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High Rise Structures Posted in Steel Structures , Structural Engineering , Structures Print This Post A high-rise is a tall building or structure Buildings between 75 feet and 491 feet (23 m to 150 m) high are considered high-rises. Buildings taller than 492 feet (150 m) are classified as skyscrapers. The materials used for the structural system of high-rise buildings are reinforced concrete and steel. Most American style skyscrapers have a steel frame, while residential tower blocks are usually constructed out of concrete. High-rise structures have certain features. The structures are high & lead to higher vertical loads and higher lateral loads (mainly due to wind stress) in comparison with lower buildings. LOADS ON THE HIGHRISE STRUCTURES Vertical Loads Dead loads arise from the weigh to the individual construction elements and the finishing loads. Live loads are dependent on use depending on the number of stories; live loads can be reduced for load transfer and the dimensioning of vertical load-bearing elements.

High Rise Structures

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Page 1: High Rise Structures

High Rise Structures Posted in Steel Structures, Structural Engineering, Structures Print This Post

A high-rise is a tall building or structure

• �Buildings between 75 feet and 491 feet (23 m to 150 m) high are considered high-rises. Buildings taller than 492 feet (150 m) are

classified as skyscrapers. • The materials used for the structural system of high-rise buildings are

reinforced concrete and steel. Most American style skyscrapers have a steel frame, while residential tower blocks are usually constructed out

of concrete. • High-rise structures have certain features. The structures are high &

lead to higher vertical loads and higher lateral loads (mainly due to wind stress) in comparison with lower buildings.

LOADS ON THE HIGHRISE STRUCTURES

Vertical Loads

• Dead loads arise from the weigh to the individual construction

elements and the finishing loads. • Live loads are dependent on use depending on the number of stories;

live loads can be reduced for load transfer and the dimensioning of vertical load-bearing elements.

Page 2: High Rise Structures

� However, the reduction of the total live load on a construction element may

not exceed 40%.

Horizontal Loads

• Calculation of lateral loads should be carefully scrutinized. • It generally arises from unexpected deflections, wind and earthquake

loads

Unexpected Deflections

• It arises from imprecision in the manufacture of construction elements

and larger components. • Another cause is the uneven settling of the foundation at an in-

homogeneous site. • Any deflection produces additional lateral forces.

Wind Loads

• High-rise buildings are susceptible to oscillation. It should not be viewed as statically equivalent loads, but must be investigated under

the aspect of sway behaviour.

• Wind tunnel experiments are used to see the influence of the building?s shape on the wind load.

• The ability of wind loads to bring a building to sway must also be kept in mind. This oscillation leads both to a perceptible lateral acceleration

for occupants, and to a maximum lateral deflection.

Earthquake Loads

Definition

• Seismology (from the Greek seismos= earthquake and logos= word)

• scientific study of earthquakes • propagation of elastic waves through the Earth.

• studies of earthquake effects, such as tsunamis • diverse seismic sources such as volcanic, tectonic, oceanic,

atmospheric, and artificial processes such as explosions.

Earthquake

• Produce different types of seismic waves.

• It travel through rock, and provide an effective way to image both sources and structures deep within the Earth.

Page 3: High Rise Structures

Seismic Waves

There are three basic types of seismic waves in solids:

• P-waves

• \S-waves • P-and/or S-waves.

• The two basic kinds of surface waves (Raleigh and Love).

Pressure waves,/Primary waves /P

• Travel at the greatest velocity within solids and are therefore the first

waves to appear on a seismogram.• P-waves are fundamentally pressure disturbances that propagate

through a material by alternately compressing and expanding

(dilating) the medium, where particle motion is parallel to the direction of wave propagation.

Shear waves/secondary waves/S

• Transverse waves that travel more slowly than P

appear later than P

• Particle motion is pShear waves do not exist in fluids such as air or water.

Type of High-Rise Structure

1. Braced Frame

2. Rigid Frame Structure3. Infilled Frame Structure

4. Flat Plate and Flat Slab Structure5. Shear wall structure6. Coupled wall structure

There are three basic types of seismic waves in solids:

waves.

The two basic kinds of surface waves (Raleigh and Love).

Primary waves /P-waves,

Travel at the greatest velocity within solids and are therefore the first

waves to appear on a seismogram. waves are fundamentally pressure disturbances that propagate

through a material by alternately compressing and expanding

ilating) the medium, where particle motion is parallel to the direction of wave propagation.

