High-rise structural systems


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This ppt is all about the high-rise structural systems and the methods of construction.
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High-rise structural systems

  2. 2. INTRODUCTION AND DEFINITIONHigh rise is defined differently by different bodies.Emporis standards-“A multi-story structure between 35-100 meters tall, or a building ofunknown height from 12-39 floors istermed as high rise.Building code of Hyderabad,India-A high-rise building is one with fourfloors or more, or one 15 meters ormore in height.The International Conference on FireSafety –"any structure where the height canhave a serious impact on evacuation“Massachusetts, United States GeneralLaws –A high-rise is being higher than 70 feet(21 m).
  4. 4. Structural LoadsWind LoadsSeismic Loads• Gravity loads– Dead loads– Live loads– Snow loads• Lateral loads– Wind loads– Seismic loads• Special load cases– Impact loads– Blast loads
  5. 5. • A type of rigid frame construction.• The shear wall is in steel or concrete to provide greater lateralrigidity. It is a wall where the entire material of the wall is employedin the resistance of both horizontal and vertical loads.• Is composed of braced panels (or shear panels) to counter theeffects of lateral load acting on a structure. Wind & earthquake loadsare the most common among the loads.• For skyscrapers, as the size of the structure increases, sodoes the size of the supporting wall. Shear walls tend to be used onlyin conjunction with other support systems.Shear wall system
  6. 6. FRAMED-TUBE STRUCTURES]The lateral resistant of the framed-tube structures is provided by verystiff moment-resistant frames that form a “tube” around theperimeterof the building.The basic inefficiency of the frame system for reinforced concretebuildings of more than 15 stories resulted in member proportionsof prohibitive size and structural material cost premium, and thussuch system were economically not viable.The frames consist of 6-12 ft (2-4m) between centers, joined by deepspandrel girders.Gravity loading is shared between the tube and interior column orwalls.When lateral loading acts, the perimeter frame aligned in thedirection of loading acts as the “webs” of the massive tube of thecantilever, and those normal to the direction of the loading act as the“flanges”.The tube form was developed originally for building of rectangularplan, and probably it’s most efficient use in that shape.Dewitt chestnut
  7. 7. THE TRUSSED TUBEThe trussed tube system represents a classicsolution for a tube uniquely suited to the qualitiesand character of structural steel.Interconnect all exterior columns to form a rigidbox, which can resist lateral shears by axial in itsmembers rather than through flexure.Introducing a minimum number of diagonals oneach façade and making the diagonal intersect atthe same point at the corner column.The system is tubular in that the fascia diagonalsnot only form a truss in the plane, but alsointeract with the trusses on the perpendicularfaces to affect the tubular behavior. This createsthe x form between corner columns on eachfaçade.Relatively broad column spacing can resultedlarge clear spaces for windows, a particularcharacteristic of steel buildings.The façade diagonalization serves to equalize thegravity loads of the exterior columns that give asignificant impact on the exterior architecture.John HancockCenter introducedtrussed tube design.Recently the use of perimeter diagonals – thusthe term “DIAGRID” - for structural effectivenessand lattice-like aesthetics has generated renewedinterest in architectural and structural designersof tall buildings.Introducing a minimumnumber of diagonals oneach façade andmaking the diagonalintersect at the same pointat the corner column
  8. 8. The concept allows for widercolumn spacing in the tubularwalls than would be possiblewith only the exterior frametube form.The spacing which make itpossible to place interior framelines without seriouslycompromising interior spaceplanning.The ability to modulate thecells vertically can create apowerful vocabulary for avariety of dynamic shapestherefore offers great latitudein architectural planning of atall building.Burj Khalifa, Dubai.Sears Tower, Chicago.BUNDLED TUBE SYSTEM
  9. 9. TUBE-IN-TUBE SYSTEMThis variation of the framed tubeconsists of an outer frame tube,the “Hull,” togetherwith an internal elevator andservice core.The Hull and core act jointly inresisting both gravity and lateralloading.The outer framed tube and theinner core interact horizontally asthe shear and flexural componentsof a wall-frame structure, with thebenefit of increased lateralstiffness.The structural tube usually adoptsa highly dominant role because ofits much greater structural depth.Lumbago Tatung HajiBuilding, Kuala Lumpur
  10. 10. Construction materialsAdvantages are: Plasticity Easily availability Easy in casting Non corrosive Can be cast in situDisadvantages are: Cost of form Dead weight Difficulty in pouringCONCRETE:- cellular concrete of clay-gypsum &invention of light weight concrete.FERRO CONCRETE:-it is layer of fine meshsaturated with cement.GUNITE:- it is also known as shot Crete.compressed air to shoot concrete onto(or into) a frame or structure. Shot Crete isfrequently used against vertical soil or rocksurfaces, as it eliminates the need forformwork.GLASS:- float glass with double glass is used in tallbuildings .Tempered glass is used in tall buildings insteadof plain glass, as that would shatter at suchheight.Materials used for high rise buildings: concrete, steel, glass, cladding material, high aluminacement used for roofs & floors. It contains bauxite instead of clay, cement, Portland cement oflime stone, silica.
