Burj khalifa

Burj Khalifa The tallest Building in The World Dr/ Shreef Sheta

Safa Mohamed Al Saeed / Diploma 2012/2013

Mansoura University

Faculty of Engineering

Index

3 Construction of Burj khalifa

4 Monitoring Program , fire safety ,supply systems

2 Structural and Architectural System

1 Introduction

General Information Comparison of Burj Khalifa with other skyscrapers

1. Introduction

General Information

Official Name: Burj Khalifa Bin Zayed Also Known As: Burj Dubai Built: 2004-2010 Cost: $4,100,000,000 Designed By: Skidmore, Owings & Merrill Structural engineer : William F. Baker Main contractor: Samsung C&T Developer: Emaar Properties Type: Skyscraper Total Stories: 206 Inhabited Stories :106 Elevators: 57 , speed:10m/sc Maximum Height: 2,717 Feet / 828 Meters Total area: 4,000,000 sq.m Location: No. 1, Burj Dubai Boulevard,

Dubai, United Arab

2. Comparison of Burj Khalifa with other skyscrapers

DescriptionBurj Khalifa, the tallest man-made building in human history, standing at 828m, is certainly a beautiful piece of artwork, combined with the precision in mathematics and engineering.

Different from other skyscrapers,

Burj Khalifa is characterised by an entirely distinctive facade, with a pointed spire on the top of the building, accompanied by 26 helical levels. Viewed from above, the building itself can be easily distinguished by the special Y-shape of its cross-sections, with the curves at each ends symbolising the onion domes – an essential element in Islamic architecture.

Comparison of the cross-sections

Comparison of Burj Khalifa with other skyscrapers

Burj Khalifa compared with some other tall structures

1. Architectural Style

2. Structural System

3. Cladding System

4. Interior Finishes

Design inspiration The advantages of the tower shape design The tower uses Elevators

Flower shape The architecture features a triple-lobed footprint, an abstraction of a desert flower named Hymenocallis.

The tower is composed of three elements arranged around a central core.

Twenty-six helical levels decrease the cross section of the tower incrementally as it spirals skyward.

A Y-shaped floor plan maximizes views of the Arabian Gulf. Viewed from the base or the air.

Design inspiration

Architectural design

1. The three wings

2. Y shape

3. The central coreThe Gradient spiral of

the tower levels

Design inspiration

LAYOUT

1

3

2

The advantages of the tower shape design

The advantages : Foundation : The modular, Y-shaped structure,

with setbacks along each of its three wings provides an inherently stable configuration for the structure and provides good floor plates for residential.

Usage : The Y-shaped plan is ideal for residential and hotel usage, with the wings allowing maximum outward views and inward natural light.

Nature : Gradient spiral design hinders the swirling wind .fig.1

Top level

Middle level

Lower level

Tower levelswind

wind

wind

Tower uses

The Burj Khalifa project is a multi-use development tower with a total floor area of 460,000square meters that includes residential, hotel, commercial, office, entertainment, shopping , leisure, and parking facilities.

9

76

1

7

211

3

4

5

8

10

67Layout details:1.Burj khalifa arrival court

2.Armani hotel entry

3.Residential entry

4.Viewing deck

5.Lake front promenade

6.Tower garden

7.Water feature

8.childern’s play area

9.Recreation area

10.Service yard

11.Office entry

The advantages :

spire

Level 160 to 168

Level 40 to 42

Level 77 to108

Level125 to135

Level112 to121

Level109 to111

Level 76

Level136 to138

Level 38 to 89

Level 19 to 37

Level 9 to16

Ground to level 8

Level 155

Level 139 to 154

Level 124

Level 123

Level 122

Level 73 to 75

Level 44 to 72

Level 43

A

Level 17 ,18

B

Level 156 to 159

Mechanical floor housing electrical sub-stations, water tanks and pumps, air handling units, etc

The right wing :Spire : Over 200m long and houses

communications equipment .Level 156 to159 : Broadcast and telecoms companies .Level 125 to 135 : The corporate suites .Level 112 to 121 : The corporate suites .Leve77 to108 : Private residences .Level 76 : Sky lobby (fitness facilities, jacuzzi, swimming pools and recreational room) . level 38 to 39 : Armani hotel Dubai .Level 19 to37: The residence .Level 9 to 16 : Armani residence .Concourse, ground to level 8 : Armani hotel Dubai .