Shear waves/secondary waves/S-waves,

Transverse waves that travel more slowly than P-waves and thus

appear later than P-waves on a seismogram.

Particle motion is perpendicular to the direction of wave propagation. Shear waves do not exist in fluids such as air or water.

Rise Structure

Rigid Frame Structure Infilled Frame Structure

Flat Plate and Flat Slab Structure Shear wall structure Coupled wall structure

The two basic kinds of surface waves (Raleigh and Love).

Travel at the greatest velocity within solids and are therefore the first

waves are fundamentally pressure disturbances that propagate through a material by alternately compressing and expanding

ilating) the medium, where particle motion is parallel to the direction

waves and thus

erpendicular to the direction of wave propagation. Shear waves do not exist in fluids such as air or water.

Page 4: High Rise Structures

7. Wall-frame structure

8. Framed tube structure 9. The trussed tube

10. Tube in tube or Hull core structure 11. Bundled tube structure

12. Core and Outriggers system 13. Hybrid structure

Braced Frame

• Braced frames are cantilevered vertical trusses resisting laterals loads primarily through the axial stiffness of the frame members.

• The effectiveness of the system, as characterized by a high ratio of stiffness to material quantity, is recognized for multi-storey building in

the low to mid height range. • Generally regarded as an exclusively steel system because the

diagonal are inevitably subjected to tension for or to the other directions of lateral loading.

• Able to produce a laterally very stiff structure for a minimum of additional material, makes it an economical structural form for any

height of buildings, up to the very tallest.

Advantages:-

• Girders only participate minimally in the lateral bracing action-Floor

framing design is independent of its level in the structure. • Can be repetitive up the height of the building with obvious economy

in design and fabrication.

Disadvantages:-

Obstruct the internal planning and the locations of the windows and doors; for this reason, braced bent are usually incorporated internally along wall and partition lines, especially around elevator, stair, and service shaft.-

Diagonal connections are expensive to fabricate and erect.

Page 5: High Rise Structures

Rigid Frame Structure

Consist of columns and girders joined by moment resistant connections.

Lateral stiffness of a rigid frame bent depends on the bending stiffness of the columns, girders, and connection in the plane of the bents. Ideally suited for

reinforced concrete buildings because of the inherent rigidity of reinforced concrete joints. Also used for steel frame

connections in steel tend to be costly. While rigid frame of a typical scale that serve alone to resist lateral loading have an economic height limit of about 25 stories, smaller scale rigid frames in the for of perimeter tu

typically rigid frames in combination with shear walls or braced bents, can be economic up top much greater heights.

Advantages:-

• May be place in or around the core, on the exterior, or throughout the interior of the building with minimal constraint

module. • The frame may be architecturally exposed to express the grid like

nature of the structure.• The spacing of the columns in a moment resisting frame can match

that required for gravity framing.30 storiesonly; member proportions and materials cost become

unreasonable for building higher than that.

ACT Tower, Himatsu Japan

Rigid Frame Structure

Consist of columns and girders joined by moment resistant connections.

rigid frame bent depends on the bending stiffness of the columns, girders, and connection in the plane of the bents. Ideally suited for

reinforced concrete buildings because of the inherent rigidity of reinforced concrete joints. Also used for steel frame buildings, but moment

connections in steel tend to be costly. While rigid frame of a typical scale that serve alone to resist lateral loading have an economic height limit of about 25 stories, smaller scale rigid frames in the for of perimeter tu

typically rigid frames in combination with shear walls or braced bents, can be economic up top much greater heights.

May be place in or around the core, on the exterior, or throughout the interior of the building with minimal constraint on the planning

The frame may be architecturally exposed to express the grid like

nature of the structure. The spacing of the columns in a moment resisting frame can match

that required for gravity framing.-Only suitable for building up to 20 storiesonly; member proportions and materials cost become

unreasonable for building higher than that.

