Burj al arab-uae


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Burj al arab-uae

  1. 1. A rticleBurj Al-Arab, UAEStructural Steel Construction ForA Mega ProjectBy Dato’ A K Nathan, Managing Director, Shin Eversendai Sdn BhdI n recent years, all over the world, the construction industry is emerging very rapidly both inengineering and technology, andcontributing significantly to economicdevelopment. In the later part of thepast century, there has been extensiveusage of steel in the constructionindustry and steel explored much morepossibilities to substitute otherconventional materials.With today’s structural steel framing,grace, art and function can cometogether in almost limitless ways; itoffers new solutions and opportunities,allowing architects to stretch theirimagination and actually create some ofthe most challenging structures theyhave designed in their minds.Structural steel has entered a new era.Today it provides not only strength tobuildings but also beauty. Steel is notonly being used to provide a stableframework for a structure but in manycases is also chosen for its aesthetic Burj Al Arabappearance. dominating the Dubai coastline. This contractor. Now Eversendai isEversendai have had the good fortune all-suite hotel reflects the finest that dominating their presence in theto 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 excellencewas The Burj Al Arab. It will demonstrate for the 15 th tallest building in the The Burj Al Arab means “Tower of thethe versatility of steel for various world. Arabs” is situated at Dubai, Unitedapplications and also illustrate the Arab Emirates, designed by Mrvarious 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 theDesigned to resemble a billowing sail, signature project and it has paved the Persian Gulf on a man made islandone of the most fascinating, majestic, way for Eversendai’s entry into the connected to the main land by awonder structures in the world, the Middle East’s booming construction private curving bridge. It has access byBurj Al Arab soars to a height of 321m, market as a specialist structural steel Land, Sea and Air. 77 3 r d Q u a r t e r 2 0 0 6
  2. 2. A rticleIt is one of the most fascinating, with a woven, Teflon-coated fiber glass smallest suite occupies an area of 169 sqcomplex 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 stayingThe structure is a standing example for in a suite begins at US$1,000 per nightthe quote “Architect’s Dream, Engineer’s This Burj Al Arab building is a hybrid V and increases to over US$15,000 perNight 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 impressivebuilding due to its flexibility and engineering master piece. This V- We are proud to say that this projectconstructability. shaped frame wraps around the V was the major break through for reinforced concrete tower containing Eversendai Engineering in Middle EastThe Burj Al Arab building is made of 28 the hotel rooms and lobbies. The two region. The Project was been awardedstoreys of split levels (56 storey) with structures connect along a shored, to Eversendai purely based on its100,000 m 2 floor area, 60000 m3 of reinforced concrete spine at the base of construction methodology, capabilityconcrete, 9,000 ton of reinforcing steel, the V, and at two points along the and reliability. Eversendai scope12,000 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 buildingthe piles rely on friction as there is only and was potentially dangerous to erect. Total Steel works are phased intopiles 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 60began in1994, and its doors were tons. Exoskeleton Rear leg Erectionopened 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 legshelipad, and extending from the other burned and the welding defect ratio on both sides of the building startingside of the hotel, over the ocean, is a was less then 1%. from the ground level to 273 metersrestaurant supported by a cantilever and connected to the front legs startingstructure. A remarkable element of its The Burj Al Arab does not have ordinary from 208m. The total weight of thearchitecture is the outer beachward rooms; rather it is divided into 202 structure is about 2,800 tons. Thesteel 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 tieHybrid V shape structure back the rear leg to the core wall to 78 3 r d Q u a r t e r 2 0 0 6
