1) Tall buildings are defined differently depending on the context but generally refer to buildings where lateral loads from wind and sway must be considered in the structural design. 2) There are several reasons for building tall, including limited land availability in cities, prestige, and showing economic or political power. 3) Early tall buildings used masonry load-bearing walls but reinforced concrete and steel frames allowed for much greater heights. 4) Planning considerations for tall buildings include economics, soil conditions, structural systems, mechanical systems, and fire safety.

1. TALL BUILDING
LECT 3

2. INTRODUCTION
• The term ‘tall buildings’ is not defined in specific term related to height
or the number of storeys. A building is considered tall when its
structural analysis and design
are in some way affected by the lateral loads, particularly sway caused
by such loads.
• According to Emporis Standards Committee (ESC) Tall Building is defined
as a building 35 meters or greater in
height, which is divided at regular intervals into occupiable levels. To be
considered a high-rise
buildinga structure must be based on solid ground, and
fabricated along its full height through deliberate
processes (as opposed to naturally-occurring formations).
• According to the regulations of Danish, German and some other
European countries, the 72ft. (21.6m = 8stories buildings), having fire-
fighting equipment, are known as tall buildings.
• Definitions represented by the U.S. Council on tall buildings and urban
settlement refers to tall buildings as these in which the height,
influences the planning,
construction and spaces application aspects of the building considerably
without specifying the number of stories

3. THE FACTS ABOUT TALL
BUILDING…

4. REASON FOR USING TALL BUILDING
SPACE LIMITATION PRESTIGE
• the process urban migration
•increase in the population
density of cities
•increasing land prices
make it necessary to maximize
space utilization by building
upwards.
•free imposing advertisements
for their owners and even the
city it is sited.
•as a show of political or
economic power
•dominate the landscape and
easily become landmarks
•human ego and competition

5. EVOLUTION OF TALL BUILDINGS
Reinforced concrete established.
Architectural emphasis on reasons, functional and
technological facts. Transition of structural systems
from rigid frame to more efficient structural
systems
Steel structures and sophisticated services such as
mechanical lifts and ventilation, limitations on the
height of buildings were removed
Masonry wall bearing structures with thick and
messy walls. The horizontal and lateral loads of the
structures were mainly resisted solely by the load
bearing masonry wall

6. 1st. EVOLUTION OF TALL BUILDINGS
Reliance Building
Chicago,1894
Guaranty
Building,Buffalo, 1895
Carson Pirie Scott
Department
Store,Chicago,1904

7. 2nd. EVOLUTION OF TALL BUILDINGS
Woolworth
Building,New York,
1930
Chrysler Building,New
York, 1930
Empire State Building,
New York, 1931 (highest
structure in 19th century)

8. 3rd. EVOLUTION OF TALL BUILDINGS
World Trade Centre,
New York,1972
Sears Tower,
Chicago,1974
Petronas Twin Tower,
Kuala Lumpur,1996

9. WORLD TALLEST BUILDING

10. WORLD TALLEST BUILDING

11. WORLD TALLEST BUILDING

12. TRY TO GET LISTS OF A WORLD
TALLEST BUILDINGS

13. PLANNING
CONSIDERATIONS
 The selection of a tall building structure is
not based merely on understanding the structure in its
own context.
 The selection may be more function of factors related to
cultural, social, economical and technological needs.
 Some of the factors are
 General Economic Considerations
 Soil Condition
 Height to width Ratio of a Building
 Fabrication and Erection Consideration
 Mechanical Systems Considerations
 Fire Rating Considerations
 Local Considerations
 Availability and Cost of Main Construction Materials

14. GENERAL ECONOMIC CONSIDERATIONS
 How much the projects costs to build.
 How much the finished project costs to operate
(e.g
expenses associated with utilities, maintenance,
insurance, taxes, interest on borrowed money)
 As the height of the building increases, more
and more space is needed for structure,
mechanical systems and elevators, leaving less
rental space.
 The costs of elevators and mechanical systems
increase with height.
 Cost for sophisticated construction equipment
as building get taller

15. SOIL CONDITION
 The performance of a building is dependent on t
he strength of the soil which it is founded.
 The foundation or substructure binds the
superstructure to the soil.
 If the bearing capacity of the soil is rather low,
piles or caissons may be required to reach the
proper foundation support.

