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Contents Abstract ............................................................................................................................................ 3

1National Stadium, Singapore ........................................................................................................... 4

1.1 General Information ................................................................................................................ 4

1.2 Specifications and features ...................................................................................................... 5

1.2.1 Spectator seating .............................................................................................................. 5

1.2.2 Dome and retractable roof ................................................................................................ 6

1.2.3 Stadium pitch .................................................................................................................... 7

1.3 Top Truss Goes Into Singapore National Stadium ..................................................................... 8

1.4 Key Feature.............................................................................................................................. 9

1.5 Innovative in structure ........................................................................................................... 10

2 GRAND CANYON SKYWALK –THE GLASS BRIDGE ........................................................................... 11

2.1 General Information .............................................................................................................. 12

2.2 Designing An Engineering Marvel ........................................................................................... 13

2.3 Building Grand Canyon Skywalk ............................................................................................. 13

2.4 New Glass Panels Provide A Crystal-Clear View ...................................................................... 14

2.5 Designing The Skywalk ........................................................................................................... 15

2.6 Innovative in structure ........................................................................................................... 16

3 MARINA BAY SANDS, SINGAPORE ................................................................................................. 17

3.1 General Information .............................................................................................................. 17

3.2 Project Team ......................................................................................................................... 18

3.3 Hotel Towers ......................................................................................................................... 18

3.4 Structural Flare ...................................................................................................................... 19

3.5 Construction .......................................................................................................................... 21

3.6 SkyPark .................................................................................................................................. 23

3.7 Feature .................................................................................................................................. 24

3.8 Structural Optimization Studies.............................................................................................. 25

3.9 Construction Sequence .......................................................................................................... 26

4 CCTV Headquarters Beijing, China ................................................................................................. 28

4.1 General Information .............................................................................................................. 29

Location ...................................................................................................................................... 29

4.2 Concept ................................................................................................................................. 30

Spaces ......................................................................................................................................... 30

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4.3 Construction .......................................................................................................................... 31

Towers..................................................................................................................................... 32

4.5 Structure................................................................................................................................ 33

Seismic studies ........................................................................................................................ 33

Basic Quality Targets ................................................................................................................ 33

4.6 Exoskeleton ........................................................................................................................... 34

4.7 Foundations ........................................................................................................................... 35

4.8 Connections ........................................................................................................................... 36

Conclusion ....................................................................................................................................... 37

References ............................................................................................................................... 38

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Abstract

The basic elements of civilization or civil engineering are infrastructure, dam, airport,

ports, and artificial islands. With the growing urbanization with population growth is posing

huge challenge difficulties for the modern civil engineers.

The present work provides a unique forum for sharing knowledge gained on real

world projects, solutions to real world problems, and research outputs that are practically-

oriented. This topic seeks to build a vital link between structural engineering practitioners and

researchers, a platform for presenting and exchanging design ideas, identifying technical

challenges, and showcasing engineered solutions.

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1National Stadium, Singapore

1.1 General Information

The National Stadium is a stadium replacing the old stadium in Kallang, Singapore. It opened

on 30 June 2014.

Located in Kallang, Singapore, the National Stadium is a multi-purpose arena used mostly for

football matches featuring a dome and retractable roof. It is the only stadium in the world

custom designed to host football, rugby, cricket and athletics events. With a mechanised and

automated retractable seating configurations on the lowest tier, the arena can also host

concerts, cultural and other entertainment purposes at any time.

It takes approximately 48 hours to reconfigure seating arrangements to suit an upcoming

event. The stadium has a maximum seating capacity of 55,000 for football and rugby, 52,000

for cricket and 50,000 spectators for athletics events.

Owner Stadium Singapore Sports Hub

operator Dragages Singapore Pte. Ltd

Broke

ground

29 September 2010

Opened 30 June 2014

Construction

cost

S$1.87 billion

Architect Arup Associates (Sports venues), DP Architects (Non-sport

venues, QP), AECOM (landscape)

Structural Arup

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Construction work for the sports hub started in 2010 due to the delays caused by the 2008

financial crisis and soaring construction costs. By September 2011, the pilling and the

foundation of the stadium was completed and construction on the steelwork of the stadium

fixed roof started. On July 2013, the installation of the stadium final primary steel ‘runway

truss’ for the roof was completed marking the completion of the steelwork on the National

Stadium’s fixed roof in preparation for installation of the retractable roof. The stadium was

set to be completed in April 2014, however, In February 2014, Sports Hub CEO Philippe

Collin Delavaud announced that the National Stadium's completion was pushed back to June

2014.

