CCTV Headquarters China: Advanced building services

CASE STUDY:

CCTV HEADQUARTERS, CHINA GROUP MEMBERS: • • • • •

ANUSHA AGRAWAL – 18A NISHNA GADDAM – 18A SAKSHI VISHWAKARMA – 18A PRIYANSHI GARG – 18C HARSHAL GUND – 18C

INTRODUCTION

Architect: Rem Koolhaas

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Location: Beijing, China Engineer: Arup Completion date: May 16, 2012 Floor Count: 51 Floor Area: 389079 m2 Height: 234m (768 ft)

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CONCEPT • Highly unusual shape, described as a 'threedimensional cranked loop’.

• Carved out of a structural hollow pyramid.

• The building is formed by two leaning towers, bent 90° at the top and bottom to form a continuous tube.

DESIGN STRATEGY • To concentrate all the activity and every program in a single system.

• Accommodation of all major functions of media at national scale with a single loop of interconnected activities.

• Defies the laws of gravity.

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STRUCTURAL SYSTEM • It is a Diagrid Truss-Tube structure with interior columns.

STEEL STRUCTURAL SYSTEMS

COLUMNS

TUBE SYSTEMS

• This structure is usually used for structures that go up to 90 stories.

• Used here because of: a. tilted towers b. seismic zone c. Wind loads • It can also be classified as a trussed tube-in tube.

• Varying Columns height according to the levels.

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STRUCTURAL SYSTEM TOWER CORE-1 CANTILEVER CORE-5

CORES • There are 7 cores throughout the building.

TOWER CORE-2 TOWER CORE-3

• Helps to provide structure for different floor plate forms.

• 4 located in the towers

BOTTOM CORE-6 BOTTOM CORE-7

• 3 located in the cantilever and bottom structure • The core of the cantilever is supported by a 2 story tall transfer deck that carries the load back to the tube structure.

TOWER CORE-4

• The cores cater multiple building services as explained in further slides.

CANTILEVER • Proposed method 1: Constructing a temporary tower at the full height of the overhang to use as a platform for construction of the overhang in-place.

• Proposed method 2: Constructing the base of the overhang on the ground, then lifting it into place between the two towers.

PROPOSED METHOD - 1

PROPOSED METHOD - 2

CHOSEN METHOD

• Chosen method: Constructing the overhang as a series of cantilevers from each tower until they meet in the middle.

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AREA DISTRIBUTION

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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• Function of Basement: Water Storage

BASEMENT

Air Exchange

Electrical Parking

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Resists upward force of water pressure around site 3 stories Retaining walls 50 per cent increase in floor area Zero footprint More parking

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The elevator consultant specified over 90 elevators and 21 escalators for the whole project. Two substations, one in the top of each Tower, are dedicated to supplying some of this. To limit the size and number of escape stairs in the Towers, the lifts are used in parallel with the stairs.

PUBLIC SPACE AND VERTICAL CIRCULATION HIGHLIGHTING ELEVATORS

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SERVICE BUILDING • The north-eastern block of the CCTV site is occupied by the two-story ring-shaped service building.

• It is a combination of the central energy center (for both CCTV and TVCC), the special broadcasting vehicle parking lot and the guards' dormitories. The accommodations for the guards are located in the ring floating above E8 road, establishing an optical closure from the ceremonial plaza towards the east of the site.

• The lower portion of the ring in the south accommodates large broadcasting vehicles. The small vehicle garage, the energy center, and the fire control center are located within the boxshaped section to the north of E8 road.

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COOLING THROUGH VAV SYSTEM IS ECONOMICALLY BENEFICIAL. CCTV HAD POOR EXPERIENCE WITH CEILING-MOUNTED FAN COIL UNITS: LEAKS, CONDENSATION, AND REGULAR MAINTENANCE OF FILTERS AND FANS AT HIGH LEVEL WERE AMONG THEIR CONCERNS. ALSO, CHILLED WATER AND CONDENSATE DRAINS WERE UNACCEPTABLE ABOVE CEILINGS OR ANYWHERE AT HIGH LEVEL, EXCEPT IN MECHANICAL PLANTROOMS, TO REDUCE THE RISK OF DRIPS OR LEAKS DAMAGING BROADCAST EQUIPMENT. VAV SYSTEMS WITH TERMINAL REHEAT WERE AGREED AS THE PREFERRED OPTION.

