Download - Strucutres 1 Eso
Unit 5. Structures
What are we going to learn in this unit? 5.1 What is a structure? 5.2 Efforts. 5.3 Structural elements 5.4 Resistant structures 5.5 Stable structures 5.6 Structural Cross Sections 5.7 Artificial structures Final activities
Rubrics Indicador Prueba Puntos
8. Define estructura y nombra estructuras naturales y artificiales E x a m e n Estructuras 2
9. Define una carga y pone ejemplos E x a m e n Estructuras 1
10. Conoce y relaciona los esfuerzos mecánicos con los efectos que producen
E x a m e n Estructuras 4
11. Identifica los esfuerzos que sufren objetos cotidianos y algunos elementos estructurales
E x a m e n Estructuras 2
12. Identifica los elementos estructurales de estructuras conocidas
E x a m e n Estructuras 1
13. Explica qué es una estructura resistente y Aplica la triangulación para mejorar su resistencia
E x a m e n Estructuras 2
14. Explica qué es una estructura estable y Aplica la diferentes recursos para mejorar su estabilidad
E x a m e n Estructuras 2
15. Reconoce la importancia de la forma de los perfiles utilizados en estructuras entramadas
E x a m e n Estructuras 2
16. Clasifica diferentes estructuras en masivas, abovedadas, entramadas, colgantes y trianguladas
trabajo estructuras
2
Unit 5. Structures
What are we going to learn today?
What is a structure?, Types and how it has changed through History
Unit 5. Structures
Which structures do you know?
5.1 What is a structure? What is a structure?
A structure is a group of elements that together are able to resist forces and to transmit them to the ground
5.1 What is a structure? Types of structure
We can find natural and artificial structures. Most of the artificial structures are based
on natural structures Natural Artificial
Exercise 5.1a 1.- Define a Structure 2.- Draw five natural structures and five
artificial structures. Natural Artificial
5.1 What is a structure?
The structures have to be resistant and stable Stable: Resistant
5.1 What is a structure?
Structures along history From very old times new materials have changed constructions.
Structure Period Material Improvement
Cabin
File Temple
Aqueduct
Cathedral
Bridge
Skycraper
Exercise 5.1 b. Make a table with these structures explaining their materiales, period, and the improvements and defects they had:
Sol Exercise 5.1 b
5.2 Efforts
What are we going to learn today?
What is an structural load? What is an effort? Types of efforts
5.2 Efforts
The structures have to resist different charges
5.2 Efforts
A load is a force applied to an object, like a truck over a bridge
5.2 Efforts
An effort is a force that appears when a structure receives an external load
Load
Internal effort
load
Internal effort
5.2 Efforts
These are the main efforts that a structure can receive:
Traction is an effort that makes an object longer
5.2 Efforts
Compression: is an effort that makes an object shorter
Flexion: is an effort that bends an object
5.2 Efforts
Shear (guillotine): separates an object into two pieces
Torsion: twists objects
Exercise 5.2a Could you define Charge? Why there weren’t any skyscraper
500 years ago?
5.2 Efforts Which efforts are applied in the following
examples?
A B
C
D
E
Ejrecicio 5.2b Efforts • Which efforts are applied in the following examples?
A B
C
Image Structure Effort
A Cable B Motorbike C Guide rope
solución
5.2 Efforts
D
E
Image Structure Effort
D Column E Bridge
• Which efforts are applied in the following examples?
5.2 Efforts
Image Structure Effort
F Nut
G Rivet
F G
• Which efforts are applied in the following examples?
Ejercicio 5.2c Efforts What effort does a column resist? What
material should we use to make the columns of a building? Why?
Exercise Nº 4 page107
solución
Ej 5.2d Efforts Keys are made with a resistant material
like steel? What effort does a key resist?
Exercise Nº 5 page107
5.2e Efforts Which efforts are applied in the
following examples? G
Image Structure Effort
A Bar/spring B Bar/spring C Spring D Spring
E Bar/spring F Bar/spring G Bar
Exercise page 107Nº 6
Solution
5.3 Structural elements
What are we going to learn next?
What elements can we find in a structure?
5.3 Structural elements
These are the most common elements that can be found in a structure
• Foundations • Columns • Girders • Arches • Cables
5.3 Structural elements
Foundations are the base of any building and they are situated under the ground and made of concrete
concrete
5.3 Structural elements
Girders are horizontal bars that receive flexion efforts
Columns are vertical bars that receive compression efforts
Girder
Column
Foundation
Forces Forces
Girder
Forces
Column
Girder
Forces
Foundation
Column
Girder
Forces
Foundation
Column
Girder
Forces
5.3 Structural elements
Arch: A semicircular shape that joins the gap between two pillars. Compresion
Traction bars: Cables or bars which support traction efforts.
