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RCC Properties for the Design of Large and Not-so-Large Dams
Amanda Garduño Gallo
NOVEMBER 5–7NASHVILLE, TENNESSEE
CONTENT
RCC Properties for the Design of Large and Not-so-Large Dams
BACKGROUND
LOCATION OF REFERENCE PROJECTS
SCHEME OF REFERENCE PROJECTS
RCC ZONING IN THE REFERENCE DAMS
MAIN PROPERTIES FOR THE DESIGNER
RCC MIXTURE STUDIED
STRENGTH OF PARENT RCC
STRENGTH OF LIFT JOINTS
LONG TERM DEFORMATION (CREEP)
THERMAL PROPERTIES
COMMENTS AND CONCLUSIONS
1
2
4
9
13
14
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18
20
NOVEMBER 5–7, NASHVILLE, TENNESSEE
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NOVEMBER 5–7, NASHVILLE, TENNESSEE
RCC Properties for the Design of Large and Not-so-Large Dams
BACKGROUND: Participation of CFE in RCC dams
NAME, LOCATION MAIN
PURPOSESTUDIES
CONSTRUCTION OF THE DAM
HEIGHT m
CREST LENGTH m
OWNER
San Rafael, Nayarit D 1992* 1993-1994 48 176 CFE
Las Blancas, Tamaulipas D 1996* 1998-1999 ≈ 32 2795 CNA
Estí, Panamá H 1997* 2000-2003 30 180 AES Panamá
Corral de Palmas, Nvo. León C 2002* 2002-2004 109 250 State
Amata, Sinaloa D 1996* 2004-2005* 23 218 CFE
Zapotillo, Jalisco S 2006* 2011- 125 320 CNA
Los Hilamos, Guerrero D 2005* Project ≈ 27 ≈ 370 CFE
Las Cruces, Nayarit H 2009* Project 185 815 CFE
San Julian, Chihuahua S 2014* Project ≈ 33 200 Private
Santiago, Ecuador H 2014* Project 195 300 CELEC Ecuador
El Chaparral, El Salvador H 2017 2015-2019* 85 325 CEL El Salvador
EXAMPLES OF CFE PARTICIPATION IN RCC STUDIES
C = Flood Control; D = Diversion; H = Hydropower; I = Irrigation; S = Water Supply( * ) CFE participation during studies or construction. ( ≈ ) Approximate
CNA = Comision Nacional del Agua, CFE = Comision Federal de Electricidad
1 / 21
NOVEMBER 5–7, NASHVILLE, TENNESSEE
RCC Properties for the Design of Large and Not-so-Large Dams 2 / 21
LOCATION OF LARGE DAMS
Project Las Cruces is located 65 kmNorth of Tepic, capital city of NayaritState.
The dam and main structures are onSan Pedro river.
Project Santiago is located in thesoutheast of Ecuador, in the Morona-Santiago Province.
The dam and main structures are onSantiago river, downstream of theconfluence of rivers Zamora andNamangoza.
NOVEMBER 5–7, NASHVILLE, TENNESSEE
RCC Properties for the Design of Large and Not-so-Large Dams 3 / 21
Project located in the northeast of ElSalvador, in San Miguel Department.
The dam and main structures are on theTorola river, tributary of the Lempa river.
First attempt, by 2008 to 2010. Then,moving the dam location about 670 mupstream, 2015-today (under construction).
RCC DAM
Project in Guadalupe y Calvomunicipality in the south of ChihuahuaState.
The dam and main structures are onSan Julian stream.
LOCATION OF NOT SO LARGE DAMS
RCC DAM
NOVEMBER 5–7, NASHVILLE, TENNESSEE
RCC Properties for the Design of Large and Not-so-Large Dams
SCHEME OF LAS CRUCES, MEXICO
4 / 21
CharcateristicsRCC gravity dam, 185 m height and about 2.0 Mm3 of RCC
Foundation Ignimbrite, Fairly competent
Seismicity (Peak Ground Accel.) OBE of 0.08 g, and MCE of 0.16 g
Basin area 24,175 km2
Weather Temperatures from 10 °C to 40 °C, average humidity 75 %
Crown Elevation at 245 masl, length of 815 m, width of 8 m
Axis/Radius Axis is straight in the center, with asymmetrical wings
Downstream and upstream slope Downstream 0.8:1.0, Upstream 0.1:1.0
Diversion tunnels Two, of 14 m diameter D shaped section in the left abutment, length ≈ 586 m
Spillway Channel on left abutment
Powerhouse Exterior powerhouse with 2 units, located in the riverbed.
