. This has led to the development of FE model update methods that aim to calibrate the numerical model based on data obtained by structural health monitoring (SHM). However, a general framework that provides a realistic life cycle performance assessment of structures by efficiently incorporating monitored data into structural identification has not yet been impeccably presented. Bayesian modeling can characterize uncertain structural parameters as random variables and provide a systematic methodology for integrating a probabilistic SHM framework into model updating. Unfortunately, these lead to complex and time-consuming, causing limitations in their application. Metamodeling techniques which are effective stochastic predictors can be used to decrease the computational burden in the model updating. This study aims at adapting Polynomial-Chaos-Kriging metamodeling technique integrate to Bayesian model updating process to overcome the computational difficulties and reduce different source of uncertainty with using SHM, then, make more accurate reliability assessment. Therefore, an experimental study is used to assess reliability of structure that is exposed to different types of corrosion effects.Article Citation - WoS: 7Citation - Scopus: 9Frequency Domain Data Merging in Operational Modal Analysis Based on Least Squares Approach(Elsevier, 2020) Hızal, ÇağlayanAssembling of multi-setup measurements emerges as a challenging problem in the structural health monitoring applications and may cause some important issues in the estimation of global modal parameters such as frequency, damping ratio and modal shape vector. To overcome this problem, a novel frequency domain pre-identification data merging method is proposed in this study. In the proposed methodology, to obtain a single measurement set, a least squares approach is employed resulting in a global response that is scaled from the multi-setup data. For the verification of the proposed merging procedure, one numerical, two experimental studies and one real data application have been conducted. The results obtained from the numerical, experimental and real data analysis indicate that the presented methodology provides rather high-quality estimations for multi-setup measurement problems. © 2020 Elsevier LtdArticle Citation - WoS: 2Citation - Scopus: 3Rotary Inertia and Higher Modes Effect on the Dynamic Response of Timoshenko Beams on Two-Parameter Elastic Foundation(Turkish Chamber of Civil Engineers, 2019) Hızal, Çağlayan; Çatal, Hikmet HüseyinThis study investigates the effects of rotary inertia and higher modes on the dynamic response of the axially loaded Timoshenko beams on two-parameter foundation with generalized elastic end conditions. A simplified modal analysis procedure is presented by using the conventional separation of variables method. The effect of rotary inertia on the solution of free vibration differential equation is discussed. A numerical example is presented to investigate the coupled effect of rotary inertia and higher modes on the bending moment and shear force responses.