• Geomechanics and Engineering
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• 제2권2호
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• pp.89-106
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• 2010

Sliding within the dam foundation is one of the key failure modes of a gravity dam. A two-dimensional (2-D) physical model test has been conducted to study the sliding failure of a concrete gravity dam under overloading conditions. This model dam was instrumented with strain rosettes, linear variable displacement transformers (LVDTs), and embedded fiber Bragg grating (FBG) sensing bars. The surface and internal displacements of the dam structure and the strain distributions on the dam body were measured with high accuracy. The setup of the model with instrumentation is described and the monitoring data are presented and analyzed in this paper. The deformation process and failure mechanism of dam sliding within the rock foundation are investigated based on the test results. It is found that the horizontal displacements at the toe and heel indicate the dam stability condition. During overloading, the cracking zone in the foundation can be simplified as a triangle with gradually increased height and vertex angle.

• Advances in concrete construction
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• 제9권5호
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• pp.503-510
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• 2020

Concrete dams are important structures due to retaining amount of water on their reservoir. So such kind of structures have to be designed against static and dynamic loads. Especially considering on critical importance against blasting threats and environmental safety, dams have to be examined according to the blast loads. This paper aims to investigate structural response of concrete gravity dams under blast loads. For the purpose Sarıyar Concrete Gravity Dam in Turkey is selected for numerical application with its 85 m of reservoir height (H), 255 m of reservoir length (3H), 72 m of bottom and 7 m of top widths. In the study, firstly 3D finite element model of the dam is constituted using ANSYS Workbench software considering dam-reservoir-foundation interaction and a hydrostatic analysis is performed without blast loads. Then, nearly 13 tons TNT explosive are considered 20 m away from downstream of the dam and this is modeled using ANSYS AUTODYN software. After that explicit analyses are performed through 40 milliseconds. Lastly peak pressures obtained from analyses are compared to empirical equations in the literature and UFC 3-340-02 standard which provide unified facilities criteria for structures to resist the effects of accidental explosions. Also analyses' results such as displacements, stresses and strains obtained from both hydrostatic and blasting analysis models are compared to each other. It is highlighted from the study that blasting analysis model has more effective than the only hydrostatic analysis model. So it is highlighted from the study that the design of dams should be included the blast loads.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 학회창립 10주년 기념 1999년도 가을 학술발표회 논문집
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• pp.643-646
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• 1999

Downstream surface of the concrete gravity dam receives thermal stress due to atmosphere temperature change. So in this paper, the behaviors of crack located in the downstream surface were investigated, when considering the temperature change.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2009년도 정기 학술대회
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• pp.530-533
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• 2009

This study deals with 2D and 3D nonlinear seismic damage analysis of a concrete gravity dam using the finite element program ABAQUS and the concrete damaged plasticity model. 2D and 3D spillway sections of the dam are simulated. First the frequency analysis is conducted to compare the fundamental frequency and estimate the value of damping coefficient. Then the seismic analysis is conducted using the simulated ground acceleration motion. The relative displacement between the crest and bottom of the dam is obtained and compared for the maximum value and occurrence time. The results indicate that the plane-stress assumption gives similar results of maximum relative displacement and final damage distribution with 3D analysis.

• Earthquakes and Structures
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• 제26권1호
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• pp.59-75
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• 2024

This paper presents a dam-reservoir interaction model that includes, water compressibility, sloshing of surface water, and radiation damping at the far-end reservoir, to investigate the influence of concrete deterioration on seismic behavior along with seismic performance of gravity dams. Investigations on seismic performance of the dam body have been conducted using the linear time-history responses obtained under six real and 0.3 g normalized earthquake records with time durations from 10 sec to 80 sec. The deterioration of concrete is assumed to develop due to mechanical and chemical actions over the dam lifespan. Several computer programs have been developed in FORTRAN 90 and MATLAB programming languages to analyze the coupled problem considering two-dimensional (2D) plane-strain condition. According to the results obtained from this study, the dam structure shows critical responses at the later ages (75 years) that could cause disastrous consequences; the critical effects of some earthquake loads such as Chi-Chi with 36.5% damage and Loma with 56.2% damage at the later ages of the selected dam body cannot be negligible; and therefore, the deterioration of concrete along with its effects on the dam response should be considered in analysis and design.