16. HEIGHT TO WIDTH RATIO
OF A BUILDING
• As the minimum height-to-
width ratio increases, so
should the building’s inherent
stiffness
• The stiffness of the building
structure is dependent on
size and number of bays,
structural systems and
rigidity of members and
connections.
• The general height-to-width for a
plane frame structure in the range
of 5 to 7

17. FABRICATION AND ERECTION
CONSIDERATION
 The planning of fabrication and
erection procedures may indicate
important factors concerning structural
systems selection.
 Should be a minimum number of structural pie
ces to shorten construction time, complicated
closed form shapes should be avoided and
field welding should be minimized.

18. Mechanical Systems
Considerations
 Average more than one-third of
total tall building costs.
 Effects on the building overall
appearance and economic
selection of a structural systems

19. FIRE RATING
CONSIDERATIONS
 Almost all floors are beyond the reach of fire truck ladders, firefighting and rescue
action are from the inside of a building.
 Total emergency evacuation is impossible within a reasonably short period of time.
 Must be able to ensure the following:
 structural integrity for a certain period of time.
 confinement of the fire, to prevent it from spreading to certain building areas.
 adequate exit systems.
 effective smoke and fire detection systems.
 sprinklers and necessary smoke and heat venting

20. LOCAL
CONSIDERATIONS
For example, height limitation, zoning regulations

21. AVAILABILITY AND COST OF
MAIN CONSTRUCTION
MATERIALS
If a desired material is hard to acquire,
it may delay the building schedule and
add significantly to building costs

22. DESIGN CONSIDERATION

23. METHOD OF CONSTRUCTION
• CONVENTIONAL?
– In Malaysia, in-situ reinforced concrete is the norm for
constructing tall buildings. Skilled and unskilled workers
experienced in such work and the associated machinery
and materials are readily available. Pre-cast concrete is
sometimes used in low and medium rise residential
buildings. Concrete is either mixed on site or ready-mixed.
The concrete is poured into a hopper and usually lifted by
crane to the final position. The concrete is emptied in the
formwork, vibrated and cured.

24. • INDUSTRIALISED?
– Prefabrication do not necessary has to be in a factory located away
from the site. The prefabricated components could be built on a
production line on site. But if the high rise building has limited space,
this approach is not suitable.
– The principle of prefabrication is that the components should be made
at a place where workers could work safely and comfortably, thus
ensuring better quality and then transported to the site to be
assembled in their final positions. This principle could be used for
many types of components that are normally associated with in-situ
production. It is safer and better quality work is provided if these
components could be assembled on site and then lifted in its
assembled form to its final position rather than the normal practice of
in situ production. For example, reinforcement cages for the columns
and beams could be fabricated on the ground and then lifted by lift to
be placed at their final positions.

25. • STEEL OR REINFORCED CONCRETE?
– Reinforced concrete is the normal way of constructing high rise buildings in Malaysia.
This is partially due to the abundance of limestone and the setting up of several large
cement factories around Malaysia. Steel rebar is manufactured in Malaysia but hot
rolled structural steel has to be imported. One often quoted advantage of using
structural is that unlike reinforced concrete, it is a ‘dry’ form of construction involving
only assembly of the steel thus a shorter period of time. However, the use of steel
structural members for the structural frame of the building in Malaysia requires a period
of preplanning and takes account of transport times as these have to be sourced from
India, South Korea, China and Japan where there are hot rolled steel producers. This
consumes some of the so-called time savings. In addition, the assembly of the steel
structural frame needs the involvement of teams of highly skilled structural steel
workers and crane operators. These persons are mostly found in North America and
Europe. Their wages are relatively higher than the imported Indonesian, Bangadeshi and
Vietnamese workers. Furthermore, there is an available pool of foreign workers who
have had sufficient experience and some measure of skill in concreting despite them not
having any formal training in concreting. The major drawback of reinforced concrete is
that it is a wet process and needs more working space.

26. • SPECIAL TECHNIQUES?
– Sometimes the architects of tall buildings wish to create
exclusivity of their designs by employing innovative
construction techniques and structural systems.
– The use of innovation construction techniques must take
into account the economic availability of local and foreign
workers and consultants who are skilled and capable of
handling the technology. It must be remembered that new
systems will have teething problems and time will be spent
solving these problems during the construction period.

27. ARCHITECTURAL CONSIDERATION
• The shape of a tall building is basically a long vertical
box or cylinder. There is limited scope to create
innovative building shapes .
• Architects give tall buildings their identity by the way
they design the facade or outside appearance of the
building. They also design the interior finishes of the
building.
• When an architect designs the floor plan of the
building, he has to aim for maximum floor area to
sell or rent to possible tenants.

