DERDAP DAM
(IRONI
GAIIE)
The
Ejerdap
(lron
Gate)
gra-
vity concrete dam is the
lar-
gest
civil engineering
pro-
ject
of
its
kind
in
Yugosla-
via
and
Roumania. The
cons-
truction of thils
dam is
characterized by an unusual-
ly
large
quantity
of
material
built into
the
dam and also
by the construction of
foun-
dation
pits
on
gne
of
the
largest rivers o{'
the
world.
Complicated and frequently
original treatments had
to
be used
in
the course
of its
construction-
The dam together
with
two
incorporated
hydroelectric
power
stations offers
the
possibility
of
crtilizing
the
water
potential
of the
Da-
nube as well
as an integral
solution
to the
problems
of
navigation in
the lron
Gate
section.
The rirrer
at
this
point
possesses
extraordina-
ry
water
power
potential
caused by
Ereat
discharges
and considerable
heads. The
construction of
tlhe
dam
cau-
se the
rapids
which'
were
the
main
obstacles
to navi-
gation
to
disappear.
The middle
part'of
the
dam
consists of a
gravity
over-
flow dam and has 14
spill-
way
bays vrrith
ia
trctal
length
ol'
441
m.
The
discharge
of flood
flows
is
carried
out
tlrrough
14
spillway
bilys
and
by the
use of turbiines.
Thre
capacity
of
the spillway
is
14x1,200
:
16,800
m3/s"
The
capacity
of one
turtrine is
about 760
mr3/s.
Double
hook
gates
with
dimensions
of
25.0 x
1t1.70
m were
provided
on
the
spillwa'y
bays.
They
are
provided
with
h)'draulically
operated
,geofs
(servomo-
to,rs)
for
the liifting and
lo-
wering
of
the
galfes.
Gates
of
the
same
dii;mensions, lif-
t€,d and
loweratd
by
means
of two
portal
cranes
of 2
x
160.0
-
320.0 tonrs
capacity,
have
been
installed
for
pe-
riods
in which
overhall is
necessary.
Two
machine
houses
form
part
of
the dam and
are
located
onie
oln
each
side
o{' the
dam. Eiachr of
them
is
214 rn
long
and houses
six
generating
sets of 171
MW
each. The'
trotal rated
power
of
the
station is
2C150
MW, wittr
an installed
discharge
of 8,?'00
ry1r/s. The
head
of tlhe
plq6t
ranges
between
21,90 m
:,and
34.50
m.
Three bottom outlets for
use
,
as spillways
during
the con-
"
struction
were
constructed
on each
machine
house.
On
the
bottom outlets
there are
5.5 x 8.7 m steel
sliding
ga-
tes.
Lifting and
lowering
of
gates
is carriecl
out by
means of a
portal
crane of
160
tons
capacity.
On
both the river
banks
there irs one two-step navi-
gation
lock.
Each lock
cham-
ber
is 310 x
34 m, and the
minimum
depth
at
its
en-
trance
iis
5.0 m.
The rivrar banks
and the na-
vigation locl<s are connected
by earthfill
dams of
a total
length of about 300 m.
The
roc;k mass
on the dam
site
consists of
various
cry-
stalline
schists, and is
di-
stinctly
heterogeneous, most'
damagingly
in
the riverbed
of the
Danube.
There
i:;
a fault on the over-
flow dam section where
the
rock
nnass
structure has
been
greatly
changed and
degraded
by meclhanical
di-
splacement.
The rock i5 of very
low
per-
meabilityrso that
very
small
quantity'
of
grout
.mix
Was
used both
for
corrtact
grou-
st
bI
re
of
of
m
m
anrl
for
the
grout
cur-
conrstructflon
of
the
pro-
was
carriied
out in
two
-.s
and was
made
possi-
by
cofferdams
of diffe-
types.
lnternational
ri-
trafl'ic
was
controlled
du-
the
entire
construction
the
project.
The
closing
the
river was
brought
ut by
means
of
concre-
bloclks
and Iarge
rocks;
hydrqulic
parameters
ma-
this one
oif the
most
rult
jobs
of its
type
in
world.
struction
work
started
in
and its
final
putting
opdration
is
scheduled
1971
. The
realization
of
intefnational
project
was
qossiblle
by
agree-
l
[etween
Yugoslavia
Ro{manier
and
by the
Ro{manier
and
by the
aborqtion
of
expertb
of
r co{ntries.
GROSS
SIECTION
OF
THE
OVERFLOW
DAMI
SECTION
DU
BARR
DEVHR$ANIT
.s5
I zs.os
E