1. A rticle
Burj Al-Arab, UAE
Structural Steel Construction For
A Mega Project
By Dato’ A K Nathan, Managing Director, Shin Eversendai Sdn Bhd
I
n recent years, all over the world,
the construction industry is
emerging very rapidly both in
engineering and technology, and
contributing significantly to economic
development. In the later part of the
past century, there has been extensive
usage of steel in the construction
industry and steel explored much more
possibilities to substitute other
conventional materials.
With today’s structural steel framing,
grace, art and function can come
together in almost limitless ways; it
offers new solutions and opportunities,
allowing architects to stretch their
imagination and actually create some of
the most challenging structures they
have designed in their minds.
Structural steel has entered a new era.
Today it provides not only strength to
buildings but also beauty. Steel is not
only being used to provide a stable
framework for a structure but in many
cases is also chosen for its aesthetic Burj Al Arab
appearance.
dominating the Dubai coastline. This contractor. Now Eversendai is
Eversendai have had the good fortune all-suite hotel reflects the finest that dominating their presence in the
to be involved in steel structure the world has to offer. An architectural Middle East.
projects of diverse types one of which marvel, it is an engineering excellence
was The Burj Al Arab. It will demonstrate for the 15 th tallest building in the The Burj Al Arab means “Tower of the
the versatility of steel for various world. Arabs” is situated at Dubai, United
applications and also illustrate the Arab Emirates, designed by Mr
various complexities:- It is the world’s tallest hotel structure. Thomas Wills Wright. It stands in the
This project has become Eversendai’s sea, 280m away from the beach in the
Designed to resemble a billowing sail, signature project and it has paved the Persian Gulf on a man made island
one of the most fascinating, majestic, way for Eversendai’s entry into the connected to the main land by a
wonder structures in the world, the Middle East’s booming construction private curving bridge. It has access by
Burj Al Arab soars to a height of 321m, market as a specialist structural steel Land, Sea and Air.
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2. A rticle
It is one of the most fascinating, with a woven, Teflon-coated fiber glass smallest suite occupies an area of 169 sq
complex and challenging project ever cloth. The Burj al-Arab features the m, and the largest one covers 780 sq m.
undertaken by Eversendai. tallest atrium lobby in the world It is one of the most expensive hotels in
standing at 180m. the world to stay in. The cost of staying
The structure is a standing example for in a suite begins at US$1,000 per night
the quote “Architect’s Dream, Engineer’s This Burj Al Arab building is a hybrid V and increases to over US$15,000 per
Night Mare”. shape structure constructed in concrete night; the Royal Suite is the most
up to 209 m and blended with structural expensive, at US$28,000 per night.
Steel is the best-opted material for this steel creating an impressive
building due to its flexibility and engineering master piece. This V- We are proud to say that this project
constructability. shaped frame wraps around the V was the major break through for
reinforced concrete tower containing Eversendai Engineering in Middle East
The Burj Al Arab building is made of 28 the hotel rooms and lobbies. The two region. The Project was been awarded
storeys of split levels (56 storey) with structures connect along a shored, to Eversendai purely based on its
100,000 m 2 floor area, 60000 m3 of reinforced concrete spine at the base of construction methodology, capability
concrete, 9,000 ton of reinforcing steel, the V, and at two points along the and reliability. Eversendai scope
12,000 ton of structural steelworks, curving atrium wall. includes the site assembly, alignment,
80000 m2 of cladding, 10000 m2 of teflon welding and erection of structural steel
- coated fiber glass cloth and sits on 250 Ninety percent of the steel structures works.
piles of 1.5m in size, 45m under the sea, constructed were outside the building
the piles rely on friction as there is only and was potentially dangerous to erect. Total Steel works are phased into
piles embedded in sand to hold the Three self-climbing tower cranes with a Exoskeleton Rear leg, Horizontals,
building up. maximum lift capacity of 64 tons at 8.0 Diagonals, Rear Brace Frame, Helipad,
meters radius were used. Some of the Sky Restaurant, Atrium and the Mast :-
Construction of the Burj Al Arab hotel embedment weighed as high as 60
began in1994, and its doors were tons. Exoskeleton Rear leg Erection
opened to guests in December,1999.
The top is the mast and below it is the About 100 tons of electrodes were The exoskeleton is made up of two legs
helipad, and extending from the other burned and the welding defect ratio on both sides of the building starting
side of the hotel, over the ocean, is a was less then 1%. from the ground level to 273 meters
restaurant supported by a cantilever and connected to the front legs starting
structure. A remarkable element of its The Burj Al Arab does not have ordinary from 208m. The total weight of the
architecture is the outer beachward rooms; rather it is divided into 202 structure is about 2,800 tons. The
steel wall of the atrium, which is covered duplex suites with split levels. The structure was made of two build up H
sections of 1.8 metre wide by 4.5 metre
deep plate girders (inner and outer legs)
connected by a lattice braced members
and segmented to 40 ton capacity 12m
in length to create the gentle curve in
concurrence with the building edge
developing the shape of a sail.
The assembled segment were lifted and
erected in position using the tower
cranes from ground floor to top, one
over another using specially designed
lifting lugs with 20 ton chain hoists in
the pre-determined lifting location to
lift the segment in required angle.
After each segment were erected,
temporary struts were introduced to tie
Hybrid V shape structure back the rear leg to the core wall to
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3. A rticle
Rear Brace Frame same process of erection to complete
the three portions of X rear braces in
The two cores on the rear side of the the building.
building are 40m apart and connected
by huge cross bracings of fabricated Diagonals
box sections called the rear braces.
