1 Pertemuan 09 BANGUNAN AIR Matakuliah: S0182/Studi Kasus Dalam Teknik Sipil Tahun: Juli 2005 Versi: 01/01

2 Learning Outcomes Mahasiswa dapat memperhitungkan berbagai kemungkinan dan memilih alternatif yang terbaik bagi penyelesaian masalah.  C3, C4

3 Outline Materi Kasus yang selalu dijumpai di proyek Kasus yang mungkin terjadi dengan kondisi khusus Analisa pemecahan masalah

4 Type of DAM Arch Dams An arch dam is a curved dam which is dependent upon arch action for its strength. Arch dam are thinner and therefore require less material than any other type of dam. Arch dams are good for sites that are narrow and have strong abutments.

5 Arch Dams - Anatomy

6 Arch Dams - History It is rather astonishing that the Romans only sparcely applied the arch in dam constructions, a design otherwise so masterfully employed in their buildings and bridges. One of the few true arch dams built by the Romans was located in the Vallon de Baume, France in order to supply the nearby city with water. The dam was 12 m high and 18 m long.

7 Arch Dams - History Kebar and Kurit The Mongolians built the first arch dams since the Romans. The earliest one was built around 1300 near Kebar, Iran. The Kebar dam was 26 m high, 55 m long. The arch did not abut against the canyon walls, instead it passed on both sides into straight wing walls. The second Mongolian arch dam was built around 1350 in Kurit, Iran. The Kurit dam is especially remarkable for its extraordinary height of 60 m -- it was the world's highest dam until the early 1900's. The dam was built in a very narrow canyon and its crest length reached only 44% of the height. It therefore remained erect, despite the fact that a large segment of lower half of the vertical downstream face broke away.

8 Arch Dams - History Postmedieval Europe Elche The first true arch dam in Europe since the Roman times was built from 1632 to 1640 near Elche, Spain. The Elche dam's main arch was 75 m long at the crest. The Elche dam was designed by Joanes del Temple.

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10 Type of DAM Buttress Dams Buttress dams are dams in which the face is held up by a series of supports. Buttress dams can take many forms -- the face may be flat or curved. Explore the links below to learn more about buttress dams.

11 Buttress Dams - Anatomy

12 Buttress Dams - History Roman Buttress Dams Esparragelejo Whenever Roman engineers, often erroneously, judged the stability of a dam wall to be inefficient, they backed it up by irregularly spaced buttresses. But some dams were too thin. Buttress could not prevent the failure of the super thin, 0.9 m dam wall at Ituranduz. By contrast, some dams were over designed. The Olisipo dam was 6.5 m thick and didn't need help from its buttresses. The most remarkable of the Roman buttress dams is the one near the village of Esparragalejo. The 5.6 m high and 320 m long dam was supported in its central part with 12 buttresses averaging 1.2 m wide, 3.2 m thick and spaced 8.6 m apart. However, the novel feature was that the downstream face of the 2 m wide dam wall became curved between the buttresses. Thus, the first multiple arch dam was born!

13 Buttress Dams - History Roman Buttress Dams Esparragelejo

14 Buttress Dams - History Buttress Dams in Postmedieval Europe Castellar The Castellar storage dam in Spain was built around 1500 and had three water wheels to power its mill house. The sturdy end and walls of the mill house were actually buttresses ensuring the dam's stability. It is certainly no coincidence that this structural concept re-emerged in a region in which the Romans had built many buttress dams.

15 Buttress Dams - History Evolution of the Modern Buttress Dam Today we understand buttress dams as derivations from the massive gravity type with the introduction of intermediate spaces. These spaces allows the discharge of water seeping through the dam and its foundation, thus greatly reducing uplift pressures. Given the absence of uplift, more substantial savings were possible by inclining the upstream face, thereby mobilizing the vertical water load on the upstream face for sliding stability.

