By- Nawal Kishor Dwivedi M.Tech Structural Engineering, MNIT Jaipur

 6 RD TALLEST BUILDING IN THE WORLD, MARCH 2014  TALLEST BUILDING IN WORLD FROM 1998 TO 2004  PRECEEDED BY INTERNATIONAL COMMERCE CENTER, HONG KONG,CHINA  SURPASSED BY NANJING GREENLAND FINANCIAL COMPLEX,CHINA  LOCATION : KLLC, JALAN AMPANG, KUALA LUMPUR, MALAYSIA

 TYPE : COMMERCIAL, TOURIST ATTRACTION  CONSTRUCTON STARTED ON 1 ST MARCH 1993 AND COMPLETED ON 1 ST MARCH 1996  COST : US$ 1.6 BILLION  OWNER : KLLC HOLDINGS  NUMBER OF STOREY: 88 (+ 4 BASEMENT FLOORS)  TOTAL HEIGHT : m (Architectural ) m ( Roof )  LIFTS/ELEVATORS : 78

 FLOOR AREA : m sq  MATERIAL : CONCRETE, STEEL  ARCHITECT : CESAR PELLI  STRUCTURAL ENGINEER : THORNTON THORMASETI  CONTRACTORS : TOWER 1 : HAZAMA CORPORATION TOWER 2 : SAMSUNG ENGG.& CO.

 EACH TOWER : 88 STOREYS  TOWER 1 :PETRONAS HEAD QUARTERS  TOWER 2 :LOCAL AND INTERNATIONAL PRIVATE TENANTS, KLCC HOLDINGS  SMALLER CIRCULAR BUSTLE OR ANEXX ADDED TO EACH TOWER RISING 44 STOREY  TOWERS CONNECTED BY SKY BRIDGE AT 41 ST & 42 ND STOREY

 SKY BRIDGE: CENTRE-LINE SPAN: METRES; WIDTH, 5.29 METRES HEIGHT, 9.45 METRES  FINISHED CEILING HEIGHT: 2.65 METRES  HEIGHT OF PINNACLES: METRES  FLOOR AREA VARRIES AS TOWER ACCENDS  CENTRAL CORE GROSS AREA :510 m sq approx  FACILITIES : 3 LEVEL CONCERT HALL 6 STOREY RETAIL AND ENTERTAINMENT PARK PETROLEUM RESEARCH CENTRE 4 STOREY BASEMENT PARKING etc.

 EARLY EXCAVATION PROBLEM : LIMESTONE BEDROCK  METRIC TON WEIGHT OF EACH TOWER  TO BE SPREAD ON MAT FOUNDATION  PRESSURE EXERTED BY EACH TOWER : 1140 K-Pa (more than twice bearing cap. of soil available)  ALSO BED ROCK WAS SLOPING – MAY LEAD TO FAILURE  CONSTRUCTION SITE SHIFTED 60 m AWAY  FINALLY RESTED ON CONCRETE MAT ANCHORED WITH CONCRETE FRICTION PILES  4.5 M THICK RAFT SUPPORTED ON M RECTANGULAR PILES

 LONGER PILES WHERE DEEP BED ROCK- TO AVOID DIFFERENTIAL SETTLEMENT  M45 CONCRETE USED FOR PILES  cu m OF M60 CONCRETE USED IN RAFT  CHILLED WATER USED- MINIMIZE DIFFRENTIAL TEMPERAURE

 CENTRAL CORE IN EACH TOWER  ACCOMMODATE – LIFTS, EXIT STAIRS, MECHANICAL SERVICES  TWO SOLID WALLS RUNNING N-S AND E-W- WEB  CANTILEVER BEAMS PROJECTING-MAKES IT STIFF  TAKES MORE THAN HALF THE TWISTING MOMENT  HIGHLY REINFORCED THICK CORNER WALLS- RESIST WIND  CORE VARRIES FROM 22 sq m TO 19 X 22 m IN FOUR STEPS  OUTER WALLS 750 TO 350 mm  INNER WALLS COSTANT 350 mm- TO AVOID COMPLICATION WITH LIFT SHAFT  CONCRETE GRADE DROPS FROM Mpa AS IT ACCENTS

