The burj khalifa project is located near down -town dubai, UAE.

This is a multi-use tower that includes residential, hotel, commercial offices, entertainment, shopping, and parking facilities.

It is the world’s tallest structure ever built.

Its construction began on 21 September 2004, the exterior of the building was finished on 1 October 2009.

It was under construction for six years.

It was inaugurated on 4th January 2010.

The total cost for the project was about US $1.5 billion.

Height =828m

Numbers of floors=162

Total area=465,000 square meters

Concrete used=250,000 cubic meters

Steel used=39,000 tonnes

Glass used=83,600 square meters

Architect/Structural/Design: Skidmore, Owings and Merrill (SOM), Chicago.

Chief Architect & Engineer: Adrian Smith & Bill Baker

Field supervision: Hyder Consulting Ltd.

General contractor: Samsung/BeSix/Arabtec

Foundation contractor: NASA Multiplex

Project Management: Turner Construction Company

Developer: Emaar Properties, Dubai

The design of Burj Khalifa is derived from the geometries of desert flower Hymenocallis.

The desert flower is indigenous to both the region and patterning system embodied in Islamic architecture.

The tower is organized around a central hexagonal core with three wings.

Each wing consists of four bays where, at each 7th floor, one outer bay peels away as the structure spiral into the sky.

The floor plan is characterized with a Y shape which maximizes the views of the Persian Gulf and provide tenants with plenty of natural lights.

The structure is designed using:

1. Reinforced concrete (High performance concrete) from the foundation to level 156.

2. Structural steel braced frame from level 156 to the pinnacle.

Building a skyscraper poses challenges thattest the mind of any engineer. Burj Khalifastands a whopping 828m in the air makingit the tallest building in the world.

However, this was not accomplished withoutovercoming several major engineering designobstacles.

Here are some of the challenges andinnovations that the designers of Burj Khalifaovercame and engineered:

Select and optimize the tower structural system for strength, stiffness, cost effectiveness, redundancy, and speed of construction.

Utilize the latest technologies and construction methods.

Manage and locate the gravity load resisting system so as to maximize its use in resisting the lateral loads.

Incorporate the latest innovations in analysis, design, materials, and construction methods.

Limit the building Movement (drift, acceleration, tensional velocity, etc.) to within the international accepted design criteria and standards.

Control the dynamic response of the tower under wind loading.

The tower’s lateral load resisting system consists of high performance reinforced concrete ductile core walls.

Walls are linked to the exterior reinforced concrete columns through a series of reinforced concrete shear wall panels.

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 or composite link beams at every level.

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.

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).

Structural steel

Braced Frame System

Reinforced Concrete

Core wall/Frame System

Gravity load management is also critical as it has direct impact on the overall efficiency and performance of the tower.

The gravity load flow line should be smooth.

The total material needed to support the gravity load and that required to resist the combined effect of gravity and lateral loads is shown in figures.

The composite link beams were used as means of transferring the gravity loads into the center corridor Spine web walls (650mm),to the hammer head walls and nose columns for maximum resistance to lateral loads.

Along these load flow lines the strain gages are installed to track the gravity load flow.

The reinforced concrete center core wall at level 156 provides the base support for the spire and pinnacle structure.

As with any tall building, wind plays a major factor in the construction and design process.

In order to begin building, the design team of Burj Khalifa conducted over 40 wind tunnel tests at Guelph, Ontario, Canada.

The 3D analysis and dynamic analysis indicated that the tower sways 1.5m at its highest point.

Engineers spent months in wind tunnels with scale models perfecting this “Y” shaped design. Wind could strike the tower from any one direction and the opposing leg of the “Y” would remain unstressed.

The wind engineering management of the tower 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.

As the wind encounters a different shape at each new tier the wind vortices never gets organized, thus reduced the wind forces.

The foundations for the structure was one ofmany challenges faced during the designprocess.

The site was already mostly flat, but theground around the surface was not nearstrong enough mostly comprised of loose tomedium sands on the surface level and evenweek sandstone and siltstone underneaththat.