Consist of columns and girders joined by moment resistant connections.

rigid frame bent depends on the bending stiffness of the columns, girders, and connection in the plane of the bents. Ideally suited for

reinforced concrete buildings because of the inherent rigidity of reinforced buildings, but moment-resistant

connections in steel tend to be costly. While rigid frame of a typical scale that serve alone to resist lateral loading have an economic height limit of about 25 stories, smaller scale rigid frames in the for of perimeter tube, or

typically rigid frames in combination with shear walls or braced bents, can

May be place in or around the core, on the exterior, or throughout the on the planning

The frame may be architecturally exposed to express the grid like

The spacing of the columns in a moment resisting frame can match

Only suitable for building up to 20 –storiesonly; member proportions and materials cost become

Page 6: High Rise Structures

In-filled Frame Structure

Most usual form of construction for tall buildings up to 30 stories in height Column and girder framing o

filled by panels of brickwork, block work, or castof the in-filled serve also as external walls or internal partitions, the system

is an economical way of stiffening and strengthecomplex interactive behaviour of the infill in the frame, and the rather

random quality of masonry, has made it difficult to predict with accuracy the stiffness and strength of an in

Flat-Plate and Flat Slab Structure

Fig. WTC OSAKA JAPAN

filled Frame Structure

Most usual form of construction for tall buildings up to 30 stories in height Column and girder framing of reinforced concrete, or sometimes steel, is in

filled by panels of brickwork, block work, or cast-in-place concrete. Because filled serve also as external walls or internal partitions, the system

is an economical way of stiffening and strengthening the structure. The complex interactive behaviour of the infill in the frame, and the rather

random quality of masonry, has made it difficult to predict with accuracy the stiffness and strength of an in-filled frame.

Fig. Infilled Frame.

nd Flat Slab Structure

Most usual form of construction for tall buildings up to 30 stories in height f reinforced concrete, or sometimes steel, is in-

place concrete. Because filled serve also as external walls or internal partitions, the system

ning the structure. The complex interactive behaviour of the infill in the frame, and the rather

random quality of masonry, has made it difficult to predict with accuracy the

Page 7: High Rise Structures

• Is the simplest and most logical of all structural forms in that it

consists of uniforms slabs, connected rigidly to supporting columns. • The system, which is essentially of reinforced concrete, is very

economical in having a flat soffit requiring the most uncomplicated formwork and, because of the soffit can be used as the ceiling, in

creating a minimum possible floor depth. • Lateral resistance depends on the flexural stiffness of the components

and their connections, with the slab corresponding to the girder of the rigid frame.

• Particularly appropriate for hotel and apartment construction where ceiling space is not required and where the slab may serve directly as

the ceiling. • Economic for spans up to about 25 ft (8m),above which drop panels

can be added to create a flat-slab structure for span of up to 38 ft (12m).

• Suitable for building up to 25 stories height.

Shear Wall Structure

Concrete or masonry continuous vertical walls may serve both architecturally

partitions and structurally to carry gravity and lateral loading. Very high in plane stiffness and strength make them ideally suited for bracing tall building Act as vertical cantilevers in the form of separate planar walls, and

as non-planar assemblies of connected walls around elevator, stair and service shaft. well suited to hotel and residential buildings where the floor-by

floor repetitive planning allow the walls to be vertically continuous and where they serve simultaneously as excellent acoustic and fire insulators

between rooms and apartments. Minimum shrinkage restraint reinforcement where the wall stresses are low, which can be for a substantial portion of the

wall.

• Tensile reinforcement for areas where tension stresses occur in walls when wind uplifts stresses exceeds gravity stresses.

• Compressive reinforcement with confinement ties where high

compressive forces require the walls is designed as columns. Individual shear walls, say at the edge of a tall building, are design as

blade walls or as columns resisting shear and bending as required. • High strength concrete has enable wall thickness to be minimized,

hence maximizing rentable floor space. • Technology exists to pump and to place high-strength concrete at high

elevation. • Fire rating for service and passenger elevator shafts is achieved by

simply placing concrete of a determined thickness.

Page 8: High Rise Structures

• The need for complex bolted or side-welded steel connections is

avoided. • Well detail reinforce concrete will develop about twice as much

damping as structural steel. This advantage where acceleration serviceability is critical limits state, or for ultimate limits state design

in earthquake-prone area.

Action to be considered:-

• Shear wall formed around elevator and service risers requires a

concentration of opening at ground level where stresses are critical. • Torsional and flexural rigidity is affected significantly by the number

and the size of opening around the shear walls throughout the height of the building.

• Shear wall vertical movements will continue throughout the life of the building.

• Construction time is generally slower than for a steel frame building. • The additional weight of the vertical concrete elements as compared to

steel will induce a cost penalty for the foundations. • An increase in mass will cause a decrease in natural frequency and

hence will most likely produce an adverse affect of the acceleration response depending on the frequency range of the building. But shear wall systems are usually stiff and cause a compensating increase in

natural frequency.