The left wing :Level 139 to 154 : The corporate suites .Level 124 : At the top observation deck Level 123 : Sky lobby ( business lounge and library) .Level 122 : At.mosphere restaurant .Level 44 to 72 : The residence . Level 43 : Sky lobby (fitness facilities, jacuzzi, swimming pools and recreational room) .

A : PODIUM : Provides a base ( 150m wide, six levels ) anchoring the tower to the ground . Provides separate entries

for the corporate suites , residence and Armani Hotel .

B : Foundation

Level’s uses

Podium concourse

Tower plans

Podium level1

Ground floor

Tower plans

Tower plans

Tower plans

Level 113

Level 145

Elevators

The building is expected to hold up to 35,000 people at any one time.

Otis Elevators has installed 57 elevators, and 8 escalators.

33 high-rise elevators including 2 double-decks.

138 floors served by main service elevator.

504 meters – main service elevator rise, the world’s highest.

10 meters per second – speed of elevators .

60 seconds – approximate time from ground to level 124.

10.000 kilograms – weight of hoist ropes.

Amani hotel : 0-8 level

Residences : 17-37 level

Armani hotel : 38-39 level

Residences : 44-72 leveL

Private Residences : 77-108 leveL

Corporate suites

service elevator

Structural system material Structural system description The consideration loads on the tower

Structural System Material

The tower superstructure of Burj Khalifa is designed as an all reinforced concrete building with high performance concrete from the foundation level to level 156, and is topped with a structural steel braced frame from level 156 to the highest point of the tower.The structure of Burj Khalifa was designed to behave like a giant column with cross sectional shape that is a reflection of the building massing and profile.

Dimensional finite element structural analysis model

Structural material : concrete , steel

Structural System: Buttressed Core

+ 828m

+ 585.7m

- 3.7m


Mat foundationConcrete

structure


steel structure from level 156 to the top

Structural system description

Structural system in general :

These corridor walls and hammerhead walls behave similar to the webs and flanges of a beam to resist the wind shears and moments.At mechanical floors, outrigger walls are provided to link the perimeter columns to the interior wall system, allowing the perimeter columns to participate in the lateral load resistance of the structure; hence, all of the vertical concrete is utilized to support both gravity and lateral loads.

. The structural system for the Burj Dubai can be described as a “buttressed-core” and consists of high-performance concrete wall construction.Each of the wings buttresses the others via a six-sided central core, or hexagonal hub.fig.1This central core provides the torsional resistance of the structure, similar to a closed pipe or axle.Perimeter columns and flat plate floor construction complete the system.Corridor walls extend from the central core to near the end of each wing, terminating in thickened hammer head walls.

Structural system description

Fig.1

central core

Corridor walls

hammerhead walls

This is the tier methodology for all the tiers of the structure.

It will be covered in more detail as the thread moves on with the construction.

1) Lateral load Resisting System :

The consideration loads on the tower

The tower’s lateral load resisting system consists of high performance, reinforced concrete ductile core walls linked to the exterior reinforced concrete columns through a series of reinforced concrete shear wall panels at the mechanical levels.The core walls vary in thickness from 1300mm to 500mm. The core walls are typically linked through a series of 800mm to 1100mm deep reinforced concrete link beams at every level.These composite ductile link beams typically consist of steel shear plates, or structural steel built-up I-shaped beams, with shear studs embedded in the concrete section.

The link beam width typically matches the adjacent core wall thickness .At the top of the center reinforced concrete core wall, a very tall spire tops the building, making it the tallest tower in the world in all categories. The lateral load resisting system of the spire consists of a diagonal structural steel bracing system from level 156 to the top of the spire at approximately 750 meter above the ground. The pinnacle consists of structural steel pipe section varying from 2100mm diameter x 60mm thick at the base to 1200mm diameter x 30mm thick at the top (828m).

