Tall Building Presentation

7/27/2019 Tall Building Presentation

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TALL BUILDING ENGINEERING

ECS712

TWO INTERNATIONAL FINANCIAL CENTREHONG KONG

Prepared by:

Mohd Azuan Tukiar 2010300175Mohd Firdaus Barjumin 2009954675

Prepared for:

Prof. Ir. Dr. Hjh Siti Hawa Hamzah



Content of Presentation

Introduction to Two IFC

Architecture Design

Structural System

Geology and Foundation System

Studies Undertaken to Assess the Structural Implication

Remarks



Introduction to Two IFC1. The 88 storey of building was completed in 2003 with

height of 412m

2. Currently was at 12th places of tallest building in the worldaccording to the CTBUH Tall Building Database

3. The International Finance Center forms part of HongKong station Development on the central reclamationHong Kong

4. The development comprises of 47 million sq ft of primereal estate comprises of: 2.8 million sq ft office

0.8 million of retail and 2 hotels that totally over 1,00 rooms altogether

140,000 sq ft of designed public opened space and amenities

1,800 car parking space



Developers

Central Waterfront Properties1. Sun Hung Kai Properties Ltd2. Henderson Land Development Co Ltd3. Bank of China Group Investment Ltd4. Hong Kong & China Gas Co Ltd

Architect1. Cesar Pelli & Assc.2. Rocco Design Limited

Structural & GeotechniqueConsultant

Ove Arup & Partners

M&E Consultant J. Roger Preston Ltd

Main Contractor 1. E. Man2. Sanfield Contractors

Structural Steelwork Contractor1. NKK Corporation2. Sumimoto Corporation.



Architecture Design of Two IFC

To achieve a mix of high quality office, hotel andretail expansion of Central Business Districtfunction as envisaged under Metropolitanframework.

To provide focal buildings which will compatiblewith the other nearby planned development inthe new reclamation area, and

To maintain high degree of inter visibility betweenVictoria Harbor and the Central Business District’s

landmark building in vicinity



Architecture Design of Two IFC

Master Layout Plan has planned to have 5 towers.However, due to commercial and environmentalaspect, it was decide to combine 2 office tower andTwo International Finance Center conceived

Height further highlight with vertical fins on the externalfaçade which is gradually lightened in color as itmounts to its top. The simple fin gave an extra value inaesthetic.

The color of building will appear to have varyingshades when looking at it at an oblique manner.

Towards to the top, a series of staggered step back reduce the plan dimension to 39mx39m at roof level.



Structural System of Two IFC Tall building must have stability against

overturning, uplift and/or sliding of the structureas a whole.

Strength of the structural components of thebuilding also required to be sufficient towithstand imposed loading without failure duringthe life of the structure.

Tall building also need to satisfied serviceabilitycriteria, where inter storey and overall deflectionsare expected within acceptable limits.



Structural System of Two IFC

The necessities of Two IFC design was to maximizethe views from the tower and to have flexibilityoffice layout

Outrigger system was adopted in preferences toother common tall building system.

This system contains three main elements which

are the

1. outrigger beam,

2. the core wall and

3. the exterior (external) columns.




Typical Floor Framing




RC Core Wall

1. Dimension of 27mx29m at the base with perimeter wall 1.5m and 1.25m thick

2. The core is constructing using conventionalreinforced concrete of grade 60 concrete

3. The use of core-wall system can be very effectiveand efficient structural system used in reducingresponses due to lateral load




Maximum Wind Drift for Central Core with &without Outriggers




Outriggers System

1. Core is stabilized by three outriggers each threestorey high

2. Located at the mechanical and refuge floor zonewhich is at R2/F to 33/F, R3/F to 55/F and to R4/F to67/F




Punched concrete core wall type outriggersprovide insufficient stiffness for providing anopening of significant M&E access.

Therefore, it is necessary for steel truss to increasethe strength and stiffeners of perforated core.




Steel truss with shear stud before embedded intoreinforced concrete core wall




Belt Truss

1. Belt truss are used to tie the peripheral columnbuilding while the outrigger engaged them with

reinforced concrete core wall

2. Study showed that the use of outrigger and thebelt truss has improved the serviceability of thestructure




Four options are compared which1. model without belt truss and outriggers (MT0),

2. model with one belt truss and outriggers (MT1),

3. model with double belt truss and outrigger (MT2)

4. model with triple belt truss with outriggers (MT3)

There is 34% reduction in deflection by the useof one outrigger at the effective level

41% and 51% drop is achieved by the use oftwo and three outrigger levels with respect tomodel without belt truss and outriggers




Comparisons of various outrigger options




Secondary Column

300x300mm dimension of column

Support gravity load only

There are three zone of such column each

extending a maximum of 20 storey which

are supported of transfer (belt) trusses at

each of the outrigger level




The loads from the secondary column are effectivelycollected by these trusses and transferred to themega column

At the higher level where the corners of the floor plate are stepped back, these columns are removedthen the floor plates are cantilevered from the megacolumn

Considered for not having these columns throughoutthe building, however it will cause a significant costimpact due to additional weight of floor steel andexpected the large cantilevered floor system




Mega Column

8 mega-columns rising from the raft at the base ofthe cofferdam up to the roof, supporting theexternal frame of the entire building at 24 meters

center to center

The mega column comprises of compositesteel/concrete in which the steel elements areencased with reinforced concrete

The structural steel component was split into anumber of sub sections that could be lifted andconnected with ease.



