evolution and description of highrise or tall buildings structural system..

1. STRUCTURE , TECHNOLOGY & MATERIALS OF
TALL BUILDINGS (HIGHRISE)
GROUP_3
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2. CONTENT:
• Structural loads.
• Load distribution system.
• Structural members.
• Structural Typology.

3. Structural load :
Structural loads are forces, deformations, or accelerations applied to a structure or its components.
Types of loads
• Dead load
• Loads that are relatively constant over time.
• Also known as permanent or static loads.
• Live load
• Dynamic or impose or moving loads,
temporary of short duration.
• Considerations: impact, momentum,
vibration, slosh dynamic of fluid.
• Environmental loads
These are loads that act as a result of weather,
topography and other natural phenomena. These are:
• Seismic load
• Snow, rain and ice load
• Wind loads
• Thermal loads (temperature changes leading to thermal expansion)
• Lateral pressure of soil, groundwater or bulk materials
Reference: Wikipedia

4. Seismic Load:
• Buildings undergoes dynamic motion
during earthquake.
• Building is subjected to inertia forces
that act in opposite direction to the
acceleration of earthquake
excitations.
• These inertia forces, called seismic
loads, are usually dealt with by
assuming forces external to the
building.
Reference: http://www.aij.or.jp/jpn/symposium/2006/loads/Chapter7_com.pdf

5. Foundation diagram for resisting seismic load
Reference: http://www.aij.or.jp/jpn/symposium/2006/loads/Chapter7_com.pdf

6. Wind Load:
Wind load has the ability to bring a building to
sway.
V max.
V max.
Variation of wind velocity with height
Wind velocity increases with the increase
of height.

7. Variation of wind load with the variation of forms
Round shape
Minimum wind pressure
Irregular shape
Maximum wind pressure
Plan view

8. WIND TURBULENCE :
When any moving air mass meets an obstruction,
such as building, it responds like any fluids by
moving to each side, then rejoining the major
airflow.
The Ventury effect is one type of turbulent wind
action. Turbulence develops as the moving air mass is
funneled through the narrow space between two tall
buildings. The corresponding wind velocity in this
space exceeds the wind velocity of the major airflow

9. LOAD DISTRIBUTION SYSTEM :
All type of loads can be considered
as_
•Vertical load &
•Lateral load
Vertical loads transfer through_
•Bearing wall
•Column
•Core
•Diagonal frame
Lateral loads transfer through_
• Shear wall
• Slab Core
• Beam Core/Column
• Diagonal Frame

10. Structural member:
Beam :
Beam is a rigid structural member designed to carry
and transfer loads across spaces to supporting
elements.
Column :
A rigid relativity slender structural member designed
primarily to support axial compressive loads
applied at the member ends.
In high rise buildings it can be use as mega column,
concrete filled tubular(CFT) etc.
Shear wall:
A vertical diaphragm or wall acting as a thin, deep
cantilever beam in loads to the ground foundation.
Bracing :
It is a structural element for positioning,
supporting, strengthening or restraining the
member of a structural frame.

11. Core :
Core is one of the most important structural and functional
elements of the high rise building.
The core of a building is the area reserved for elevators’ stairs,
mechanical equipments and the vertical shafts that are necessary
for ducts, pipes and wires.
Its wall are also the most common location for the vertical wind
bracing.
The placement of the service core stems from four generic types
which are :
- Central core
- Split core
- End core
- Atrium core
Central core End core Atrium coresplit core

12. Type I : Shear Frames
Type II : Interacting Systems
Type III: Partial Tubular Systems
Type IV: Tubular Systems (CTBUH, 1980)
Structural typology:
According to ‘Council on Tall Buildings and Urban habitat’ there are four types
of structural system-
According to Mir M. Aliand Kyoung Sun Moon, Structural systems of tall buildings
can be divided into two broad categories-
1.interior structures and
2.exterior structures.
According to material it can be also-
1. Concrete type and
2. steel type

13. EXTERIOR STRUCTURES
In newer skyscrapers, like the Sears Tower in Chicago, engineers moved the
columns and beams from the core to the perimeter, creating a hollow, rigid
tube as strong as the core design, but weighing much, much less.
INTERIOR STRUCTURES
By clustering steel columns and beams in the core, engineers create a stiff
backbone that can resist tremendous wind forces. The inner core is used as
an elevator shaft , and the design allows lots of open space on each floor
Interior structure
1. Rigid Frames
2. Shear Wall Hinged Frames
3. Shear Wall (or Shear Truss) -
Frame Interaction System
4. Outrigger Structures
Exterior structure
1. Tube
2. Diagrid
3. Space Truss Structures
4. Super frames
5. Exo-skeleton
Interior and exterior classification is based on the distribution of the components of the
primary lateral load-resisting system over the building.