The consideration loads on the tower:

R/C Hammer Head Wall

[1300 mm]

R/C Corridor Shear Wall

[650 mm]

R/C Perimeter Column

[3500x600]

R/C Hexagonal Core

Wall [600mm]

R/C Nose Columns

[1500mm]

Edge of R/C

Flat Plate

R/C Link Beam

Typical Hotel Level


R/C Outrigger Walls

To Nose Columns

R/C Outrigger Walls

To Perimeter Columns

R/C Hexagonal

Core Wall

Edge of R/C

Flat Plate

R/C Link Beam

Typical Mechanical Level

2) Gravity Load Management :


Gravity load management is also critical as it has direct impact on the overall efficiency and performance of the tower and it should be addressed at the early design stage, during the development and integration of the architectural and structural design concept.The limitations on the wall thicknesses (500-600mm) of the center core and the wing walls thickness (600mm) allowed, art of working with concrete, the gravity load to flow freely into the center corridor Spine web walls (650mm) to the hammer head walls and nose columns for maximum resistance to lateral loads.

Core wall

elevation

Wing B core

wall elevation

Set back

level

Outrigger

wall

Softened corners


Wind Engineering in general Shape strategies to reduce excitation :

Tapering and setbacks

Varying cross-section shape

Spoilers

Porosity or openings

Several wind engineering techniques were employed into the design of the tower to control the dynamic response of the tower under wind loading by disorganizing the vortex shedding formation (frequency and direction) along the building height and tuning the dynamic characteristics of the building to improve its dynamic behavior and to prevent lock-in vibration.

3) Wind Load

Wind Engineering Management


The wind engineering management of Burj Khalifa was achieved by : Varying the building shape along the height while continuing, without interruption, the building gravity and lateral load resisting system.reducing the floor plan along the height, thus effectively tapering the building profile.Using the building shapes to introduce spoiler type of effects along the entire height of the tower, including the pinnacle, to reduce the dynamic wind excitations.Change the orientation of the tower in response to wind directionality, thus stiffening the structure normal to the worst wind direction.

Importance

of wind

loads

Building height

Relationship between importance of

wind and height


The tower shape resists wind loadWind tunnel test

Over 40 wind tunnel tests were conducted on Burj Dubai to examine the effects the wind would have on the tower and its occupants.These ranged from initial tests to verify the wind climate of Dubai, to large structural analysis models and facade pressure tests, to micro-climate analysis of the effects at terraces and around the tower base

4) Earthquake Analysis :


Dubai outside the scope of the seismic activity .Liquefaction analysis of Burj Khalifa soil showed that it is not a problem

Burj Khalifa is located in Dubai, which is a UBC97 Zone 2a seismic region (with a seismic zone factor Z = 0.15 and soil profile Sc).

Thus Earthquake loads did not govern the concrete tower design (wind loads govern) but it does govern the design of the steel spire above the concrete tower.

How ever, Burj Khalifa resisted

earthquake of M5.8 magnitude that occurred in southern Iran on July 20, 2010. While the magnitude of this earthquake was diminished when it reached Dubai and was relatively small (less than 1milli-g at BK site),

Cladding system in general Cladding system details Cladding Pressure Testing

Cladding system in general

Cladding system : curtain wall The exterior cladding is comprised of

reflective glazing with aluminum and textured stainless steel spandrel panels and stainless steel vertical tubular fins.

Close to 26,000 glass panels, each individually hand-cut, were used in the exterior cladding of Burj Khalifa.

Over 300 cladding specialists from China were brought in for the cladding work on the tower.

The cladding system is designed to withstand Dubai's extreme summer heat, and to further ensure its integrity, a World War II airplane engine was used for dynamic wind and water testing.

The curtain wall of Burj Khalifa is equivalent to 17 football (soccer) fields or 25 American football fields.

Cladding material : Stainless Steel

Cladding System details

Curtain-Wall Detail

1. aluminum vertical mullion.

2. clear reflective insulating vision glass.

3. stainless-steel vertical fin.

