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DEPARTMENT OF ARCHITECTURE

ABUBAKAR TAFAWA BALEWA UNIVERSITY, BAUCHI

ARC 615: ADVANCED BUILDING STRUCTURES

LESSON 7: HIGH RISE BUILDING STRUCTURES

1.1 Introduction

1.2 History of high rise structures

1.3 Generations of structural systems used in high-rise

structures

1.4 Structural systems forms used in high-rise structures

1.5 Advantages and disadvantages of high rise structures

1.6 Structural problems of high rise structures

1.7 Wind loading of high rise structures

1.8 Vertical transportation in high rise structures

1.9 Factors influencing choice of structural system of high rise

buildings

1.10 Foundation design

1.11 Think green

1.12 Examples of high rise structures

1.13 References

1.1 Introduction

1.2 History of High Rise Building Structures

1.2.1 Definition of High Rise Buildings

A multi-story structure between 35–100 meters tall, or a building of unknown

height from 12–39 floors (Emporis Standards)

A building with four floors or more, or 15 to 18 meters or more in height (Indian

Building Code).

Any structure where the height can have a serious impact on evacuation

(International Conference on Fire Safety in High-Rise Buildings).

A building higher than 75 feet (23 meters), or about 7 stories (National Fire

Protection Association).

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Generally, a high-rise structure is considered to be one that extends higher than the

maximum reach of available fire-fighting equipment. In absolute numbers, this is

about 23 meters or about 7 to 10 stories.

1.2.2 Types of High Rise Buildings

Office buildings.

Hotel buildings.

Residential and apartment buildings. An apartment building is a building containing

more than one dwelling unit.

Mixed-use buildings. A mixed-use building may contain offices, apartments,

residences, and hotel rooms in separate sections of the same building.

1.2.3 Demand for High Rise Buildings

Scarcity of land in urban areas.

Increasing demand for business and residential space.

Economic growth.

Technological advancements.

Innovations in structural systems.

Desire for aesthetics in urban settings.

Concept to of city skyline.

Cultural significance and prestige.

Human aspiration to build higher.

1.2.4 Development of High Rise Buildings

Tower of Babel

According to the Old Testament, after the Flood, people wanted to make a name for

themselves by building a city called Babel with a tower that reached into heaven. The

tower was constructed using brick for stone and tar (asphalt) for mortar. This brick tower

was designed so that the “top may reach unto heaven” (Genesis, 11:4), but its building was

discontinued after God confounded their speech and scattered them upon the face of the

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Earth. The Third Apocalypse of Baruch describes how they “sought to pierce the heavens,

saying, Let us see (whether) the heaven is made of clay, or of brass, or of iron”. The Book of

Jubilees gave the height as 2,484 metres, which is about three times the height of the Burj

Khalifa (Jubilees 10:18-27; Charles, 1913; Wikipedia, 2017x).

Plate 7.1: Artist’s impression of the Tower of Babel by Pieter Bruegel the Elder (1563). Source: Open History Society (2013).

Roman Insula

As early as 3rd century BC.

Five or six stories high (70 Roman feet).

Mostly built with wood frames; and they were so high and poorly built that they

were in constant danger of collapse or destruction by fire.

The skyscraper

Invention of the world’s first safety lift in 1853.

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In the 1870s, steel frames became available, gradually replacing the weaker

combination of cast iron and wood previously used in construction. Until then, the

walls had to be very thick to carry the weight of each floor.

Foundations: use of piles which were driven into the ground all the way to the

bedrock.

Modern building services: incandescent lamps, central heating, and forced-air

ventilation, followed in the 20th century by fluorescent lights and air-conditioning,

addressed the issue of providing adequate lighting, heating, ventilating, and air-

conditioning.

1.2.5 Tallest Buildings in the World (Chronologically)

Table 1: Chronology of tallest buildings in the World.

