Browsing by Author "Soysal, Berat Feyza"

Now showing 1 - 6 of 6

Citation - WoS: 6
Citation - Scopus: 7
Crack Width - Seismic Intensity Relationships for Concrete Gravity Dams
(Taylor & Francis Ltd, 2024) Soysal, Berat Feyza; Arici, Yalin; 157572; 06.05. İnşaat Mühendisliği; 06. Mühendislik Fakültesi; 01. Çankaya Üniversitesi
Seismic assessment of plain concrete structures like gravity dams is generally conducted based on cracking. The responses of two types of gravity dams, i.e. the conventional and roller compacted concrete (RCC), were investigated in this study using a discrete element tool coupled with special reservoir elements. Using incremental dynamic analysis, the relationship between the seismic intensity measures and crack widths on the U/S face of the monolith was obtained. The damage accumulation on conventional and RCC dams was different: The cumulative cracking on the upstream face of the monolith correlated well to a seismic intensity measure representing base shear.
Citation - WoS: 4
Citation - Scopus: 5
The Effect of Vertical Motions on Damage Accumulation on Concrete Gravity Dams
(Wiley, 2023) Soysal, Berat Feyza; Arici, Yalin; Ay, Bekir Ozer; 157572; 06.05. İnşaat Mühendisliği; 06. Mühendislik Fakültesi; 01. Çankaya Üniversitesi
The effect of vertical ground motions on the seismic response of dams has long been a concern in the seismic design and evaluation of concrete gravity dams. The guidelines regarding the use of vertical motions in time history analysis (THA) are not clear due to the complexity of the effect as well as the large uncertainty in the motion selection process. The goal of this study is to assess the significance of vertical motions' effects on concrete gravity dams considering the relevant variability due to ground motion, system frequency response as well as the shaking level. To this end, a carefully selected ground motion set providing realistic vertical(V)/horizontal(H) loading was used in nonlinear THAs of three different systems with different modal properties. In order to evaluate the intensity of shaking on the vertical motions' effect, the responses were calculated at different seismic levels corresponding to operation, design, and maximum shaking levels. Along with traditional demand parameters commonly employed in assessing seismic response, cracking on the base and at the upstream face of the monolith was adopted as demand measures using a model capable of yielding discrete cracking on the system. The effect of vertical motions was quantified by comparing the response of H + V to H only shaking. The results show the vertical shaking can significantly affect upstream cracking for the operation or design level earthquakes, the effect increasing for larger dams.
Citation - WoS: 6
Citation - Scopus: 7
A Modified Applied Element Model for the Simulation of Plain Concrete Behaviour
(Emerald Group Publishing Ltd, 2023) Soysal, Berat Feyza; Arici, Yalin; Tuncay, Kagan; 157572; 06.05. İnşaat Mühendisliği; 06. Mühendislik Fakültesi; 01. Çankaya Üniversitesi
A modified applied element model to simulate the behaviour of plain concrete continuum structures including discrete cracking is proposed in this study. In the classical applied element model, Poisson effects are fully ignored. To remediate this issue, diagonal elements are introduced to include the Poisson effect, and the constitutive parameters are rigorously determined using the Cauchy-Born rule and the hyper-elastic theory. The formulation is validated for linear elastic problems and the consistency and convergence behaviour of the numerical approach is shown. Tensile softening formulation using the concept of fracture energy is utilised for the nonlinear range. In this range, the approach is validated using the classical benchmark tests with pure tensile, split-tensile, combined shear-tensile and bending dominated push-over loading. The load-displacement behaviour and crack response were captured successfully, showing the proposed methodology can be used to quantify discrete cracks on large systems, such as dam monoliths, from initiation to significant damage levels.
