The Taipei 101 Tower in Taiwan - Case Study Example

The Taipei 101 tower in Taiwan According to Bhadeshia (2005), The Taipei 101 Tower attained status of the world’s tallest building in 2004 upon its completion (figure 9 and 10). On July, 21st 2007, Burj Dubai in Dubai, United Arab Emirates overtook the Taipei 101 Tower height. Burj Dubai has 141 floors as of march 2009, but the title of the world tallest building is still held by Taipei 101 Tower because international architectural standards consider a building as a structure that has potential of being fully occupied. Burj Dubai will claim the title when it will be completed in September 2009 if it its construction goes by schedule (Bhadeshia, 2005). The Taipei 101 Tower was preceded by Petronas twin towers height-wise. The Taipei 101 Tower is located in Xinyi District, Taipei in republic of china. The Taipei 101 Tower was constructed between 1999 and 2004. The Taipei 101 Tower has a spire height of 509.2 metres (1670.60 feet), roof height of 449.2 metres (1473.75 feet) and top floor height of 439.2 metres (1440.94 feet). The Taipei 101 Tower has a floor space area of 412,500 square metres (4,440,100 square feet). The Taipei 101 Tower has 61 elevators that include double deck shuttles and two high speed observatory elevators (Bhadeshia, 2005). The Taipei 101 Tower was constructed at a cost of United States Dollars 1.76 Billions. The companies involved in the construction process were C.Y. Lee and partners who were the architects; the main contractor was KTRT joint venture and Samsung Engineering and Construction. The Taipei 101 Tower is owned by Taipei Financial Center Corporation and managed by Urban Retail Properties limited (Bhadeshia, 2005). The Taipei 101 Tower received Emporis skyscraper award in 2004. The Taipei 101 Tower is considered one of the Seven Wonders of the World (Newsweek magazine 2006) and seven wonder of engineering (Discovery Channel, 2005). The Taipei 101 Tower holds the ground to highest architecture award at 509.2 metres that was formerly held by Petronas tower (452 metres), ground to roof tallest building at 449.2 metres that was previously held by Sears Tower (442 metres), ground to highest occupied floor at 439.2 metres that was previously held by Sears Tower (412.4 metres). The record for the greatest height from the ground to pinnacle is still held by Sears Tower in Chicago at 527 metres (Bhadeshia, 2005). The site where Taipei 101 Tower lies is prone to seismic activity (Joseph, Poon and shieh, 2006). The Taipei 101 Tower is located 200 meters from a tectonic plate. The site soils are mainly clay sandwiched with stone gravel and loam from typhoons. The clay soil is compressible and suffers risks of expansion and contraction upon being exposed to extremes of temperatures. Presence of clay has negative impacts of increasing moisture penetration from the ground to the floor. The site also suffers from high speed winds that attain a velocity of 250 kilometers per hour (Bhadeshia, 2005). The site excavations were done to ensure the support structures were provided with a six storey (71 feet) or 21.5 meters deep basement (Bhadeshia, 2005; Joseph, Poon and shieh, 2006). Due to looseness of the soil and need for the stability of the structure, the Taipei 101 Tower support structures were dug 30 metres into the bedrock in order to address issues of seismic waves and offer required stability owing to site locations in coastal areas that were prone to typhoons and cyclones (architectureweek, 2005). The tower portion basement measures 90 metres by 90 metres and has an excavated depth of 20 metres. The mat foundation of the Taipei 101 Tower has a thickness range of 3 metres to 4.7 metres which is bound to pile foundation with aim of supporting the entire weight of the building. The concrete strength of the mat foundation is calculated to 6000 psi. The mat foundation of Taipei 101 Tower has nine units with every unit having a volume of 3000 cubic metres. During its construction, the cement was poured by using embedded sensor that helped to monitor mass concrete temperature (architectureweek, 2005). The choice of steel at Taipei 101 Tower was based on the fact that steel is light hence would reduce loads on the foundation and costs of the foundation, to keep building weight at the most possible minimum and reduce seismic effects on the building by minimizing the weight of the building (Joseph, Poon and shieh, 2006). The steel was also used in order to minimize material handling at the site of construction (architectureweek, 2005). During joinery work of the steel framework, a spectacular wind and water proof platform was utilized and an ultrasonic test carried out for every welded joinery work performed. The Taipei 101 Tower has 25 storey truncated pyramidal base and eight-eight storey flared modules that are topped with an observatory deck together with a spire. At the base of every module is a braced core, lower multi-storey outriggers and single storey outriggers (Bhadeshia, 2005 and Joseph, Poon and shieh, 2006). The Taipei 101 Tower faced many constraints like access of transit automobiles that transported construction materials because of proximity of the other buildings. The street had to be closed and entrances to the site blocked to confine the workplace. There were concerns about reduction of ground stabilization of