CFRDs  
Face slab of  
205m  
Bakún CFRD  
t
h
e
h
n
hig  
i
Malaysia.  
Sharing international  
experiences in CFRDs  
International  
this  
exchange information with other organisations  
Professor Bayardo Materon is the president of the  
Society of CFRDs. Here he tells IWP&DC more about the role of  
the society, and takes a closer look at recent developments  
this part of the dam construction us  
in the study, research and knowledge of  
type of dam.  
in  
The first preparatory committee of the  
International  
with the support of Chen Qian as the general  
cr ry Alberto Scuero , Cao Keming  
(China) and Paulo Cruz (Brazil) were v  
presidents, while John S Y Tan ng  
appointed deputy cr ry general.  
Society of CFRDs was nominated  
ind try.  
s
e
e
t
a
.
(Italy)  
i
ce  
-
(
S
i
a
p
o
r
e
)
was  
o c  
e
l
e
br  
a
t
e 20 years of Chinese  
Cyprus, Germany,  
Barry Cooke was invited to the meeting bu  
could not attend and so asked me to present  
J
a
p
a
n
,
Thailand and Turkey.  
s
e
eta  
construction of concrete face rockf  
dams (CFRDs), an engineering  
i
ll  
J
t
I was nominated president in 2005. With the  
active cooperation of Qian, Cruz and Manoel  
T
symposium was organised inYichang, China  
mb 2005. pr from more  
than 20 countries participated ud ng  
Australia, Brazil, Malaysia, ng ud  
Iran, France, India, US, Italy,  
i
n
articles and participate in this important event.  
It was the proposal from Chen Qian of China  
that initiated the creation of an international  
club or society where designers and builders of  
CFRDs could share their experience and  
F
r
e
i
t
a
s
from Brazil, we have been present  
in  
S
e
p
t
e
e
r
R
e
esentatives  
many seminars discussing the design and  
i
nc  
l
i
construction of CFRDs. We have investigated  
and participated in the understanding of the  
S
i
a
p
o
r
e,  
S
an,  
S
w
i
t
ze  
r
l
a
nd  
,
ad  
e
qu  
a
t
e
design of this type of dam in narrow  
10 INTERNATIONAL WATER POWER & DAM CONSTRUCTION  
September 2012  
CFRDs  
Using anti–spalling reinforcement in  
canyons and developed solutions for future  
design of higher structures.  
tested preliminary innovative procedures  
to  
the central compression joints.  
control face slab cracks in the face construction.  
Introducing compressible fillers in the central  
compression joints to mitigate excessive  
compression stresses.  
The International Society of CFRDs  
participated in the 5th Dam Engineering  
Conference in Lisbon, Portugal in 2007. In  
Distressing signs  
t
h
i
s
During 2005-6 three CFRDs pre  
compression d ss with a sudden and  
noticeable increase in leakage through  
central portion of the dam. The dams were: Barra  
sented high  
Incorporating additional vertical joints near  
abutments in narrow valleys.  
Conference Dr Humberto Marengo, from the  
Federal Commission of Electricity in Mexico,  
pr d the experience of designing and  
constructing El Cajon CFRD in Mexico, one of  
i
s
t
r
e
es  
the  
Using competent well designed water stops.  
e
s
e
n
te  
Grande (185m) in Brazil; Campos Novos  
in Brazil; Mohale (145m) in Lesotho.  
(202m)  
Following  
these rules recent CFRDs have  
the highest CFRDs built in the world  
excellent performance.  
with  
been built successfully such as:  
These dams were located in narrow valleys,  
with uniform graded b producing relative  
low modulus of compressibility  
Shuibuya (233m) in China.  
In early 2008 the society was  
o
ffi  
c
i
a
ll  
y
asalt  
Bakun (205m) in Malaysia.  
El Cajón (188m) in Mexico.  
La Yesca (206m) in Mexico.  
Kárahnjúkar (196m) in Iceland.  
registered in California, US with the support of  
Hydrou, an Engineering firm from China.  
The journal of the society CFRD World has  
been published from the beginning with articles  
(50-60MPa).  
