Concrete Dams: Three Gorges Dam in China Professor Kamran M. Nemati Second Semester 2005 1 Advanced Topics in Civil Engineering ATCE-II ATCE ATCE ATCE - - II II II Concrete Dams and Three Gorges Dam Kamran M. Nemati Visiting Professor Tokyo Institute of Technology Concrete Dams U.S. Delegation to TGP-Nov. 99
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Concrete Dams: Three Gorges Dam in China
Professor Kamran M. Nemati
Second Semester 2005 1
Advanced Topics in Civil EngineeringATCE-II ATCEATCEATCE---II II II
Concrete Dams
and
Three Gorges Dam
Kamran M. Nemati
Visiting Professor
Tokyo Institute of Technology
Concrete Dams
U.S. Delegation to TGP-Nov. 99
Concrete Dams: Three Gorges Dam in China
Professor Kamran M. Nemati
Second Semester 2005 2
Advanced Topics in Civil EngineeringATCE-II ATCEATCEATCE---II II II
Concrete Dams
Three Gorges Dam
� Goals:g Flood Prevention
g Navigation improvement
g Power generation
� Location:g Yangtze River downstream from
Three Gorges
� World’s Largest:g Height 181 meters
g Power 18 200 MW
g Reservoir volume 39.3 billion m3
g Concrete volume 27.94 million m3
Concrete Dams
Timeline
� 1919 - Sun Yat-sen proposed project
� 1931 and 1935 - Floods killed over 200,000 people
� 1944 - J. L. Savage, the chief designer of both the
Grand Coulee and Hoover dams, sent by United
States Bureau of Reclamation to survey area and
consult with Chinese engineers
� 1970 - Construction began on Gezhouba dam
� 1992 - Chinese Government adopted official plan for
the dam project
� 2009 - Expected completion of the TGP
Concrete Dams: Three Gorges Dam in China
Professor Kamran M. Nemati
Second Semester 2005 3
Advanced Topics in Civil EngineeringATCE-II ATCEATCEATCE---II II II
Concrete Dams
Stages of Construction
� Phase 1 (1993-1997)
g Water diversion channel
g Construction of transverse cofferdams
� Phase 2 (1998-2003)
g Construction of the spillway, left powerhouse and navigation
facilities
� Phase 3 (2004-2009)
g construction of the right bank powerhouse
Concrete Dams
� Triangular shape
� Vertical Upstream face
� Uniformly sloped Downstream face
� Grout curtain
Structure of Gravity Dams
Concrete Dams: Three Gorges Dam in China
Professor Kamran M. Nemati
Second Semester 2005 4
Advanced Topics in Civil EngineeringATCE-II ATCEATCEATCE---II II II
Concrete Dams
Major Forces:� Gravity of Dam
� Force of Reservoir
� Uplift Force
Others:� Thermal Stress
� Internal structural forces
� Sedimentation pressure
Forces acting on the dam
Concrete Dams
Calculation of Forces
� Force of Gravity of the DamConcrete volume = 27.94*106 m3
Density of concrete = 2407.82 kg/ m3
F = mg=(6.727*1010 kg)(9.81 N/kg)
� Horizontal Pressure of water
Upstream:
Depth = (1/3)*175 m = 58 m
Density of water = 1 kg/ m3
Downstream:
Depth = (1/3) * 83 m = 28 m
Mass = 6.727*1010 kg
Force = 9.599* 1011 N
Pressure = 58 kg/m2
Pressure = 28 kg/m2
Concrete Dams: Three Gorges Dam in China
Professor Kamran M. Nemati
Second Semester 2005 5
Advanced Topics in Civil EngineeringATCE-II ATCEATCEATCE---II II II
Concrete Dams
Uplift Force
� Newton’s 3rd Law - Action/Reaction
� Due to choice of foundation most force of
gravity dam dissipated to surrounding area
� Uplift force, compared with gravity is
minimal
Concrete Dams
Sedimentation
� Major concern for engineers
� Potential cause of:
� Abrasion of spillway and structure
� Accelerated wear of turbine runners
� Increased pressure on dam structure
� Prevention measures:
� Dikes to prevent sediment from settling
� Silt-flushing outlets in the water intakes
� Erosion prevention via tree planting
� Dredging to remove build up
Concrete Dams: Three Gorges Dam in China
Professor Kamran M. Nemati
Second Semester 2005 6
Advanced Topics in Civil EngineeringATCE-II ATCEATCEATCE---II II II
Concrete Dams
Mass Concrete
� Goal
g Prevent cracking of structure
g Must control heat fluctuations
Mass concrete is “…any large volume of cast-in-place concrete with dimensions large
enough to require that measures be taken to cope with the generation of heat and
attendant volume change to minimize cracking”
Higginson, Elmo C. Mass Concrete for Dams and Other Massive Structures.
Concrete Dams
Heat of Hydration
•Dry Cement•No hardening properties
•Compounds in non-
equilibrium, high-energy
states
Conservation of Energy:
The reaction creating the cement is reversed by the hydration process. This causes all of
the energy added to the compounds to produce the cement to be released again in the
reaction.
•Hydrated Cement•Has hardening properties
•Compounds move to
stable, low energy states
•Produce heat as a by-
product
Concrete Dams: Three Gorges Dam in China
Professor Kamran M. Nemati
Second Semester 2005 7
Advanced Topics in Civil EngineeringATCE-II ATCEATCEATCE---II II II