1.2 Specifications and features

1.2.1 Spectator seating

Cricket seating arrangements Football seating arrangements

Athletics seating arrangement

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The stadium has configurable spectator tiers depending on the event being hosted, namely

"Football/Rugby mode", "Cricket mode" and "Athletics mode". To configure from athletics

mode to football/rugby mode, the lowest spectator tier can be moved 12.5m forward, hiding

the athletics running track underneath the seats and bringing spectators close to the pitch to

provide optimum spectator viewing distances. An energy efficient cooling system is also

designed to deliver cooled air to every seat in the stadium while using less than 15 per cent of

energy as compared to a conventional air-conditioned stadium, providing every spectator a

cool and comfortable time to enjoy an event.

1.2.2 Dome and retractable roof

Retractable Roof Opening & Closing Arrangements

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The National Stadium currently holds the record of the largest dome structure in the world.

The retractable roof itself will take an approximate 25 minutes to open or close. The roof is

made out of a lightweight material called ETFE, which is weather-resistant and blocks the

sun's heat giving shade and protecting spectators from the hot and humid Singapore weather

during the day and potential torrential rain at any point of time. At night, the retractable roof

doubles as a giant projector screen on both sides, which can display images such as the

Singapore Flag during the National Day Parade.

1.2.3 Stadium pitch

Special Growth Lights For Speed Up The Growth Of The Grass

Desso GrassMaster was installed as the original grass pitch when the stadium opened. The

sandy pitch was criticised by Juventus manager Massimiliano Allegri during a pre-season

friendly there in August 2014 and resulted in his decision not to field Carlos Tevez due to

injury concerns. Afterwards, S$1.5 million of special growth lights were installed to stimulate

and speed up the growth of the grass, with one of the main concerns being getting the pitch

ready for the 2014 Suzuki Cup at the end of the year. In October 2014, Brazil coach Dunga

criticised the state of the pitch, which had not improved much since the Juventus match,

when his side were in Singapore to play a friendly against Japan. Although Brazil won the

Match 4-0, he said after the match that the sandy pitch had prevented his side from playing

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their best football. Eventually, the grass still failed to grow well and was replaced by the

Eclipse Stabilised Turf in May 2015.

1.3 Top Truss Goes Into Singapore National Stadium

The new National Stadium have the largest free-spanning dome roof in the world, covering

310 metres wide. This dome incorporate a moving roof, ensuring the stadium is protected

from extreme weather conditions. The result is a stadium design with an integrated bowl

cooling system that uses less than 15 per cent of energy as compared to a conventional air-

conditioned stadium.

fixed roof which has around 12,000 elements – along with a retractable roof over the stadium

pitch with the approximate weight of about 1,000 tons – a testament to the high level of

engineering and ingenuity that has gone into this innovative design.

The highest truss of the new National Stadium at Singapore Sports Hub has been completed –

measuring at approximately 77.5 metres above pitch level.

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1.4 Key Feature

Cooling system

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1.5 Innovative in structure

The defining feature of the stadium is its roof: spanning 310 metres, it is the world’s largest

free-span dome is itself as a innovative.

retractable roof

A retractable roof is another essential innovative feature that it provides shade and thus

cooling when required and of course shelter from rainfall. The roof is left open when The

Stadium is not in use, keeping the grass pitch in healthy condition.

Rearrangeable seating

The lowest tier of seats can be mechanically and automatically retracted, making the National

Stadium the only stadium in the world able to accommodate events from football, rugby,

cricket and athletics, to concerts, cultural shows and community events at any time in the

year.

Designing For The Tropics

A radical cooling system ensures that the stadium will be comfortable whatever the occasion

or sporting event. Instead of being supplied at a high level, cooled air will be introduced

beneath stadium seats. This will also minimise the volume of air cooled and thus

considerably cut energy use.

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2 GRAND CANYON SKYWALK –THE GLASS BRIDGE

Higher Than The Tallest Skyscraper

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2.1 General Information

Grand Canyon Skywalk is located 4,000 feet above the Colorado River.

Consists of more than 1 million pounds of steel and 83,000 pounds of glass.

In total, it weighs 1.2 million pounds.

