Seminer ppt
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This document discusses seismic response prediction of concrete arch dams. It begins with an introduction to arch dams, describing their curved shape and suitability for narrow valleys. It then discusses various classifications of arch dams based on thickness ratios and structural heights. The document reviews literature on dynamic analysis of arch dams, noting factors like reservoir boundaries, water compressibility, and dam-foundation interaction. It provides an example of the Idukki Dam in Kerala, India, the first arch dam built in the country. Finite element modeling is mentioned as a tool for seismic response prediction of concrete arch dams.
Seminer ppt
- 1. SESMIC RESPONSE PREDICTION OF CONCRETE ARCH DAM Manish Sharma Dr. Md.Imteyaz Ansari M.tech student Assistant Professor Department of Civil Engineering Jamia Millia Islamia (A Central University), New Delhi, India 110025
- 2. CONTENTS ❖ Introduction ❖ Purposes ❖ Classifications ❖ Literature Review ❖ Modeling ❖ References
- 3. INTRODUCTION ❖ Dam is a solid barrier constructed at a suitable location across a river valley to store flowing water. ❖ A dam is a structure which prevents the flow of water and accumulates it in a reservoir. ❖ A barrier constructed across a waterway to control the flow or raise the level of water.
- 4. PURPOSES 1. Flood control 2. Drinking and domestic water supply 3. Irrigation 4. Industrial water supply 5. Hydroelectric energy production 6. Retention and control of sediments 7. Inland navigation 8. Improvement of water quality 9. Fish Farming 10. Recreation facilities
- 5. ARCH DAM ❖ An arch dam is curved in plan, with its convexity towards the upstream side. They transfers the water pressure and other forces mainly ❖ An arch dam is quite suitable for narrow canyons with strong flanks. ❖ The section of an arch dam is approximately triangular like a gravity dam but the section is comparatively thinner. ❖ An arch dam is most suitable for narrow gorges. ❖ Since they are thinner than any other dam type, they require much less construction material, making them economical and practical in remote areas. ❖ The foundation or abutments for an arch dam must be very stable and proportionate to the concrete. To the abutments by arch action.
- 8. CLASSIFICATION Classified based on the ratio of the base thickness to the structural height (b/h) as: ❖ Thin, -less than 0.2, ❖ Medium-thick, -between 0.2 and 0.3, ❖ Thick, -over 0.3. Classified with respect to their structural height are:[ ❖ Low dams - up to 30 ❖ Medium high dams - between 30–91 m ❖ High dams - over 91 m
- 9. There are two basic designs for an arch dam: – ❖ Constant radius arch dams :- Radius of curvature throughout the structure is constant and upstream face is vertical. ❖ Variable-radius dams:- Which have both upstream and downstream curves that systematically decrease in radius below the crest. A dam that is double-curved in both its horizontal and vertical planes may be called a dome dam.
- 10. IDUKKI DAM, KERALA- FIRST ARCH DAM IN INDIA ➢ Location:- Idukki, Kerala, India ➢ Purpose:- Power Generation, Flood Control ➢ Type of Dam:- Concrete, double curvature parabolic, thin arch. ➢ Height :- 168.91 m (554ft) ➢ Length :- 365.85 m (1,200ft) ➢ Dam volume:- 450,000 m3 (16,000,000cuft) ➢ Spillways:- Nil ➢ Reservoir Total capacity:- 1,996×106 m3 (1,618,184acre·ft) ➢ Active capacity :- 1,459×106 m3 (1,182,831acre·ft) ➢ Inactive capacity: - 536×106 m3 (434,542acre·ft) ➢ Catchment Area:- 649.3 km2 (251sqmi) ➢ Surface area :- 60 km2 (23sqmi) ➢ Normal elevation :- 732.62 km2 (283sqmi) ➢ Installed capacity:- 780 MW
- 12. DIFFERENT PARAMETERS TO BECONSIDERED IN THE DYNAMIC ANALYSIS OF ARCH DAM:- ❖Semi- unbounded size of reservoir. ❖ Foundation rock domains. ❖ Dam-water interaction. ❖ Wave absorption at the reservoir boundary. ❖ Water compressibility. ❖ Dam-foundation rock interaction. ❖ Variations in ground motion at dam-rock interface. ❖ Material non-linearity.
