HIGH-RISE BUILDINGS

Presented by

Muhammad Sulman Sarwar 2008-CIVIL-23

Kaleem ullah 2008-CIVIL-17

Mehmood Munawar 2008-CIVIL-19

Usman Bhatti 2008-CIVIL-45

Definition

A high-rise Building as defined by Emporis

Data Community is

“A building 35 meters or greater in height, which is

divided at regular intervals into occupiable

levels.”

What are High-Rise Building ?

There is no consensus on what constitutes a tall building or at

what magic height, number of stories, or proportion a building

can be called tall.

A dividing line should be drawn where the design of the

structure moves from the field of statics into the field of

structural dynamics.

From structural point of view, a building is considered as tall

when its structural analyses and design are affected by the

lateral loads, particularly sway caused by such loads. Under

wind load the overturning moment at the base of a building

varies in proportion to the square of the height of the building,

and lateral deflection varies as the fourth power of the height

of the building, others things being the equal.

Design Considerations

There are three major factors to consider in the design of all structures: Strength

rigidity and

stability

As height increases, the rigidity and stability requirements become more important, and they are often the dominant factors in the design. So the size of the members may be increased

beyond and above the strength requirements.

change the form of the structure into something

more rigid and stable to confine the deformation

and increase stability.

Design Considerations

P-Δ effect, in which the eccentricity of the gravity

load increases to such a magnitude that it brings

about the collapse of the columns as a result of

axial loads.

Therefore, an important stability criterion is to

assure that predicted wind loads should be below

the load corresponding to the stability limit.

The second consideration is to limit the lateral

deflection to a level that will ensure that

architectural finishes and partitions are not

damaged.

Material Requirements

In general, for high-rise buildings the resistance to

overturning moment and lateral deflection will

almost always require additional material over and

above that required for gravity load alone.

The material required for floor framing is a

function of the column-to-column span and not the

building height.

However, the material required for the vertical

system, such as columns and walls, in high-rise

structure is substantially more than that of a low-

rise building.

Material Requirements

The material increases in the ratio (n + 1) / 2, where n is

the number of floors, because the vertical components

carrying the gravity loads will need to be strengthened

for the full height of the building, requiring more vertical

steel than a one-story structure having the same floor

area.

For example in a steel building using rigid frame action,

the total weight of approximately 117 kg/m2 of structural

steel is split evenly at about 39 kg/m2 for each of the

three subsystems, namely,

-floor framing,

-gravity columns, and

-wind bracing system.

Average Weight per unit floor Area

is decreasing

Historically, the unit weight of structural framing members in term of, say, average weight per unit floor area appears to be progressively decreasing over the years.

For example, a survey of tall building built in the period 1950 – 1990 will verify that in this period it was possible to build a 100-story building with perhaps no more than 147 kg/m2 of steel as compared to the 205 kg/m2 of steel used for the Empire State Building in the 1930’s.

Reasons for gradual decrease in

weight per unit area of Building

1. Innovative design concepts. Structural engineers are continually seeking better and more efficient methods of resisting the lateral loads.-Increase the effective width of subsystems to resist the overturning

moment.

-Design systems such that the components interact in the most efficient manner.

-Use interior or exterior bracing for the full width of the building.

2. Use of high-strength low-alloy steels. Today it is a common practice to use 345 MPa steel in most composite floor framing systems, gravity columns, and not too infrequently in lateral-load-resisting elements.

3. Increased use of welding as compared to bolting, which effects a saving in the range of 8 to 15 percent in the weight of steel.

Reasons for this gradual decrease

in weight of Building

4. Increased use of composite construction.

5. Application of computers to both the design

and the analytical processes.

6. Gradual increase in the allowable stresses in

the materials based on research and

successful past performance.

7. A reduction in the weight of other construction

materials, like partition and curtain walls.

Factors for Reduction of

Reinforcement and Concrete in

concrete construction1. New framing techniques, such as skip joist

construction in which every other joist is eliminated, have caught on in high-rise construction with a consequent reduction in the weight of structural frame.

2. Increased use of mechanical couplers in reinforcement for transferring both compression and tensile forces.

3. Use of welded cage for column ties, beam stirrups, etc., which reduces the amount of reinforcement steel.

4. Use of high strength concrete; 40 MPa is quite common, and strengths up to 70MPa are being specified on vertical components of high-rises.

Factors for Reduction of

Reinforcement and Concrete in

concrete construction5. Use of lightweight aggregate typically reduces 50

to 100 kg/m2 in the dead load of the structure,

resulting in savings of approximately 10 to 15

percent in the reinforcement requirement.

6. Most codes do not require as great a thickness of

slabs when structural lightweight concrete is used.

