Assgnmnt 2 k. Tapak

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C5306 (KEJURUTERAAN TAPAK)

Civil Engineering Department

Title: Assignment 2

Name Registration no.

Batholomew Davis ak Rido 05DKA09F2013

Jeffery Igat ak Gadup 05DKA09F2028

Programme : DKA6-S1

Session: June 2012



SCHEME

Title Marks

1) Introduction of the building /5m

2) The factor of foundation’s selection /10m

3) The type of foundation /5m

4) The characteristics of foundation /5m

5) Reference & Appendix 5/m

Marks Total /30m



INTRODUCTION

(TOKYO SKYTREE IN JAPAN)

Tokyo Skytree (東京スカイツリー Tōkyō Sukaitsur ī ?) is a broadcasting, restaurant, and

observation tower in Sumida, Tokyo, Japan. It became the tallest structure in Japan in 2010 and

reached its full height of 634.0 metres (2,080 ft) in March 2011, making it the tallest tower in the

world, displacing the Canton Tower, and the second tallest structure in the world after Burj

Khalifa (829.84 m/2,723 ft).[5]

Led by Tobu Railway and a group of six terrestrial broadcasters headed by NHK, the tower

project forms the centre piece of a large commercial development equidistant from Tokyo

Skytree and Oshiage train stations, 7 km (4.3 mi) north-east of Tokyo station. One of its main

purposes is to relay television and radio broadcast signals; Tokyo's current facility, Tokyo

Tower with a height of 333 m (1,093 ft), no longer gives complete digital terrestrial

television broadcasting coverage because it is surrounded by many high-rise buildings. The

project was completed on 29 February 2012, with the tower opening to the public on 22 May

2012.

The design was published on 24 November 2006, based on the following three concepts:

Fusion of futuristic design and traditional beauty of Japan,

Catalyst for revitalization of the city,

Contribution to disaster prevention "Safety and Security".

The base of the tower has a structure similar to a tripod; from a height of about 350 m (1,150 ft)

and above, the tower's structure is cylindrical to offer panoramic views of the river and the

city. There are observatories at 350 m (1,150 ft), with a capacity of up to 2000 people, and 450 m

(1,480 ft), with a capacity of 900 people. The upper observatory features a spiral, glass-covered

skywalk in which visitors ascend the last 5 meters to the highest point at the upper platform. A

section of glass flooring gives visitors a direct downward view of the streets below.

http://en.wikipedia.org/wiki/Help:Installing_Japanese_character_sets



http://en.wikipedia.org/wiki/List_of_tallest_towers_in_the_world

http://en.wikipedia.org/wiki/Tokyo_Skytree#cite_note-4




http://en.wikipedia.org/wiki/List_of_tallest_towers_in_the_world




THE FACTOR OF FOUNDATION’S SELECTION

1. The strength of foundation

In the case of a slender tower like the Sky Tree tower, it’s foundation is particularly

subjected to a larger force. So, the foundation of the Sky Tree tower needs to be designed

to resist such larger forces by making it’s piles nodular -wall shapes to increase the

friction resistance. The nodes of those piles resem ble in function “pins of spiked shoes”.

Also, by being continuously connected in radial directions, the walled piles are expected

to have a function like roots of a giant tree by the piles being monolithically integrated

into ground. Below is the figure of foundation that used in Tokyo Skytree tower.

2. The Environment factor

In order to reduce vibrations in case of earthquakes, they have setting up the “Center

Column Vibration Control System” that’s modeled on a five story pagoda. This control

system will reduce the reponse shear force by 40 percent during an earthquake. So, the

massive foundation comprises cast in situ piles, reaching down 35 metres below ground.



3. Project Size

Of course, such a huge project is nothing without the proper foundation, and it’s the Sky

Tree’’s foundation that gives the buildings it’s name. Beneath each of the tower’s three

legs is a cluster of 50-m (164-ft) deep walled piles with steel reinforced concrete nodes,

which Nikken Sekkei compares to the root systems of a gigantic tree with the ground.

4. Wind Factor

The tower’s foundation is subjected to strong uplift and compressive force from winds,

earthquakes, and other factors. The knuckle walls” developed by Obayashi are wall

shaped piles with nodular protuberances. These nodules solidly anchor the piles in the

ground and substantially increase their load bearing capacity. Additionally, knuckle walls

are highly rigid by virtue of their shape, making them highly resistant to horizontalseismic factors.