- 13. DAM WATER INTERACTION ❖ Hydro dynamic effects are generally important in the response of arch dam so more than for gravity dams. ❖ Tensile stress in dam due to upstream ground motion are more than doubled when hydro dynamics effect are included.
- 14. RESERVOIR BOUNDARY ABSORPTION ❖ Partial absorption of hydrodynamic pressure waves by the sediments invariably deposited at the reservoir bottom and sides, or even by rock underlying the reservoir. ❖ In general, assuming a non absorptive (rigid) reservoir boundary leads to an unrealistically large response for dam with impounding water, practically due to vertical and cross stream ground motion.
- 15. WATER COMPRESSIBILITY ❖ Westegards classical formula for the added hydrodynamic mass, commonly used in dynamics analysis of dam. ❖ Water compressibility would be significant in the response most concrete dams because ( Es) is generally much higher and ( f res. / f dam) is corresponding smaller.
- 16. DAM–FOUNDATION ROCK INTERACTION ❖ In standard FEM foundation rock is assumed to be mass-less . ❖ In which only flexibility is considered but inertial and damping effect are ignored, is popular because the foundation impedance matrix (Frequency –dependent stiffness matrix) is very difficult to determine.
- 17. LITERATURE REVIEW ➢ Anil K.Chopra ,2008–identified the limitations of the traditional design procedures, the factors that should be considered in the dynamic analysis are discussed, and procedures for earthquake response history analysis are summarized. ➢ M. A. Hariri-Ardebili et al,2011- Reservoir fluctuation effects on seismic response of concrete arch dams are investigated. Structure nonlinearity is originated from material nonlinearity due to tensile cracking and compression crushing of mass concrete . ➢ Violeta Mircevska atal.,2014- The magnitudes of the hydrodynamic pressures at the dam-fluid interface depend on the amount of energy transmitted to the fluid by the vibration of the reservoir boundaries. Although the reservoir topology can have a considerable impact on the amount of generated energy.
- 18. LITERATURE REVIEW ➢ Feng and Wei.et.al.,2014- A comparative study on the performance and ultimate bearing capacity of dams. A set of safety factors was presented with regard to dam heel cracks and the ultimate bearing capacity of a high arch dam. ➢ Masterarbeit .,2016- Developed a software based calculation of the 3D coordinates of double curved arch dams . To calculate these 3D coordinates, it is possible to determine the geometry of double curved arch dams and modify it for optimization purposes. ➢ Gao lin and shichun chi.,2017 - feasibility study of vibration control systems applied to massive structure, a 292m high arch dam was carried out. Seismic analyses of the arch dam including nonlinear behavior of joint movements demonstrate, that installation of viscoelastic dampers in the contraction joints can reduce the maximum tensile stresses at major part of the dam to a great extent.
- 20. REFERENCES ❖ Chopra, A. K., and Wang, J.-T. (2008). “Analysis and response of concrete arch dams including dam-water foundation rock interaction to spatially varying ground motions.” ❖ Varshney, R. S., Hydro Power Structures ❖ Wikipedia http://en.wikipedia.org/wiki/Dam ❖ http://www.idk.kerala.gov.in/index.php?option=com_content&view=article&id =85 & Itemed=58 ❖ Akköse, M., Bayraktar, A., and Dumanoğlu, A. A. (2016). “Reservoir water level effects on nonlinear dynamic response of arch dams.” J. Fluids Struct., 24(3), 418–435. ❖ M .A. Lotfollahi Yaghin and M.A. Hesari, “Dynamic Analysis of arch concrete dam under Earthquake force with ABAQUS”, Journal of applied sciences 8:26482658,2008
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