Year Name Location

1885 Home Insurance Building Chicago, Illinois

1890 World Building New York City

1892 Masonic Temple Building Chicago, Illinois

1894 Manhattan Life Insurance Building New York City

1898 St. Paul Building New York City

1899 Park Row Building New York City

1908 Singer Building New York City

1909 Metropolitan Life Tower New York City

1913 Woolworth Building New York City

1930 Manhattan Company New York City

1930 Chrysler Building New York City

1931 Empire State Building New York City

1971 – 1973 World Trade Center New York City

1974 Sears Tower Chicago, Illinois

1998 Petronas Towers Kuala Lumpur, Malaysia

2004 Taipei 101 Taipei, Taiwan

2009 Burj Dubai Dubai, United Arab Emirates

1.2.6 Tallest Buildings in the World by 2017 (Top 15)

1. Burj Khalifa (828 m, Dubai, UAE, 2010).

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2. Makkah Royal Clock Tower Hotel (601 m, Mecca, Saudi Arabia, 2012).

3. Ping An Finance Centre (599 m, Shenzhen, China, 2017).

4. Lotte World Tower (554 m, Seoul, South Korea, 2016).

5. One World Trade Centre (541 m, New York, USA, 2014).

6. Guangzhou CTF Finance Centre (530 m, Guangzhou, China, 2016).

7. Taipei 101 (508 m, Taipei, Taiwan, 2004).

8. Shanghai World Financial Centre (492 m, Shanghai, China, 2008).

9. International Commerce Centre (484 m, Hong Kong, 2010).

10. Changsha IFS Tower T1 (452 m, Changsha, China, 2017).

11. Petronas Towers 1 &2 (452 m, Kuala Lumpur, Malaysia, 1998)

12. Zifeng Tower (450 m, Nanjing, 2010).

13. Suzhou IFS (450 m, Suzhou, China, 2017).

14. Willis Tower formerly Sears Tower (442 m, Chicago, USA, 1974).

15. KK100 (442 m, Shenzhen, China, 2011).

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Figure 7.x: Top ten world’s tallest buildings by 2014.

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Plate 7.2: Empire State Building, New York (1931). 102 storeys, 443 m tall. Steel frame, full-width moment frames.

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1.3 Generations of Structural Systems Used in High-Rise Structures

There are 3 generations of high rise buildings (O’Hagan, 1977).

1.3.1 First generation

The exterior walls of these buildings consisted of stone or brick, although sometimes cast

iron was added for decorative purposes. The columns were constructed of cast iron, often

unprotected; steel and wrought iron was used for the beams; and the floors were made of

wood. Elevator shafts were often unenclosed. There were no standards for the protection

of steel used in the construction of these high-rises.

1.3.2 Second Generation

The second generation of tall buildings are frame structures, in which a skeleton of welded-

or riveted-steel columns and beams, often encased in concrete, runs through the entire

building. This type of construction makes for an extremely strong structure, but not such

attractive floor space. The interiors are full of heavy, load-bearing columns and walls.

Examples: Metropolitan Life Building (1909), the Woolworth Building (1913), and the

Empire State Building (1931).

1.3.3 Third generation

Within this generation there are those of steel-framed construction (core construction and

tube construction), reinforced concrete construction, and steel-framed reinforced concrete

construction.

Steel-Framed Core Construction

These structures are built of lightweight steel or reinforced concrete frames, with exterior

all-glass curtain walls. The so-called curtain walls consist of thin, vertical metal struts or

mullions, which encase the large glass panels constituting most of the wall surface. The

curtain wall, built for lighting and temperature-conditioning purposes, does not have the

strength to stand by itself and is supported by a frame of steel or concrete, which

constitutes the structure of the building (Salvadori, 1980).

Steel-Framed Tube Construction

Tube structures represent a modern change in the design of steel-framed buildings which

enables them to be built extra tall and yet remain strong enough to resist the lateral forces

of winds and the possible effects of an earthquake. Tube construction uses load-bearing

exterior or perimeter walls to support the weight of the building. The key to stability is a

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resistance to lateral wind or earthquake forces, which grow dramatically in magnitude

with the building’s height. If not counteracted by proper design, these forces would cause a

tall building to slide on its base, twist on its axis, oscillate uncontrollably, bend excessively

or break in two. Because the core and perimeter columns carry so much of the load, the

designers could eliminate interior columns, with the result that there is more open floor

space for tenants. Floor areas tend to be larger, with few partitions using floor-to-ceiling

walls and barriers (Seabrook, 2005).