• Structural Engineering and Mechanics
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• 제48권1호
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• pp.17-39
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• 2013

In the present paper, a coaxial rotating smeared crack model is proposed for mass concrete in three-dimensional space. The model is capable of applying both the constant and variable shear transfer coefficients in the cracking process. The model considers an advanced yield function for concrete failure under both static and dynamic loadings and calculates cracking or crushing of concrete taking into account the fracture energy effects. The model was utilized on Koyna Dam using finite element technique. Dam-water and dam-foundation interactions were considered in dynamic analysis. The behavior of dam was studied for different shear transfer coefficients considering/neglecting fracture energy effects. The results were extracted at crest displacement and crack profile within the dam body. The results show the importance of both shear transfer coefficient and the fracture energy in seismic analysis of concrete dams under high hydrostatic pressure.

• 한국방재학회 논문집
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• 제4권1호
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• pp.1-14
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• 2004

본 연구의 목적은 무엇보다도 콘크리트중력식 댐의 내진안전성 평가방법을 정립하는 데에 있다. 그렇게 하기 위하여 지진시 구조물의 거동을 파악하고 내진성능을 평가해야 한다. 본 연구에서는 구조해석 프로그램을 사용한 동적해석을 통하여 지진시의 피해상황을 알아보았다. 물의 중량으로 인하여 댐에 가해지는 동수압은 부가질량법을 이용하여 계산하였다. 본 연구에서 알아낸 바에 의하면 지반상태에 따라 경계조건을 부여해 주는 것이 필요하며 특히 댐의 모양이 불균일하거나 갑작스런 기하학적인 변화가 있을 때에는 댐의 상하류방향 지진 만이 아닌 댐축방향 지진에 대한 해석이 반드시 필요하다는 것이 밝혀졌다.

• 콘크리트학회논문집
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• 제12권3호
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• pp.31-37
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• 2000

When a crack is produced in a concrete structure, a micro crack zone of fracture process zone (FPZ) appears at the crack tip. To investigate the behaviour of this the micro crack zone, nonlinear fracture mechanics (NLFM) must be applied. However, when a massive concrete structure such as a concrete gravity dam is considered, the micro crack zone can be neglected and the structure can be assumed to have linear elastic fracture mechanics (LEFM) behaviour. This study is divided into two main topics : (1) Calculating stress intensity factor (SIF) at the crack tip by surface integral method and (2) Investigating the propagation of the initial crack. If the initial crack propagates, the angle of the propagation is calculated by using maximum circumferential tensile strength theory. This study, also, contains the effects of body forces and water pressures on the crack face.

• Water Engineering Research
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• 제2권4호
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• pp.199-207
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• 2001

A computer-assisted desktop is developed for layout design of a concrete gravity dam on the basis of safety and economy. Using a set of regression equations, a dam layout is proposed. With reference to the regression equations and relevant input data, overall dam dimensions are determined by satisfying the stability criteria jointly under usual, unusual, and extreme loading conditions with the desired hydraulic conformity. Among several feasible alternatives, the program enables a designer to select the optimum layout, which corresponds to the minimum total cost of the structure. The method is applied to a case study to examine dimensions of proposed alternatives and to compare them with those of an existing dam.

• 한국지진공학회논문집
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• 제6권1호
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• pp.33-41
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• 2002

최근 1995년 일본의 고베 및 1999년도에 터키와 대만 등지에서 일어난 강진으로 많은 사상자와 피해가 발생되었고 일본 및 대만의 경우 일부 댐의 피해가 발생되었다. 댐의 경우 지진 발생시 국부적인 구조물의 손상뿐만 아니라 주변 주거지역에 많은 인명피해를 유발하기 때문에 국내에서도 내진설계기준 강화 이전의 콘크리트 중력식 댐에 대한 내진 안전성 평가의 필요성을 인식하게 되었다. 본 연구에서는 미국, 일본 및 캐나다의 내진설계기준 및 안전성 평가기법을 분석하여 국내 실정에 적합한 내진 안전성 평가 지침을 마련하였다. 평가단계는 제3단계로 구성하였다. 제1단계는 기초 문헌자료를 이용한 내진 안전성 평가 필요여부를 구분하는 예비평가단계이며 제2단계 평가는 진도법을 적용한 유사정적해석을 수행하여 성능기준 만족여부를 판단한다. 제3단계 평가는 제2단계를 만족하지 못하였을 경우 대상구조물에 동적해석을 적용하여 정밀한 평가를 수행한 후 성능기준을 평가한다. 본 연구에서는 현재 국내에서 운영중인 콘크리트 중력식 댐을 선정하여 본 평가 방법을 적용하였다.