Its foundation is strong enough to support about 71 million pounds–the equivalent of

71 fully loaded 747 airplanes.

The glass walls are approximately 5’-7” high, extending 4’-6” above the glass floor –

safer than code yet low enough that guests do not feel confined.

Grand Canyon Skywalkis 10 feet wide.

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2.2 Designing An Engineering Marvel

In 1996, businessman David Jin, from Las Vegas, NV, approachedthe Hualapai Tribe

with the idea of a glass walk wayover the Grand Canyon. He won approval from the

tribe in 2003.

Grand Canyon Skywalk was designed and engineered by Lochsa Engineering & MRJ

Architects and built by Executive Construction Management, all based out of Las

Vegas, NV.

Engineers conducted tests on the geologic stability of the site and researched the

foundation by testing the compressive strength of the rock.

They found that the Red Limestone rock could withstand 16,000 pounds of pressure

per square inch.

Engineers also conducted extensive testing during the planning and design phase to

ensure the Grand Canyon Skywalk could easily withstand the high winds that have

been known to blow through the Grand Canyon.

The design originally extended 30 feet over the edge of the rim of the Grand Canyon

but eventually evolved into a horseshoe-shaped bridge extending 70 feet past the edge

of the Grand Canyon wall.

2.3 Building Grand Canyon Skywalk

On October 6, 2004, the Hualapai Tribe blessed the site, and one month later drilling

for the Grand Canyon Skywalk began. Drilling lasted one and a half years.

Next came a foundation consisting of eight columns that support box beams. Each

box beam is 6 feet high, 32 inches wide and has 2-inch thick walls. Grand Canyon

Skywalk is designed to absorb vibration and avoid galloping in windy conditions.

The beams were custom fabricated in Utah in 40 ft. sections

then trucked to Grand Canyon West.

Grand Canyon Skywalk was assembled on site.The first permanent caps were

attached to the eight concrete columns to support it. Pieces of the bridge were put into

place and welded together once aligned. The welding took four months to complete.

Three tuned mass dampers specifically calibrated to meet the wind and weight

requirements of the location were placed inside the horseshoe frame, making it

structurally sound. Mass dampers help distribute the weight on the glass bridge.

A special manipulator was designed to lift the glass panels to the Grand Canyon

Skywalk with large suction cups.

Two-and-a-half years after the groundbreaking ceremony,the Grand Canyon Skywalk

rollout began. Engineers used the same rod and plate method used on the Egyptian

pyramids to roll it out over the Grand Canyon.

On the first day, it was rolled halfway out. Rollout was completed in two days.

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The First Walks

Grand Canyon Skywalk opened to the general public on March 28,2007.

2.4 New Glass Panels Provide A Crystal-Clear View

Operators recently replaced the Grand Canyon Skywalk’s 46 glass panels for the first

time since it opened. The project was completed in May, 2011.

Rioglass manufactured the glass in Logrono, Spain, about 4.5 hours North of Madrid.

Rioglass specializes in strong glass made for embassies and other buildings that need

bomb -proof glass.

A 150-foot crane was trucked to the Grand Canyon Skywalk to lift each 1,800 - pound

piece of glass into place.

Work was done at night so that the Grand Canyon Skywalk could remain open during

the day.

The new glass panes consist of five layers of glass bonded together and measuring2 ½

inches thick.

Each panel has a thin “sacrificial” layer of glass that can be removed and replaced by

hand when it becomes scratched, instead of bringing in a large crane to replace glass.

Each panel can support 100 lbs per square ft., equivalent to about 800 people,

although only 60 to 120 people are allowed on the Grand Canyon Skywalk at a time

depending on the number of visitors on a given day.

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Grand Canyon Skywalk Attendance

Over 1.8 million tourists have visited the Grand Canyon Skywalk

since it opened in March of 2007.THE WEST RIM OF THE GRAND CANYON

Grand Canyon is a chasm about 277 miles long and up to 18 miles wide.

Grand Canyon Skywalk is located on the West Rim, on land owned by the Hualapai

Nation.

Grand Canyon was carved by the Colorado River, which flows West through the

Canyon and averages about 300 feet wide and 100 feet deep. Grand Canyon took an

estimated 6 million years to form.