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Figure 7.x: Types of Tubular Systems.

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Reinforced Concrete Construction

Parallel to the development of tall steel structures, substantial advancements in high-rise

structural systems of reinforced concrete have been made since 1945. The first of these

was the introduction of the shear wall as a means of stiffening concrete frames against

lateral deflection, such as results from wind or earthquake loads. The shear wall acts as a

narrow deep cantilever beam to resist lateral forces. Concrete requires no additional

fireproofing treatments to meet stringent fire codes, and performs well during both natural

and manmade disasters. Because of concrete’s inherent heaviness, mass, and strength,

buildings constructed with cast-in-place reinforced concrete can resist winds of more than

320 kilometres per hour and perform well even under the impact of flying debris.

Steel-Framed Reinforced Concrete Construction

These structures are a mixture of reinforced concrete construction and steel-framed

construction, hence the name steel-framed reinforced construction. An example would be a

steel framed structure with a concrete shear core and composite floors built with steel

decking. The term mixed construction is sometimes used to describe this type of high-rise

construction.

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1.4 Structural Systems Forms Used in High-Rise Structures

Figure 7.1: Evolution of Structural System Forms for high Rise Buildings (Lateral Load Resisting Systems).

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Figure 7.x: Steel Structural Systems and the Number of Stories.

Rigid frames: Rigid frames connect the columns and girders by moment-resistant

connections. They resist lateral deformation by joint rotation. They require high

bending stiffness of columns and beams. Rigid joints are essential for stability. They

are not effective for heights over 30 storeys.

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Figure 7.2: Shear Frame Structural System.

Infilled frames: The reinforced concrete frame of columns and girders is in-filled by

panels of brickwork, blockwork or cast-in place concrete. When subjected to lateral

loads, the infill acts as a strut along the compression diagonal to brace the frame.

Braced frames: In the braced frame system, the lateral load resistance is provided

by the “web” formed by the diagonal members tied to the girders. This creates a

vertical truss, with the columns acting as the chords. The horizontal shear is

resisted by the horizontal component of the web members. This system is highly

efficient and economical in resisting lateral loads for any height of building,

including the very tallest.

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Figure 7.2: Braced Frame Structures.

Shear walls: Shear walls made from reinforced concrete may serve as both

architectural and structural partitions, capable of carrying gravity and lateral loads.

Their very high in-plane stiffness and strength make them ideal for bracing tall

buildings. In a shear wall building, the shear walls are the primary lateral load

resistance. Shear walls act as vertical cantilevers in the form of separate planar

walls and non-planar assemblies, typically around elevator, stairs and service

shafts. Shear walls are stiffer than rigid frames, and are economical to about 55

stories.

Figure 7.3: Shear Wall Structural System.

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Figure 7.4: Shear Wall Structural System.

Wall frame: The combination of shear walls and rigid frames is called a wall-frame

structure. The structure is constrained to adopt a common deflected shape to both

systems through the horizontal rigidity of the girders and slab. The walls and frame

interact horizontally, especially at the top, to produce a stiffer and stronger

structure. The combination increases the economy of height to the 65 story range,

well above the range of rigid frames or shear walls alone. Most wall-frames are

reinforced concrete. However, steel buildings may use the braced frame to offer

similar benefits of horizontal interaction.

Framed tube: The essence of the framed-tube are the four very stiff moment-

resisting frames that form the “tube” around the perimeter of the building. The

frames consist of closely spaced columns, typically 2 to 4 m, tied together by

horizontal deep spandrel girders. The outer tube carries 100% of the lateral loads,

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and 75 to 90% of the gravity loads. The remaining gravity load is carried by the

small cluster of core columns (or shear walls). This form is the most significant

modern development in tall buildings. Examples are the World Trade Centre, Sears

Tower, Petronas Towers and the Burj Khalifa.