Problem associated with formwork systems:

• A significant time lag will occur between footing construction and wall construction, because of the fabrication and erection on site of the

moving formwork systems

• Time will be lost at the levels where wall are terminated or decrease in thickness, alignment of the shear walls are within tolerance.

• Regular survey check must be undertaken to ensure that the vertical and twist alignment of the shear walls are within tolerance.

• In general it is difficult to achieve a good finish from slip-form formwork systems, and hence rendering or some other type of

finishing may be necessary.

Page 9: High Rise Structures

Coupled Wall Structure

• Consist of two or more shear walls in the same plane, or almost the same plane, connected at the floor level

• The effect of the shearsets of wall to behave in their partly as a composite cantilever, bending about the common centroidal axis of the walls.

• Suited for residential construction wher

walls, which separate the apartments, consist of in

pairs, or trios, of shear walls between which there are corridor or window openings. Besides using concrete construction, it occasionally

been constructed of hplate or box girders, as part of steel frame structure.

Coupled shear walled structure

Shear wall Structure

Coupled Wall Structure

Consist of two or more shear walls in the same plane, or almost the same plane, connected at the floor levels by beam or stiff slabs.

The effect of the shear-resistant connecting members is to cause the sets of wall to behave in their partly as a composite cantilever, bending about the common centroidal axis of the walls.Suited for residential construction where lateral-load resistant cross

walls, which separate the apartments, consist of in-plane coupled

pairs, or trios, of shear walls between which there are corridor or window openings. Besides using concrete construction, it occasionally

been constructed of heavy steel plate, in the style of massive vertical plate or box girders, as part of steel frame structure.

Coupled shear walled structure

Consist of two or more shear walls in the same plane, or almost the s by beam or stiff slabs.

resistant connecting members is to cause the sets of wall to behave in their partly as a composite cantilever, bending about the common centroidal axis of the walls.

load resistant cross

plane coupled

pairs, or trios, of shear walls between which there are corridor or window openings. Besides using concrete construction, it occasionally

eavy steel plate, in the style of massive vertical

Page 10: High Rise Structures

Wall-Frame Structure

• The walls and frame interact horizontally, especially at the top, to

produce stiffer and strongcombination is appropriate for the building in the 40

well beyond that of rigid frames or shear walls alone.• Carefully tuned structure, the shear of the frame can be made

approximately uniform over be repetitive. Although the wall

a concrete structural form, with shear wall and concrete frames, a steel counterpart using braced frames and steel rigid frames offers

similar benefits of horizontal interaction.• The braced frames behave with an overall flexural tendency to interact

with the shear mode of the rigid frames.

Majestic building, Wellington, New Zealand.

The lateral resistant of the framed

moment-resistant frames that form a “tube” around the perimeter of the building. The basic inefficiency of the frame system for reinforced concrete

Frame Structure

The walls and frame interact horizontally, especially at the top, to

produce stiffer and stronger structure. The interacting wallcombination is appropriate for the building in the 40 –

well beyond that of rigid frames or shear walls alone. Carefully tuned structure, the shear of the frame can be made

approximately uniform over the height, allowing the floor framing to be repetitive. Although the wall-frame structure is usually perceived as

a concrete structural form, with shear wall and concrete frames, a steel counterpart using braced frames and steel rigid frames offers

r benefits of horizontal interaction. The braced frames behave with an overall flexural tendency to interact with the shear mode of the rigid frames.

Wall frame structure

Majestic building, Wellington, New Zealand.

The lateral resistant of the framed-tube structures is provided by very stiff

resistant frames that form a “tube” around the perimeter of the building. The basic inefficiency of the frame system for reinforced concrete

The walls and frame interact horizontally, especially at the top, to

er structure. The interacting wall-frame –60 story range,

Carefully tuned structure, the shear of the frame can be made

the height, allowing the floor framing to frame structure is usually perceived as

a concrete structural form, with shear wall and concrete frames, a steel counterpart using braced frames and steel rigid frames offers

The braced frames behave with an overall flexural tendency to interact

Majestic building, Wellington, New Zealand.

tube structures is provided by very stiff

resistant frames that form a “tube” around the perimeter of the building. The basic inefficiency of the frame system for reinforced concrete

Page 11: High Rise Structures

buildings of more than 15 stories resulted in member proportions of

prohibitive size and structural material cost premium, and thus such system were economically inviable. The frames consist of 6-12 ft (2-4m) between

centers, joined by deep spandrel girders. Gravity loading is shared between the tube and interior column or walls. When lateral loading acts, the

perimeter frame aligned in the direction of loading acts as the “webs” of the massive tube of the cantilever, and those normal to the direction of the

loading act as the “flanges”. The tube form was developed originally for building of rectangular plan, and probably it?s most efficient use in that

shape.