It was apparent from the beginning thatthere was going to be some deeply set pillarssupporting the foundation.

The pillars that were to be used were tested in the laboratory and found to have a maximum axial load capacity of 64MN.

Based on this number and the layout of the projected building, a layout of 192 bores piles were laid out running about 50m deep into firmer grounds underneath.

The piles were 1.5m in diameter and staggered about 4m from one another spread through the foundation.

An assessment of the foundations for the structure was

carried out and it was clear that piled raft foundations

would be appropriate for both the Tower and Podium

construction.

Tower piles were 1.5m diameter and 47.45m long.

The podium piles were 0.9m diameter and 30m long.

The thickness of the raft was 3.7m.

The task of laying concrete from ground level to heights soaring above 1600 feet had simply never been done before.

To do this, engineers simulated the effects of pumping concrete to grand heights by testing concrete through horizontal pipes on the construction site.

Engineers successfully used 80 MPa of pressure to pump concrete to a height of 1972 feet.

During the construction of the Burj Khalifa people from all over the world came to work on different aspects of the building.

During the height of construction over 12,000 workers were on site every day, and after all was said and done over 60 contractor companies had made their mark on this extraordinary project.

Managing all these people and all these operations was no small task that was only complicated by the extreme conditions of the building site.

Impressive safety measures were implemented throughout the building of the Burj Khalifa.

Workers initially were put through an extensive training course.

The higher you climbed the more thorough was the safety, which also depended on the type of work that was to be done.

Strict, “almost military like” rules (Mohammad Moiz Al Deen, health and safety manager at Burj Khalifa) including a strict no smoking policy were enforced throughout the project, with over 100 people being fired for various incidents.

The stack effect is a common problem in most high rise buildings and is also prevalent but less pronounced and dangerous in everyday buildings and houses.

The stack effect is the movement of air into and out of buildings. Commonly, the warmer air is lighter and less dense than cold air. Therefore the warm air will rise to the top of the building while the cold air will try to fill the cracks in the bottom of the building.

This could be disastrous to a building as tall as Burj Khalifa. Cracks in the foundation could cause complete structural failure.

To mitigate this effect, the designers of the building used several air duct systems to move the warm air out of the building.

The stack effect cannot be completely eliminated however it can be mitigated and used as a ventilation system for the upper part of the building.

The development of the Survey and SHMprograms at Burj Khalifa included;

Testing all concrete grades to confirm the concrete mechanical properties and characteristic (strength, modulus of elasticity, shrinkage and creep characteristics, durability, heat of hydration, etc.)

Survey monitoring programs to measure the foundation settlement, column shortening, and tower lateral movement from the early construction stage until the completion of the structure.

Strain monitoring program to measure the actual strains in the columns, walls, and near the outrigger levels to confirm the load transfer into the exterior mega columns.

Installation of the temporary real-time health monitoring program to measure the building lateral displacement and acceleration during construction, and to identify the building dynamic characteristics (frequencies, damping, etc) during construction.

This system included bi-directional accelerometers, GPS system, and weather station (wind speed, wind direction, humidity, and temperature).

Typical Strain Gage Monitoring System Concept and Layout for the tower superstructureand foundation systems.

Detailed summary of the temporary real time monitoring program configuration and building movement during construction (due to Sept. 10 2008 earthquake in Iran)

Installation of a permanent real-time structural health monitoring (SHM) program to measure the building acceleration, movement, dynamic characteristics (frequencies, mode shapes), acceleration time history record and tilt of the foundation at the base of the tower, wind velocity profile along the entire height, weather station, and fatigue behaviour of the spire/pinnacle.

Detailed summary of the permanent real-time Structural Health Monitoring (SHM) program concept developed by the author for Burj Khalifa.

Concrete construction showed to be at its infancy where nobody has dreamt of creating such a tall building using concrete.

Burj khalifa project has demonstrated that as the technologies advance, the super tall building won’t be a dream anymore.

Burj khalifa is a step forward in meeting the technological challenges of future construction.

Burj khalifa simply proved that ‘Nothing is Impossible ’

Thank You