neighboring buildings during excavation, removal of debris and hoisting of materials. Accessibility to the site was also limited by landscaping in the neighboring buildings and load limits imposed on adjacent buildings. Other constraints included inter-storey drifts and stability of the columns and beam loaded by compression and bending because the site lies on a faultline and possibilities of the building being brought down by earth movements. Inter-storey drift result even when vertical and horizontal seismic forces, normal forces and bending moments and elastic inter-storey drifts have been calculated. The construction also faced constraints in waste management since the building site was faced with lack of space resulting into a logistic challenge of brining construction materials and removal of waste materials (architectureweek, 2005 and Joseph, Poon and shieh, 2006). Other constraints included lifting of materials like steel and concrete through the height of the building. The Taipei 101 Tower also faced construction constraints that were based on adherence to construction directives due to Taipei 101 Tower proximity to Sungshan Airport the concerns were based on conflicts with flight paths that could have led to reduction of the Taipei 101 Tower height after proposal to increase the height from its previous 60 storey (Joseph, Poon and shieh, 2006). The construction of the Taipei 101 Tower was guided by a well maintained slope walls and ground retaining walls (Bhadeshia, 2005). Two construction approaches were adopted during construction of Taipei 101 Tower. These included the up-method construction approach and top-down construction approach. The up-method approach was implemented by erecting the steel structures upwards which was followed by reinforcement cement floorwise (architectureweek, 2005). The ground retaining wall of Taipei 101 Tower is 1.2 metres deep with a 50 metre deep slurry wall together with a buttress for soft basin formation. Ground retaining walls addresed concerns of deterioration and stability loss which could have predisposed collapse resulting into injuries of construction staff and damage to peroperty. The construction factored sustanable ground retaining walls to manage possible costs that could have been incured during remedial construction work (architectureweek, 2005). Measures were put in place to ensure natural terraces hazard mitigation were in place. The choice of retaining walls with exception of masonry walls was a favorite choice since ground retaining walls required little maintenace (Bhadeshia, 2005). The choice for earth retaining structures was also meant to address health and safety issues . The ground retaining walls provided safeguards and required support during excavation and construction (Bhadeshia, 2005). The Taipei 101 Tower deep basement and water retaining construction satisfied code of practice for protection of structures against water from ground and code of practice for design and installation of damp proof course in masonry construction. Slope and embarkment considerations ensured construction work conformed with assessment of ground movement of water and their possible effects on adjacent buildings and structures and satisfied measures for preventing ground water ingress (Joseph, Poon and shieh, 2006; Joseph, Poon and shieh, 2006). The Taipei 101 Tower used pre-casted technique. The Taipei 101 Tower materials were assembled offsite into larger building elements. The Pre-casting cladding had sound proofing properties and combustible hence provided required fire resistant property. The Taipei 101 Tower concrete was air and watertight hence achieved ability to control weathering performance and restrict corrosion. The insulation was incorporated on the lining of internal face between concrete structures (architectureweek, 2005). The proposed thermal mass concrete facilitated reduction of Taipei 101 Tower projected heating and cooling loads (Bhadeshia, 2005). Large panels were used between floor slabs or grid width and this ensured no need for the secondary structural columns. They were supported on every floor with stacking at the ground level and fixed by bolting to holes on steel structural and channels casted on the concrete structures. Grid width panels decreased mid-span loading on the structural slab edge. Offsite prefabrication was carried out to increase onsite productivity so that work was independent of on-site activities subject to stabilizing costs of construction and construction time (Joseph, Poon and shieh, 2006). The Taipei 101 Tower is made of five steel plates that have a strength range lying between 412-510 MPa. The Taipei 101 Tower steel plates have a tensile strength that ranges between 570 Mpa to 720 MPa. The Taipei 101 Tower has a carbon equivalent of 0.29 signifying that the steel has minimal alloys hence the steel is weldable due to reduced alloy components (Bhadeshia, 2005). The Taipei 101 Tower is supported by 380 concrete filled steel piles that have been sank eighty metres into the soil and 30 metres into bedrock (figure 6). The strength of the cement was calculated to 10,000 psi for high performance concrete (Bhadeshia, 2005). Each pile measures 1.5 metres in diameter and can withstand a load range of between 1000 metric tones to 1320 metric tones (Bhadeshia, 2005). Stability of the Taipei 101 Tower was