2.5 Designing The Skywalk

From a design perspective, Principal of MRJ Architects, Mark R. Johnson wanted to create a

unique experience for visitors to the Grand Canyon. His goal was to create a feeling of being

“unsupported”, of floating in the air, of a total freedom. Glass was central to this goal.

The specific requirements set for the glass were:

Glass as clear as possible

Loading

Short duration - Wind load (up- and downward)

Long duration applied to the glass floor

- Uniform applied traffic load (1h)

- Concentrated traffic load (1h)

- Self-weight

Human safety – impact load for the balustrade

Slip resistant top surface of the glass floor

Sustained upper use temperature of 50°C

The glazing method takes into account differential movement between the 2 steel

support beams due to e.g. different expansion; seismic effects; etc.

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2.6 Innovative in structure

The Skywalk is an innovative because it is the first-ever cantilever shaped glass walkway to

suspend more than 4,000 feet above the canyon’s floor and extend 70 feet from the canyon’s

rim.

Also its foundation is strong enough to support about 71 million pounds – the equivalent of

71 fully loaded 747 airplanes.

Each panel has a thin “sacrificial” layer of glass that can be removed and replaced by hand

when it becomes scratched, instead of bringing in a large crane to replace glass.

The Skywalk was assembled on top of the canyon wall in line with its final placement and

moved into final position by a jack and roll rig. The Skywalk infrastructure itself weighs a

little over 1,000,000 pounds (450,000 kg) without counterweights but including the tuned

mass dampers, railing hardware, glass rails, glass deck and steel box beams. At the time of

roll-out, the Skywalk weighed approximately 1.6 million pounds (730,000 kg). The process

was completed in two days.

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3 MARINA BAY SANDS, SINGAPORE

3.1 General Information

Marina Bay Sands is an Integrated Resort fronting Marina Bay in Singapore. Developed

by Las Vegas Sands, it is billed as the world's most expensive standalone casino property

atS$4 billion, including cost of the prime land.

With the casino complete, the resort features a 2,561-room hotel, a 1,300,000-square-foot

(120,000 m2) convention-exhibition centre, the 800,000-square-foot (74,000 m

2) The

Shoppes at Marina Bay Sands mall, a museum, two large theatres, seven "celebrity chef"

restaurants, two floating Crystal Pavilions, an ice skating rink, and the world's largest atrium

casino with 500 tables and 1,600 slot machines. The complex is topped by a 340-metre-long

(1,120 ft) SkyPark with a capacity of 3,900 people and a 150-metre (490 ft) infinity

swimming pool, set on top of the world's largest public cantilevered platform, which

overhangs the north tower by 67 metres (220 ft).

The 20-hectare resort was designed by Moshe Safdie Architects.

Engineering was provided by Arup and Parsons Brinkerhoff (MEP).

The main contractor was SsangYong Engineering and Construction

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3.2 Project Team

Structural, Civil, Geotechnical, Façade, Fire, Traffic, Acoustic and Audio Visual,

Security and Risk Engineering, and 3D Building Modeling: Arup

Owner: Las Vegas Sands Corporation

Design Architect: Safdie Architects

Executive Architect: Aedas Ltd. Pte.

MEP Engineers (Design): R.G. Vanderweil, LLP

MEP Engineers (Production): Parsons Brinckerhoff

Landscape Architect (Design): Peter Walker & Partners

Landscape Architect (Production): Peridian International, Inc.

Contractors: Bachy Soletanche (Substructure, Foundations)

JFE Engineering Corporation (SkyPark)

Ssangyong Engineering & Construction (Hotel)

VSL Heavy Lifting (SkyPark)

Yongnam Holdings (Museum, SkyPark)

3.3 Hotel Towers

Construction of the 55-story hotel towers was on the critical path. As such, the design of

these one-of-a-kind buildings became an early focus for the AE team. The base of the towers

flare to create a common, contiguous tapered lobby atrium running the length of all three

towers.

The taper of the base created a significant technical challenge because of the form’s

asymmetry and because the curved eastern legs cause each tower to lean against the opposing

vertical legs. As a result, the primary lateral force demands imposed on the building are

governed by the effects of gravity rather than either wind or seismic effects.

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The hotel’s south tower rises majestically over the contiguous lobby below. Courtesy-

of Timothy Hursley.

3.4 Structural Flare

Reinforced concrete shear walls, varying in thickness from 28 inches at their base to 20

inches at higher floor levels, are located on 33-foot centers within each of the three towers.