5. The design of project

Japan’s unique process in solving various difficult problems which are peculiar to Japan

such as foundations considerations, earthquake resistance, complex regulations and

many that are introduced through real designs, models and Computer Graphics (CG).



6. The cultural features

The most unusual feature of this newly-completed addition to city’s skyline is its needle-

like form and mixed design foundation. As an architectural starting point, developers laid

out a foundation that would see the construction of a community inheriting the DNA of Janpanese Shitamachi craftsmanship and creating a new urban culture through human

interaction. This involved designing a town with a tower that was to be created with the

cultural and aesthetic feel of historical Japanese artistry.

7. The type of soil

On the other hand, in addition to the conventional subsoil investigation, a special study

(micro-motion array observation), which is not usually required, was conducted to know

the soil formation down to the deepest level of some 3 km from the ground surfaces. By

the use of the soil information thus obtained, the soil behavior during an earthquake could

be simulated more precisely than otherwise to ascertain how the tower sways at this site.

8. Large bending and shearing forces from the above structure

Large bending and shearing forces from the above steel frame tower work on the

foundation structure as can be seen at figure below, and accordingly the SRC wall into

which the steel plate wall is built in conformity with the plane shape of the foundation

was arranged in the foundation structure. The thickness of the steel plate wall was set at

55mm and 22mm, and of the RC wall at 2700mm and 1900mm.



THE TYPES OF FOUNDATION USED IN

TOKYO SKYTREE TOWER

A foundation for high tower is usually having a surface of a substantially regular

geometric shape, said foundation compromising, a plurability of prefabricated slabs are

arranged in a plurality of layers to be assembled on site and joined together so as to

function as a monolithic foundation that has been used for Tokyo Skytree Tower in

Tokyo, Japan. So, among the 2 types of foundation that been used for Tokyo Tower in

civil engineering is shallow foundation.

The types of shallow foundation used in this tower is Mat foundation . For the

foundation work, it is cast in place concrete piles and underground continuous wall piles.

A mat is essential a very large spread footing that usually encompasses the entire

footprint of the structure. They also are known as raft foundations. For Tokyo Skytree

tower, it is made of reinforced concrete. Below is the figure shown for top view of Tokyo

Tower.

The figure above is has 3 legs for construction of foundation and it is called Typical Self Supporting

Tower Foundations.



Tokyo Skytree is a type of self supporting towers. So, the number of borings depends on the

width of the tower face and the type of foundation used. The chart below summarizes the general

recommendations.

Foundation Face Width Borings Depth (see note)

Drilled pier * 6'-25' 1 25'+

Drilled pier *25+ 1 at each leg 25'+

Pier & pad *6'-25' 1 25'+

Pier & pad *25'+ 1 at each leg 25'+

Mat All 1 at each leg 25'+

* Not recommended for a width less than 6'-0"

The foundation structure of the Tokyo Skytree tower was constructed on a bearing stratum composed of

a rigid diluvial gravel layer located in GL-35m or deeper. It is composed of continuous subterranean

reinforced concrete (R.C) pile walls with high strength and rigidity and cast in place R.C piles. In

particular, for the base section of the tower structure, common continuous subterranean R.C pile walls

were arranged and just beneath for kanae truss.



THE CHARACTERISTICS OF FOUNDATION

1. Cast in place concrete piles

Cast in place concrete piles that using in Tokyo Skytree ground surface is to eliminate

the need for pile driving machinery which can cause dangerous vibrations and precipitate

landslides and which is sometimes too costly for use on small jobs. Because of the

instability of the earth, no vibration could be done. To solve this problem, the

construction crew drilled holes and then placed steel beams in these.

Cast in place piles in the Tokyo Skytree tower are likely to have unintended defects

during construction, such as soft bottom, segregation of concrete and contraction or

enlargement of the cross section.

2. Wall piles

When the contractor constructing a tower on the reclaimed ground is the dependence

in the conditions of the soil. In order to penetrate to the firm gravel and to establishrigidity to the soft soil layer to prevent liquefaction, a continuous wall pile system is

adapted for this tower. As for the tower foundation system, a continuous wall pile

foundation is chosen for the large scale tower to be constructed on the reclaimed ground.

Even if shear force caused by ground drift during earthquake becomes larger compared to

a cast in place concrete pile foundation, it can be expected to reduce the force acting on

the long period structure of this tower. Thus, the safety of the structure can be increased.