Installed Power 240 MW (2 Francis type turbines); average annual generation 783 GWh
NOVEMBER 5–7, NASHVILLE, TENNESSEE
RCC Properties for the Design of Large and Not-so-Large Dams
SCHEME OF SANTIAGO, ECUADOR
5 / 21
CharcateristicsRCC arch-dam, 205 m height and about 3.2 Mm3 of RCC
FoundationSequence of siltstone, sandstone breccia, sandstone tuff and volcanic breccia
Seismicity (Peak Ground Accel.) OBE of 0.20 g, and MCE of 0.27 g
Basin area 22,260 km2
Weather Temperatures from 14 °C to 32 °C, average humidity 94 %
CrownElevation at 455 masl, length 457 m, width of 12.5 m in the wings and 10.3 m in the spillway
Axis/RadiusHorizontal radious is 252 m in the center, and is variable in the wings; vertical radius increases with the height
Slopes Upstream slope is variable, downstream slope is 0.6:1.0 in the spillway section.
Diversion tunnels Three, of 18.8 m horseshoe section in the right abutment, length ≈ 830 m
Spillway Centered in the dam body controlled by 7 gates
Powerhouse Underground, in the left abutment
Installed Power 3630 MW (6 Francis type turbines); average annual generation 14,800 GWh
6 / 21
NOVEMBER 5–7, NASHVILLE, TENNESSEE
RCC Properties for the Design of Large and Not-so-Large Dams
SCHEME OF PROJECT IN EL SALVADOR
The dam was moved 670 m upstream to avoid geological problems of the original site.
CharacteristicsRCC gravity dam, 85 m height and about 430,000 m3 of RCC
Foundation Basalt
Seismicity (Peak Ground Accel.)
OBE5% of 0.26 g and MCE7% of 0.40 g
Basin Area 1,575 km2
Weather Temperatures from 22 °C to 28 °C, humidity 50-80 %
Crown Elevation at 214.5 masl, length of 325 m, width of 7 m
Axis Straight
SlopesUpstream 0.1:1.0, Downstream 0.84:1.0 (foundation to 197 masl) and 0.44:1.0 (el. 197 to 214 masl)
Diversion By two channels in the left abutment
Spillway Controlled by four gates (11.5 m height), centered in the dam
Powerhouse Excavated and covered, in the left abutment, with 2 units.
Installed Power 64 MW (2 Francis type turbines, 32 MW each)
NOVEMBER 5–7, NASHVILLE, TENNESSEE
RCC Properties for the Design of Large and Not-so-Large Dams
CONSTRUCTION OF PROJECT IN EL SALVADOR
7 / 21
Stilling basin
Right abutmentLeft abutment
Left abutment
Stilling basin
Upstreamcofferdam
Downstreamcofferdam
Bottom outlet
Diversionchannel
Photos: July 2018
8 / 21
NOVEMBER 5–7, NASHVILLE, TENNESSEE
RCC Properties for the Design of Large and Not-so-Large Dams
SCHEME OF PROJECT IN CHIHUAHUA, MEXICO
RCC Dam
Diversionchannel
San Julianstream
Test section
Spillway
CharacteristicsRCC gravity dam, 32.5 m height and about 81,250 m3 of RCC
Foundation Tonalite, fairly competent
Seismicity (Peak Ground Accel.)