Suitable for reinforced concrete and steel construction and has been used for

building ranging from 40 to more than 100 stories. Aesthetically, the tube externally evident form is regarded with mixed enthusiasm; some praise the

logic of clearly expressed structure while other criticizes the grid like façade as small-windowed and uninterestingly repetitious. Depending on the height

and dimensions of the building, exterior columns spacing should be in order of 1.5 m to 4.5 m on center maximum. Spandrel beam depths for normal

office or residential occupancy application are typically 600 mm to 1200 mm. Frame tube in structural steel requires welding of the beam-column joint to

develop rigidity and continuity. The formation of fabricated tree elements, where all welding is performed in the shop in a horizontal position, has made

the steel frame tube system more practical and efficient. The 110 story World Trade Center twin towers, New York are examples whereby the

structuralist notion of a punched wall tube with extremely close exterior columns is architecturally exploited to express visually the inherent

verticality of the high rise building.

Page 12: High Rise Structures

The Trussed tube:

• The trussed tube system represents a classic solution for a tube uniquely suited to the qualities and character of structural steel.

• Interconnect all exterior columns to form a rigid box, which can resist lateral shears by axial in

• Introducing a minimum number of diagonals on each façade and making the diagonal intersect at the same point at the corner column.

• The system is tubular in that the fascia diagonals not only form a truss in the plane, but also interact with the trusses on the perpendicular

faces to affect the tubular behaviour. This creates the x form between corner columns on each façade.

• Relatively broad column spacing can resulted large clear spaces for windows, a particular chara

The trussed tube system represents a classic solution for a tube uniquely suited to the qualities and character of structural steel.

Interconnect all exterior columns to form a rigid box, which can resist lateral shears by axial in its members rather than through flexure.

Introducing a minimum number of diagonals on each façade and making the diagonal intersect at the same point at the corner column.The system is tubular in that the fascia diagonals not only form a truss

e, but also interact with the trusses on the perpendicular

faces to affect the tubular behaviour. This creates the x form between corner columns on each façade. Relatively broad column spacing can resulted large clear spaces for windows, a particular characteristic of steel buildings.

The trussed tube system represents a classic solution for a tube uniquely suited to the qualities and character of structural steel.

Interconnect all exterior columns to form a rigid box, which can resist its members rather than through flexure.

Introducing a minimum number of diagonals on each façade and making the diagonal intersect at the same point at the corner column. The system is tubular in that the fascia diagonals not only form a truss

e, but also interact with the trusses on the perpendicular

faces to affect the tubular behaviour. This creates the x form between

Relatively broad column spacing can resulted large clear spaces for cteristic of steel buildings.

Page 13: High Rise Structures

• The façade digitalisation serves to equalize the gravity loads of the

exterior columns that give a significant impact on the exterior architecture.

Tube-in-Tube or Hull Core Structure

• This variation of the framed tube consis“Hull,” together with an internal elevator and service core.

• The Hull and core act jointly in resisting both gravity and lateral

loading.

• The outer framed tube and the inner core interact horizontally as the shear and flexural components of a wall

benefit of increased lateral stiffness.• The structural tube usually adopts a highly dominant role because of

its much greater structural depth.

The façade digitalisation serves to equalize the gravity loads of the

exterior columns that give a significant impact on the exterior

Tube or Hull Core Structure

This variation of the framed tube consists of an outer frame tube, the “Hull,” together with an internal elevator and service core.The Hull and core act jointly in resisting both gravity and lateral

The outer framed tube and the inner core interact horizontally as the l components of a wall-frame structure, with the

benefit of increased lateral stiffness. The structural tube usually adopts a highly dominant role because of

its much greater structural depth.

The façade digitalisation serves to equalize the gravity loads of the

exterior columns that give a significant impact on the exterior

ts of an outer frame tube, the “Hull,” together with an internal elevator and service core. The Hull and core act jointly in resisting both gravity and lateral

The outer framed tube and the inner core interact horizontally as the frame structure, with the

The structural tube usually adopts a highly dominant role because of

Page 14: High Rise Structures

Bundled-Tube structures

• The concept allows for wider columnwould be possible with only the exterior frame tube form.