The shear walls serve as the primary vertical and transverse structural system of all three

buildings. Additional concrete core walls located within both legs of each building restrain

the hotel in the longitudinal direction and help prevent out-of-plane buckling of the relatively

narrow shear walls within both legs of the towers. Indeed, the requirement for such restraint

was established very early in the design following rigorous buckling analyses of both legs.

Post-tensioned 8-inch flat slabs span directly between the shear walls. This arrangement

maximizes structural efficiency and creates a simple floor slab solution that can be built

rapidly. The flat slab scheme also provides flexibility in the hotel room layout,

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accommodates a relatively tight 9-foot 10-inch typical floor-to-floor height, and

accommodates flexibility of building services distribution and coordination throughout each

floor.

Story-height steel trusses located within the Level 23 mechanical floors connect the legs of

the tower and resist the large shear forces that occur where these meet above the central

atrium. At ground floor level, the base slab is post-tensioned to resist the horizontal thrusts

generated by the inclined legs.

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3.5 Construction

Because of the extreme flare of the legs of the towers, the opposing shear walls tend to flex

and drift laterally during construction. It was therefore crucial that the design carefully

consider the construction sequence; a simple in-place structural analysis would be

inappropriate. To this end, Arup conducted a series of construction stage analyses of various

erection scenarios early in the design process in order to quantify the amount of displacement

and locked-in stress that would accumulate within each tower under each scenario. The study

concluded that substantial temporary works would be necessary to properly limit both effects,

but that some degree of locked-in stress could not be avoided. During the Tender Process, the

engineering team worked closely with the hotel contractors to devise a scheme that utilized

temporary shoring to brace the inclined shear walls against the vertical walls to good effect.

Temporary shoring of the hotel towers during construction minimized the amount of locked-

in stress accumulated within the opposing legs of each building. Courtesy of Arup.

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Additional studies demonstrated that by introducing prestress within both the vertical and

inclined shear walls, these movements and resulting stresses could be further reduced. A final

construction stage analysis of the chosen method of erection was then conducted to serve as a

benchmark for construction. As the towers were erected, a real-time monitoring system was

implemented to compare the actual stress levels against this benchmark, enabling back-

analysis and design modification of the constructed tower in the event that the actual

measurements deviated from the targets.

Measurements of the walls included the:

angular rotation at the top of the tower

maximum displacement of elevation in all three axes

differential movement between vertical and inclined walls

differential movement between adjacent wall bays

differential movement among all three towers (which affects the support provided to the

SkyPark)

In addition, immediate displacements arising from self-weight effects were offset via pre-

camber during construction. However, because of their asymmetry, further complicated by

concrete creep and shrinkage effects, the towers are expected to continue to deform laterally

until these movements converge after approximately 30 years. These predicted long-term

displacements have been accounted for in the design and specification of the vertical

transportation systems, core layouts, building services, and building finishes and façade

details.

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3.6 SkyPark

At 1,115 feet long, 131 feet wide, and cantilevering 213 feet at an elevation of over 650 feet

above grade, the hotel rooftop SkyPark is the world’s longest habitable cantilevered

observation deck and has become a symbolic icon for Singapore in the process.

The SkyPark appears to float high above the hotel towers. With a cantilever of 218

feet, the roof deck is the longest habitable cantilevered observation deck in the world.

Courtesy of Arup.

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3.7 Feature

This feature component boasts 2.5 acres of landscaped gardens comprising 250 trees up to 26

feet in height and over 650 plants, necessitating in excess of 81,000 cubic feet of soil;

signature restaurants; a 495-foot long infinity edge swimming pool containing over 375,000

gallons of water, and an observation platform offering unrivalled 360 degree views of the

Bay and surrounding city.

The SkyPark’s infinity edge pool offers commanding views of Marina Bay and Singapore’s

. central business district beyond. Courtesy of Timothy Hursley.

To be successful, the design had to reconcile several competing demands: the aesthetic goal

of creating an elegant park high above the towers, the minimum weight and efficiency

demands required to limit the adverse effects on the towers below, and the constructability

requirements necessary to enable pre-assembly and rapid construction on site.

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3.8 Structural Optimization Studies

A number of framing options were considered for the SkyPark early in the design process.