  11. 11. • Raft foundation: one of the most common foundation. It is known for its load distributingcapability. With the usage of this type of foundation the enormous load of the building getsdistributed & helps the building stay upright and sturdy. Loads are transferred by raft into theground.• Pile foundation: used for high rise construction. loadof building is distributed to the ground with the helpof piles. Transfer the loads into the ground with anAdequate factor of safety.• Combined raft-pile: is the hybrid of 2 foundation. ItConsists of both the pile and raft foundation. Usefulin marshy sandy soil that has low bearing capacity.Foundation Types
  12. 12. CONSTUCTION METHODS AND TECHNIQUESSlip forming, continuous poured, continuously formed, or slip formconstruction is a construction method in which concrete is poured intoa continuously moving form. Slip forming is used for tall structures (suchas bridges, towers, buildings, and dams), as well as horizontal structures,such as roadways. Slip forming enables continuous, non-interrupted,cast-in-place "flawless" (i.e. no joints) concrete structures which havesuperior performance characteristics to piecewise construction usingdiscrete form elements. Slip forming relies on the quick-settingproperties of concrete, and requires a balance between quick-settingcapacity and workability. Concrete needs to be workable enough to beplaced into the form and consolidated (via vibration), yet quick-settingenough to emerge from the form with strength. This strength is neededbecause the freshly set concrete must not only permit the form to "slip"upwards but also support the freshly poured concrete above it.In vertical slip forming the concrete form may be surrounded by aplatform on which workers stand, placing steel reinforcing rods into theconcrete and ensuring a smooth pour. Together, the concrete form andworking platform are raised by means of hydraulic jacks. Generally, theslipform rises at a rate which permits the concrete to harden by the timeit emerges from the bottom of the form
  13. 13. SLIP FORM CONSTRUCTIONSlipforming is an economical, rapid and accurate methodof constructing reinforced concrete. At its most basiclevel, slipforming is a type of movable formwork which isslowly raised,allowing the continuous extrusion of concrete.
  14. 14. CLIMB FORM CONSTRUCTIONCLIMB FORM CONSTRUCTIONis an economical, rapid and accurate method ofconstructing reinforced concrete, or post-tensionedconcrete structures. At its most basic level, slipforming isa type of movable formwork which is slowly raised,allowing the continuous extrusion of concrete.
  15. 15. TABLE FORM/FLYING FORMA table form/flying form is a large pre-assembledformworkand falsework unit, often forming a complete bayofsuspended floor slab. It offers mobility and quickinstallationfor construction projects with regular plan layoutsor longrepetitive structures, so is highly suitable for flatslab, andbeam and slab layouts. It is routinely used forresidential flats, hotels, hostels, offices andcommercial buildings.
  16. 16. SYSTEM COLUMN FORMWORKThe column formwork systems now available are normallymodular in nature and allow quick assembly and erectionon-site while minimising labour and crane time. Theyare available in steel, aluminium and even cardboard(not reusable but recycled) and have a variety of internalface surfaces depending on the concrete finish required.Innovations have led to adjustable, reusable column formswhich can be clamped on-site to give different column sizes.
  17. 17. VERTICAL PANEL SYSTEMSCrane-lifted panel systems are commonly used onbuilding sites to form vertical elements and usuallyconsistof a steel frame with plywood, steel, plastic orcompositefacing material.The systems are normally modular in nature,assemblytimes and labour costs are considerably lower thantraditional formwork methods with far fewercomponentsrequired. They offer greater opportunities for reusefordifferent applications on site.Panel systems are extremely flexible and the largercrane-lifted versions can be used for constructingstandardconcrete walls, perimeter basement walls, columnsand inconjunction with jump form climbing systems.
  18. 18. JUMP FORM SYSTEMSGenerally, jump form systems comprise the formwork andworking platforms for cleaning/fixing of the formwork,steelfixing and concreting. The formwork supports itself on theconcrete cast earlier so does not rely on support or accessfrom other parts of the building or permanent works.Jump form, here taken to include systems oftendescribed as climbing form, is suitable for constructionof multi-storey vertical concrete elements in high-risestructures, such as shear walls, core walls, lift shafts, stairshafts and bridge pylons. These are constructed in astaged process. It is a highly productive system designedto increase speed and efficiency while minimising labourand crane time.Systems are normally modular and can be joined toform long lengths to suit varying construction geometries.Three types of jump form are in general use:
  19. 19. TYPES OF JUMP FORMNormal jump/climbing form –units are individuallylifted off the structure and relocated at the nextconstruction level using a crane.Guided-climbing jump form –also uses a crane butoffers greater safety and control during lifting as unitsremain anchored/guided by the structure.Self-climbing jump form –does not require a crane asit climbs on rails up the building by means ofhydraulicjacks, or by jacking the platforms off internal recessesin the structure. It is possible to link the hydraulicjacks and lift multiple units in a single operation.
  20. 20. TUNNEL FORMTunnel form is used to formrepetitive cellular structures,and is widely recognised as amodern innovation thatenables the construction ofhorizontal and verticalelements (walls and floors)together.Significant productivity benefitshave beenachieved by using tunnel form toconstruct cellularbuildings such as hotels, low- andhigh-rise housing,hostels, student accommodation,prison and barracksaccommodation.
  21. 21. THANK YOU !