FLOOR PLAN

CORE WALL LAYOUT

 COLUMNS CAST IN REUSABLE STEEL FORMS  FINELY FINISHED COLUMNS OPEN TO VIEW AT MOST OF THE FLOORS  16 TOWER COLUMN- VARRY ALONG HIGHT IN DIA.  2.4 m TO 1.4 m DIA  CONCRETE VARRIED FROM M80 TO M30 IN 3 STEPS  12 BUSTLE COLUMS – 1.4m TO 1m  SETBACKS AT 60, 73 AND 82  SLOPING COLUMS OVER 3 STOREY HEIGHTS  ABOVE FLOOR 84 – HIGH SLOPE – STEEL COLUMN USED TO AVOID COMPLICATION

COLUMN SIZE AND COLUMN GRADE

SLOPING COLUMN

 TAPERED RING BEAMS ALL AROUND  DEPTH 1.15 m AT COLUMN TO 725 mm AT FLAT ZONE  SPAN VARIATION DUE TO COLUMN CHANGES AND SET BACKS  BEAM GRADE MATCHES COLUMN GRADE TO SIMPLIFY PUMPING OUTRIGGERS  E-W OUTRIGGER LINK CORE AND COLUMNS AT FLOOR  3 LEVEL BEAMS LINKED BY MID SPAN POSTS – HELP RESIST WIND EFFECT

 DOUBLE DECK BRIDGE SPANNING 58.4 m  CONNECTS TWO TOWER AT SKYLOBBY ELEVATOR TRANSFER STATION  ON FLOOR 41 AND 42  EASY CIRCULATION B/W UPPER TOWER FLOORS  MINIMIZE LIFT USAGE  REDUCES FIRE EXIT REQUIREMENT  GREAT HEIGHT AND SPAN  REQUIRES STEEL FOR LIGHT WEIGHT AND EASY CONST.  TWO HINGED ARCH SUPPORTS THE SPAN  SELF CENTRING ACTION FROM RESTRAIN AT ARCH CROWN AND SPHERICAL PIN AT SUPPORTS

 EACH TOWER CROWNED BY- 73 m TAPERING TOP  ACCOMMODATES – BUILDING MAINTENANCE MACHINE, AVIATION LIGHTING AND LIGHTING PROTECTION  DUE TO STEEP SLOPING COLUMN  CONCRETE CONSTRUCTION IMPARACTICAL  STEEL USED THROUGHOUT  LOWER PINNACLE- 8 STRUCTURAL STEEL FRAMES  UPPER PINNACLE – SINGLE MAST OF TAPERING CIRCULAR CROSS SECTION 

PINNACLE ELEVATION

 CROSS WIND EFFECTS ON STRUCTURE AND USER COMFORT  ANALYTICAL MODELLING :  3D MODELLING USING SAP90  INCLUDING PERIMETER BEAMS, COLUMNS, CENTRAL COLUMN REPRESENTING CORE & OUTRIGGER SYSTEM  COLUMN GROSS CROSS SECTION PROPERTIES USED- COMPRESSIVE STRESSES DOMINANT  ELASTIC MODULI ‘E’ VALUES VARIED WITH STRENGTH ACCORDING TO ACI318  ‘E’ VALUES NOT REDUCED FOR CREEP- SHORT TERM WIND LOADING  BEAMS ASSUMED TO BE ‘CRACKED’- AVG. STIFFNESS I/2

 WIND MODELLING  DESIGN WIND 35 m/s ASSUMED AT 10m ELEVATION  RETURN PERIOD 50 YEARS  FORCING FUNCTION DETERMINED USING IT  ANALYSIS FOR DYNAMIC FORCE AT 1-2% DAMPING  RESULTS REVEALED  2% DAMPING REDUCES BASE SHEAR  VALUES WELL BELOW LIMITS  NO REQIREMENT OF TUNED DAMPERS  SIMILAR DYNAMIC MODELLING DONE FOR SKY BRIDGE,PINNACLE  SKY BRIDGE REQIRED TUNED MASS DAMPERS-3 EACH LEG

 MIXED CONSTRUCTION FOR COST AND USABILITY BENEFIT  USE OF HPC – REASONABLE SECTIONS, LOW COST, MORE SPACE  CONCRETE CONSTRUCTION- SIMPLE EQUIPMENTS LESS SKILL, EASY CONNECTION  CONCRETE – BENEFITS WIND BEHAVIOUR –INHERENT STIFFNESS AND DAMPING  STEEL – FAST AND FLEXIBLE ERECTION- PEMITS LAST MINUTE CHANGE  WIND EXCITATION –BENIFICIAL FOR–SIZE 55mm to.3m