HVAC SERVICES

TV STUDIO VARIABLE AIR VOLUME (VAV) AIR SUPPLY 10

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Any recirculated air in the building would pass through the AHU filters, trapping aerosols, so air-conditioning would be unlikely to contribute to the spread of this infection; most would occur by close contact within the workplace.

The plants serving broadcast functions would have the heating and humidification capacity to operate in an emergency without recirculation.

In a future infection problem, the 100% outside air emergency override would allow these areas to continue operation with reduced dissemination risk, even if other parts of the building had to be shut down.

LOCATION OF PLANTROOMS

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The 10kV radial feeders of the duplicated site distribution system are run from the consumer’s switchboard and routed via separate cable routes in a service tunnel to the building basements.

The power supply to the lifts is generator-backed, and cooling to the lift motor rooms is on the ‘essential’ circuit.

LOCATION OF SUBSTATIONS AND ELECTRIC SUPPLY DIAGRAM

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WATER-SUPPLY AND DRAINAGE SERVICES • Both CCTV and local codes required greywater in addition to cold water and drinking water, giving three cold water systems to integrate into an already complex building.

• The main water storage in the basement is transferred and distributed to draw-off points throughout the CCTV building.

• Intermediate break tanks, with variable volume pump sets and sensitive pressure-regulated control, will avoid excessive operating pressure and comply with local plumbing code requirements.

• The drinking water will be derived from the incoming domestic main, and then treated with localized particle and UV filtration at each zone before passing into the storage tank.

• Distribution will be as a pumped circulation main to constantly turn over the supply and avoid stagnation.

• To maintain the water systems’ integrity, the wastewater will also be separated to collect grey water from wash hand basins, showers, air-conditioning condensate drainage, and waste cooling water.

• The local authority is proposing to treat and return grey water from a centralized city plant.

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FIRE SUPPRESSION These include: • street hydrants around the perimeter of all three buildings to protect external areas and facades.

• internal fire hydrants and hose reels on the floors, positioned so that the jet of two fire hydrants or hose reels can reach any point.

• water cannon extinguishing systems in CCTV’s main entrance lobby and the TVCC atrium, as their height exceeds the effective operating height of the fast response type sprinkler system.

• foam cannon extinguishing system to protect the helipad on the CCTV roof.

• deluge systems for the CCTV studios and TVCC theatre stage, with open type deluge nozzles installed under the latter’s grid.

• water sprays for the diesel generator rooms.

• sprinklers in offices, hotel rooms, all general areas, corridors, and lobbies (fire hazard classification Medium Hazard II).

• Inergen (mixture of nitrogen, argon and carbon dioxide) gas suppression systems for ‘sensitive’ rooms where water spray risk was a concern and cleanup of residue can be a problem. These are fed from a centralized supply and are divided into nine zones in CCTV and seven zones in TVCC. 14

ANALYSIS • For such high rise buildings we can also provide a separate service building that connects with the city mains to deal with major services such as fire, electrical and water supply throughout the building.

• In this building VAV system is preferred to VRF system as it allows better temperature control for large commercial buildings.

• To limit the size and number of escape stairs in a high rise building, lifts can be used in parallel with the stairs.

• Floor area of basement can be increased so as to accommodate parking and other services like AHU and water storage, etc.

• The shafts carrying chilled water pipes should be located to air handling unit room or within the room.

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BIBLIOGRAPHY • • • • •

CTBUH Journal | 2008 Issue III Case Study: CCTV Building - Headquarters & Cultural Center The Arup Journal 2/2005 Time lapse images courtesy of OMA http://www.abeno.project-takenaka.com/abeno_e/saigai/sai-01.php The CCTV foundation system. http://www.360doc.com/content/10/1210/02/16546_76642178.shtml • CCTV Building, A Structural Design Overview http://www.slideshare.net/peterbach/cctv-building-a-structural-designoverview • CCTV Structural Analysis https://prezi.com/anmn7ckwvjtj/cctv-structuralanalysis/ • https://rasmusbroennum.files.wordpress.com/2009/02/2005.pdf 16

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