3. Mat Foundation

For Tokyo Skytree tower, the foundation used is economic due to combination of

foundation and floor slab. The shallow form requires little excavation below of the tower

ground. It is suitable foundation choosen because the tower structures on ground is

relatively poor strength in it is almost used of filled ground with mixed bearing capacity.



REFERENCES

1. Wikipedia of Tokyo Skytree tower, Google search.

en.wikipedia.org/wiki/Tokyo _ Skytree

2. PDF, SCTT31 Construction of Tokyo Skytree download.

3. http://wisdotresearch.wi.gov/wp-content/uploads/tlscippiling1.pdf

4. blogs.wsj.com/.../ tokyo-skytree-branding-the-worlds-tallest-fre...

5. www.huffingtonpost.com/.../ tokyo-sky-tree-tokyo-tower_n_8...

http://wisdotresearch.wi.gov/wp-content/uploads/tlscippiling1.pdf

http://www.huffingtonpost.com/.../tokyo-sky-tree-tokyo-tower_n_8











http://wisdotresearch.wi.gov/wp-content/uploads/tlscippiling1.pdf



APPENDIX

Tokyo Sky Tree -

Tokyo Sky Tree (東京スカイツリ) is a construction project started in July 2008

in Oshiage, Sumida-ku, Tokyo (see map below). Originally conceived as"New Tokyo Tower" (新東京タワ), it is a broadcasting, restaurant and

observation tower with a maximum height of 634 metres. That height waschosen to reflect the word musashi , the name of the former province of Musashi (武蔵) that included parts of the modern-day Tokyo, Saitama and

Kanagawa Prefectures: 6 (六 mu), 3 (三 sa), 4 (四 shi ).

Sky Tree is the tallest structure in Japan, the world's tallest free-standing

tower (officially recognised by Guinness World Records on November 17,2011), and the second-tallest construction after the Burj Khalifa in Dubai (at830 metres). It was completed in February 2012, the grand opening took

place on May 22, 2012.

The design concept was based on three premises:

o "To Be a New Symbol of Tradition and the Cutting Edge"



o "To Be the Gate to Urban Revitalization"o "To Be a Tower Watching Over Safety and Security"

The project is financed by a consortium of Tobu Railway, the national

network NHK and five other terrestrial broadcasters. It is designed byNikken

Sekkai, and built by the contractor Obayashi Corp., with estimatedconstruction costs amounting to 40 billion JPY.

The site area includes an eastern and western shopping mall and covers

36,900 square metres in total. Sky Tree's structural system is made of reinforced concrete, steel-reinforced concrete and steel structures, the

massive foundation system comprises cast-in-situ piles, reaching down 35metres below ground, and in-ground continuous wall piles in nodes made of

steel-reinforced concrete, reaching down 50 metres. In order to reducevibrations in case of earthquakes, etc., Nissen Sekkei employed a Center

Column Vibration Control system (柱制振システム, shimbashira-seishin) that's

modelled on a five-story pagoda. According to Nissen Sekkei, this controlsystem will reduce the response shear force by 40 percent during an

earthquake.

Hirotake Takanishi, PR manager for Tobu Tower Sky Tree, maintains that theanti-quake measures could reduce quake vibrations by 50 percent.

Simulations had proved that the Sky Tree would withstand an 8.0-magnitude

earthquake, and could withstand even stronger ones, but it couldn't bedefinitely said what its upper limit was. The shimbashira (central column) is

made of reinforced concrete that is structurally separate from the exterior

steel truss. It acts as a counterweight when the tower sways. Engineers areconfident because five-storied pagodas with shimbashira columns havenever been toppled by earthquakes in Japan. Another key design element is

that the tower will gradually change in cross-section from triangular at thebase to round at the 300-metre point, which will help it to better withstand

strong winds.

Even before its grand opening, Tokyo Sky Tree has already turned into a

major tourist attraction, and the formerly tranquil shitamachi neighbourhoodof Azumabashi will undoubtedly benefit from the new infrastructure and the

expected stream of visitors. A ride to the first observation deck (at 350

metres) will set an adult back 2,000 yen, to the second deck at 450 metres3,000 yen.

http://www.jref.com/cgi-bin/jump.cgi?ID=976












http://www.nikken.co.jp/ensk/skytree/structure/structure_04.php













A tower under consruction in Tokyo has become the world’s tallest free standing tower byreaching 601m (1971 feet)

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Assgnmnt 2 k. Tapak