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HIGH RISE BUILDINGS

CONTENTS

-High Rise BuildingsDefining Criteria.

-Skyscrapers

-Design Consideration

-Structural Systems

Foundation

Vertical Support Systems

-Structural SystemsHeight Comparison

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HIGH RISE BUILDINGS

There is no absolute definition of what constitutes a tall building.

It is a building that exhibits some element of tallness in one or more

of the following categories:

a) Height relative to context

It is not just about height, but about the context in which it exists.

Thus whereas a 14-story building may not be considered a tall

building in a high-rise city such as Chicago or Hong Kong, in a

Indian city or a suburb this may be distinctly taller

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HIGH RISE

BUILDINGSb) ProportionThere are numerous buildings which are not particularly high, but

are slender enough to give the appearance of a tall building,

especially against low urban backgrounds. Conversely, there are

numerous big/large footprint buildings which are quite tall but theirsize/floor area rules them out as being classed as a tall building.

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HIGH RISE

BUILDINGSc) Tall BuildingTechnologiesIf a building contains technologies which may be attributed as being

a product of tall (e.g., specific vertical transport technologies,

structural wind bracing as a product of height, etc.), then this

building can be classed as a tall building.

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Although great heights are now being achieved with built tall buildings

(in excess of 800 meters/2600 feet), at the start of 2010 there were only42 buildings in excess of 300 meters completed and occupied globally.

Council thus defines super tall as being any building over 300

meters/984 feet in height.

What is a Super tall Building

(Skyscraper)?

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DESIGN

CONSIDERATIONSImages of local Architecture & CultureFunction of building & its impact on urbanspaces

Socio-Economic Factors

Building Height & Local Codes

Environmental Factors.

Loads

Materials

Construction Techniques.

Site Features &

Properties.Structural System -

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STRUCTURAL SYSTEM

The Structural System of a high-rise building has to

withstand following Loads

VERTICAL FORCES

GravityStructural Loads

Live Loads

HORIZONTAL FORCES

Wind

Seismic

These forces develop overturning moment and shear deflection in

high rise structures.

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STRUCTURAL

SYSTEMFor design purpose all high-rise buildings are considered as VerticalCantilevers.

FOUNDATION

VERTICAL SUPPORT SYSTEM

FLOOR SYSTEM

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FOUNDATIONA buildings foundation is the structure which supports it in theground.The forms and materials of building foundation vary according to

ground conditions, structural materials, structural type, etc

Foundations systems are almost constructed of concrete.

Foundation systems used for high rise structure,

-Pile Foundation

- Caisson Foundation- Mat Foundation

- Spread Foundation

- Load-bearing Wall Foundation

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Foundation - PILE

FOUNDATIONFoundation consisting of vertical structural members (Piles) thatare forced into the ground by impact.

Some early skyscrapers utilized wood piles, but steel and

concrete became more practical at the beginning of the 20thcentury.

Piles can be driven to bedrock, or

more commonly, to refusal

(that is, until underlying soil resiststhe pile being driven significantly

further into the soil).

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Foundation - CAISSON

FOUNDATIONCaisson Foundations are similar in form to pile Foundation, but areinstalled using a different method, caissons (also called as Piers)

are created by auguring a deep hole into the ground, and the filling

it with concrete.

Steel reinforcement is sometimes utilized for a portion ofthe length of the caissons. Caissons are drilled either to

bedrock(called Rock Caissons) or deep into the underlying

soil strata if a geotechnical engineer finds the soil suitable to

carry the building load.

When Caissons rest on soil, they are generally Belled

at the bottom to spread the load over a wider area

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Foundation - MAT

FOUNDATIONMat Foundation (also known as Raft Foundation) are a foundationsystem in which essentially in entire building is placed on a large

continuous footing.

Mat Foundation found some use as early as the nineteenth century,and have continued to be utilized to effectively resolve special soil

or design conditions.

In locations where the soil is weak and

the bedrock is extremely deep,

Floating or Compensated Mat

Foundation are sometime utilized.

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Foundation - SPREAD

FOUNDATIONFor Spread Foundation system, the structural load is literally spreadout over a broad area under the building.

Spread Foundation system utilize one or more horizontal mats, or

pads, to anchor the building as a whole or to anchor individualcolumns or sections separately.