witnessed on March 31st 2002 when Taipei 101 Tower was hit by a earthquake of order 6.8 magnitude on richer scale. The earthquake brought down two construction cranes from 56th floor but after inspection, the Taipei 101 Tower had no structural damage (figure 5). These supporting trusses can withstand an earthquake of 10.0 magnitudes on richer scale (Bhadeshia, 2005). The Taipei 101 Tower has supporting cuboids columns of 80 millimetre thick steel plate (figure 6). The steel cuboids’ structures are filled with concrete to provide additional stiffness property. The steel structures of Taipei 101 Tower measure 2.16 metres by 3.1 metres and a pair is found in every face (Bhadeshia, 2005). The sixteen steel columns support Taipei 101 Tower gravity loads brought about by dead and live loads. The perimeter of the Taipei 101 Tower is surrounded by multiple braces on every face with additional support provided by moment tolerant steel frames (Bhadeshia, 2005). The Taipei 101 Tower columns are wrapped with a steel framework that make the structure tolerant to lateral loads brought about by winds and earth movements (Bhadeshia, 2005). The braced tubular system of Taipei 101 Tower is strengthened by cross-brazing frame that is impregnated with X-bracing over the Taipei 101 Tower stories (figure 17). The diagonal of the braced tube framework is connected to columns at every intersection. This ensures impacts of shear lag is minimized in frame and web frames. The Taipei 101 Tower structure behaves under lateral loads like a braced frame and in so doing this reduces bending of elements and components that form the frame (Bhadeshia, 2005). At the same time, this property ensures sufficient spacing of the support columns and depth of girders is decreased. The framed tube has closely spaced steel columns that are 4 metres apart and are linked by deep girders (Bhadeshia, 2005). The main purpose was to provide a tube that could have portrayed characteristics of a continuous perforated stack. Lateral resistance of tube structure was made possible by stiff movement resisting steel frame that formed a tube around the perimeter of Taipei 101 Tower hence making it possible for the gravity loading to be evenly distributed between the tube and the interior columns (Bhadeshia, 2005). The Taipei 101 Tower girders were pre-tensioned such that the central span girders were constructed in two segments (Bhadeshia, 2005). This was performed after girders were erected and diaphragms poured, girders were continuously post-tensioned from abutment to abutment to ensure structural efficiency was achieved (figure 12). At the Taipei 101 Tower, upon action of lateral loads, the perimeter frames aligned to the direction of the loads function like a web of cantilevers and those acting to the direction of the lateral loading behave like flanges (Bhadeshia, 2005). The flange property addresses the shear lag making the mid-face flange columns to be exposed to lesser stress than corner steel columns (Joseph, Poon and shieh, 2006). They therefore do not suffer stress brought about by lateral loadings. Gravity loading at Taipei 101 Tower conforms to accepted building standards for instance commercial offices uniform distributed loading is 2.5kN/m2 subject to uniform concentrated loading of 2.7kN while corresponding commercial corridors have a uniform distributed loading of 4.0kN/m2 subject to concentrated loading of 4.5kN. The Taipei 101 Tower apartment sections have uniform distributed gravity loading of 2.0kN/m2 subject to concentrated loading of 1.8kN while corresponding residential corridors have a uniform distributed gravity loading of 3.0kN/m2 subject to corresponding concentrated loading of 4.5kN (architectureweek, 2005). The Taipei 101 Tower wind loading conforms to accepted building standards and is a function of shape, slenderness and solidarity ratio of the structure and other close building structures (Joseph, Poon and shieh, 2006). The Taipei 101 Tower wind loading is subject to static approach and dynamic approach properties. The Taipei 101 Tower static approach factored Taipei 101 Tower as a rigid body in the wind that can be exposed to turbulence by Bernoulli’s principle. The construction also factored wind loading subject to dynamic approach strategy as a function of Taipei 101 Tower tallness, slenderness and vibration possibilities that resulted into adoption of a structure that satisfied wind tunneled model (architectureweek, 2005). These considerations addressed seismic forces as a function of horizontal and vertical ground motions. The construction of Taipei 101 Tower also fulfilled additional resultant forces brought about by vertical acceleration subject to earth movements (Bhadeshia, 2005). The Taipei 101 Tower therefore has potential to setup inertia forces through out the Taipei 101 Tower structure. This conformed to Newton first law of motion (law of inertia1). The Taipei 101 Tower also satisfies second Newton law of motion (law of momentum2) in that (F=Ma) Taipei 101 Tower exhibits no rigidity between the building and the foundations as opposed to a scenario where acceleration would have been equivalent between the building and the foundation. Earth movement loading was sufficiently estimated by seismic coefficient method and spectrum response method (architectureweek, 2005). The Taipei 101 Tower earth vibrations are