  3. 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 sideFramework total tonnage of this part alone is 1600 of the building. tons. The shape of the Rear Brace ismaintain alignment until the similar to “X “are erected in segments. These diagonals are transported as aExoskeleton grows to the next point of All the joints are of full penetration single fabricated piece from thepermanent connection and then welding. fabrication shop 15 km away by specialconnected permanently with the Link self propelled long trailers.Stud weighing about 10 tons to the These rear braces form as X of threeconcrete core. There were three Link portions for the whole building. The Strand jacks supported by Cat headsstuds on each side of the building, length of one brace was around 60m in were connected to the building tofixing at three points for the entire one direction from one side of the execute the lifting of the Diagonalslength of 273 metre Exoskeleton to the bottom embedment to the upper and Horizontals. Utmost care wasdiagonal brace and horizontal brace embedment of the other side of the taken to ensure that the measurementpoint and continued erection of the core, it was spliced into three pieces. length between the core and thesegment only after the erection of The first piece was about 24m and exoskeleton rear leg so that thediagonals and horizontals and finally weighs about 50 tons and was lifted by diagonals with pin connection can beconnecting 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 endAll exoskeleton are lifted in rested on the temporary lattice girderpredetermined angles adjusted by trusses running between cores tochain blocks, hooked on to the crane support the rear brace segmentaland lifted in segments. All the joints are erection. Once these two 24mts bracesof full penetration welding and were erected then the X of 12m lengthinspected by ultrasonic test. of 52 tons was erected by two tower cranes as tandem lift supported by thePlatforms were fitted at each joint for second layer of temporary latticewelding and other related works girder truss, which was erected between cores, the whole rear brace isAlignment was carried out using in inclined towards the inside of theelectronic digital total station located at building. After all welding, touch upthree different fixed locations, all inspections been carried out, all thesurveying are done very early in the temporary platforms, scaffolds and themorning to get a more accurate reading, three lattice girder trusses werekeeping in mind the movement of the removed from its position and re –structure due to thermal effects which erected to the upper portion of thegenerally develops deflection. rear braces location to continue the Front view of Burj Al Arab 79 3 r d Q u a r t e r 2 0 0 6
  4. 4. A rticleHorizontalsThe horizontal weighting about 200 tonsconnects the core wall to theexoskeleton rear leg. This structure wasassembled in one piece in the assemblyyard near the project side. TheHorizontals were transported by longspecial self-propelled trailers to theerection site.They had to be erected between twofixed points so utmost care was taken tomeasure the length between the coreand the exoskeleton rear leg.Horizontal were erected by strandjacking 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 theOnce the horizontal reached its to erect. The box girders cantilever bottom and gradually decreases to 2.5determined elevation, then it was slide out for about 30m from the main core x 2m at top. All the segments weretowards the building and placed to its wall of the building connected to bolted inside by ring plate flangeposition connected with bolts and about 200 tons of embedment. The connections. All the segments hadwelding. restaurant is having a floor size of 70m inside arrangements of permanent x 25m. The total structure is built up ladders and interval platforms toThe 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 aboveposition and kept ready for the next cycle the ground level. The beauty of the The first segment of the mast wasof operation. Once cat heads and strands restaurant is that it over looks the sea. erected after the Exoskeleton waswere removed then the Exoskeleton One of the highlights is, two 30m long erected on the trusses which runtypical erection sequence was carried girders had to be erected at 200m between two Exoskeleton legs inout 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 thestopped to continue diagonal and girders into halves and joint up in the There were manholes at periodichorizontal 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 theHelipad 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 wereside of the building, weights about 330 introduced inside the mast to have airtons made up of steel trusses and 20mm Mast circulation to workers.thick plates. Two props of 1m diametercircular steel pipes, forming an inverted The mast is about 104mts long, only Before the mast erections coming toV shape, tapered at 30º to the vertical and 54m was braced in between end with the use of the tower crane, thetied back to the center core by a 40m Exoskeleton support legs starting from other two cranes were dismantledlong 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 dismantledSky Restaurant Structure by derrick crane. After complete The overall mast was erected in dismantling of tower crane, derrick craneThe 350 ton structural steel sky segments of average 30 ton weight was dismantled manually and loweredRestaurant was one of the most complex matching the tower crane capacity. The from the roof top by winches. MBJ 80 3 r d Q u a r t e r 2 0 0 6