28. • He has to leave aside space on the floor plan for the service
core area and the building occupiers’ circulation paths. In
the building service core area, the architect allocate space
for the:-
– toilets,
– the riser cables for electricity and telecommunication
– lift shafts
– staircases
– plumbing pipes for drainage, sewerage and water supply
– airconditioning and ventilation riser ducts
– airconditioning chilled water pipes
BUILDING SERVICES
CORE AREA

29. • With so many things to put in the core area, the
architects try to reduce the amount of core areas.
• In addition, the architect may leave aside certain
floors to house the airconditioning plant, the water
tanks for water supply, airconditioning and fire
fighting systems, and the electicity distribution
equipment.
• These floors are usually in the basement, at the roof
or in floors where giant internal beams or girders
called outriggers are located.

30. Air Conditioning System

31. TIME CONSUMING
• Tenants in tall buildings make the journey from their
top floor offices to the outside the building at
ground level to eat. This will be too time consuming
and tiring, especially in a supertall building.
• Thus the architect will try to provide areas for
canteens, restaurants, shops and other facilities
within the building plan especially if it is a tall or
supertall building.

32. • In this way, people do not have to leave the building
for lunch or to shop or for leisure. In some supertall
buildings such as the Sears Tower, ‘sky lobbies’ are
provided at certain floors to house shops, eating and
recreational places.
• Thus, a supertall building is normally a city with a
city. We can see that the more taller a building is, the
more space is used for the building services and the
less the usable floor space per level.

33. Service core area
Tenant’s usable
space area
Circulation space
The floor plan of the 78 storey Central Plaza in
Hong Kong

34. STRUCTURAL CONSIDERATION
• The structural system is an integrated system
of the arrangement of members of the
structure so that it can withstand several
types of loads such as below:-
– Live and Dead Load
– Wind Load
– Differential Temperature Load
– Vibration Load
– Impact Load

35. Designing for Live and Dead Loads
• The loads exerted on a building are generally vertical due to
dead and live gravity loads. The structure transfers the vertical
loads as well as the horizontal loads to the ground. The
building can be structurally divided into two parts :-
i. Superstructure.
This consists of the floors, walls and roof that are generally above ground
level. In addition to the loads of the superstructure, there are the loads of
equipment, machinery, M&E services and people inside the
superstructure that have to be transferred to the substructure.
ii. Substructure.
This consists of the foundations that lay below ground level. The
foundations may be piles, caissons, rafts, pads or even strips. The
materials used are generally reinforced concrete or concrete encased
steel members.

36. Superstructure
Walls
Suspension system
Frame cages
SUPERSTRUCTURE
Hanger Bridge Catenary
System

37. • The main function of the vertical loading subsystem
is to transfer the dead and live loads of the
superstructure to the substructure. There are many
ways of transferring the loads.
• Walls
– Most walls in a tall building are non-load bearing. The self-
weights of these non-load bearing walls are transmitted to
the ground via the floor slab and then the columns
– Load bearing walls in tall buildings are generally made of
reinforced concrete. They are normally used as shear walls
and together with a frame cage.

38. FRAME CAGES
• Known as a framed structure, skeleton structure and
moment resisting frames
• The “frame cage” consisted of rolled iron beams and
stanchions arranged in square or rectangular grid.
The loads of the walls and floors are transferred to
the beams and column grid to the ground. Most
modern buildings use the frame cage system. Iron
have been superseded by high strength structural
steel and reinforced concrete.

39. • In order to transfer lateral loads to the ground, mega-bracing
is sometimes used in the steel frame. These are giant diagonal
members that span between giant mega columns. The mega
braces transfer the loads of the floors to the mega columns.
The mega columns transfer the loads to the foundations.
• Compared to load bearing walls, the self-weight of the frame
cage is less although the point loads at the base of the
columns may be rather high. Frame cage construction is also
relatively faster to erect especially when structural steel is the
material used. The frame cage structural members also
occupies a smaller area of the building footprint. This allows
more usable floor space for the building.

40. • Steel frame cages are more
susceptible to wind loads due to
their relatively lighter self-weight.
Thus expensive damping
mechanisms have to be
incorporated into the structure.
• Reinforced concrete frame cages
are more rigid and thus are less
likely to sway in the wind.
However, excessive wind loads
may cause tensile cracks in the
structure and thus additional
measures must be taken to
increase the R.C. frame cage’s
tensile strength.