OBE5% of 0.03 g and MCE7% of 0.21 g
Basin Area 206,800 m2
Weather Temperatures from -5 °C to 16 °C
Crown Elevation at 2490 masl, length of 172 m
Axis Straight
Slopes Upstream is vertical, Downstream 0.708:1
Diversion By a channel in left abutment
Spillway Integrated (stepped) in a block of the dam body
NOVEMBER 5–7, NASHVILLE, TENNESSEE
RCC Properties for the Design of Large and Not-so-Large Dams 9 / 21
GERCC AND BEDDING MIX
GERCC AND BEDDING MIX
GERCC
BEDDING MIX
ZONE A
ZONE B
ZONE C
ZONE D
ZONE E
ZONE F
GERCC
ZONE D
GERCC
RCC ZONING IN LAS CRUCES
CEMENT CONTENT
kg/m3 fc ft ftjA 90 11.4 1.0 0.2B 100 13.3 1.1 0.3C 130 18.1 1.5 0.4D 90 11.4 1.0 0.7E 100 13.3 1.1 0.8F 130 18.1 1.5 1.0G 200 29.2 2.5 1.7 GERCC
REQUIRED 1 YEAR STRENGTH (MPa)NOTES:ZONE
No Bedding
MixWith
Bedding Mix
Longitudinal Joint
Designer: Technoproject (Xiangyue Li Liu) Consultant: Ernest Schrader
NOVEMBER 5–7, NASHVILLE, TENNESSEE
RCC Properties for the Design of Large and Not-so-Large Dams 10 / 21
RCC ZONING IN SANTIAGO
ZONE 1
ZONE 1
ZONE A
ZONE B
ZONE B
ZONE A
ZONE C
GA
GA
GB
B7 Zoning section
Designer: CFE (Fritzludwig Ballhausen) and Roy DungarConsultant: Ernest Schrader
CEMENT+POZZOLAN CONTENT
kg/m3 fc (MPa) ft (MPa) C (MPa) O ° E40 (GPa)A 85 + 128 30 2.9 3.5 45 21.1B 66 + 92 18 1.6 1.9 45 16.8C 60 + 60 12 1.0 1.2 45 12.7
GA 85 + 128 30 2.9 3.5 45 21.1GB 66 + 92 18 1.6 1.9 45 16.8GC 60 + 60 12 1.0 1.2 45 12.71
NOTES:
Hot joint
REQUIRED 1 YEAR PARAMETERS
Reinforced Concrete f´c = 30 MPa
ZONE
NOVEMBER 5–7, NASHVILLE, TENNESSEE
RCC Properties for the Design of Large and Not-so-Large Dams
RCC ZONING PROJECT IN EL SALVADOR
11 / 21
Possible zoning proposed by CFE
Designer: Consultant: Contractor: Cartellone-HolcimSupervision: ICE (Instituto Costarricense de Electricidad)Owner: CEL (Comisión Ejecutiva Hidroeléctrica del Río Lempa)Owner Technical support: CFE
Precastpanels
fc ft ftjA 120 12 0.5 0.5B 180 15 0.9 0.9C 150 15 0.9 0.9
CEMENT CONTENT kg/m3ZONE
REQUIRED 1 YEAR STRENGTH (MPa)NOTES:
Bedding Mix
NOVEMBER 5–7, NASHVILLE, TENNESSEE
RCC Properties for the Design of Large and Not-so-Large Dams
RCC ZONING PROJECT IN CHIHUAHUA, MEXICO
12 / 21
B6
2490.0 masl
2457.5 masl
34.85 m
12.75 m
Longitudinal Joint
32.5
0 m ZONE A
GAGA
fc (MPa) ftind (MPa)A 130 12.5 1.0 Hot joints
GA 130 12.5 1.0 Grout enriched RCC
NOTES:REQUIRED STRENGTH 56 DAYSCEMENT CONTENT
kg/m3ZONE
Designer: CIPI and CFE (Fritzludwig Ballhausen)Consultant: Kenneth Hansen
NOVEMBER 5–7, NASHVILLE, TENNESSEE
RCC Properties for the Design of Large and Not-so-Large Dams
MAIN PROPERTIES FOR THE DESIGNER
13 / 21
The designer will need strength properties, elastic properties and thermal properties,. Aswell as the density. They are defined on laboratory from the “parent” RCC.
