Transcript Pertemuan 10 Bangunan Air Matakuliah : S0182/Studi Kasus Dalam Teknik Sipil

Matakuliah
Tahun
Versi
: S0182/Studi Kasus Dalam Teknik Sipil
: Juli 2005
: 01/01
Pertemuan 10
Bangunan Air
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Learning Outcomes
Mahasiswa dapat membandingkan kasuskasus yang terjadi dengan berbagai
alternatif yang dipilih  C4
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Outline Materi
• Analisa pemecahan masalah
• Beberapa alternatif pemecahan masalah
• Kasus kegagalan konstruksi yang mungkin
terjadi
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DAM FAILURE
Teton Dam Failure
• The Teton Dam, 44 miles northeast of Idaho Falls in southeastern Idaho,
failed abruptly on June 5, 1976. It released nearly 300,000 acre feet of
water, then flooded farmland and towns downstream with the eventual loss
of 14 lives, directly or indirectly, and with a cost estimated to be nearly $1
billion.
• The purpose of this web page is to present a series of slides that show the
breakup of the dam from its incipient failure stage to when the dam was
completely breached. The slides were taken by Mrs. Eunice Olson of St.
Anthony, Idaho, who presented the set to the Department of Earth
Sciences, University of Notre Dame, to sell and to subsidize, thereby, a
scholarship for undergraduate students in Earth sciences. The department,
now the Department of Engineering and Geological Sciences, no longer
sells the set, and has unofficially agreed that it would be a good thing to
place this unique collection on the web. Attempts to contact Mrs.Olson have
been unsuccessful, but nevertheless, all credit for the break up sequence of
slides belongs to her.
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DAM FAILURE
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• Over 100 years ago, a catastrophic dam
failure caused thousands of deaths and
wiped out a town. Before the failure:
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CASE STUDY DAM
El Atazar
• dam type: double curvature concrete arch
buttress purpose: water supply and
regulation
• height: 440 ft (134 m)
• width at foundation: 171.6 ft (52.3 m)
• length of crest: 1312 ft (400 m)
• storage capacity: 344,000 acre-ft.
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CASE STUDY DAM
El Atazar
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The dam may also have served the people by producing electric power, but
the decision was made to confine its purpose to water supply.
location: near Madrid, Spain
river: Lozoya, very close to where it joins the Jarama River
foundation: Silurian shale
Three joint systems pass through this foundation.
construction start date: 1968
construction end date: 1972
first partial reservoir filling: 1970
Maximum storage is 870 m above sea level. Filling began when the
diversion tunnel was closed. It filled to 824 m above sea level in 1971 and
then to 860 m in 1972. Questionnable behavior began to occur during the
filling between 1971 and 1972.
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CASE STUDY DAM
El Atazar
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CASE STUDY DAM
El Atazar
•Monitoring of the dam revealed movement, often normal in dams. But
the left side was moving more than the right. This was because the left
abutment was a hillside, more deformable than the right abutment. Also,
a support had been built on the right side of the dam, making that side
more stiff (and less moveable).
•In 1977, a crack was noticed just left of the center of the dam about
98.4 ft (30 m) above the foundation on the upstream side of the dam.
This is noted as one of the worst places for cracking to occur in an arch
dam. Water was now leaking out through the crack into drains in the
dam at a rate of 53 ft3/min.
•In February of 1978, the leak increased to a rate of 318 ft3/min as a
result of heavy rain.
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CASE STUDY DAM
El Atazar
•The crack grew almost 150 ft both to the left and to the right and could
be seen from one of the dam's inspection galleries.
•In 1979, the crack was repaired.
•In 1980, maximum storage was reached.
•In 1983, it was found that settling had occurred in the foundations and
the movements of the dam caused fracturing in the rock. The
permeability of the foundation had increased significantly.
•Treatment of the foundation has decreased the movements and the
foundation.
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CASE STUDY DAM
El Atazar
El Atazar Current Status
•The analysis of three-dimensional structures such as concrete
arch dams was demonstrated with the simulation of El Atazar dam
and showed the applicability of fracture mechanics to such
structures.
•Arch dams are critically sensitive to their foundations, again
proven by this case. The computer simulation demonstrates the
increase in stress on the upstream face when one of the
abutments is weak, resulting in cracking.
•Researchers acknowledged the need improvements in threedimensional crack growth analysis.
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