41. DIAGRID
• The latest innovation to the
frame system is the diagrid.
Instead of box-like grid
arrangements of beams and
columns, a building with a
diagrid structure uses diagonal
members that function as both
the beam and column.. The
most famous example of the
diagrid frame structure is that
of the London’s Swiss Re
building.

42. DIAGRID
• Diagrid system
• The diagrid is often used for
the perimeter exterior wall.
It is usually part of a tube-
within-tube structural
system.
• Examples IBM building,
Pittsburgh

43. SUSPENSION SYSTEM
• As the name implies, the floors of the buildings are
suspended over a long span. The supports for these floors
may be towers, hangers or catenaries. The main advantage
of these systems is the ability to provide a column free
ground floor which could then be used as a public space,
exhibition areas etc. The other floors also enjoy column
free space which allows an infinite number of space
partitioning options.
• There are three main types of suspension system:
• Hanger
• Bridge
• Catenary systems:-

44. Hanger systems
• In this system, the floor and wall loads are
transmitted upwards through vertical tensile
members to outrigger arms. The loads are then
transferred from the outriggers to one or more
pier towers that transmit the loads to the
ground. The tensile members can be hangers or
cables. The pier towers are either monolithic
reinforced concrete load bearing walls or a steel
framed tower.

45. • There are few buildings using
this system. These buildings
are difficult to design and
construct.
• Examples of buildings with
hanger systems are Hong
Kong and Shanghai Bank
building in Hong Kong, Sabah
Foundation Building in Kota
Kinabalu and the AAP building
in Sydney.

46. Catenary system
• The catenary system usually consisted of a pair of catenary
members that span between two towers of the building.
Both catenary members lie on the long facades of the
building. The catenary spans in a U-shaped configuration
somewhat like a suspension bridge between the towers.
Each catenary member supports hangers and columns.
These hangers and columns support the floor structure.
• There are two examples of this catenary system. This is the
10 story Federal Reserve Bank of Minneapolis in USA and
the 10 story First Exchange House, London.

47. The original design of the catenary structural system of the
Minneapolis Federal Reserve Bank (right) and photo of as-
built building (left)

48. • The higher the building, the more exposed it is
to wind forces. The wind exerts horizontal
loads on the building that causes the building
to sway. This is normally felt in medium rise
and tall buildings that have steel structural
frames.
• Buildings that have reinforced concrete
structural frames do not suffer this problem.
Designing For Horizontal Forces

49. • Another horizontal force that has to be considered
by engineers is the force due to earthquakes.
• The type of movement due to an earthquake is
actually up and down, and from side to side. In other
words, during an earthquake, the building feels like it
is on a boat.
• Buildings in earthquake areas are normally fitted
with shock absorbers in their foundations and
structural frames.

50. • There are three main ways of preventing
swaying (or oscillation) of tall buildings due to
wind forces
– STRUCTURAL METHOD
– DAMPING METHOD
– AERODYNAMIC METHOD

51. STRUCTURAL
METHOD
DAMPING
METHOD
AERODYNAMIC METHOD
Shear Wall
Brace frame and moment
resistant frame systems
Tubes systems
Composite systems
Passive Dampers
Active dampers
Friction dampers
Passive tuned mass dampers
Passive pendulum dampers
Tuned Liquid Dampers (aka Tuned
Sloshing Water Dampers (TSWD)
aka Tuned Liquid Column Dampers
(TLCD))

52. Structural Method
• The oscillation is minimized or removed
increased stiffening the structural frame.
Four ways can be used :
• making the building stiffer by using increasing its
weight
• fixing structural tie members (braces) in the building
structural frame
• reducing the size of the vertical bays in the frame and
• guying the structure to the ground by structural ties

53. Structural Method (Shear Walls)
• Monolithic shear walls of reinforced concrete are used to
provide stiffness. By using a monolithic wall, the wall will
be more heavier and thus stiffer. Yet increasing weight has
a disadvantage. It means that the foundations have to be
stronger and this in turn means more cost.
• Therefore heavy shear walls may not be the suitable
solution. Stiff but relatively slender shear walls are
preferable. Shear walls can be pre-stressed to increase
stiffness yet give a relatively thin wall.
• By the way, shear walls do not have to be of reinforced
concrete, it may be made of reinforced steel plate and
even reinforced masonry.

