Sharif Digital Repository

Concrete arch dam is a complex geometric structure and designing such a structure requires experience and high knowledge. One of the important parameters in designing concrete arch dams is the tensile stress in arch concrete material. The static analysis results of high arch dam structure depend on structure analysis model, intensively. Stage construction is needed to be focused in modeling high arch dams. In this study, the necessity of considering stage construction in static analysis of dam structure is focused. Modeling stage construction uses Birth and Death technique of elements. Therefore, six stage construction models are provided including applying dam wall weight outright, two... 

A three-dimensional finite element analysis was carried out to determine the annual variation of temperature and thermal stresses of a concrete arch dam. Appropriate heat transfer boundary conditions in the dam body were used for air and reservoir temperature as well as solar radiation variations. Karaj arch dam in Iran was used as a case study. The rate of convergence of the numerical solution is examined. Results of the finite element analysis show that probable cracks occur in a very narrow region of the downstream face. Thermal loads have the most significant effects for causing downstream cracks in comparison with self-weigh and hydrostatic loads. The cracked areas of downstream face... 

At present study, Endurance Time (ET) method that is a new dynamic pushover procedure is introduced and its application in predicting concrete arch dam behavior in linear domain is investigated. In this method structure is subjected to gradually intensifying acceleration functions. DEZ arch dam was selected as case study. FE model of dam-reservoir-foundation was excited in three levels of MCL, MDL, DBL using six records scaled based on design spectrum of the site and results were compared with those obtained from ET analyses. It was found that results obtained from ET method at equivalent target time are in good agreement with extreme results obtained from exciting the system using natural... 

In the present paper, effects of non-uniform excitation due to spatially variation of seismic waves under the reservoir bottom on linear and nonlinear responses of arch dams are studied. Foundation is assumed to be massed and infinite elements are utilized to model semi-infinite medium via the far-end boundary of the foundation FE model. A continuum crack propagation model based on the smeared crack approach in 3D space is introduced. Reservoir's water is assumed compressible and the coupled system is solved using the staggered method. As a case study, Amir-Kabir double curvature arch dam in Iran is selected to investigate seismic behavior of the system. Two cases are analyzed in which wave... 

In this study, multi-criteria shape optimization of an asymmetrical doublecurvature arch dam is presented. Simultaneous cost minimization of dam construction and maximum allowable tensile stress are investigated for an economical and safe design approach in the current study. Pareto front method was used to balance both the economy and safety of the design simultaneously, which can be difficult for both analysts and decision-makers. A non-dominated solution based on the important parameters of dam analysis and design is presented. To help decision-makers in their decision, two different methods are proposed. These methods for the case of an arch dam are Lombardi coefficient and equilibrium... 

A novel and robust approach is proposed to find the optimum shape of concrete arch dams located on any unsymmetrical shape of a valley. The approach is capable of finding the optimum shape for any given valley type in suitable time, based on abutment stability analysis, against thrust forces from an arch dam. The behavior and stability of a concrete arch dam is strongly dependent on the bedrock on which the dam rests. The stability of the abutment is considered a constraint in the proposed approach. In addition, a new objective function is introduced to decrease the final volume of the arch dam. Furthermore, a computer program was developed, which takes the effect of the dam foundation... 

One of the methods in limiting tensile stresses in arch dams and removing stress concentrations at the dam-foundation interface is setting the dam body on a concrete saddle called a Pulvino. In the present study, the effects of Pulvino and peripheral joints on the static behavior and seismic performance of arch dams are investigated. Dez Dam with a height of 203 m was selected as a case study and all contraction joints of the dam body were modeled using the discrete crack approach based on as-built drawings. Also, the surrounding rock was modeled as a mass-less medium tied to Pulvino. The dam-reservoirfoundation system was analyzed under static loads accounting for stage construction... 

Damage assessment of concrete arch dams is carried out through nonlinear Incremental Dynamic Analysis (IDA) of a typical arch dam. In this study the Morrow Point arch dam is subjected to a set of 12 three-component earthquakes each scaled to 12 increasing intensity levels. The dam-foundation interaction effects have been investigated by varying foundation's modulus of elasticity to be equal and half of dam concrete's modulus of elasticity. Damage propagation through the dam body is investigated and various IDA curves are created. The performance and various limit-states of the dam structure are examined based on the obtained results. Simple damage indices are proposed through comparison of... 

Investigation of the dynamic characteristics of an existing structure system based on field tests is of practical significance, since it can be employed in the field of examining construction quality, validating or improving analytical finite element structural models, or conducting damage assessment. The main purpose of this study is to investigate the dynamic characteristics of dams using the seismic response data. Whereas, in the process of frequency domain identification of dam properties, frequency response function (FRF) plays the most important role, evaluating the corresponding parameters with better accuracy has always been desirable. Therefore, a comparison was made between some... 

The purpose of this paper is to determine the optimal shape of double curvature concrete arch dams by using the sensitivity of design objective to design variables. Design sensitivities quantify the relationship between the design variables such as thickness of crown cantilever, left and right abutment thickness, crown cantilever upstream profile, radius of curvature of water and air faces on one hand and the objective function such as the volume of the concrete arch dam on the other hand. For this aim, first a methodology was developed to provide interface between a finite element method and an optimization algorithm for shape optimization of double curvature concrete arch dams. The...