During filling of the reservoir, friction forces  
between the rockfill and face slab were  
developed which resulted in high stresses  
by members detailing their experiences of n  
dams built in the  
In May 2009, the society participated in  
23rd ICOLD conference in Brazil and society  
members Materon, Cruz and published  
the book ncr e Face Rockfill Dams edited  
ugu and English. It pr real cases  
histories of 28 CFRDs including the highest  
the  
ew  
world.  
the  
0
Freitas  
C
o
e
t
in  
P
o
r
t
e
s
e
esents  
i
n
world.  
In this conference, one of the members of the  
society, Palmi Johannesson, gave a lecture about  
the design, construction and performance of  
Iceland’s Kárahnjúkar CFRD - the highest CFRD  
built in Europe with excellent performance.  
During the Second International Symposium on  
Rockfill Dams, held in late October 2011 in Rio de  
Janeiro and organised by the Brazilian Committee  
of Dams and CHINCOLD, the International  
of CFRDs updated articles on dam design  
seismic ea  
S
ociety  
i
n
a
r
s
.
The use of the GIN method for  
grouting was widely discussed and recommended  
for future design of higher CFRDs.  
Mexican Engineers from CFE, ass  
ociated to  
our organization, pr d data about La Yesca  
esente  
CFRD. Under construction in Mexico it is one of  
the highest dams in the world incorporating  
state of art in the design and construction of  
type of dam.  
this  
Equipment for  
t
r
an  
s
i
t
i
on placing. La  
Ye  
s
c
a
CFRD México.  
A recent area of discussion for the  
S
a
nb  
El Cercado (130m) and Porce III (150m)  
mb a.  
axi (186m) in China.  
International  
performance of the Zipingpu CFRD. Built  
chu China it was subject to an intensive  
S
o
c
i
e
t
y of CFRDs has been the  
breaking the slab and distressing the  
in  
i
n
reinforcement bars. Analysis and observation of  
the Campos Novos dam showed the critical zone  
of the dam located at 30-40% of the maximum  
C
o
l
o
i
S
i
an,  
seismic event in May 2008 and  
Bakun dam  
recommendations are being applied on n  
e
w
reservoir head. The correction of  
phenomena has been solved by:  
this  
As a member of the Board of Consultants, I had  
the opportunity to review, inspect and observe  
designs to prevent damage to high dams subject  
to seismic action.  
Increasing the rockfill modulus of  
the performance of Bakun dam in Malaysia  
May 2012, when the reservoir reached the  
maximum height.  
in  
compressibility. This is obtained by selecting  
well graded materials, reducing the layer  
thickness for compaction, increasing the  
number of passes of the vibratory roller  
compactor and selecting heavier drum  
An analysis of the design and construction of  
the 233m high  
reviewed by the society and some interesting  
articles have been shared between members  
produce such safe structures. General cr  
Shuibuya CFRD has been  
Bakun CFRD is 205m high with a volume of  
compacted rockfill of almost 17Mm3. The  
design of the dam follows the state of art for  
structures located in a narrow valley and  
preventive measures to control excessive  
t
o
S
e
e
t
a
ry  
weights.  
Using generous amounts of water dur  
spreading and rockfill compaction. (200-300 l/m³).  
( >12t over the drum length).  
Chen Qian is also preparing a book based on the  
successful construction of the hu buya.  
The CFRD International has also  
worked with people involved with the design  
and construction of dams and, in c unc  
with pr ss ee manufacturers, have  
ing  
S
i
Society  
Using downstream layer thickness similar  
upstream layers to avoid major differences  
deformability.  
to  
stresses in the central compression joints were  
i
n
adequately designed. The maximum  
o
n
j
tion  
settlement at the centre of the dam before  
e
-
s
t
r
e
ed st l  
September 2012  
CFRDs  
impounding was 230cm and increased to  
270cm after reaching the full supply level of  
almost 200m height.  
Face slab deflection reached a maximum  
displacement of 92cm which compares very  
well with well compacted rockfill structures of  
this height.  
The registered modulus of compressibility is  
close to 90MPa, typical of a very  
compacted r ckf ll  
The vertical joints between the parapet  
opened close to abutments in a range of 10-  
well  
o
i .  
wall  
20mm and the central joints shut as expected.  
All joints were well treated by a mastic and a  
cover of EPDM. There are no signs of over  
s
t
r
e
ss  
es in the central portion of the dam since  
the central compression joints were treated  
with  
a local Borneo timber to mitigate h  
compression stresses.  
igh  
Shuibuya CFRD. Downstream slope view.  
Leakage is only 133  
l/sec which is a very low  
value for the height of the dam of 205m.  