54. • Shear walls are located in one or more of
the following locations on the building
footprint plan.
• Central core of building
• Ends or corners of building
• As vertical fins for a tower
• As the vertical tubular wall of the tower

55. • Monolithic shear walls of
reinforced concrete are
popular in Malaysian tall
buildings because reinforced
concrete structural frames are
used in most buildings.
• Monolithic shear walls of
reinforced concrete are often
used to enclose the building
services core area. These walls
are natural firewalls that
enclose the lift shafts, escape
stairways and electrical risers.
Shear wall
Shear wall
Building with shear walls at its ends

56. Brace frame and moment resistant
frame systems
• Increasing the mass of building is the most effective way to resist
lateral forces (ASCE, 2005) but this is relatively uneconomic today. The
trend is for lighter but stiffer buildings
• i. Moment resistant frame
• The moment resisting frame is a three dimensional grid of linear
columns and beams. The members of the frames are connected
each other using rigid or semi-rigid connections.
• ii. Braced frame
• Moment resistant frames can be stiffened by adding braces to
vertical and horizontal bays of the frame. A megaframe structure
also use megabraces to stiffen the megaframe and to transmit the
floor loads of the building to megacolumns that rests on the
foundations

57. • Some vertical and/or horizontal bays of
the structural frame are braced. This
creates stiffness to the overall frame. The
arrangement of the braces usually result
in vertical truss configuration or
perimeter belt trusses or outrigger
trusses. In some frames, a vertical
megatruss is used insteaad of a shear wall
to further stiffen the frame.
• A megaframe can be built to carry the
floors of the building. To stiffen the
megaframe, megabraces are placed
across the vertical megabays. Thus the
building behaves like a vertical megatruss.

58. • A mega space frame can be used
to support the floors of the
building. The concept of load
transmittance is the same as that
of the vertical megatruss
• Many structural steel ‘pencil thin’
towers use the concept of the
‘vertical trusses’ to resist lateral
forces

59. • There are many configurations of the moment
resistant frame and shear walls to increase the
building resistance to the wind. The systems
are:-
– Tube system
– Composite system

60. Tubes
Systems
– Load bearing columns of the
exterior perimeter are
placed closely together to
form a ‘tube’. Tubes can also
be formed from
configurations of shear walls
that form a tube. Shear walls
can be perimeter walls or
cores.
– Towers use either tubular r.c.
‘stem’ structures or large
diameter steel tubular ‘stem’
structures to resist lateral
forces.

61. • Another way to create a building tube is to have an outer
perimeter of mega columns. A building tube may have mega
bracing, mega columns and mega beams that form a
perimeter box truss for the building. A perimeter box space
truss configuration can be used instead of the box truss
• Several configurations of the tube system can be found
– - Single tube
– - Tube within tube (One Shell Plaza Building)
– - Bundling of tubes (Sears Tower)
– - Braced tubes (see Alcoa Building)

62. One Shell Plaza building,
Houston Texas.Tube in
tube structure. Note the
closed spaced columns in
the outer tube.

63. Bundled tube system as used
in the Sears Tower, Chicago,
U.S.A.
View of Sears Tower structure

64. • In tall buildings using ‘tube lateral systems’, further
lateral restraint can be provided by reducing the
vertical bending moment of the buildings.
• The building structure is designed such two or more
vertical zones of floors share the bending moment.
Each zone will thus experience a lower bending
moment.
• The overall effect is that the building structure will
not experience a much lower bending moment and
less sway.

65. • There are three ways of doing this:-
i. Using perimeter structural belts every
certain height of building
• The perimeter structural belts are located on the
external perimeter wall line of the building. These
structures can be trusses, girders or monolithic walls
and usually one story in height. They are positioned
at every other number of floors so as to ‘break up’
the building into two or more vertical zones

66. ii. Using outriggers at every certain height of the
building
• The outriggers are located within the building. On plan, they
connect the outer ‘tube’ with inner ‘tube’ structure. A group of
outriggers are positioned at every other number of floors so as to
‘break up’ the building into two or more vertical zones Outriggers
can be formed from trusses or girders or monolithic walls and
usually one floor in height.
• The monolithic wall outrigger will usually have perforations to
allow the people circulation and service runs

67. iii. Combined systems
• Combination of structural belt and outriggers.
• Outriggers of a floor level is tied together by the
structural belt located on the exterior perimeter face of
the building

