Eiffel Tower

Named after its designer, engineer Gustave Eiffel, the Eiffel Tower is the tallest building in Paris. More than 200,000,000 people have visited the tower since its construction in 1889, including 6,719,200 in 2006, making it the most visited paid monument in the world. Including the 24 m (79 ft) antenna, the structure is 324 m (1,063 ft) high (since 2000), which is equivalent to about 81 levels in a conventional building.

When the tower was completed in 1889 it was the world's tallest tower — a title it retained until 1930 when New York City's Chrysler Building (319 m — 1,047 ft tall) was completed. The tower is now the fifth-tallest structure in France and the tallest structure in Paris, with the second-tallest being the Tour Montparnasse (210 m — 689 ft), although that will soon be surpassed by Tour AXA (225.11 m — 738.36 ft).

The metal structure of the Eiffel Tower weighs 7,300 tonnes while the entire structure including non-metal components is approximately 10,000 tonnes. Depending on the ambient temperature, the top of the tower may shift away from the sun by up to 18 cm (7 in) because of thermal expansion of the metal on the side facing the sun. The tower also sways 6–7 cm (2–3 in) in the wind. As demonstration of the economy of design, if the 7300 tonnes of the metal structure were melted down it would fill the 125 meter square base to a depth of only 6 cm (2.36 in), assuming a density of the metal to be 7.8 tonnes per cubic meter. The tower has a mass less than the mass of the air contained in a cylinder of the same dimensions, that is 324 meters high and 88.3 meters in radius. The weight of the tower is 10,100 tonnes compared to 10,265 tonnes of air.

The first and second levels are accessible by stairways and lifts. A ticket booth at the south tower base sells tickets to access the stairs which begin at that location. At the first platform the stairs continue up from the east tower and the third level summit is only accessible by lift. From the first or second platform the stairs are open for anyone to ascend or descend regardless of whether they have purchased a lift ticket or stair ticket. The actual count of stairs includes 9 steps to the ticket booth at the base, 328 steps to the first level, 340 steps to the second level and 18 steps to the lift platform on the second level. When exiting the lift at the third level there are 15 more steps to ascend to the upper observation platform. The step count is printed periodically on the side of the stairs to give an indication of progress of ascent. The majority of the ascent allows for an unhindered view of the area directly beneath and around the tower although some short stretches of the stairway are enclosed.

Maintenance of the tower includes applying 50 to 60 tonnes of paint every seven years to protect it from rust. In order to maintain a uniform appearance to an observer on the ground, three separate colors of paint are used on the tower, with the darkest on the bottom and the lightest at the top. On occasion the colour of the paint is changed; the tower is currently painted a shade of brownish-grey. On the first floor there are interactive consoles hosting a poll for the colour to use for a future session of painting. The co-architects of the Eiffel Tower are Emile Nouguier, Maurice Koechlin and Stephen Sauvestre.

Source: http://en.wikipedia.org/wiki/Eiffel_Tower

Petronas Twin Towers

The Petronas Twin Towers (also known as the Petronas Towers or Twin Towers), in Kuala Lumpur, Malaysia were the world's tallest buildings, before being surpassed by the Taipei 101. However, the towers are still the tallest twin buildings and office building in the world. Tower 1 was built by Hazama Corporation and Tower 2 by Samsung Engineering & Construction and Kukdong Engineering & Construction (both of South Korea). They were the world's tallest buildings from 1998 to 2004 if measured from the level of the main entrance to the structural top, the original height reference used by the US-based Council on Tall Buildings and Urban Habitat from 1969 (three additional height categories were introduced as the tower neared completion in 1996).D

Designed by Argentine-American architect César Pelli, the Petronas Towers were completed in 1998 and became the tallest buildings in the world on the date of completion. They were built on the site of Kuala Lumpur's race track. Because of the depth of the bedrock, the buildings were built on the world's deepest foundations. The 120-meter foundations were built by Bachy Soletanche, and required massive amounts of concrete.

The 88-floor towers are constructed largely of reinforced concrete, with a steel and glass facade designed to resemble motifs found in Islamic art, a reflection of Malaysia's Muslim religion. Another Islamic influence on the design is that the cross-section of the towers is based on a Rub el Hizb (albeit with circular sectors added to meet office space requirements).

In an unusual move, a different construction company was hired for each of the towers. Tower 1 was successfully completed by Hazama Corporation. The builders of Tower 2, Samsung Engineering & Construction and Kukdong Engineering (both of South Korea) found a problem during the construction, the tower was estimated to lean 25 mm on the ground with its own weight. The Tower 2 construction team succeeded one month earlier than tower 1.