But due to the construction process of RCC dams, shear strength and direct tensilestrength of lift joints are critical values for the design of RCC dams.
During the design process, it is common to start with literature properties of RCC, which haveto be validated in laboratory and in the test section.
RCC properties may be required long before the test section is ready. The big issue is toreproduce samples at laboratory scale, specially reproducing lift joints.
Typical construction of an RCC dam. Layers (lifts) of 0.3 m.
Reproduction of a test section onlaboratory.
Sawing samples from the labtest section.
NOVEMBER 5–7, NASHVILLE, TENNESSEE
RCC Properties for the Design of Large and Not-so-Large Dams
RCC MIXTURE STUDIES
14 / 21
Vertical shaft mixer capacity: about 300 lt
PROJECTS: LAS CRUCES, MEXICO SANTIAGO, ECUADOR PROJECT IN EL SALVADOR PROJECT IN CHIHUAHUA
Cement type II type II type IP (45) type I
Pozzolan Fly ash, natural pozzolans and pocessed fines (filler) Natural pozzolan Natural pozzolan component
of the cement Not consdiered
Admixture Retarding admixture Retarding admixture Retarding admixture Retarding admixture
Aggregates Crushed: alluvial or ignimbrite Crushed: calcareus or diorite Crushed: basalt Crushed: tonalite
Mixture (cement+pozzolan+water)
90+0+110 80+120+116 120+0+105 130+0+130
VeBe time > 8 s < 17 s > 25 s < 18 sDensity 2260 kg/m3 2390 kg/m3 2400 kg/m3 2249 kg/m3
Representative mixture
RCC fresh properties
Project in El Salvador is under construction. CFE didn´t participate during the studies nor for the design of the dam.
NOVEMBER 5–7, NASHVILLE, TENNESSEE
RCC Properties for the Design of Large and Not-so-Large Dams
STRENGTH OF PARENT RCC
15 / 21
Modulus of elasticity Indirect splitting tensile
PROJECTS: LAS CRUCES, MEXICO SANTIAGO, ECUADOR PROJECT IN
EL SALVADORPROJECT IN CHIHUAHUA
Cement type II type II type IP (45) type IMixture (cement+pozzolan+water)
90+0+110 80+120+116 120+0+105 130+0+130
Strength parameters 90 days age 56 days agefc 7 MPa 24 MPa 12 MPa 12.5 MPaE40 11 GPa 18 GPa 14.3 GPaTindirect 0.7 MPa 2.9 MPa 1.2 MPa 2.4 MPaTdirect 0.4 MPa Not tested 0.7 MPa 1.4 MPa*
* No tested. Inferred properties from literature correlations
Representative mixture
180 days age
Project in El Salvador is under construction. CFE didn´t participate during the studies nor for the design of the dam.
NOVEMBER 5–7, NASHVILLE, TENNESSEE
RCC Properties for the Design of Large and Not-so-Large Dams
STRENGTH OF LIFT JOINT
16 / 21
A B
SHEAR STRENGTH (≈ ASTM D 4554) LAS CRUCES, MEXICO SANTIAGO, ECUADOR EL CHAPRRAL,
EL SALVADORSAN JULIAN,
MEXICO
Preparation of samples
Lab test sections: two lifts in a formwork compacted by a single drum walk behind roller (450 kg). Then, sawed and banded (A).
Not enough aggregates, samples reproduced on 0.3 m cubic molds, one above the other, compacted with vibrating hammer (B).
Lift joints Hot, Warm and Cold joints were rerpoduced Hot joints were considered
Bedding mix Not used Not used
Not tested Not tested
Inferred properties from correlationsResults: Cohesion and friction angle, as well as residual friction angle.
NOVEMBER 5–7, NASHVILLE, TENNESSEE
RCC Properties for the Design of Large and Not-so-Large Dams
STRENGTH OF LIFT JOINT
17 / 21
Coring the lab test section
Cores. Note the lesser qualityin the joint.
Direct tensilestrength test
Modulus of elasticityin tension.