68. Composite / Hybrid
• The computer allows engineers to shorten the time for designing tall
building. It also allows more complicated designs to be feasible.
• More and more composite systems that combine several structural
systems such as shear walls, tubes and bracing systems together.
• Some types are as follows;
– Shear walls and skeleton frame acting as tubes. Shear walls are placed on
certain positions of the exterior perimeter of building frame
– Tube within tube system using shear wall core and columnade tube on
exterior perimeter
– Tube within tube system with shear wall core and braced mega frame for
exterior perimeter of building.
– Tube with tube system using shear wall construction. Interior wall fins connect
the exterior and interior tubes together.
– Tube system of steel construction with guying cables

69. Damping Devices
• These devices are generally used in lighter tall
buildings (normally of steel frame construction).
Heavy buildings use mass and stiffness as natural
dampers (normally r.c. frame buildings). Thus
dampers are seldom found in r.c. building for
resisting wind forces.
• There are several types of dampers:-
– Passive dampers
– Active dampers

70. • Passive Dampers
– There are two types i.e. the hydraulic piston dampers and
the viscoelastic friction dampers:-
• Hydraulic pistons are placed at various points in the structure.
These pistons are filled with oil. The pistons absorb most of the
resulting movement or vibration due to wind. They are usually
fitted in the vertical bays in a bracing configuration.
• Viscoelastic materials are placed at various points in the structural
frame. They are sandwiched between the steel plate connections
of the structural frame. The material inserts provide shear
resistance to the oscillation forces. See friction dampers

71. • Friction dampers
– The friction damper consists of a steel plate that is
sandwiched by two plates A special lubricant coats
the area where the plates touch so that stability is
maintained even after repeated deformation of
the plates due to movment. When the building
sways during a high wind or earthquake, the
plates absorb energy by friction and thus minimise
the swaying.

72. Application for the bolt-type friction damper
Friction damper

73. • Passive tuned mass dampers
– This damper type consists of a sliding or horizontal
moving mass tuned to move in reaction to the
horizontal movement of the building. Either large
springs or dampers are fitted to the mass and the
building structure. Passive tuned dampers are
usually found at the topmost floor. A good
example is the Citi Corp Centre building in New
York.

74. Example of Tuned Mass Dampers in Citi
Corp Centre Building in New York

75. • Passive pendulum dampers
– This is a suspended mass acting as pendulum. The
concept is similar to the passive tuned massive
damper. The new Taipei 101 building uses a 730-
ton pendulum tuned mass damper (TMD). Eight
steel cables form a sling to support the ball, while
eight viscous pistons act like shock absorbers
when the sphere swings.

76. Passive pendulum TMD of Taipei 101 building

77. • Tuned Liquid Dampers (a.k.a. Tuned Sloshing
Water Dampers (TSWD) a.k.a. Tuned Liquid
Column Dampers (TLCD))
– This damper type consists of two or more tanks (or liquid
columns) whose water contents change in response to lateral
forces. The damper can be a pair of large tanks or number of
small ones.

78. Tuned Liquid Dampers
(a.k.a. Tuned Sloshing
Water Dampers (TSWD)
a.k.a. Tuned Liquid Column
Dampers (TLCD))

79. • Active dampers
– Active tuned mass dampers are tuned to a certain
frequency. Computers allow it to adapt itself to a
big range of tuning. This makes it more effective.
– Actuators such as pistons move the mass in
response to the actual horizontal movement of
the building. The main disadvantage is its reliance
on electricity. Backup electricity supply is needed
in case of blackouts

80. Active Damper – Simulation for building

81. Kyobashi Seiwa Building using Active
Mass Damper

82. Active tuned mass damper system in Kyobashi Seiwa
building, Tokyo, Japan

84. Tuned Liquid Damper at Wall Centre building,
Vancouver, Canada

85. • Active-passive tuned mass dampers. In these
damping systems, there is active damper actuator
working with the passive damper. The active mass
damper works within the capacity range of the
actuator. But, outside the range, the passive damper
and the hydraulic become detached and the damping
is provided by the passive damper. This method
allows the use of a smaller sized passive damper at a
lower cost. This method is used primarily for lateral
forces due to earthquakes.

86. Aerodynamic
• Tower cross-sectional plan is designed to have
minimum air turbulence that could cause swaying of
the building. Reduction of air turbulence can be
obtained by:-
i. Have a circular plan rather than rectangular or
square plan for tower
ii. Flattening (or tapering) of the corners
iii. Providing for perforations at either the corners or top
of the tower
iv.Having channels in the building silhouette that allow the
wind to be channeled away from the face of the
building

87. Thank You