14. INTERIOR STRUCTURE
1. Rigid Frames:
860 & 880 Lake Shore Drive Apartments
(Chicago, USA, 26 stories, 82 m)
• The moment-resisting frame (MRF)
consists of horizontal (girder) and
vertical (column) members rigidly
connected together in a planar grid
form.
• The size of the columns is mainly
controlled by the gravity loads.
• The size of the girders, on the other
hand, is controlled by stiffness of the
frame in order to ensure acceptable
lateral sway of the building.
The two basic types of lateral load-
resisting systems in the category of
interior structures are the moment-
resisting frames and shear
trusses/shear walls.

15. 860 & 880 Lake Shore Drive Apartments
(Chicago, USA, 26 stories, 82 m)
Material : steel
Ingalls Building
(Cincinnati, USA, 16 stories, 65 m)
Material : concrete

16. SHEAR WALL HINGED FRAME
• Reinforced concrete planar solid or coupled shear
walls have been used for high-rise construction to
resist lateral forces caused by wind and
earthquakes.
• Treated as vertical cantilevers fixed at the
base.
• When two or more shear walls in the same plane
are interconnected by beams or slabs the total
stiffness of the system exceeds the sum of the
individual wall stiffness. Hinged frames are used
for this interconnection.
• The connecting beam forces the walls to act as a
single unit by restraining their individual cantilever
actions. These are known as coupled shear
walls.

17. 77 West Wacker Drive (Chicago, USA,
50 stories, 203.6 m),

18. SHEAR WALL (or SHEAR TRUSS) - FRAME INTERACTION SYSTEM
• When shear trusses or shear walls are combined with MRFs, a shear truss (or
shear wall)-frame interaction system results.
• The upper part of the truss is restrained by the frame, whereas at the lower
part, the shear wall or truss restrains the frame.
Sub category :
1. Braced Rigid Frames
2. Shear Wall Rigid Frames

19. Empire
state
building
Braced Rigid Frames
Shear Wall Rigid Frames:
Material:
Concrete
Shear Wall +
Steel Rigid
Frame
Seagram
Building, up to
the 17th floor
(New York,
USA, 38 stories,
157 m)
Cook County
Administration
Building, former
Brunswick Building
(Chicago, USA, 38
stories, 145 m)
Material:
Concrete
Shear Wall +
Concrete
Frame

20. OUTRIGGER SYSTEM
• The core may be centrally located with outriggers extending on both sides or in some cases it
may be located on one side of the building with outriggers extending to the building
columns on the other side.
• The outriggers are generally in the form of trusses in steel structures, or walls in concrete
structures.
• Outriggers serve to reduce the overturning moment in the core that would otherwise
act as pure cantilever, and to transfer the reduced moment to the outer columns
through the outriggers connecting the core to these columns.

21. Effectively resists bending by exterior columns connected
to outriggers extended from the core.

22. Belt truss

25. EXTERIOR STRUCTURE
1. Tube system
• Concept is based on the idea that a
building can be designed to resist
lateral loads by designing it as a
hollow cantilever perpendicular to the
ground.
• In the simplest incarnation of the tube,
the perimeter of the exterior consists of
closely spaced columns that are tied
together with deep spandrel beams
through moment connections.
• This assembly of columns and beams
forms a rigid frame that amounts to a
dense and strong structural wall along
the exterior of the building.
The different tubular systems are-
 Framed tube
 Braced tube
 Bundled tube
 Tube in tube

26.  FRAMED TUBE
• In a framed tube system, which is the basic tubular form, the building has closely spaced
columns and deep spandrel beams rigidly connected together throughout the exterior frames.
• Exterior column spacing should be from 5 to 15ft (1.5 to 4.5m) on centers. Practical spandrel beam
depths should vary from 24 to 48in (600 to 1200mm)
• The axial forces in the corner columns are the greatest and the distribution is non-linear for both the
web frame (i.e., frame parallel to wind), and the flange frame (i.e., frame perpendicular to wind).

27. • This is because the axial forces in the columns toward the middle of the flange frames lag behind those
near the corner due to the nature of a framed tube which is different from a solid-wall tube. This
phenomenon is known as shear lag.
• The purpose is to limit the shear lag effect and aim for more cantilever-type behavior of the
structure.
• A reasonable and practical limits can be a cantilever deflection of 50 to 80 percent of the total
lateral sway of the building.

28. Aon Center (Chicago, USA, 83 stories, 346 m)

29.  BRACED TUBE
• A braced tube overcomes this problem by stiffening the perimeter frames in
their own planes.
• This concept stems from the fact that instead of using closely spaced perimeter
columns, it is possible to stiffen the widely spaced columns by diagonal
braces to create wall-like characteristics.
• The braces also collect gravity loads from floors and act as inclined columns.
• The diagonals of a trussed tube connected to columns at each joint effectively
eliminate the effects of shear lag throughout the tubular framework.
• Therefore, the columns can be more widely spaced and the sizes of spandrels
and columns can be smaller than those needed for framed tubes, allowing for
larger window openings than in the framed tubes (Khan, 1967).
The framed tube becomes progressively inefficient over 60 stories since the web frames
begin to behave as conventional rigid frames. Consequently, beam and column designs
are controlled by bending action, resulting in large size. In addition, the cantilever
behavior of the structure is thus undermined and the shear lag effect is aggravated.