• The spacing which make it possible to place interior frame lines without seriously compromising interior space planning.

Tube structures

The concept allows for wider column spacing in the tubular walls than would be possible with only the exterior frame tube form.The spacing which make it possible to place interior frame lines without seriously compromising interior space planning.

spacing in the tubular walls than would be possible with only the exterior frame tube form. The spacing which make it possible to place interior frame lines without seriously compromising interior space planning.

Page 15: High Rise Structures

• The ability to modulate the cells vertical

vocabulary for a variety of dynamic shapes therefore offers great latitude in architectural planning of a tall building.

Core and Outrigger Systems

• Outrigger serve to reduce the overturning moment in the core that would otherwise act as a pure cantilever, and to transfer the reduced

moment to columns outside the core by the way of tensioncompression coupled, which take advantage of the increase moment

arm between these columns.

The ability to modulate the cells vertically can create a powerful

vocabulary for a variety of dynamic shapes therefore offers great latitude in architectural planning of a tall building.

Core and Outrigger Systems

Outrigger serve to reduce the overturning moment in the core that se act as a pure cantilever, and to transfer the reduced

moment to columns outside the core by the way of tensioncompression coupled, which take advantage of the increase moment

arm between these columns.

ly can create a powerful

vocabulary for a variety of dynamic shapes therefore offers great

Outrigger serve to reduce the overturning moment in the core that se act as a pure cantilever, and to transfer the reduced

moment to columns outside the core by the way of tension-compression coupled, which take advantage of the increase moment

Page 16: High Rise Structures

• It also serves to reduce the critical connection where the mast is

stepped to the keel beam. • In high-rise building this same benefit is realized by a reduction of the

base core over-turning moments and the associated reduction in the potential core uplift forces.

In the foundations system, this core and outrigger system can lead to the

need for the following:

• The addition of expensive and labour-intensive rock anchors to an

otherwise “simple” foundation alternative such as spread footing. • Greatly enlarged mat dimensions and depth solely to resist overturning

forces. • Time-consuming and costly rock sockets for caisson systems along

with the need to develop reinforcement throughout the complete caisson depth.

• Expensive and intensive field work connection at the interface between core and the foundation. This connection can become particularly troublesome when one considers the difference in construction tolerances between foundations and core structure.

• The elimination from consideration of foundation systems which might have been nsiderably less expensive, such as pile, solely for their inability to resist significant uplift.

Advantages:

• The outrigger systems may be formed in any combination of steel, concrete, or composite construction.

• Core overturning moments and their associated induced deformation

can be reduced through the “reverse” moment applied to the core at

each outrigger intersection. This moment is created by the force couple at the exterior columns to which the outrigger connect. It can

potentially increase the effective depth of the structural system from the core only to almost the complete building.

• Significant reduction and possibly the complete elimination of uplift and net tension forces throughout the column and the foundation

systems. • The exterior column spacing is not driven by structural considerations

and can easily mesh with aesthetic and functional considerations. • Exterior framing can consist of “simple” beam and column framing

without the need for rigid-frame-type connections, resulting in economies.

• For rectangular buildings, outriggers can engage the middle columns on the long faces of the building under the application of wind loads in

Page 17: High Rise Structures

the more critical direction. In core-alone and tubular systems, these

columns which carry significant gravity load are either not incorporated or under utilized. In some cases, outrigger systems can efficiently

incorporate almost every gravity column into lateral load resisting system, leading to significant economies.

Disadvantages

The most significant drawback with use of outrigger systems is their potential interference with occupiable and rentable space. This obstacle can

be minimized or in some cases eliminate by incorporation of any of the following approaches:

• Locating outrigger in mechanical and interstitial levels • Locating outriggers in the natural sloping lines of the building profile • Incorporating multilevel single diagonal outriggers to minimize the

member?s interference on any single level. • Skewing and offsetting outriggers in order to mesh with the functional

layout of the floor space.

• Another potential drawback is the impact the outrigger installation can have on the erection process. As a typical building erection proceeds,

the repetitive nature of the structural framing and the reduction in member sizes generally result in a learning curve which can speed the

process along.