Due to a lack of steel and the huge cost of importing steel, the towers were constructed on a cheaper radical design of super high-strength reinforced concrete. High-strength concrete is a material familiar to Asian contractors and twice as effective as steel in sway reduction; however, it makes the building twice as heavy on its foundation than a comparable steel building. Supported by 23-by-23 meter concrete cores and an outer ring of widely-spaced super columns, the towers use a sophisticated structural system that accommodates its slender profile and provides from 1300 to 2000 square metres of column-free office space per floor.Below the twin towers is Suria KLCC, a shopping mall, and Dewan Filharmonik Petronas, the home of the Malaysian Philharmonic Orchestra.

Other buildings have used spires to increase their height but have always been taller overall to the pinnacle when trying to claim the title. In the aftermath of the controversy, the rules governing official titles were partially overhauled, and a number of buildings re-classified structural antenna as architectural details to boost their height rating (even though nothing was actually done to the building).

Source: Wikipedia

Jembatan Ampera

Jembatan Ampera adalah sebuah jembatan di kota Palembang, Provinsi Sumatera Selatan, Indonesia. Jembatan Ampera, yang telah menjadi semacam lambang kota, terletak di tengah-tengah kota Palembang, menghubungkan daerah Seberang Ulu dan Seberang Ilir yang dipisahkan oleh Sungai Musi. Panjang jembatan ini 1.117 m (bagian tengah 71,90 m), lebar 22 m, tinggi 11.5 m dari permukaan air, tinggi menara 63 m dari permukaan tanah, jarak antara menara 75 m, dan berat 944 ton.

Pembangunan jembatan ini dimulai pada bulan April 1962, setelah mendapat persetujuan dari Presiden Soekarno. Biaya pembangunannya diambil dari dana pampasan perang Jepang. Bukan hanya biaya, jembatan inipun menggunakan tenaga ahli dari negara tersebut. Pada awalnya, jembatan ini, dinamai Jembatan Bung Karno. Menurut sejarawan Djohan Hanafiah, pemberian nama tersebut sebagai bentuk penghargaan kepada Presiden RI pertama itu. Bung Karno secara sungguh-sungguh memperjuangkan keinginan warga Palembang, untuk memiliki sebuah jembatan di atas Sungai Musi.

Peresmian pemakaian jembatan dilakukan pada tahun 1965, sekaligus mengukuhkan nama Bung Karno sebagai nama jembatan. Pada saat itu, jembatan ini adalah jembatan terpanjang di Asia tenggara. Setelah terjadi pergolakan politik pada tahun 1966, ketika gerakan anti-Soekarno sangat kuat, nama jembatan itu pun diubah menjadi Jembatan Ampera (Amanat Penderitaan Rakyat). Sekitar tahun 2002, ada wacana untuk mengembalikan nama Bung Karno sebagai nama Jembatan Ampera ini. Tapi usulan ini tidak mendapat dukungan dari pemerintah dan sebagian masyarakat.

Pada awalnya, bagian tengah badan jembatan ini bisa diangkat ke atas agar tiang kapal yang lewat dibawahnya tidak tersangkut badan jembatan. Bagian tengah jembatan dapat diangkat dengan peralatan mekanis, dua bandul pemberat masing-masing sekitar 500 ton di dua menaranya. Kecepatan pengangkatannya sekitar 10 meter per menit dengan total waktu yang diperlukan untuk mengangkat penuh jembatan selama 30 menit. Pada saat bagian tengah jembatan diangkat, kapal dengan ukuran lebar 60 meter dan dengan tinggi maksimum 44,50 meter, bisa lewat mengarungi Sungai Musi. Bila bagian tengah jembatan ini tidak diangkat, tinggi kapal maksimum yang bisa lewat di bawah Jembatan Ampera hanya sembilan meter dari permukaan air sungai.

Sejak tahun 1970, aktivitas turun naik bagian tengah jembatan ini sudah tidak dilakukan lagi. Alasannya, waktu yang digunakan untuk mengangkat jembatan ini dianggap mengganggu arus lalu lintas di atasnya. Pada tahun 1990, kedua bandul pemberat di menara jembatan ini diturunkan untuk menghindari jatuhnya kedua beban pemberat ini.

Sumber: Jembatan Ampera. (2008, Oktober 23). Wikipedia, . Diakses pada 19:04, Desember 5, 2008 dari http://id.wikipedia.org/w/index.php?title=Jembatan_Ampera&oldid=1771500.