4. horizontal spandrel panel.

5. concrete slab.

Cladding System plan Cladding System detail

Cladding System construction

Cladding System details

Cladding System

Cladding System at mechanical level

Cladding System inside view

Cladding Pressure Testing

Cladding pressure testing

A 1:500 scale cladding pressure taps . The location of each tap was determined and

agreed in consultation between SOM and the RWDI engineers.

The model was placed on a turntable in the wind tunnel.

The tunnel was configured with the existing surrounding buildings , then the tunnel was configured with the surrounding buildings of the future development in place.

Measurements were taken for 36 wind direction spaced 10 degrees apart .

The measured data is converted into pressure coefficients based on the measured mean dynamic pressure of the wind above the boundary layer .

The statistical data of the local wind climate accounts for the variable extreme wind speeds with wind direction .

Cladding Pressure Testing

2.0 kpa+-2.5 kpa

3.0 kpa

4.0 kpa4.5 kpa

3.5 kpa

4.5 kpa

+-+-+-+-+-

+-

The results of the test based calculations include both maximum positive and negative pressure based on a return period of 50 years.

The largest calculated negative cladding wind pressure was 15.5kpa , and the largest positive pressure was +3.5kpa.

The criteria are established and the contractor has completed his initial detail design , the performance of the curtain wall system must be proven.

The cladding system in Burj Khalifa was tested in the position for air infiltration , water penetration .

Tower test mock-up dynamic test for water penetration

Curtain wall wind pressure diagram

Interior Finishes

InteriorsThe interior design of Burj Dubai public areas was also done by the Chicago Office of Skidmore, Owings & Merrill LLP and was led by award-winning designer Nada Andric.The interior were inspired by local cultural while staying mindful of the building's status as a global icon and residenceIt features glass, stainless steel and polished dark stones, together with silver travertine flooring, venetian stucco walls, handmade rugs and stone flooring.

Lobby Areas (Corporate & Residential)

Interior Finishes

Spa and Pool Area

Construction Sequence Analysis (3-day cycle) Construction plan Construction Equipment

3.1 Construction Sequence Analysis

Stage 1

Reinforced concrete piles ( 1.5m in diameter and 43m long ) .Concrete mix for the piles had 25% fly ash and 7% silica fume.The mat is supported by 192 bored , Capacity of each pile is 3000 tonnes.The piles were made high density, low permeability concrete placed by tremie method utilizing polymer slurry.

Stage 2

The mat is 3.7 meters thick, and was constructed in four separate pours totaling 12,500 cubic meters of concreteA high density, low permeability concrete was used in the foundations.A cathodic protection system was also installed under the mat, to minimize any detrimental effects of corrosive chemicals, which may be present in local ground water.

Construction of the Tower Foundation


Stage 3

The corridor walls extend from the central core up to the end of wing, where they have thickened with hammer head walls. These walls behave like the web and flanges of abeam to resist the wind shears and moments.

Stage 4

The center hexagonal walls are buttressed by the wing walls and hammer head walls which behave as the webs and flanges of a beam to resist the wind shears and moments.

Construction of the Tower Superstructure

Stage 5

The wings set back to provide many different floor plates.The setbacks are organized with the tower’s grid, such that the building stepping is accomplished by aligning columns above with walls below to provide a smooth load path. As such, the tower does not contain any structural transfers.These setbacks also have the advantage of providing a different width to the tower for each differing floor plate.


Stage 6

The crowning touch of Burj Khalifa is its telescopic spire comprised of more than 4,000 tons of structural steel.The spire was constructed from inside the building and jacked to its full height of over 200 meters (700 feet) using a hydraulic pump.In addition to securing Burj Khalifa's place as the world's tallest structure, the spire is integral to the overall design, creating a sense of completion for the landmark.The spire also houses communications equipment.