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Bundled Tube Structures: The natural evolution of the framed tube form was the

use of several tubes bundled together “like tied sticks”. A bundled group of tubes

provides greater strength that a single tube. These bundled tubes were first tried by

Fazlur Khan in Chicago, when the Sears tower was finished in 1974. The new

internal webs greatly reduce the effect of shear lag in the flanges. Therefore, the

column stresses are more evenly distributed than in a single tube structure. The

bundled tubes thus provide a much larger lateral stiffness, albeit at the expense of

internal planning.

Figure 7.5: Bundled Tube Structural System.

Plate 7.3: Burj Khalifa, Dubai: Example of Bundled Tube Structural System.

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Figure 7.6: Sears Tower, Chicago: Example of Bundled Tube Structural System.

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Plate 7.4: Sears Tower, Chicago: Example of Bundled Tube Structural System.

Braced Tube Structures: The efficiency of the framed tube structures can be

improved by adding diagonal bracing to the faces. This results in greater heights

and greater spacing between the perimeter columns. The first steel braced tube was

Chicago’s 97-story John Hancock building, finished in 1969. Because the diagonals

of a braced tube are connected to the columns at each intersection, they virtually

eliminate the effects of shear lag in both the flange and the web frames. As a result,

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the structure behaves under lateral loads more like a braced frame, greatly

diminishing the bending in the members of the frames. Columns may have greater

spacing, allowing for much greater windows than with a conventional tube.

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Outrigger braced: This system consists of a central braced core, which is either a

braced frame or shear walls, plus horizontal cantilever “outrigger” trusses or

girders that connect the core to the outer columns. When the structure is loaded

horizontally, the vertical plane rotations of the core are restrained by the outriggers

through tension in the windward columns and compression in the leeward columns.

The outriggers join the columns to the core to make the structure behave as a partly

composite cantilever. The perimeter columns can also participate in the outrigger

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action by joining all the perimeter columns with the horizontal truss or girder

around the face of the building at the outrigger level. Typically, the outrigger level is

two-stories in depth and thus are usually used to harbor the building’s MEP

systems. The outrigger system has been used to 70 stories in height. If the building

has greater side dimensions, this form could reach much greater heights. The

efficiency of this form depends on how well are the perimeter columns tied to the

core through the outrigger structure.

Figure 7.7: Outrigger structural system.

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Figure 7.8: Taipei 101. Outrigger structural system.

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Plate 7.6: Taipei 101. Outrigger structural system.

Suspended Structures: A suspended structure consists of a central core with

horizontal cantilevered outrigger trusses at the roof level, from which are

suspended vertical hangers of steel cables. The floor slabs are connected to these

cables. This permits the ground floor to be exempt of any perimeter columns,

thereby allowing an open concourse. The cables have very small cross-sectional

areas compared to columns, and can be embedded around window sills. Another

advantage is the casting of the floors at ground level and then raised into position.

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The system is limited to relatively small heights (about 10 to 15 stories) because of

structural disadvantages, such as live-load floor-to-floor connection variations, and

limited core dimensions.

Core Structures: A single core serves to carry the entire gravity and horizontal

loading. It is similar to the suspended building, provides a column-free perimeter at

ground level. However, it is highly inefficient.

Figure 7.9: Core Structure System.

Core or Tube-in-Tube Structures: A variant of the framed-tube form is the

replacement of the inner, or core columns and walls, with another tube. Thus, the

hull (or external tube) and the new core tube act jointly to resist both gravity and

lateral loads. This improved form is called a tube-in-tube, or a hull-core structure. A

steel building could provide a core tube made up of braced frames, whereas a

reinforced concrete building would consist of an assembly of shear walls for the

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core. The outer framed tube (hull) and the inner core interact horizontally as the

shear and flexural components of a wall-frame structure. This provides the benefit

of a greatly increased lateral stiffness. The outer tube (hull) of course always

dominates, because of its greater structural depth. It is presumed that this form

could push the heights to an economical 120 stories. An example is the Taipei 101

Building in Taiwan.

Plate 7.7: Lumbago Tatung haji Building, Kuala Lumpur. Example of Tube in Tube Structural System.

