RCC Properties for the Design of Large and Not-so-Large Dams...SCHEME OF SANTIAGO, ECUADOR. 5 / 21....

RCC Properties for the Design of Large and Not-so-Large Dams

Amanda Garduño Gallo

NOVEMBER 5–7NASHVILLE, TENNESSEE

CONTENT


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

1516

18

20

NOVEMBER 5–7, NASHVILLE, TENNESSEE

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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

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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.



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



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



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

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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)



CONSTRUCTION OF PROJECT IN EL SALVADOR

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Stilling basin

Right abutmentLeft abutment

Left abutment

Stilling basin

Upstreamcofferdam

Downstreamcofferdam

Bottom outlet

Diversionchannel

Photos: July 2018

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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



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



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



RCC ZONING PROJECT IN EL SALVADOR

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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



RCC ZONING PROJECT IN CHIHUAHUA, MEXICO

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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



MAIN PROPERTIES FOR THE DESIGNER

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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.



RCC MIXTURE STUDIES

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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.



STRENGTH OF PARENT RCC

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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


180 days age




STRENGTH OF LIFT JOINT

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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.



STRENGTH OF LIFT JOINT

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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


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 °*






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



THERMAL PROPERTIES

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Coefficient of Thermal Expansion Adiabatic Temperature rise

PROJECTS: LAS CRUCES, MEXICO SANTIAGO, ECUADOR PROJECT IN

EL SALVADORPROJECT IN CHIHUAHUA


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 *



Thermal properties





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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.




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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

RCC Properties for the Design of Large and Not-so-Large Dams...SCHEME OF SANTIAGO, ECUADOR. 5 / 21....

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Transcript of RCC Properties for the Design of Large and Not-so-Large Dams...SCHEME OF SANTIAGO, ECUADOR. 5 / 21....