The incorporation of a outrigger at intermediate or upper levels can, if not approached properly, have a negative impact on the erection process. Several steps can be taken to minimize this possibility Provide clear and concise erection guidelines in the contract documents so that the erector can

anticipate the constraint and limitation that the installation will impose. If

possible, avoid outriggers locations or design constraints that will require “backtracking” in the construction process to install or connect the outrigger.

The incorporation of intermediate outriggers in concrete construction or large variation in dead-load column stresses between the core and the

exterior can in some cases result in the need to “backtrack”. Such a need can be minimized if issues such as creep and differential shortening are

carefully studied during the design process to minimize their impact. Avoid adding additional outrigger levels for borderline force or deflection control.

Hybrid Structure

Combination of two or even more of basic structural forms either by direct combination or by adopting different forms in different parts of the structure.

This systems provide in-plane stiffness, its lack of Torsional stiffness requires

Page 18: High Rise Structures

that additional measures be taken, which resulted in one bay vertical

exterior bracing and a number of level of perimeter Vierendeel “bandages” perhaps one of the best examples of the art of structural engineering. Hybrid structures are likely to be the rule rather tall buildings, whether to create acceptable dynamic characteristics or to

accommodate the complex shapes demanded by modern architecture. Highstrength concrete, consist of stiffness and damping capabilities of large concrete elements are combined with the lightness and constructability of steel frame exhibits significantly lower creep and shrinkage and is therefore

more readily accommodated in a hybrid frame.

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Related Topics

• High Rise Structures • High Performance Concre• High Volume Fly Ash Concrete• High Performance Concrete in Bridge Decks

onal measures be taken, which resulted in one bay vertical

exterior bracing and a number of level of perimeter Vierendeel “bandages” perhaps one of the best examples of the art of structural engineering. Hybrid structures are likely to be the rule rather than the exception for future very tall buildings, whether to create acceptable dynamic characteristics or to

accommodate the complex shapes demanded by modern architecture. Highstrength concrete, consist of stiffness and damping capabilities of large

crete elements are combined with the lightness and constructability of steel frame exhibits significantly lower creep and shrinkage and is therefore

more readily accommodated in a hybrid frame.

High Performance Concrete High Volume Fly Ash Concrete High Performance Concrete in Bridge Decks

onal measures be taken, which resulted in one bay vertical

exterior bracing and a number of level of perimeter Vierendeel “bandages” –perhaps one of the best examples of the art of structural engineering. Hybrid

than the exception for future very tall buildings, whether to create acceptable dynamic characteristics or to

accommodate the complex shapes demanded by modern architecture. High-strength concrete, consist of stiffness and damping capabilities of large

crete elements are combined with the lightness and constructability of steel frame exhibits significantly lower creep and shrinkage and is therefore

Page 19: High Rise Structures

• High Performance Concrete in Bridge Decks

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6 Comments

1. The Constructor says:

15/11/2009 at 20:03

High Rise Structures: A high-rise is a tall building or structure

·Buildings between 75 feet and 491 feet (2.. http://bit.ly/10Eehg

Reply

2. The Constructor says:

Page 20: High Rise Structures

16/11/2009 at 07:33

High Rise Structures: A high-rise is a tall building or structure

·Buildings between 75 feet and 491 feet (2.. http://bit.ly/10Eehg

Reply

3. Emo says:

09/10/2010 at 21:31

I actually think so too=] I have been browsing around the internet for some time this week, and its kinda hard to find anything interesting to read on blogs. Maybe thats because there are too many of them around =) But your place actually keeps catching my attention. Great posts, and cool design ^__^. Ill be sure to give it more time from now on .

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4. Syed Anwar Kamal says:

03/05/2011 at 05:02

Dear. I need help in finding out the minimum and maximum permissible dimension of Pre-stressed Flat Slab. Shall be grateful if I can be provided with any PSFSlab Stuctural Detail. Thanks and best regards Engr.S.A.Kamal sakamal56″@yahoo.com

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5. b.rahman says:

16/05/2011 at 14:41

this webside has helped me very much.

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6. Sabahat Ali Khan says:

Page 21: High Rise Structures

20/08/2011 at 02:21

Gr8 work indeed!!! I really appreciate it!!! Sir can u also help me on the following topic in detail:

Explain different Structural systems for high rise buildings.Give examples for the same.(Atleast 10 Systems) I would be highly grateful to you if you can help me on this topic asap.

With Best Regards

Sabahat