Typically a thickness of 12 mm of concrete can be

taken off from floor slabs without reducing the fire

rating.

7. Use of 520 MPa steel reinforcement.

8. Use of the state-of-the-art design methods.

Reasons of construction of High-

rise Buildings

Computer aided Analysis and Design has

made it an easy job to design high-rise

Buildings.

Increase in land values.

-Except in the Holy Makah where the land is rare and

is extremely expensive especially near the Holy

Mosque, where a square Meter could reach the rate

of about 40000 USD near in Makah.(3500 USD per

Square Foot)

Higher density of population.

Characteristics of a successful

Building

1. Create a friendly and inviting image that has positive values to building owners ,users , and observers.

2. Fit the site, providing proper approaches to the plaza with a layout congenial for people to live, work and play.

3. Be energy efficient, providing space with controllable climate for its users.

4. For office buildings, allow flexibilities in office layout with easily divisible spaces.

5. Most spaces oriented to provide best views.

6. Most of all, the building must make economic sense, without which none of the modern high-rise development would be a reality.

List of Top 10 High-Rise

Buildings# Building City Floors Height Year

1 Burj Khalifa Dubai 163 828 m 2010

2 Makkah Clock Royal Tower

[Abraj Al Bait]

Makkah 95 601 m 2012

3 Taipei 101 Taipei 101 509 m 2004

4 Shanghai World Financial

Center

Shanghai 101 492 m 2008

5 International Commerce

Centre [Union Square]

Hong Kong 118 484 m 2010

6 Petronas Tower 1

[Petronas Towers]

KualaLump

ur

88 452 m 1998

7 Petronas Tower 2

[Petronas Towers]

KualaLump

ur

88 452 m 1998

8 Nanjing Greenland Financial

Center

Nanjing 66 450 m 2010

9 Willis Tower Chicago 108 442 m 1974

10 Kingkey Finance Tower Shenzhen 100 442 m 2011

Completed High Rise-Buildings in

Pakistan

Sr # Name City Height Floors Year

1 Ocean Towers (formerly Sofitel) Karachi 120 m 394 ft 30 2012

2 MCB Tower Karachi 116 m 381 ft 29 2005

3 Telecom Tower Islamabad 113 m 371 ft 24 2011

4 The Centaurus Tower 1 Islamabad 114m 375 ft 32 2012

5 The Centaurus Tower 2 Islamabad 110m 361 ft 32 2012

6 The Centaurus Tower 3 Islamabad 110m 361 ft 32 2012

7 Arfa Software Technology Park Lahore 106 m 348 ft 19 2011

8 Dolmen City Karachi 102 m 335 ft 21 2011

10 Habib Bank Plaza Karachi 101 m 331 ft 22 1963

11 Chapal Plaza Karachi 101 m 331 ft 22 1985

Under Construction High-Rise

Buildings in Pakistan

Sr # Name City Height Floors Year

1 Bahria Icon Tower Karachi 320 m 853 ft 70 & 30 2014

2 Grand Hyatt Islamabad 217 m 712 ft 47 2011

3 The Centaurs Hotel Islamabad 200 m 657 ft 41 2014

4 IT Tower Karachi 183 m 600 ft 47 2012

5 World Trade Center Islamabad Islamabad 175 m 574 ft 45 2014

6 Dolmen City Office Tower 1 Karachi 150 m 492 ft 40 2012

7 Centre Point Tower Karachi 150 m 492 ft 28 2012

8 Alamgir Tower Lahore 137 m 449 ft 31 2012

9 KASB Altitude Karachi 130 m 427 ft 32 2014

10 Centaurs Corporate Tower Islamabad 110m 361 ft 25 2012

Approved and Proposed High Rise

Buildings in Pakistan

Sr # Name City Height Floors Year

1 Karachi Port Tower Karachi 593 m 1947 ft 117 2015

2 KPT Twin Tower Karachi 352 m 1155 ft 78 2015

3Pearl Continental

TowerLahore 150 m 492 ft 40 2015

4 Expo Hotel Lahore 150 m 492 ft 19 2015

5 Kohinoor Heights Faisalabad 150 m 492 ft 28 2013

6 Sign Tower Karachi 46 2015

7 Bahria Twin Towers Rawalpindi 38 2015

8 Creek Towers Karachi 30 2015

9 Avari Extension Karachi 30 2015

10 UBL Tower Karachi 60 2015

11 Marvida Tower Faisalabad 135 m 440 ft 25 2011

Burj khalifaMakkah Clock

Royal Tower

Taipei 101

Petronas

Towers

International

Commerce

Centre

Nanjing Greenland Financial Center

Kingkey

Finance TowerWills Tower

Thank you...