PROJECTS: LAS CRUCES, MEXICO SANTIAGO, ECUADOR PROJECT IN EL SALVADOR PROJECT IN CHIHUAHUA
Cement type II type II type IP (45) type IMixture (cement+pozzolan+water)
90+0+110 80+120+116 120+0+105 130+0+130
Joint strengthJoint Tdirect Hot joint 0.3 MPa * w/bedding mortar 0.6 MPa 0.8 MPa*Joint cohesion Hot joint 0.48 MPa Hot joint 1.42 MPa * 1.2 MPa*Joint friction Hot joint 50 ° Hot joint 50 ° * 45 °*
* No tested. Inferred properties from literature correlations
Representative mixture
Project in El Salvador is under construction. CFE didn´t participate during the studies nor for the design of the dam.
NOVEMBER 5–7, NASHVILLE, TENNESSEE
RCC Properties for the Design of Large and Not-so-Large Dams 18 / 21
CREEP (Long Term Deformation ≈ ASTM C 512)
A
B
C D E
CREEP LAS CRUCES, MÉXICO SANTIAGO, ECUADOR PROJECT IN EL SALVADOR PROJECT IN CHIHUAHUA
Samples sealing
Samples were wrapped with self-adhesive PVC
Samples were covered with latex (Fig. C)
Autogenous volume change
Measuring deformations
The strain measuring device didn´t provide accuracy nor repetability (Fig. B)
Dial indicators micrometers (0.001 mm accuracy) attached to samples (Fig. D)
Results Inconsistent and not reliable Plausible Creep effect wasn´t considered
The designer worked with the modulus of elasticity during the period of loading
Not tested Not testedFor samples in air and in water (Fig. A, D, E), for
"correcting" loaded samples deformations
NOVEMBER 5–7, NASHVILLE, TENNESSEE
RCC Properties for the Design of Large and Not-so-Large Dams
THERMAL PROPERTIES
19 / 21
Coefficient of Thermal Expansion Adiabatic Temperature rise
PROJECTS: LAS CRUCES, MEXICO SANTIAGO, ECUADOR PROJECT IN
EL SALVADORPROJECT IN CHIHUAHUA
Cement type II type II type IP (45) type IMixture (cement+pozzolan+water)
90+0+110 80+120+116 120+0+105 130+0+130
Diffusivity 0.00214 m2/hr 0.0029 m2/hr pending 0.003 m2/hr *Specific heat 925 J/kg °C 963 J/kg °C pending 960 J/kg oC *Temperature rise 27 °C 21 °C pending 35 oC *Expansion coefficient 0.000008 1/°C 0.000007 1/°C pending 0.000011 1/oC *
* No tested. Inferred properties from literature correlations
Representative mixture
Thermal properties
Project in El Salvador is under construction. CFE didn´t participate during the studies nor for the design of the dam.
NOVEMBER 5–7, NASHVILLE, TENNESSEE
RCC Properties for the Design of Large and Not-so-Large Dams
COMMENTS AND CONCLUSIONS
20 / 21
The most complex 3D finite element analysis,will be inaccurate if it is not feeded with theproperties of the RCC and foundation of the site.
The larger the dam, it may requiere more data.For example, the creep effect (desirable torelieve stress and strain buildup), which issignificant on really large dams.
Designer and laboratory have to be in closecommunication working together, consideringthe particularities of each project.
NOVEMBER 5–7, NASHVILLE, TENNESSEE
RCC Properties for the Design of Large and Not-so-Large Dams
COMMENTS AND CONCLUSIONS
21 / 21
Conservative properties (low strength orhigher temperature rise) for the RCC may notendanger the structure, but the may:
Induce a larger section of the dam, Ask for higher cement content, Require improving lift joints with bedding mixwhere it is not needed. Lead to undesirable cooling methodologies, Slow the construction process, Increase cost.
If the designer overestimates strengthproperties or even the density of the RCC, theproject could be risky or unsafe.
Knowing RCC properties foreach project, enables a safedesign and optimizes resources.
Gracias
Thanks
NOVEMBER 5–7NASHVILLE, TENNESSEE