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CAPITAL GATE

1. INTRODUCTION

2. FACTS ABOUT CAPITAL GATE

3. STRUCTURAL ELEMENTS FOUNDATION CORE FAÇADE SUN SHADING

4. AMENITIES

5. PROJECT DATA

6. SUMMARY

7. REFERENCE

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AGENDA

• Capital Gate is the 35 storey focal point of Abu Dhabi's capital centre

• Certified by the guinness book of records as the farthest leaning tower

• Constructed with steel diagrid technology and prestressed precambered elliptical core

• The tower is 160 meters high with a lean of 18 degrees i.e. 35 meters overhang and has a massive eccentric deadweight

• Floors 2 to 16 accommodate commercial and office space and the top floors accommodate the hyatt hotel

• The tower has a organic shape which was inspired by the wind shaped sand structures in the desert

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INTRODUCTION

The vertical and horizontal cross-sections of the tower are all unique

Every one of the 12,500 panes of glass on the facade is a different size, although each pane is triangular.

The cross section of the tower changes from curved triangular to curved rectangular as the tower progresses upwards

The structure has two diagrid systems i.e. an external diagrid and an internal diagrid which is linked to the central core with eight pin jointed structural members

The external diagrid comprises of 8250 members which are of different thickness,length and orientation

The project was completed within two years

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FACTS ABOUT CAPITAL GATE

FOUNDATION: The foundation consists of a rectangular

raft footing supported on 400 concrete piles of 1 meter diameter

Half of the piles are under compression and run to a depth of about 20 meters

The other half of the piles run to a depth of about 30 meters and anchor tightly to the soil and are in tension due to the massive eccentric overhang of the building

The 2 meter deep raft footing was made up of 7000 cum of reinforeced concrete to distribute the loads evenly on the piles

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STRUCTURAL ELEMENTS

The core was pre cambred meaning it was initially tilted away from the overhang of the building and was straightened by the dead load of the building

The core was built using the technique called jump forming

The concreting was done at night to avoid the extreme day heat which may cause the concrete to dry and crack

Slump tests were carried out on evey batch of concrete Concreting was done by pumping and 250 mm slump

concrete was used The core was post tensioned A total of 146 tendons were incorporated into the core

through ducts

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THE CORE:

Each tendon was 20 meters long and splice overlap was upto 5 meters

Pneumatic jack was used to stretch each tendon at a time

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FAÇADE:

The façade /body was made up of steel cross sections called cruciforms

The external diagrid consists of 720 of such cruciforms

Each cruciform if having different curvature,length and thickness

The external cruciforms were made up of 600×600 mm hollow rectangular sections,the thickness of the sections ranged from 80 mm at the bottom to 40 mm at the top of the tower

The internal diagrid cruciforms were made with 80 mm diameter hollow circular sections

The dimensional accuracy +/- 1mm The floor height is 4 meters

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The exterior is made up of 26000 triangular glass panes called c240

The glass panes consist of two silver coatings

Each triangular glass pane has a unique shape

18 triangular panes connected to each other by hinge joints formed a diamond shaped panel measuring 8×8 meters

The diamond panels were connected to each other by a two layer seal which made it water proof and also allowed it to change shape

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the top 18 floors houses an attrium which reduces the eccentric weight of the building

The internal diagrid support the weight of the 18 floors and is funnel shaped

The internal diagrid is connected to the core by 8 pin jointed structural members on the 18th floor also known as mechanical floor

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There’s a two storey extension cantelevered 12 meters from the tower

They are braced to the external diagrid with circular steel members which reach diagonally down to the mechanical floor

The extension houses a swimming pool

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The sun shading also known as the ‘splash’ starts from the 18th floor and extends to the abu dhabi national exhibition centre grandstand

It is made up of steel members interlocked to form a mesh The splash protects the building form direct sunlight and reflects

upto 30% of the incident radiation thus decreasing the air conditioning required

The splash is supported by circular members which are connected to the external diagrid

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SUN SHADING:

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FLOOR PLANS:

1st floor plan 2nd floor plan 13th floor plan 15th floor plan

ELECTRICAL SERVICES: All common area lighting, power, two escape staircases and elevators are fed from

the landlord’s distribution network. One passenger elevator is backed up by standby generator power, for use in case of emergency. All life safety systems and essential services are backed up by the standby generator. In addition, some of the life safety system and essential system outlets are backed up by uninterrupted power supply (UPS) to ensure availability of power at all times.

