Transcript Slideshows

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CONTENTS
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Lesson 1
– Model Making Workshop - Structure of Tall
Buildings and Towers
• Introduction to Tall Buildings
• Loads and Forces on Buildings
 Vertical Forces
 Horizontal Forces
 Internal Forces
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• Typical Structural Systems in Tall Buildings
• Project Brief on Tower-Making Workshop
Class activity
• Role Play
| Model Making Workshop – Structure of Tall Building and Tower | Lesson 1 – Model Making Workshop
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Lesson 1
Model Making Workshop –
Structure of Tall Buildings
and Towers
| Model Making Workshop – Structure of Tall Building and Tower | Lesson 1 – Introduction to Tall Buildings
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Introduction to Tall Buildings
Do you know these tall buildings?
How tall are they?
What are the structures?
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How tall are they?
The Leaning Tower of Pisa (55.86 m) was built in 1372,
using marble stone in a Romanesque style. Its current
leaning appearance is due to sub-soil settlement.
The Eiffel Tower is a 320-m-high steel
structure that was completed in 1889 as the
entrance arch for that year’s World’s Fair.
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• In the early 20th century, cities
became bigger and denser. Urban
populations were growing but
land supply was limited. High-rise
buildings became an essential
solution to the problem.
• New technologies and building
materials, such as industrial
reinforced concrete, steel and
elevators, made high-rise
structures feasible and drove
innovation.
The 90-m-high Royal Liver Building in
Liverpool was one of the first concrete buildings
in the world. It was completed in 1911 after a
Neoclassical design by Walter A. Thomas.
© Chowells － Wikipedia User
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The 36-storey Equitable Building in New York was
completed in 1915. Its architect, Ernest R. Graham, used
a Neoclassical style despite the building’s modernity: it
was the first building equipped with elevators. It
triggered the implementation of height limits and
setbacks for tall buildings to allow sunlight to reach
street level.
The modernist Wainwright Building in St.
Louis was completed in 1891 by architects
Dankmar Adler & Louis Sullivan. Its 10-storey
are supported by an early steel framing system.
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Loads and Forces on Buildings
The statics of a building deal with its structural stability.
According to Newton’s First Law, when an object is in
equilibrium, the sum of all forces equals zero.
What are the sources of forces that act on the building
structure?
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There are three types of loads generally:
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Dead Load
– Dead loads are the loads of the structure and fixed components.
– It is a permanent force that is relatively constant for a extended period of
time.
– The force is gravitational.
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Live Load
– Live load is a changing force generated by mobile objects inside the
building, such as people within the building or stock in a warehouse.
– The force is gravitational.
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Environmental Load
– Environmental loads are forces acting on the building from its environment
and may include wind, rain, earthquakes and temperature changes.
– The forces created can be either horizontal or vertical, positive or negative.
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Vertical Forces
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Dead loads and live loads
contribute to the vertical forces on
the structure of buildings.
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Vertical loads are transferred from
the floors to the columns and walls,
and eventually to the soil or
bedrock.
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At times, environmental loads also
act vertically.
Dead loads
e.g. Weight of the
building
Environmental loads
e.g. Wind
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Horizontal Forces
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Environmental loads contribute
most of the horizontal forces acting
on the structure of a building, with
loads from wind being the most
common.
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Architects refer to these horizontal
forces as shear force.
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Adding cross bracing or shear
walls can improve structural
resistance to shear forces.
Environmental loads
e.g. Wind
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Internal Forces
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The internal strength of the entire structure
must be = or > the total forces applied on the
building
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The ability to withstand all forces depends on
the structural component’s dimensions
and the solidity and elasticity of the
material.
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Internal forces :
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Compressive and Tensile Forces
According to Newton’s Third Law, forces
act in pairs. In structural terms, tensile
force pulls a structural element apart while
compressive force compresses it.
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Torque
If opposing forces are applied at
different points, a structural element may
become twisted.
Compressive Force
Tensile Force
Torque
Internal forces in a structural element
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Typical Structural Systems
in Tall Buildings
Installation of outriggers at the
International Commerce Centre
© Raymond Wong
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Core and Outrigger structure
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The International Commerce
Centre is built using a ‘Core and
Outrigger’ concept.
The core at the centre of the
building bears most of the
vertical load,
while columns at the perimeter
carry less weight and are thus
smaller in dimension.
Loads are transferred to the core
through steel outriggers that
balance the lateral forces on the
whole building.
Outrigger connecting the core and the columns
Plan of International Commerce Centre
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Steel
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It is a common construction material
for tall buildings
good performance in withstanding
compressive and tensile forces, as
opposed to concrete’s low tensile
strength in compression.
Steel bars can be used to reinforce
concrete to add extra structural
performance.
Relatively weak in fire-resistance.
The Bank of China Tower is a steel trussed-tube
structure. The whole building acts as a single
tubular truss, with the diagonals wrapping the
building to transfer loads.
Bank of China Tower
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Truss
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Common structural element in architecture.
Steel members are joined together into triangular shapes, which
are able to resist external forces.
When joined together, these triangles can form large truss systems
that can span long distances.
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Truss
Common types of truss
© Structural Building Components Association
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Summary
• Although humans have long attempted to build
tall structures, skyscrapers began to appear in
our cities in the late 19th century as a result of
technological breakthroughs in building
materials and methods, including reinforced
concrete, steel, and elevators.
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Summary
• Buildings bear three types of loads: dead loads,
live loads and environmental loads
• All loads are resolved into vertical and
horizontal forces on the structure.
• Typical structural systems used in tall buildings
include core and outrigger structures, steel
frames and trusses.
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Class Activity:
Model Making WorkshopTower
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Class Activity - Model Making Workshop - Tower
Step 1- Divide the class into groups of four to
five.
Step 2- Each group is required to build a
tower that should be:
• Structurally stable and aesthetically pleasing
• Height
• Weight-height ratio
• Resistant to wind
• Load supporting
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Class Activity - Model Making Workshop - Tower
Tools needed
• Sketching papers and pencil
• Scissors, cutters, tape, glue
• Different weights (10 g/ 50 g/ 100 g/ 500 g/ 1 kg)
• Weight scale
• Measuring tape
• Electric fans
Suggested materials
• Cardboard
• Bamboo sticks
• Recycled cans
• Recycled plastic bottles
• Fishing line
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