dampened by a suspended steel ball that weighs 660 tones(Joseph, Poon and shieh, 2006; Bhadeshia, 2005). The Taipei 101 Tower steel ball is suspended from 92nd floor to 88th floor (Bhadeshia, 2005). The steel ball was made from stacks of steel plates that had different dimensions (Bhadeshia, 2005). The steel ball is linked to pistons that have potential to allow oil to flow through small holes hence achieving the vibration damping properties (Bhadeshia, 2005). The steel ball measures 5.5 metres in diameter and has 41 layers of 1250 milimeters steel that has been welded together (figure 5). The Taipei 101 Tower 60 metre spire relies on two smaller vibrations dampers whose primary function is to limit ground buffeting. These concerns addressed concerns of possible metal fatigue the small dampers weigh 4 tones and are placed on rail fitting around the interior column of spire (Bhadeshia, 2005). Any energy that is absorbed by the dampers in the spire is dissipated into a system of springs beneath the mass (figure 7 and 8). The Taipei 101 Tower has simple connections, rigid connections and semi-rigid connections, construction joints and movement joints. Simple connetions of the Tanaipei 101 Tower were made such that they enabled the beam end to rotate freely. This type of construction enabled Tanaipei 101 tower to transfer shear and axial forces between connecting membranes. The simple connection joints do not transfer bending moment hence adoption of rigid and semi rigid connections. Rigid connections were made such that the angle between the beams and joint could have restoring properties hence combined functions of transfer of shear stress, axial forces and bending moments from the beam to the steel column. The constructions joints were provided for to facilitate concrete structure to be cast in a manageable form in order to provide stability and strength factors. The constructions joints helped to provide axial tension, axial comprehension, bending, shear stress and torsion. Hirib construction joints were used on the beams and slabs while concrete retarder was applied for preparation of the construction joint (figure 3). This process was followed by removal of cement paste and laitance when concerete was set. The Tanaipei 101 tower movement joints (figure 2 and 4) were provided for to ensure relative movement across the joints. The Tanaipei 101 tower movement joints used were discontinous. The use of discotinous joints enabled the structure to translate or rotate in any direction depending on the applied external force (figure 2). Other joints used on the Tanaipei 101 Tower were meant to transfer force between building elements (Bhadeshia, 2005; architectureweek, 2005). The other uses of the discontinous joints were to address effects of temperature variations, to resist ground movement like shrinkage and creep under stress as wella as static and dynamic loads like live loads and dead loads including earth movements like quakes (figure 1). The structural design incorporated a tuned mass dampener for countering external forces brought about by earth quakes, wind loading and typhoons that are very common in the pacific region. The structure has a mast/spire complex. The Taipei 101 Tower starts at the base as a square that gently slopes inwards and outwards to form a trapezoidal shape (architectureweek, 2005). The distance between the base and the shaft of Taipei 101 Tower has a belt that runs around the structure and has a belt-buckle structure at the centre of each side that takes shape of an ancient coin. This structure is repeated at top of every flaring trapezoidal section. The Taipei 101 Tower looks like a trapedoidal shapes that have been stack on each other (figure 11). The cement used for the construction3 has a density of 0.9g/cm3 hence less dense than water (1.0g/cm3). The cement used for construction of the Taipei 101 Tower is high strength cement (HSC), self-compacting cement (SCC) properties and has excellent early and late strength characteristics. Different strength characteristics of the cement were used in different parts of the steel framework that ranged from 6000 psi for the mat foundation and 10000 psi for the concrete columns. The high performance cement had minimal moisture absorbent properties and provides recommended water proof properties. The cement also meets criteria for finite element analysis and withstands free thermal strain4, creep strain5, Transient strain6 and stress-related strain7 (architectureweek, 2005) The Taipei 101 Tower construction materials used provided required passive fire protection. The construction products are fire resistive to as a function of ease of fire ignition and propagation or growth rate of the fire. The Taipei 101 Tower passive fire protection mechanism ensures spread of fire within internal structures and linings is limited. This ensured internal fire spread via the linings and structure was restricted. The lifts are fire resistant and cannot provide for invisible spread of fire. The doors and windows have cavity barriers to prevent penetration of smoke and flames. The floor to floor compartments ensure spread of fire is prevented (figure 15). The Taipei 101 Tower has saw toothed corners (figure 16). The saw-toothed corners reduce vortex shedding that produces wind sways and at the same time decrease accelerations and inter-storey drifts. This