16 Buttress Dams - History Evolution of the Modern Buttress Dam

17 Type of DAM Gravity Dams Gravity dams are dams which resist the horizontal thrust of the water entirely by their own weight. Concrete gravity dams are typically used to block streams through narrow gorges. Because it is there weight holding the water back, concrete gravity dams tend to use a large amount of concrete. This can be expensive. But many prefer its solid strength to arch or buttress dams. Explore the links below to learn more about gravity dams

18 Gravity Dams - Anatomy

19 Gravity Dams - History The Roman Empire Emperor Nero (AD 54-68) had a 40 m high, 13.5 m wide, and 80 m lonldam built for a pleasure lake near his villa at Subiaco, Italy. The dam was one of the earliest Roman dams and remained the highest the Romans ever built. Moreover, the Subiaco dam and two smaller dams nearby are the only Roman dams in Italy. Although the dam was to thin, it remained intact until it failed in Records blace the blame on two monks who took it upon themselves to remove stones from the dam, apparently in an attempt to lower the level of the lake which was flooding their fields.

20 Gravity Dams - History

21 Gravity Dams - History Evolution of the Modern Gravity Dam The Correct Shape In 1765 and 1800, the first triangular gravity dams were built in Mexico. Unfortunately, it remains unknown who their ingenious builder was. Amazingly, he/she had adopted the modern shape almost one century before it was developed in France. In 1850, French engineer J. Augustin Tortene de Sazilly ( ) showed in a lecture that the most advantagous profile for a gravity dam is triagle with a verticle upsteam face. Sazilly also analyzed three recent French navigation dams in a paper published posthumously in He used the cross sections of these three dams to illustrate the confusion and uncertainty in the design of gravity dams. In fact, two of the dams were wrongly inclined on the upstream side!

22 Gravity Dams - History

23 Gravity Dams - History

24 Gravity Dams - History Latest Ideas in Gravity Dams Steel A relatively new development in the construction of gravity dams is incorporation of post-tensioned steel into the structure. This helped reduce the cross section of Allt Na Lairige Dam in Scotland to only 60 percent of that of a conventional gravity dam of the same height. A series of vertical steel rods near the upstream water face, stressed by jacks and securely anchored into the rock foundation, resists the overturning tendency of this more slender section. This system has also been used to raise existing gravity dams to a higher crest level, economically increasing the storage capacity of a reservoir. However, since reaching their prime in the 1960s, gravity dams have become something like a dying species, the dinosaurs of an era which especially the idustrialized countries with their high labor cost no longer can afford.

25 Type of DAM Embankment Dams Embankment dams are massive dams made of earth or rock. They rely on their weight to resist the flow of water. Explore the links below to learn more about embankment dams.

26 Embankment Dams - Anatomy

27 Embankment Dams - History Ancient Times Sadd-el-Kafara The ruins of the Sadd-el- Kafara embankment dam were discovered over 100 years ago in the Garawi ravine in Egypt. The dam was built around 2600 BC and was 14 m high and 113 m along the crest. It is the oldest dam of such size known in the world. The of the dam was to retain the water from rare, but violent, floods.

28 Embankment Dams - History The Postmedieval Europe Saint Ferreol The proposal of a large water supply reservoir turned out to be the key to build the Languedoc canal in France, which connected the Mediterranian Sea with the Atlantic Ocean. The reservoir would be used to conpensate the losses of water in the canal during the dry season. After the approval by King Louis XIV, the designs for the canal and dam were drawn up in The construction of the Saint Ferreol dam began in 1666 and was completed in The dam consisted of a water retaining wall supported by a downstream embankment. In case of a too rapid depletion of the reservoir, the water retaining wall was stabilized by a lower embankment built against the upstream face. The result may be regarded as an earthen dam with a masonry core. With its height of 36 m, the Saint Ferreol dam remained the heightest embankment in the world for 165 years!

29 Embankment Dams - History The Postmedieval Europe

30 Embankment Dams - History Evolution of Modern Embankment Dams Embankment dams in the U.S. prior to 1930 had a poor track record. Of those over 490 ft high, almost 10% failed, usually due to overtopping in a flood. Overtopping is when the water level in the reservoir reaches maximum height and begins to flow over the top of the dam. The South Fork dam in Johnstown,PA was one of the first to use rockfills, or loose rocks, on the downstream face. This dam failed after being overtopped in 1889, kill over 2000 people.