Citation - WoS: 6
Citation - Scopus: 6
Predicting Seismic Damage on Concrete Gravity Dams: a Review
(Taylor & Francis Ltd, 2024) Arici, Yalin; Soysal, Berat Feyza; 157572; 06.05. İnşaat Mühendisliği; 06. Mühendislik Fakültesi; 01. Çankaya Üniversitesi
The seismic assessment of concrete gravity dams is a problem of prediction of cracking and the corresponding consequences. With the widespread use of general-purpose finite element programs, the work in the field has shifted towards quantifying the behaviour in a framework for assessment. The nonlinear analysis and coupling with foundation-reservoir interaction, conversely, is still a challenging task. The modelling approach has significant effects on the analysis results and the assessment framework. The field remains an active area for research with many outstanding issues regarding damage quantification and assessment compared to any other major infrastructure component. A comprehensive overview of the seismic assessment of gravity dams is presented in this work with the goal to outline the issues in the field. Different models and modelling choices are compared in the context of damaged state assessment of gravity dams. The links between practical difficulties and theoretical issues are critically discussed. The aleatoric and epistemic uncertainties in the field, and their sources, are presented. Areas of future work are identified for improvement in seismic assessment as well as reducing and quantifying the uncertainties in the prediction of damaged states for concrete gravity dams.
The Significance of Vertical Shaking on Seismic Assessment of Gravity Dams: A Case Study
(Springer International Publishing AG, 2024) Arici, Yalin; Soysal, Berat Feyza; Ay, Bekir Ozer; 06.05. İnşaat Mühendisliği; 06. Mühendislik Fakültesi; 01. Çankaya Üniversitesi
Vertical motions' effects have recently been recognized in building codes. The corresponding effects on infrastructure components is less certain. Current industry practice ignores vertical shaking based on earlier recommendations obtained using linear analyses. The goal of this study is to assess this suggestion for a case study and investigate the significance of the use of vertical motion, along with the horizontal component, during the seismic assessment of dam structures. A 50 m concrete dam monolith was used to this end and the effects of the vertical motion was assessed for two groups of engineering demand parameters (EDP). Such displacement and crack based EDPs are commonly used in the assessment of gravity dams. The response of the chosen system with and without the contribution of vertical ground motion was obtained and compared. The results show an increase in the horizontal displacement and vertical acceleration on the system when vertical ground motion was used along with the horizontal, in lieu of the horizontal only shaking case. The cracking around the neck of the system can be significantly different with the use of vertical motion, both with regard to extension and distribution.
Citation - WoS: 1
Citation - Scopus: 1
The Use of Discrete Element Models for the Seismic Assessment of Concrete Gravity Dams
(Elsevier Science inc, 2024) Soysal, Berat Feyza; Arici, Yalin; 06.05. İnşaat Mühendisliği; 06. Mühendislik Fakültesi; 01. Çankaya Üniversitesi
The assessment of the seismic performance of gravity dams is a difficult engineering problem requiring consideration of the cracking in a brittle medium as well as the interaction of the reservoir and the massive concrete structure. The problem is challenging from a practical point of view as well; a clear-cut damage indicator for assessing the performance of these systems is not present. The generally used finite element method (FEM)/rotating crack combination led to the utilization of indirect global demand parameters like crest displacements or damaged area ratios as damage indicators. While very robust in terms of the solution, the aforementioned combination leads to highly diffused crack patterns for large shaking, limiting the interpretation of the results for these systems on which discrete cracks' extent and widths are the primary damage measures. This limitation can be overcome by utilizing methods that simulate the discrete fracture phenomenon; in this study, the nonlinear seismic behavior of a concrete gravity dam-reservoir system was investigated using the developed discrete element framework, the modified applied element method (MAEM). Using incremental dynamic analysis, the cracking on the dam body was compared with those of the FEM qualitatively first, followed by a quantitative comparison focused on the propagation of the cracking using fragility curves. Then, the use of crack widths as a damage indicator was utilized, and model outcomes were compared. The utilized model reduced the diffusion of cracking commonly observed in FEM models using total strain smeared crack formulation and predicted more adverse behavior in terms of total crack widths and crack propagation.