property of Taipei 101 Tower helps to provide comfort and health of building users (Joseph, poon and Shieh, 2006). The Taipei 101 Tower construction complies with sustainable principle on protection of the environment and creation of safe environments. The Taipei 101 Tower concrete provided thermally sustainable structure that serves as a reservoir of thermal energy. The Taipei 101 Tower ventilation properties were highly prioritized to provide adequate ventilations subject to Taipei 101 Tower tallness and slenderness. The Taipei 101 Tower windows and skylights were constructed to facilitate entry of sufficient daylight in so doing decreasing reliance on electricity and bringing about energy conservation. The use of glass at Taipei 101 Tower decreased need for painted wall hence providing a safe healthy environment free from chemicals that could affect health and safety of occupants. The roofing system has no effect on atmosphere and climate. The Taipei 101 Tower roof is built such that it meets requirements of urban heat island effect by addressing concerns like storm water quality, occupants’ quality of air and solid waste disposal mechanisms that comply with environmental protection regulation (architectureweek, 2005). Adoption of a green roof or vegetated roof was meant to address concerns brought about by stormwater runoff that has potential to clog sewer systems. The green roof has therefore ability to decrease pollution spills into rivers and limit airborne pollutants. The Taipei 101 Tower roof design and supporting structures satisfy requirements for shape and geometry of the structural system of the building, climatic conditions and site environment. The Taipei 101 Tower roof design complies with structural thermal insulation subject to insulation8 and ventilation properties. The roof has steel framework that support superstructures membranes that are tensioned to promote weather barrier and reinforce weather-tightness (figure 13). The roof assembly consists of roof deck, air and vapor retarder, roof insulation and roof covering while the roof system is made up of air and vapor retarders, roof insulation and roof covering. The roof deck has a steel deck with welded connections. The roof deck has been galvanized to reduce corrosion in the event of roof leakage (figure 14). Each of the grain galvanized structure measures 10 millimeters. The screw attachment is used in lieu of welding since it provides reliable attachments. The roof membrane is monolithic and serves as an air retarder. The Taipei 101 Tower deck penetrations are sealed at parapets with 15 millimetre double ply membranes that create air retarder. The insulation is made up of rigid boards. Perlite which has a low R- value was used as cover board because it has good fire resistance9. The roof is able to withstand structural loads that include live and dead loads. The live loads include water and snow. The dead loads include weight of the roof structure. The Taipei 101 Tower roof wind load has mechanically fastened systems that transfers wind effects from the roof membrane via the fasteners for instance bars and plate fastenings linked to the roof deck to the steel ball damper (Bhadeshia, 2005). The roof wind load membranes have elongation resistive properties and insulation system is airtight. The Taipei 101 Tower roof wind load fastenings comply with recommended criteria for roof integrity and durability. The roof has delaminated insulation cap beneath the membrane that sustains roof’s potential to withstand and tolerate wind loads subject to trapped moisture that might be moving, condensing or freezing into the roof assembly. The Taipei 101 Tower roof insulation has low unit RSI value corresponding to the height of the roof flashing. Adoption of mechanically fastened roof made it possible for the Taipei 101 Tower to adopt a variety of insulations as opposed to a roof where insulation lies beneath the membrane. The roof has chemical resistant receptor pans that collect and retain chemical contaminants hence protecting Taipei 101 Tower from chemical attack. The Taipei 101 Tower has cut-offs and drip pans at roof openings and roof perimeter. The Taipei 101 Tower roof has efficient control flow drainage system that directs water into the municipal sewer system. The Taipei 101 Tower has roof scuppers around the roof perimeter for controlling flow of water. The Taipei 101 Tower roof is constructed with class A construction products that have high fire resistant properties. The roofing system is bolted to flexible steel decks that have potential to deflect over traffic during roof installation and after roof installation (architectureweek, 2005; Joseph, poon and Shieh, 2006). The Taipei 101 Tower provides for thermal movements like expansion, contraction and vibration. Bibliography architectureweek. (2005, march 2nd). taiwan on top. Retrieved march 28th, 2009, from http://www.architectureweek.com/2005/0302/building_1_2.html Bhadeshia, H. (2005). The Taipei 101 Tower, Taiwan: The tallest building on earth, made using steel. Retrieved March 28th, 2009, from The Taipei 101 tower: http://www.msn.ac.uk/phase-trans/2005/t101/t101.html Joseph,L. M.,Poon, D & Shieh, S.S. (2006, june 6th). The taipei 101 tower. Retrieved march 28th, 2009, from structure mag : http://www.structuremag.org/archives/2006-6/F-taipei-101-june-06.pdf Read More