These included various truss, beam, steel diagrid, and segmented hollow concrete bridge

alternatives, among others. All such schemes were assessed for both their weight and ease of

construction. The design team, in conjunction with the fabricators and erectors, converged

upon a system of post-tensioned segmental steel box girders 33 feet deep by 12 feet wide

with 13/8-inch sidewalls and 23/8-inch flanges as the primary structural system for the

cantilevering segment, and a system of primary steel bridge trusses for those segments

spanning between the hotel towers. The bridges directly atop each tower are supported on

raking steel "V" struts extending from the hotel roof directly over the concrete shear walls.

The segments between each tower span as simply-supported trusses onto the ends of the

adjoining segments.

The relative displacements of all three towers vary dramatically, owing to their subtle

geometric differences. Movement joints located between each tower accommodate such

differential movements arising from thermal expansion, wind-induced movements, and other

time-dependent lateral movements generated from creep and shrinkage arising from the

asymmetry of the towers. Careful detailing through the infinity edge pool accommodates

these joints and gives the impression of a clean monolithic roof deck running continuously

across the towers.

Another important consideration in the design of the SkyPark cantilever was its response to

wind-induced vibrations, and vibrations arising from rhythmic human activity such as

dancing and running. The introduction of a 5-ton tuned mass damper within the design of the

cantilever served to mitigate these effects. Subsequent dynamic testing of the completed

SkyPark has verified the performance of this system.

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3.9 Construction Sequence

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The SkyPark was prefabricated off-site in 14 primary segments. The bridging sections

extending between adjacent towers each consist of three 400-ton bridge trusses that were pre-

assembled at grade. These were then strand jacked into place over a span of 16 hours. The

final cantilevering portion was likewise prefabricated in segments at grade to ensure proper

fit-up. The entire assembly was then disassembled and each segment was hoisted in turn via

strand jacks cantilevering from a moveable gantry attached from secondary beams at roof

level, themselves spanning between the main box girders of the previously installed segment.

In total, over 7,000 tons of SkyPark steelwork was erected in just 13 weeks.

The overall form of the Marina Bay Sands Hotel was driven by the architectural requirement

for a continuous atrium running the length of all three towers. The resulting geometric flare

was resolved structurally via prestressed concrete base slabs and multi-story shear trusses

located between opposing building halves through the mid-level mechanical rooms. The

hotel’s asymmetry demanded detailed construction sequence analyses to assess the towers’

continual deflection during erection. Moreover, the unique form of each tower resulted in

differential movements under imposed load, which further complicated the engineering

design of the rooftop SkyPark and its support. Each of these challenges was addressed and

resolved through close collaboration among the design, construction, and client teams.

The iconic Marina Bay Sands Integrated Resort has become a shining beacon for Singapore. Courtesy

of Darren Soh.

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4 CCTV Headquarters Beijing, China

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4.1 General Information

Alternative

names

China Central TV Headquarters

Central Chinese Television Tower

General information

Construction

started

1 June 2004

Completed 16 May 2012

Owner China Central Television

Management China Central Television

Height

Roof 234 m (768 ft)

Technical details

Floor count 51

3 below ground

Floor area 389,079 m2(4,188,010 sq ft)

Lifts/elevators 75

Design and construction

Architect Office for Metropolitan Architecture

East China Architectural Design & Research Institute

Developer China Central Television

Structural

engineer

Ove Arup & Partners

Main

contractor

China State Construction and Engineering Corporation

Location

The mega-structure was built at the foot of the Third Ring Road East Beijing, Guanghua

Road, China, on a plot of 20 hectares, in the new Central Business District Chaoyang. The

CCTV building was part of a park for the media, aimed at creating a landscape of public

entertainment areas shooting outdoors and production studios as an extension of the central

green axis of the CBD (Central Business District)

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4.2 Concept

Koolhaas imagined a building whose three dimensional form offer CCTV staff to perform the

functions within a "continuous loop" referring to a closed circuit television, and presented the

beginning of an engineering challenge.

The new building consists of two high L-shaped towers, joined at the top and bottom at an

angle that forms a loop, which has been described as a cross on Z. Designed by OMA as a

reinvention of the skyscraper as a loop, the construction of the building began in 2004. With

approximately 473 000m2, houses the headquarters of CCTV television studios, offices and

broadcast facilities and production. This is the largest project of OMA and its first major

building in China.