The diagonals are of huge tubular
The box sections were brought into the triangular truss geometry having the
site in transportable segments. The maximum cross section at the middle
cross sections of the boxes are 2.2m by length and merged as one member at
1.4m and made of from 25mm to 40 the ends. The Diagonal vary from 76m
mm thick plates. The box sections are to 90m in length and weigh 160 to 180
assembled and welded at the ground ton. The Diagonal connects with a
level by the side the building. 300mm diameter pin connection to
the core-wall and the Rear-leg
This brace ties both the cores together structure. There are six diagonals
to give stability to the structure. The erected at different levels on both side
Framework total tonnage of this part alone is 1600 of the building.
tons. The shape of the Rear Brace is
maintain alignment until the similar to “X “are erected in segments. These diagonals are transported as a
Exoskeleton grows to the next point of All the joints are of full penetration single fabricated piece from the
permanent connection and then welding. fabrication shop 15 km away by special
connected permanently with the Link self propelled long trailers.
Stud weighing about 10 tons to the These rear braces form as X of three
concrete core. There were three Link portions for the whole building. The Strand jacks supported by Cat heads
studs on each side of the building, length of one brace was around 60m in were connected to the building to
fixing at three points for the entire one direction from one side of the execute the lifting of the Diagonals
length of 273 metre Exoskeleton to the bottom embedment to the upper and Horizontals. Utmost care was
diagonal brace and horizontal brace embedment of the other side of the taken to ensure that the measurement
point and continued erection of the core, it was spliced into three pieces. length between the core and the
segment only after the erection of The first piece was about 24m and exoskeleton rear leg so that the
diagonals and horizontals and finally weighs about 50 tons and was lifted by diagonals with pin connection can be
connecting to the front legs starting two tower cranes as a tandem lift and connected with ease.
from 208m. erected between core embedment
from one side and the another end
All exoskeleton are lifted in rested on the temporary lattice girder
predetermined angles adjusted by trusses running between cores to
chain blocks, hooked on to the crane support the rear brace segmental
and lifted in segments. All the joints are erection. Once these two 24mts braces
of full penetration welding and were erected then the X of 12m length
inspected by ultrasonic test. of 52 tons was erected by two tower
cranes as tandem lift supported by the
Platforms were fitted at each joint for second layer of temporary lattice
welding and other related works girder truss, which was erected
between cores, the whole rear brace is
Alignment was carried out using in inclined towards the inside of the
electronic digital total station located at building. After all welding, touch up
three different fixed locations, all inspections been carried out, all the
surveying are done very early in the temporary platforms, scaffolds and the
morning to get a more accurate reading, three lattice girder trusses were
keeping in mind the movement of the removed from its position and re –
structure due to thermal effects which erected to the upper portion of the
generally develops deflection. rear braces location to continue the Front view of Burj Al Arab
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4. A rticle
Horizontals
The horizontal weighting about 200 tons
connects the core wall to the
exoskeleton rear leg. This structure was
assembled in one piece in the assembly
yard near the project side. The
Horizontals were transported by long
special self-propelled trailers to the
erection site.
They had to be erected between two
fixed points so utmost care was taken to
measure the length between the core
and the exoskeleton rear leg.
Horizontal were erected by strand
jacking method similar to Diagonals,
using the same cat heads platforms.
and potentially dangerous structures mast is in oval shape of 2.5m x 5m at the
Once the horizontal reached its to erect. The box girders cantilever bottom and gradually decreases to 2.5
determined elevation, then it was slide out for about 30m from the main core x 2m at top. All the segments were
towards the building and placed to its wall of the building connected to bolted inside by ring plate flange
position connected with bolts and about 200 tons of embedment. The connections. All the segments had
welding. restaurant is having a floor size of 70m inside arrangements of permanent
x 25m. The total structure is built up ladders and interval platforms to
The strand jacks and the cat head on eight cantilevered box sections facilitate access and maintenance.
platforms were removed from its and two end trusses at 200m above
position and kept ready for the next cycle the ground level. The beauty of the The first segment of the mast was
of operation. Once cat heads and strands restaurant is that it over looks the sea. erected after the Exoskeleton was
were removed then the Exoskeleton One of the highlights is, two 30m long erected on the trusses which run
typical erection sequence was carried girders had to be erected at 200m between two Exoskeleton legs in
out up to its level to the next diagonal level but the crane did not have the horizontal plane.
and horizontal fixing point and then lifting capacity so we had to split the
stopped to continue diagonal and girders into halves and joint up in the There were manholes at periodic
horizontal strand jacking operation. air with full penetration welding, it intervals, through that workers had
was a real challenge and Eversendai access to go and come out from the
Helipad Structure took it up and performed beyond mast to the nearby Exoskeleton
everyone’s expectation in a record temporary scaffolding arrangement.
This structure is at 212m level at the rear duration of 40 days. Temporary Safety exhaust fans were
side of the building, weights about 330 introduced inside the mast to have air
tons made up of steel trusses and 20mm Mast circulation to workers.
thick plates. Two props of 1m diameter
circular steel pipes, forming an inverted The mast is about 104mts long, only Before the mast erections coming to
V shape, tapered at 30º to the vertical and 54m was braced in between end with the use of the tower crane, the
tied back to the center core by a 40m Exoskeleton support legs starting from other two cranes were dismantled
long spine truss weighing 120 tons, 208m level on the core wall and the except the crane near to mast.
support the total Helipad structure. balance cantilevers vertically 50m way
above the Exoskeleton. Finally the third crane was dismantled
Sky Restaurant Structure by derrick crane. After complete
The overall mast was erected in dismantling of tower crane, derrick crane
The 350 ton structural steel sky segments of average 30 ton weight was dismantled manually and lowered
Restaurant was one of the most complex matching the tower crane capacity. The from the roof top by winches. MBJ
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