Space Structures (Space Frames): The space frame serves the dual function of

resisting gravity and lateral loads, thereby becoming one of the most efficient

structural forms. Its lightweight and high efficiency permit these frames to reach

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the greatest heights. A notable example is Hong Kong’s 76 story Bank of China

building. Space frames are usually complex to analyse, and difficult to provide

proper load transfer connections between the floors and the main frame. These

connections are costly and sometimes awkward. One solution is to have an inner

braced core, which serves to collect the lateral loads and the inner region gravity

loading, from the slabs over a number of multi-storey regions. At the bottom of each

region, the lateral and gravity loads are transferred out to the main joints of the

space frame. These structures are very pleasing aesthetically and have great appeal

to architects and the general public.

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Plate 7.5: Bank of China, Hong Kong: Example of Bundled Tube Structural System.

Hybrid Structures: The modern trend in architecture, especially the so called

postmodern building, is to create non-regularly shaped buildings. The structural

engineer will find these structures do not conform to a single form. Analysis must

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therefore use several combinations of the previously discussed forms. The structure

may comprise for example, of a tube and outrigger system superimposed on each

other, or of a tube system on three faces with a space frame on a faceted fourth face.

The improvements in both computer hardware and software, permit us to

approximate acceptable solutions to these complex structures.

1.5 Advantages and disadvantages of high rise structures

1.5.1 Advantages of high rise structures

Reduced Cost

Use tall buildings decreases land price per capita, street cost per capita, and cost

of underlying facilities

Save costs of construction and reduced cost of residential units

Compressed cities decrease volume of infrastructures of cities and reduce costs

Perspective

Possible creation of cozy and relaxed atmosphere far from crowdedness; urban

perspective

Due to visual highlight, high rise buildings can help orientation of cities

Prevention of Horizontal Extension

Decreased suburban development and decreased damage to environment

A suitable model for housing in cities facing limited physical horizontal

extension

Social

Possible creation of suitable space for improving social facilities and urban

services

1.5.2 Disadvantages of high rise structures

Environmental

Environmental pollutions due to vehicle congestion

Destroy nature and environment in case of incorrect location

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Tall buildings block fresh air circulation and sunlight (Rahnama et al, 2014).

Traffic

Increased traffic volume due to increased plot ratio of tall buildings

Increased distance between place of occupants, because of erected tall

residential

complexes as mass building projects

Social

Social degeneration, social isolation and alienation in tall residential complexes

Decreased health social relations among occupants of tall buildings due to their

scale and nature

Cultural

Spatial limitation of tall buildings prevents activities rooted in local culture from

being accomplished

Incompatibility of ideology and culture of occupants of tall buildings with their

spaces

Priority of high rise buildings over low rise ones

Safety

Vulnerability of tall buildings relative to low rise buildings against accidents

such as earthquake

In cases where such accidents as fire occur, the fire will spread

Possibility of accidents including falling down the stairs and falls from height

Health

Pressure from weight of tall building breaks soil layers and connects sewage

networks with groundwater supplies

Existence of car parking lots in a closed space in tall buildings makes pollution

stable.

Aesthetic

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Erection of tall buildings near each other prevents natural perspectives such as

sunrise and sunset, from being seen from low rise buildings

Mass building of tall blocks causes the environment to be drab

1.6 Structural problems of high rise structures

Strength of materials.

Proportion of structural area to useable space.

Wind loading.

Seismic activity.

Vertical communication.

1.7 Wind loading of high rise structures

1.7.1 Building Shapes and Aerodynamics

Rectangular

Circular

Triangular

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Figure 7.10: Drag Coefficients of various Building Shapes

Figure 7.11: Vortex Shedding Effects

1.7.2 Modification to Building Shapes to reduce Wind Effect

Stair Step Corner

Through Building Openings

Rotate ad Twist

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Plate 7.8: Rough Corner can Reduce Vortex Shedding Effects.

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Plate 7.9: Openings reduce wind forces (reduced ‘sail area’).

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Plate 7.10: Rotate to minimize load from prevailing direction. Twist avoids simultaneous vortex shedding along height.

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1.7.3 Damping and Dynamics

Damping directly reduces building accelerations

Some damping inherent in construction (Concrete framing > steel framing)

When inherent damping is not sufficient, provide supplementary damping

Dampers occupy space : Quantity and location based on modes to be treated

Costs include purchase, installation, tuning, maintenance, inspection.