3.2 (3-day cycle) Construction plan

Technologies used to achieve 3-day cycle The tower consists of more than 160 floors and is expected to be completed within a very tight schedule and 3-day cycle. Hence, the following key construction technologies were incorporated to achieve the 3-day cycle set for the concrete works:

Auto Climbing formwork system (ACS) Rebar pre-fabrication High performance concrete suitable for providing high strength, high durability requirement, high modulus, and pumping Advanced concrete pumping technologyFormwork system that can be dismantled and assembled quickly with minimum labor requirements Column/Wall proceeding method, part of ACS formwork system

Sequence of Construction and ACSFigures1and 2 depict the construction sequence of the tower and show the auto climbing formwork system (ACS), designed by Doka. The ACS form work is divided into four sections consisting of the center core wall that is followed by the wing wall construction along each of the three tower wings. Figure 2 also demonstrates the following construction sequence:

The center core wall construction is followed by the center core slab construction.The wing wall construction is followed by the wing flat plat slab construction , and…..the nose columns are followed by flat plate and flat slab construction at the nose area. In addition, the core walls are tied to the nose columns through a series of multi-story outrigger walls at each of the mechanical levels.


3to 5 levels below

6to 8 levels below

Work sequence

Section A-A

3 levels below

Core slab

Lobby slab

2 levels below

2 levels below

Nose slab Wing core wall Center core wall Corner slabSequence of Construction

Figure.1


Center

core wall

Automatic self climbing system

wing

core wall

Nose

column

Automatic self climbing system

Round steel form

slabPanel form system

With drop head prop

Sequence of Construction

Figure.2


The Doka climbing forms


Sequence of Construction

Center core wall

Wing wall

Nose column

Outer slab of

center core wall

Typical wing slab

Wing wall


Rebar pre-fabricationMost of the reinforcing bars for the core walls, wing walls, and the nose columns were prefabricated at the ground level.FIG.4 This rebar fabrication and pre-assembly method resulted:

Quality control Reduced the number of workers going up and down the tower. The rebar was assembled in double story modules to speed up the vertical element construction time.

FIG.3

FIG.4


Composite Link Beams

In addition to connecting the vertical core wall elements rigidly for maximum strength and stiffness for the lateral load resisting system, the link beams are also used as means of transferring and equalizing the gravity loads between the vertical members (core-wall elements and nose columns). This equalizes stresses and strains between the members Because the link beams are subject to large shears and bending moments, many of the link beams had to be composite (steel members encased in high strength concrete).

Composite Link

Beam Installation

3.3 Construction Equipment

Construction Equipment : Cranes Tower Hoist Concrete Pumping

CranesSite Logistic PlanThe Burj Dubai site area is approximately 105,600m2 and encompassing the tower, the office annex, the pool annex, and the parking areas, divided into three zones (Zone A, Zone B, and Zone C). The site logistic works and planning works are constantly evolving to reflect current construction activities, lay-down areas, site traffic circulation, etc.

Snap Shot of Site Logistic Plan


WEST WING External Line

Of 500 Thickness

con`c wall

19,783

1,000

1,000

11,322

11,52

19,78319,95611,522

1,00

0

T/C#M1

M440D 2,400x2,400

T/C#M2

M380D

2,400x2,400

T/C#M3

M2220D

2,000x2,000

South WingEast Wing

Here is a drawing of the 3 cranes that will rise with the core, M1 to M3

Three high capacity self climbing luffing type tower cranes were optimally selected and located at the center core of the tower as shown in Figures 10 and 15.


Figure 1 depicts the location of the main hoists and the hoist specifications. The hoists were installed in three different phases following the construction sequence of the tower.The four main PEGA twin-cage hoists will have a single run to a height or around 400 m, traveling at a top speed of 100 m/min. Hoists will eventually reach levels approaching 700 m.

Tower Main Hoist

Tower Main Hoists System

figure 1


Concrete Pumping equipment

Three major pumps were placed at the ground level as shown in Figure 1 and 2. Pumping line 1 situated at the center core, with pumping lines 2, 3 and 4 at the south, west, and east wings of the core.An additional pumping line 5 was located at the center core area for emergency use. , most of the concrete has been pumped directly to the highest concrete elevation, that in excess of 585m.A secondary pump at level 124 was in place in case of an emergency situation.