The building is supplied at 11KV from an Abu Dhabi Distribution Company (ADDC) primary substation and network to basement sub-station.

Power is transformed to the operating voltage of 415 volts by five, 1,500KVA transformers installed in the substation. Main distribution boards (MDBs) are fed from the transformers installed in the basement low voltage (LV) switchgear room, adjacent to the substation. MDBs distribute power to the development, through cable routes, rising bus bars, sub-main distribution boards (SMDBs) and distribution boards (DBs).

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AMENITIES

MECHANICAL SERVICES: Fresh air ventilation, fan coil unit (FCU) systems,fresh air handling units (AHUs), smoke

extract ventilation system, variable volume air-conditioning system, and chilled water (CW) system are provided.The cooling requirement is served by TABREED district chilled water network, facilitated by an energy transfer station at the basement and Level 1 of the building as the primary supply of chilled water network consisting of two units of rated heat exchangers. The resulting or secondary chilled water lines will be metered as being conveyed by four rated pumps serving AHUs and FCUs mounted at all floors of the building.

PLUMBING: Sanitary wares, water tanks, domestic water systems, soil/waste/vent and overflows,

irrigation system and rainwater system have been included. The main source of the building’s potable water, from the ADWEA distribution line, is

stored in a tank at the basement floor, which undergoes a filtration system. The concrete water tank is a double compartment type, allocated for domestic water, fire protection system, and irrigation source.Aside from preliminary filtration, the domestic water passes through a proven anti-legionella chemical dosing system. Water tanks are provided at basement, Level 1 and Level 17, with compliance to ADDC requirements of minimum 2 days consumption storage.

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Cost of the project was $233 million 600 people labour force from different countries 400 sub contractors Completion Date: 2011 Height to Architectural Top: 165 meters Stories: 35 Total built up Area: 53,100 square meters Primary Uses: Hotel/Office Project Developer: ADNEC Group Architect: RMJM Structural Engineer: RMJM MEP Engineer: RMJM Façade Consultant: Hyder Consulting Landscape Consultant: Al Khatib Cracknell Main Contractor: Al Habtoor Engineering Steel Contractor: Eversendai Façade Contractor: Waagner Biro Project Manager: Mace

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PROJECT DATA

September 2007 – work commences November 2007 – Pile driving starts April 2008 – Core wall construction starts February 2009 – Façade commences May 2009 – Reaches 100 m in height June 2009 – Incline starts to take shape October 2009 – Attains final height of 160 m December 2009 – Completion of exterior core structure January 2010 – First phase of splash completed February 2010 – Interior fit-out commences March 2010 – Commencement of link bridge to Abu Dhabi National Exhibition Centre April 2010 – Commencement of atrium roof 2011 – Completed construction Opening date 21 Dec 2011

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PROJECT TIMELINE:

While clearly a unique structure was built using some of the world’s most advanced construction techniques, ADNEC believes the tower’s appeal goes far beyond an architectural and engineering marvel.Functionality and purpose have been a prime focus.Capital Gate houses Abu Dhabi’s first Hyatt Hotel, the five-star Hyatt Capital Gate, as well as approximately 15,000 square meters of office space.The tower is also strategically important to Abu Dhabi and visually represents the emirate’s progress and evolution. It is the focal point of a world class business district, and is inter-connected with the thriving Abu Dhabi National Exhibition Centre , which hosted more than 200 events in 2011, welcoming around one million visitors. Capital Gate’s visitors or tenants have access to the world-class amenities within the building as well as elsewhere within the ADNEC development, including facilities such as a fully-operational airport check-in facility.The Guinness world record for “world’s furthest leaning manmade tower” has shone a spotlight on Capital Gate and Abu Dhabi, as has a “Megastructures” documentary on National Geographic Channel (“The Leaning Tower of Abu Dhabi”), broadcast in more than 166 countries to an estimated television audience of more than 200 million.The people of Abu Dhabi feel a sense of honor in Capital Gate. They are confident Capital Gate’s aesthetic splendor and technical achievement will generate admiration and discussions around the world for years.

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SUMMARY

www.wikipedia.com CTBUH Journal, 2012 Issue II CTBUH Journal, 2013 Issue III www.skyscrapercentre.com www.capitalgate.eu

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REFERENCE