Figure 7.12: Tuned mass damper.

1.7.4 Seismic activity and high rise structures

Seismic Design Issues

Less critical than wind for tall building with long natural period (minimum base

shear may govern seismic)

Inter-story drift (maximum at upper floors)

Ductile detailing still important!

Geometric compatibility

Performance Based Design

1.8 Vertical transportation in high rise structures

1.8.1 Types of vertical transportation in high rise structures

Stairs

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Elevators

Escalators

Ramps

1.8.2 Elevator Planning

Building access plays a crucial role in the development and feasibility of high-rise

construction plans. Internal transportation systems function as the building’s main artery,

determining the functionality and quality of life within the tower block, yet they also result

in a considerable loss of rentable floor space on each level. Moreover, the elevator core is

often the building’s support structure, especially in narrower constructions. For this

reason, it is very important that a traffic flow specialist be involved in the initial orientation

phases of a high-rise construction project, as well as the developer, architect and structural

engineer. Specifications for internal transportation must be drawn up whereby routing and

usage remain logical, while occupying as little space as possible. Above all, the capacity

required for stairs, elevators and shafts need to be determined (Deerns Consulting

Engineers, 2017).

1.8.3 Elevator Design Criteria

Height of the building and its individual storeys.

Distribution of the population throughout the building.

Main entrance levels (points of entry and exit).

Distribution of population over elevator groups (if the same destination can be

reached using more than one group).

Stair usage.

1.8.4 Primary Considerations for Estimating Elevator Group Requirements:

Number of elevators per group.

Nominal elevator load capacity (based on car floor area).

Realistic car occupancy.

Nominal elevator speed.

1.9 Factors Influencing Choice of Structural System of high Rise Buildings

Time for design and planning

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Construction time

Cost of construction

Life cycle cost: the present value of the total cost of a building over its operating life,

including initial capital cost, occupation cost, operating cost and the cost incurred

derived from the disposal of the building at the end of its life.

Fire safety

Acoustics

Installation of service systems (MEP, HVAC).

1.10 Foundation Design

Intensive soil investigation and analysis

Concentrated building weight affecting strength and settlement studies

Construction sequences

Model deep basement “anchor” against overturning vs. baseline at top of mat

Pile depths – verticality

Dewatering for deep basements

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1.11 Think Green

Plate 7.11: EDDIT Tower, Singapore.

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Plate 7.12: O14, Dubai

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1.12 Examples of high rise structures

Figure 7.x: Examples of Steel Structural Systems.

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Plate 7.13: The Petronas Towers, Kuala Lumpur, Malaysia. Source: Author’s photograph (2011).

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Plate 7.14: The Burj Khalifa in Dubai. Standing at 930 metres, this remains the tallest building and the tallest man-made structure in the world. Source: Author’s photograph (2011).

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Empire State Building, New York, USA

Burj Al Arab, Dubai (Occupied: 197 m, to tip: 321m).

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Hearst Tower by Norman Forster, 300 W 57th Street, New York, USA (182 m).

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1.13 References

Charles, R. H. (1913). The Book of Jubilees. In: The Apocrypha and Pseudepigrapha of the

Old Testament, Clarendon Press, Oxford.

O’Hagan, J. T. (1977). High Rise/Fire and Life Safety. 2nd printing. Saddle Brook, NJ: Fire

Engineering, A PennWell. Pp 145-146.

Open History Society (2013). Tower of Babel – Donald Trump. Retrieved from

http://www.openhistorysociety.org/wp-content/uploads/2012/06/Tower-of-Babel-

Donald-Trump1.jpg.

Salvadori, M. (1980). Why Buildings Stand Up: The Strength of Architecture . New York: W.

W. Norton; p. 22.

Seabrook, J. (2001). The Tower Builder, Why did the World Trade Center buildings fall

down when they did? The New Yorker. November 19, 2001:66.

Wikipedia (2017). Tower of Babel. Retrieved from

http://en.wikipedia.org/wiki/Tower_of_Babel.