Spaces

The building challenges the typical search pursuing final height of the skyscraper. Arose from

a common platform, the two towers are inclined towards each other and merge into a

perpendicular cantilever of 75 meters. The design combines the entire process of television

work, previously dispersed in several places of the city, creating a loop of interconnected

activities.

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Functional Areas

The 473.000m2 building are divided as follows

64.200m2 administration 54.900m2 multi - purposes , 65.800m2 new productions, 31.800m2

broadcasting production programs 105.400m2, 30.000m2 staff facilities, parking 61.500m2,

15.000m2 services spaces plus a hotel, a visitor centre and a large theatre .

4.3 Construction

The building is not a traditional tower, but a loop of six horizontal and vertical sections

covering 473,000 m2 of floor space, creating an irregular grid on the building's facade with

an open centre. Its construction is considered a structural challenge, especially because it is in

a seismic zone. The overhang extends perpendicular 75m west and 67m south.

The building was constructed by joining three volumes created a unique final volume. In

order not to block the structural differentials this connection was scheduled to take place at

dawn, when the steel of the twin towers were cooled and raised and managed the same

temperature.

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Towers

Tower 1

The highest tower 234 meters in 54 plants, with a footprint of 40x60mm, 2.400m2 and an

area of 405,000 m² floor rises. The main hall of 10,000 m2, in Tower 1, is a three-story

atrium underground and three above ground level extends. It has a direct connection to the

underground network of Beijing, and is the place of arrival and departure of the 10,000

workers who come to the headquarters of CCTV. Connected to the lobby, 12 studies, the

largest of 2,000 m2 perform the primary function of the building: create TV.

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The tower consists of a series of horizontal and vertical sections that establish it as a structure

attached to land and not as a skyscraper. This will contain the administration, news,

broadcasting, studios and production areas .

Tower 2

Tower 2 has a height of 210m in 44 plants and a footprint of 40x52m, 2.000m2 . The smaller

building houses the Cultural Center Television (CCTV ). This has a hotel, a visitor center, a

large public theater and conference facilities and exhibitions for 1500 seats.

The headquarters of CCTV allows a degree of public access to production facilities

unparalleled in the Chinese media. An "Open Loop" takes visitors through the building,

exposing the daily work of the studies and the history of CCTV, culminating over the

cantilever, with spectacular views of the financial district, the Forbidden City and the rest of

Beijing.

4.5 Structure

Seismic studies

Because the seismic design of the CCTV building was outside the scope of Chinese

regulations, Arup proposed, from the outset, a design approach based on the technique,

adopting the first principles and modern methods as guidelines to achieve set performance

objectives at different levels of seismic events. Checks explicit and quantitative design were

made using linear and nonlinear seismic analysis allowed to verify compliance with the three

levels of seismic design required by the authorities.

Basic Quality Targets

No structural damage when subjected to an earthquake of level 1 with an average return

period of 50 years.

Repair structural damage when subjected to an earthquake of level 2 by return period of

475 years.

Accepted but forecast severe structural damage collapse when the building is subjected to

an earthquake of level 3, for an average return period of 2500 years.

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In the place where CCTV rise, values horizontal ground acceleration associated with the three

levels of design earthquakes are 7.20 and 40% respectively of gravity. The structure was a

challenge for engineers. They had to design a construction plan for two towers supported in

60° to 90° bend in its top and bottom, to meet, forming a continuous loop. The towers were

built in the opposite diagonal corners with a footprint of 160 x 160 meters, on a base of 45m

in height and 9 floors, connected by a podium in a 'L'. In its upper part were co- joined by a

bridge to 'L' parallel to the podium. Thin concrete cores inside the building support internal

floors. Basements with 4 levels reaching up to 18m below ground .

4.6 Exoskeleton

An exoskeleton system of diagonal grids has been adopted on the external faces of the

building to a loop structure that oppose gravity and any lateral force. The positioning of the

columns and down tubes reflects the distribution of forces in the surface skin of the building.

Diagonal columns grids have the same width exposed, but the depth varies according to the

load, while the diagonals are all plate girders 1m x 60 cm, with the only variation in the

thickness of the steel. The building is designed breaking Chinese codes design for such a

structure, but the system was accepted to be a very innovative design.