Structural System of Two IFC Column Schedule




Plinth for mega column



Fixing steel bars (50 mm diameter bars at the basesection) around the stanchions of a mega-columnbefore encasing it in concrete



Structural System of Two IFC Floor System

1. Composite steel/concrete floor with125mm thick slab acting compositely with the permanentdecking supported at up to 3m intervals of varietysteel beam size

2. The typical floor to floor height was 4.17m

3. The floor component is comprises of 460mm deepsteel secondary beam spanning 11.4m to 13.5mfrom the core to 900mm deep

4. Primary girders spanning 24m between the megacolumn, The beam sections were graduallyreduced in size for higher levels




1. The inclusion of diagonal beam which conjunction withthe primary girder on the main faces provided continuous

tension ring around the floor plate thus enhanced

robustness and provide direct buckling restraint to the

column

2. The 24m primary girder comprised of asymmetric

fabricated section was structurally continuous with the

mega column

3. The weight of floor beam steel is 36kg/m2 based on the

gross constructed floor area



24 m edge beam spanning between the mega-columns at the lower section of the tower




The foundation of the high rise development inHong Kong has traditionally been piles or caissonbearing on the un-weathered rock normally at

depth of up to 40m or 50m

With the extension of land reclamation into theharbor the depth to rock has generally increased

up to 70 to 80m




Grade 3 granite with permissible bearing capacity of5Mpa was found approximately 35meters belowground level.

Above of this are layers of decomposed granite andalluvium and over the top 20 meters were layers of fillthat have been reclaimed for three years earlier.

Initially, the foundation was decided to have 72nosof end bearing bored piled with 3meter in diameter and cofferdam was also required to enable pilecape constructed at 30m below ground level.




With reasonably constant rock head level asdetermined in site investigation, it was proposedraft foundation to be cast bearing directly onrock, thus omitting the need for bored piled

Rock level to the south west of the tower baseappeared with a maximum depth of rock up to-50 mPD, which was too deep for normal openexcavation




To overcome the problem, mixed foundationsolution was adopted

In location where to have maximum depth up to -50PD, barrettes (rectangular-section piles) wereinstalled to provide support to the building raft.

The whole excavation process was carried outdown to the formation level at -32 mPD. Includingthe treatment to the localized bedrock, the work took about 16 months to complete.



Studies Undertaken to Assess theStructural Implication

Lateral Response of Building

Impact of Aircraft component on the keyelement of Structure

Vaporization of key element of the Structure



Lateral Response of Building

Wind tunnel performed by Roman William Davies & Irwin

Inc (RWDI) and Cermak Pterka Peterson (CPP)

Resulting from the study showed global characteristicbase bending moment and base shear were19,000MNm & 128MN respectively

Lateral acceleration were predict & compared againstNBCC, ISO and Davenport Criteria for occupancycomfort and it found that acceleration deemedacceptable w/o need any supplementary damping.

Lateral deflection under wind loading were H/450 inorthogonal direction & H/380 in the diagonal where H isheight of the building above pile cap



Impact of Aircraft component on the key element ofStructure

Analytical study undertaken by Arp Extreme EventMitigation Task Force

Investigated the performance of range of typicalcolumn in high rise structure when subject to the impactfrom an aircraft engine travelling at speed

Engine speed of 200mph(89.4m/s) and using columndimension of 3m x 1.8m RC encased composite columnhousing 604kg/m steel section

Finding- the composite mega column of Two IFCperformed well by exhibiting only limited concretecrushing and plastic straining of steel section



Vaporization of key element of the Structure

Study in the event where that such element areremoved

Finding:

Tower remain stable despite the column beingremoved

Tower experienced a gravity load path re-distribution

Increase gravity load in the outrigger is resistedby RC core which has demonstrate adequatelyredistribute these gravity load



Remarks Two IFC used of outriggers system as their

structural form

3 main elements of outriggers system which iscore wall, outrigger beam, mega column

Core wall dimension of 27mx29m at the base withperimeter wall 1.5m and 1.25m thick construct usingRC Grade 60.

Outrigger beam each three storey high located atthe mechanical and refuge floor zone which is atR2/F to 33/F, R3/F to 55/F and to R4/F to 67/F



Remarks

8 mega-columns supporting the external frame of theentire building at 24 meters center to center comprises of composite steel/concrete in which thesteel elements are encased with reinforced concrete

with varies grade concrete

For foundation system, mixed foundation solutionwas adopted. In location where to have

maximum depth up to -50PD, barrettes(rectangular-section piles) were installed toprovide support to the building raft.



Q & A

Tall Building Presentation

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