Tower Pump Equipment and Pipe Lines


Pipe Lines Diagram

Monitoring Program Fire safety system. Air supply system. Power supply system. Water supply system.

3.1Monitoring Program

Structural Health Monitoring Program and Network

The survey monitoring program ( SHM) is used in Burj Khalifa to measure the sustainability of

The tower ,during construction process , and also after tower occupation . The monitoring program consists of sensors , which fixed at several positions at the tower

To measure the resistance load system behavior , thus sensors is connected with net work computers to get the output data details . Since completion of the installation of the SHM program at Burj Khalifa, most of the structural system characteristics have been identified and included measuring the following:

Building acceleration at all levelsBuilding displacements at level 160M3Wind profile along the building height at most balcony areas, including wind speed & direction, which still needs calibration to relate to the basic wind speed.Building dynamic frequencies, including higher modesExpected building damping at low amplitude due to both wind and seismic eventsTime history records at the base of the tower.


Measured vs. predicted tower lateral movement, at tower’s geometric center, at every setback level and the tower’s center position with time.


Detailed summary of the permanent real-time Structural Health Monitoring (SHM) program

concept developed by the author for Burj Khalifa.

4.2 Fire safety system

Fire and life safety

plan system

The design of Burj Khalifa undertook with special attention to the fire safety and evacuation speed. The capacity of concrete surrounds of total stairwells besides building service and fireman's elevator has been so effective that it can easily bear 5,500 kg. That is why it is known for being the tallest service elevator in the world. Pressurized and air-conditioned refuge areas are designed on almost every 25 floor of this tower to ensure better safety as occupants can’t literally walk down to 160 floors in one go

4.2 Fire safety system

4.2 power supply system

Normal power supply and distribution systems

11KV Multiple feeds up the building

Multiple 11KV/400y/230V Transformers

located at mechanical floors

400Y/230V Local zone vertical bus

400Y/230V switch boards

11KV incoming DEWA service

The maximum amount of electrical energy required by the tower 50 million volt-amp .

4.3 Air supply system

Air supply systems – HAVC (Heating Ventilating and Air-Conditioning)

Fresh air intake through

Slots of louvers

Supply fans and air handling

units

Vertical supply air distribution

Through ducted vertical risers

6 mechanical zones

Major plant rooms at 7 levels

Hydraulically isolated system

4.4 water supply system

Domestic water supply system

High level tank

Gravity express down - high pressure

Local zone Gravity Down -

Intermediate tank

Express fill line up

Hotel tank

Main water storage tanks (Fire and residential)

Transfer pumps

Hotel main storage tank

Low pressure through PRV’S

Identical principal for sprinkler system

Production capacity:946000 liters

Validating the Structural Behavior and Response of Burj Khalifa :Synopsis of the Full Scale Structural Health Monitoring Programs ………………… Ahmad Abdelrazaq / Executive Vice President, Highrise & Complex Building, Samsung C & T, Seoul, Korea Burj Khalifa Tower , Wind Tunnel Testing of Cladding and Pedestrian Level …………. Peter A. Irwin, William F. Baker, Stan Korista, Peter A. Weismantle, and Lawrence C. Novak Burj Khalifa, Dubai, United Arab Emirates…………… Edward Mak Structural Engineering of World’s Tallest Building Burj Khalifa (Dubai) …………PDHengineer.com WIND ISSUES IN THE DESIGN OF TALL BUILDINGS…………….. Peter A. Irwin / Los Angeles Tall Building Structural Design Council May 7, 2010 Burj Dubai 400m high hoists,and rising…………………. ACCESS INTERNATIONAL / January-February 2007 Brief on the Construction Planning of the Burj Dubai Project………….. Ahmad Abdelrazaq / Executive Vice President, Highrise Building Team, Samsung Engineering & Construction BURJ KHALIFA, WORLD.S TALLEST STRUCTURE……… Dr.N.Subramanian / Consulting Structural Engineer, Maryland, U.S.A.http://www.archinomy.comwww.burjkhalifa.aehttp://archrecord.construction.comhttp://www.skyscraperlist.comhttp://www.sayedsaad.com

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