I
n
The role and advantages of CFRDs  
conclusion it must be considered that the  
performance of the dam is outstanding.  
The selection of a CFRD for a project has many advantages from a technical point of  
and can be more co om  
The compacted rockfill using new equipment developed by the industry allows  
in dam volume, with steeper slopes, and the placing is not affected by weather conditions.  
Water load from the reservoir is transmitted into the foundation thus giving the dam an  
inherently safe feature.  
view  
e
n
ical.  
Progress  
a reduction  
Progress in the design and construction of  
CFRDs, as Barry Cooke stated, is empirical and  
based on experience and precedent. Increasing  
the height of structures has required  
better rockfill compaction and a reduction  
In climates with high precipitation CFRD is ideal since the best compacted rockfill is  
reached, adding 20-30% of water to the volume to be p d.  
these  
lace  
i
n
Grouting techniques using modern procedures, such as the GIN method, are independent of  
the dam construction since the impervious grout curtain is located outside of the dam body.  
The developed techniques for the plinth and face slab slip forming, offer faster solutions for  
layer thickness, aiming to obtain higher r  
modulus of compressibility.  
ockfill  
Very good progress has been obtained  
the development of compactors with vibratory  
rollers. This equipment is fabricated  
with  
the construction of the dam reducing the construction  
The innovative method of the extruded curb, developed for the first time in Brazil during the  
construction of the Ita CFRD, has simplified the treatment of the upstream slope  
economic su  
The CFRD can be built in stages offering strategic advantages for the Contractors.  
For large dams in wide valleys, rockfill may be placed on abutments ahead of river  
This permits excavated rock to be placed directly into the dam avoiding s ockpili g.  
Ramping of rockfill is permitted in any direction, minimising hauling roads and facilitating  
traffic for the rockfill placing. This is a great advantage when compared with restrictions for  
rockfill with filters and transitions as the earth or asphalt core dams.  
There is less contingency cost for a CFRD than for a core dam. The contingencies  
processing core and transitions are av d.  
schedule.  
with  
t
o
re  
lts.  
concentrate over the smooth drum pressures  
higher than 5t/m with a total weight over the  
diversion.  
drum exceeding 12t. The range of vibratory  
t
n
frequency produced by fabricants varies  
between 1400 to 2000 vpm.  
a
Progress in the design of external water stops  
in  
have been developed to allow movements up  
30cm. The pressure over the impervious element  
(PVC or EPDM) is controlled by geo-textiles  
a capacity to support pressures equivalent to the  
height of the reservoir with a y factor of 2.  
These designs allow the construction of dams  
very ee abutments, such as the Mazar  
Ecuador or Chaglla CFRD (205m) under  
construction in ru  
to  
oide  
Placement rates of rockfill are very high. In large dams placement rates have exceeded  
with  
1Mm3 a month.  
safet  
All of the above can help facilitate fast construction and a safe CFRD with economic results.  
i
n
s
t
p
in  
Future activities  
P
e
.
The placing of transition material 2B has  
progressed by using a well graded material  
The International Society of  
C
F
R
DS  
Selection of the best articles related to CFRDs for the next symposium at the 5th  
anniversary of the society to be held from 12-15 November 2012 at Tianjin,  
To continue with the pre-stressed experiment developed for Simutasi pre-stressed CFRD,  
in conjunction with design institute and steel manufactures in China. Preliminary r su  
indicate an innovative solution for crack prevention at the face b.  
future activities include:  
with  
China.  
equipment for pavement construction. In the  
Mexican CFRDs a sophisticated equipment  
a
e
lts  
places the pre compacted 2B material reducing  
losses of material and avoiding segregation.  
sla  
The society will also continue to cooperate with other institutions and engineering  
The development of very light slipforms  
productions up to hr have helped  
design and build a f r and safe face slab and  
with  
organisations in the design of higher dams up to a height of 300m.  
5
-
6
m
/
to  
Specialists and dam designers are invited to come and exchange ideas and visit our w  
ebsite:  
aste  
p
l
i
n
t
h
s
.
All  
t
h
ese design and construction  
For membership enquiries contact: Far Young m  
considerations permit the construction of an  
efficient dam with qu performance.   
a
d
e
a
t
e
12 INTERNATIONAL WATER POWER & DAM CONSTRUCTION  
September 2012