Spread Foundations are also known

as Footing Foundation and are

often utilized in low-rise buildings.

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Foundation - LOAD-BEARING WALL

FOUNDATIONMany building foundation, including most buildings that havebasement levels, use slurry walls at the edge to hold out the

surrounding earth.

In every few cases, this slurry wall or another underground wall

element becomes a major load bearing part of a high rise buildingsfoundation.

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VERTICAL SUPPORT

SYSTEMThe most of the structural system are grouped in three main types :1) Rigid Frame System

2) Shear Wall System

3) Tubular System

There are number of systems for high rise construction whichhave been derived out of the single or combination of these

types.

Rigid Frame

Rigid Frame and Core

Trussed FrameBelt-trussed Frame and Core

Bearing Walls

Bearing Walls with Cores

Tube-In-Tube

Trussed Tube

Bundled TubeCantilevered Slabs

Space Truss

Flat Plate

Skip-Stop Interstitial

Suspension

Self-Supporting

Boxes Staggered

Truss

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RIGID FRAME SYSTEM-Rigid frame systems are very inefficient.

-Each and every member must help in the transfer of lateral loads to

the foundations through rigid connections

- These systems are usually very regular and not of great height.

Building Examples

860 & 880 Lake Shore Drive Apartments

(Chicago, USA, 26 stories, 82 m),

Business Men's Assurance Tower (Kansas City,

USA, 19 stories),

Height Limit

Steel 30

Concrete 20

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RIGID FRAME WITH CORE

SYSTEM-In this hybrid system, a stiffening core has been addedto the standard rigid frame in order to reduce the lateralsway of the structure.

-This system is also known as Framed Tube System.

Building Examples

Aon Centre (Chicago, USA, 83 stories, 346 m),

Water Tower Place (Chicago, USA, 74 stories, 262 m)

Height Limit

Steel 80

Concrete 60

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TRUSSED FRAME SYSTEM

-This system attempts to combine the efficiency of the

truss with the stiffness of the rigid frame.

-The rigid frame could be used to transfer the vertical

loading and the truss for the lateral loading.

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BELT-TRUSSED FRAME WITH

CORE SYSTEM

-Large trusses tie the facade columns to the core so

that the whole building acts as one large system of

interdependent parts.

-The trusses are called "cap Trusses" when they are at

the top of the building, and "Belt Trusses" when they

are at intermediate points.

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STAGGRED TRUSS SYSTEM-Trusses utilized to transfer the lateral loads to the

core.

-Very large columns and bracing.

- Stiff transfer floors allow for internal flexibility.

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BEARING WALL SYSTEM

-Vertical structural elements carry the loads directly to

foundations.

-The height of the structure is limited mostly by the

strength of the bearing materials.

-This system depends upon its massive weight to

resist lateral loading.

-Bearing Wall systems are commonly used in

apartments in which the spans between walls isrelatively small.

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BEARING WALL WITH CORE

SYSTEM-The core is often placed in a central location. This is dueto the convenience for the distribution of building services& for an increased structural integrity.

-Bearing walls with core(s) allow for a greater free floor

area and is thus more popular for office buildings than theparallel Bearing Wall systems. This is a common system

for reinforced concrete structures of moderate height.

Kanchanjunga Apartments, Mumbai.

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TUBE IN TUBE SYSTEM-The exterior and interior columns of the structure are

placed so closely together that they not only appear to be

solid, but they act as a solid surface as well.

-The entire building acts as a huge hollow tube with a

smaller tube in the middle of it.

-The lateral loads are shared between the inner andouter tubes.

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BUNDLED TUBE SYSTEM-This was the natural extension of the "Tube-in-Tube"

system.

-The stiffness and strength of these very tall buildings is

generated by all of the "tubes" of the building being

"bound" together to act as one big bundle.

Sears Tower

(Chicago, USA, 108

stories, 442 m)

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CORE WITH CANTILEVER

SYSTEM-Solid Core supports cantilevered floor slabs which areoften post-tensioned.-This has the advantage of freeing the facade and

clearing the interior floor space of columns.

-The disadvantage is the additional thickness required as

the cantilever increases.

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STRUCTURALSYSTEMinner

support

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STRUCTURALSYSTEMskin

support