30. John Hancock Center (Chicago, USA, 100 stories 344 m)
Architect: Skidmore, Owings & Merril
Braced
frame
Braced Frame material /configuration : STEEL

31. Onterie Center (Chicago, 58 stories, 174 m)
Architect: Skidmore, Owings & Merril
Braced frame
Braced Frame material /configuration :
CONCRETE

32.  BUNDLED TUBE
• A bundled tube is a cluster of
individual tubes connected together to
act as a single unit.
• For such a structure, the three-
dimensional response of the
structure could be improved for
strength and stiffness by providing
cross walls or cross frames in the
building.
• Also allowed for wider column spacing
in the tubular walls, which made it
possible to place interior frame lines
without seriously compromising interior
space planning of the building.
• It is possible to add diagonals to them
to increase the efficient height limit.

33. Sears Tower (Chicago, USA, 108 stories, 442 m)
Material /Configuration : STEEL
Section A-A Section B-B
Section C-C
Two additional
tube omitted
Section D-D
• 9 steel framed tubes are bundled at
the base.
• Some of which are terminated at
various levels with two tubes
continuing between the 90th floor
and the roof.

34. Carnegie Hall Tower (New York, USA, 62 stories, 230.7 m)
Material /Configuration : CONCRETE
Bundle
Tubes

35.  TUBE IN TUBE
• The stiffness of a framed tube can also be
enhanced by using the core to resist part of
the lateral load resulting in a tube-in-tube
system.
• The floor diaphragm connecting the core and
the outer tube transfer the lateral loads to
both systems.
• The core itself could be made up of a solid tube,
a braced tube, or a framed tube. Such a system is
called a tube-in-tube.
• It is also possible to introduce more than one
tube inside the perimeter tube.
• The inner tube in a tube-in-tube structure can act
as a second line of defense against a malevolent
attack with airplanes or missiles.

36. Millennium Tower
Architect: Norman Foster
• The exterior columns & beams are spaced
so closely that the façade has the
appearance of a wall with perforated
window opening.
• The entire building acts as a hollow tube
cantilevering out of the ground.
• The interior core increases the stiffness of
the building by sharing the loads with the
façade tube.
Inner Tube
(Core)
Outer Tube

37. 2. DIAGRID SYSTEM
• With their structural efficiency as a varied version of the tubular systems.
• For diagrid structures, almost all the conventional vertical columns are eliminated.
• This is possible because the diagonal members in diagrid structural systems can
carry gravity loads as well as lateral forces due to their triangulated
configuration in a distributive and uniform manner.
• Efficiently resists lateral shear by axial forces in the diagonal members but have
Complicated joints.

38. 30 St Mary Axe, also known as Swiss Re
Building (London, UK, 41 stories, 181 m)
Material /Configuration :
STEEL
• Steel framed tube type
structural system
• Triangular steel frame
generates the tube
• Beams are supported by
diagonal steel member
• Requires less steel then
conventional steel frame
Triangular grids are exposed in façade
Triangular steel frame

39. O-14 Building (Dubai)
Material /Configuration : CONCRETE

40.  Space truss structures are modified
braced tubes with diagonals
connecting the exterior to interior.
 In a typical braced tube structure, all the
diagonals, which connect vertical corner
columns in general, are located on the
plane parallel to the facades.
 However, in space trusses, some diagonals
penetrate the interior of the
building.
3. SPACE TRUSS STRUCTURE

41. Bank of China (Hong Kong, China, 72 stories, 367 m)

42. 4. SUPERFRAMES
• A super frame is composed of mega columns comprising braced frames of large
dimensions at building corners, linked by multistory trusses at about every 15
to 20 stories.
• The concept of super frame can be used in various ways for tall buildings, such as the
56-story tall Parque Central Complex Towers of 1979 in Caracas, Venezuela and the
168-story tall Chicago World Trade Center proposed by Fazlur Khan in 1982 (Ali,
2001; Iyengar, 1986).
Parque Central
Complex Towers
Chicago World Trade
Center

43. 5. EXO-SKELETON
• In exoskeleton structures, lateral load-resisting systems are placed outside the
building lines away from their facades. Examples include Hotel de las Artes in
Barcelona.
• Due to the system’s compositional characteristics, it acts as a primary building
identifier – one of the major roles of building facades in general cases.
• Fire proofing of the system is not a serious issue due to its location outside the
building line.
• However, thermal expansion/contraction of the system, exposed to the ever-
changing outdoor weather, and the systemic thermal bridges should be
carefully considered during design.

44. Hotel de las Artes (Barcelona, Spain, 43 stories, 137 m)
Exterior skeloton

48. References :
• Council on Tall Buildings and Urban Habitat. (CTBUH)
• Structural Developments in Tall Buildings: Current Trends and Future
Prospects -Mir M. Ali† and Kyoung Sun Moon
• http://www.aij.or.jp/jpn/symposium/2006/loads/Chapter7_com.pdf
• High-rise building structure -Wolfgang Schueller
• www.greatbuilding.com .
• www.riba.com .