Exercise 5.3a. Estructural elements
1.- Draw the main elements of a structure showing the efforts with arrows
2.-Look around your classroom and find how many columns and girders are there.
Solution
Sol ex 5.3a. Estructural elements
1.- Draw the main elements of a structure showing the efforts with arrows
2.-Look around your classroom and find how many columns and girders are there.
Exercise
5.4 Resistant structures As we know a structure has to
be resistant.
A resistant structure keeps its shape when forces are applied.
5.4 Resistant structures What are we going to learn next?
What is a resistant structure?
Why are most structures form by triangles?
5.4 Resistant structures We have two easy ways to create resistant structures
Triangles Archs
5.4 Resistant structures Other resistant structure, the arch Arch: Provides resistance to
structures by distributing the effort of the structure.
5.4 Resistant structures
The triangle
is the only geometric shape that cannot be deformed by applying forces to any angle.
5.4 a Resistant structures
Homework make triangle with 3 tubes 5 cm long each connected with a cord.
Look to the roof of your gym and describe the structures
5.4 Resistant structures
The use of triangular structures is very interesting because they are very resistant, light and easy to construct.
crane pylon
5.4 Resistant structures
Triangulation makes it possible to transform shapes into a combination of triangles and therefore makes them
non-deformable.
Exercise 5.4a Resistant structures
1.- Indicate the name of three structures based on triangles. 2.-Add bars to these structures to form triangles and make them non-deformable
5.5 Stable structures
What are we goin to learn? How can we make it more stable?
5.5 Stable structures The structures have to be stable.
A structure is stable when it keeps its position when forces are applied.
5.5 Stable structures
Stability is obtained by distributing the mass evenly.
Mass centre evenly distributed
Mass centre unevenly distributed
5.5 Stable structures
The mass centre is where all the weight is concentrated
He has the mass centre evenly distributed
5.5 Stable structures When the mass is not evenly distributed, you
can stop the object from falling in different ways
hold
such as increasing its hold to the ground.
5.5 Stable Structures How is the centre of gravity maintained in
the following situations?
?
?
?
? ?
?
?
5.5 Stable Structures How is the centre of gravity maintained in
the following situations?
Increasing the mass distribution with two feet
5.5 Stable Structures How is the centre of gravity maintained in
the following situations?
Using cables we can hold the antenna
5.5 Stable Structures How is the centre of gravity maintained in
the following situations?
Placing triangles that attach the lamppost to the ground
5.5 Stable Structures How is the centre of gravity maintained in
the following situations?
Lowering the gravity point.
5.5 Stable Structures How is the centre of gravity maintained in
the following situations?
Increasing the weight at the base.
5.5 Stable Structures How is the centre of gravity maintained in
the following situations?
Stretching his legs, so the mass is evenly distributed
5.5 Stable Structures How is the centre of gravity maintained in
the following situations?
A triangulated structure allows the panel to resit the force of the wind
5.6 Structural Cross Sections
What are we going to learn?
Why are some columns like a I and no solid?
5.6 Structural Cross Sections Nowadays we use non solid girders or columns,
they are called cross sections
In order to obtain more resistant and stable cross sections they have shapes adapted to their use
5.6 Structural Cross Sections They are used in constructions because they
are lighter and cheaper than the solid ones because they need less material
Solid Colum Cross Sections
5.6 Structural Cross Sections There are different shapes, and each one
has a special aplication.
Open cross sections: V. T, U, L, X and H.
Closed cross sections: O, ☐,Δ.
Exercise 5.6 Structural Cross Sections Make using paper these cross sections 5 cm
and find out which one is more resistant
5.7 Types of artificial structures
What are we going to see now?
Strucures classification
5.7 Types of artificial structures
Massive: a great concentration of material predominates
5.7 Types of artificial structures
Vaulted : Arches, vaults and domes are important holding and supporting elements leaving a great free space below.
Arches vaults domes
5.7 Types of artificial structures
Sub-frame: made up by timber(wood), steel or concrete intersecting elements
The structural elements of a sub-frame are the girders, pillars or columns, and foundations.
Foundation
Column
Girder
Forces
5.7 Types of artificial structures
Sub-frame: made up by timber(wood), steel or concrete intersecting elements
The structural elements of a sub-frame are the girders, pillars or columns, and foundations.
Foundation
Column
Girder
Forces
5.7 Types of artificial structures
Triangulated: Made up by linking many triangles forming flat or spatial networks.
crane Oil rig pylon
5.7 Types of artificial structures Suspended: They are held by cables
5.7 Types of artificial structures Exercise: Give at least 3 examples of each type of
artificial structure
Massive Arches Sub-frame Triangulated Suspended