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4.7 Foundations

The design of the foundations required that the loads applied to the superstructure were

redistributed through the "pilecap" raft to engage the batteries enough to provide adequate

strength and stiffness. To validate the spread of load cell group, a complex iterative process

of analysis was used, adopting a nonlinear soil model . Superstructure loads were applied to a

discrete system model piled raft. Several hundred combinations direcionales charges were

automated in a spreadsheet for GSRaft control software iterative analysis of soil-structure

interaction nonlinear. This procedure repeatedly changed the input data in response to the test

results to model the charge redistribution between piles when their safe working load was

reached. Next, the analysis was repeated until the results were combined and all batteries

were within allowable capacities. The envelope of these hundreds of analysis was then used

to design the reinforcement in the raft itself.

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4.8 Connections

Installation of first connection element

The strength of the braces and edge beams must be transferred through and sections of the

column with minimal disruption to the tensions already present in the column. The

connection is formed by replacing the flanges with a large column of steel plates "butterfly",

which pass through the face of the column and are then connected with the clips and the edge

beams. To simplify the detail and construction of concrete around the steel section, no

network column connection is done . Seals must operate with braces, beams and columns as a

"strong joint / weak component". Connections must withstand the probable maximum load

that was delivered to them from the clamps, with minimal performance and a relatively low

degree of stress concentration . high levels of stress can lead to breakage of fragile welds

under cyclic seismic loading, a common cause of failure in connections observed after the

1994 Northridge earthquake in Los Angeles. The connections, representing the typical causes

and more severe, were modelled from the original AutoCAD drawings using

MSC/NASTRAN, a package of finite element analysis of high resistance models were

analyzed by subjecting them to the full range of forces that can be developed before braces

buckle or yield to assess the magnitude of stress and the degree of stress concentration in the

joints. then the butterfly shape plate was adapted to soften the corners and notches until

potential regions of performance were minimized and degree of concentration of efforts

placed at normal levels allowed in the practice of civil and mechanical engineering.

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Conclusion

The defining feature of the stadium is its roof: spanning 310 metres, it is the world’s largest

free-span dome is itself as a innovative.

A retractable roof is another essential innovative feature that it provides shade and thus

cooling when required and of course shelter from rainfall. The roof is left open when The

Stadium is not in use, keeping the grass pitch in healthy condition.

Rearrangeable seating -The lowest tier of seats can be mechanically and automatically

retracted, making the National Stadium the only stadium in the world able to accommodate

events from football, rugby, cricket and athletics, to concerts, cultural shows and community

events at any time in the year.

The Skywalk is an innovative because it is the first-ever cantilever shaped glass walkway to

suspend more than 4,000 feet above the canyon’s floor and extend 70 feet from the canyon’s

rim.

Also its foundation is strong enough to support about 71 million pounds – the equivalent of

71 fully loaded 747 airplanes.

Each panel has a thin “sacrificial” layer of glass that can be removed and replaced by hand

when it becomes scratched, instead of bringing in a large crane to replace glass.

The Skywalk was assembled on top of the canyon wall in line with its final placement and

moved into final position by a jack and roll rig. The Skywalk infrastructure itself weighs a

little over 1,000,000 pounds (450,000 kg) without counterweights but including the tuned

mass dampers, railing hardware, glass rails, glass deck and steel box beams. At the time of

roll-out, the Skywalk weighed approximately 1.6 million pounds (730,000 kg). The process

was completed in two days.

SkyPark-At 1,115 feet long, 131 feet wide, and cantilevering 213 feet at an elevation of over

650 feet above grade, the hotel rooftop SkyPark is the world’s longest habitable cantilevered

observation deck and has become a symbolic icon for Singapore in the process.

The taper of the base created a significant technical challenge because of the form’s

asymmetry and because the curved eastern legs cause each tower to lean against the opposing

vertical legs. As a result, the primary lateral force demands imposed on the building are

governed by the effects of gravity rather than either wind or seismic effects.

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The building challenges the typical search pursuing final height of the skyscraper. Arose from

a common platform, the two towers are inclined towards each other and merge into a

perpendicular cantilever of 75 meters.

An exoskeleton system of diagonal grids has been adopted on the external faces of the

building to a loop structure that oppose gravity and any lateral force. Diagonal columns grids

have the same width exposed, but the depth varies according to the load. The building is

designed breaking Chinese codes design for such a structure, but the system was accepted to

be a very innovative design.

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S.J. Bennison, C. A. Smith, A. Van Duser, & A. Jagota, “Structural Performance of

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CCTV Headquarters at Structurae

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