Introduction to Structures

Structure

It is a set of elements designed to withstand stress without breaking or deforming.

In nature there are a multitude of structures from the trunk that supports a tree to our skeleton. All of them support efforts to overcome gravity and in the case of skeletons they also allow movement.

In the technical field the construction of structures to make homes, boats or vessels is as old as civilization itself. Nowadays, structures can be very complex and allow the construction of buildings, cars, airplanes, bridges, pylons, dams and countless devices without which the current world, as we know it, would not exist.

Origin of structures

The structures can be differentiated depending on their origin:

Natural	Tree trunk. Turtle shell. Human skeleton. Mollusk shells. Bird's Nest.
Artificial	Suspension bridge. Structure of a building. Computer case. Construction crane. Wall.

Classification of structures

Depending on their elements we can classify the structures into the following groups:

Massive

Formed by a large mass of material with hardly any gaps.

Examples: Water dam. Pyramid. Walls.

Hoover Dam.

Adam Kliczek, CC BY-SA 3.0 International, via Wikimedia Commons.

Vaulted

Formed by arches and vaults.

Examples: Gothic cathedral ceiling. Roman bridge. Aqueduct. Pantheon of Rome.

Arches of the Segovia aqueduct.

Carlos Delgado, CC BY-SA 3.0 International, via Wikimedia Commons.

Triangulated

Formed by bars joined together in triangles.

Examples: Construction crane. Eiffel Tower. High voltage tower.

Bridge with triangular structure.

Waz8, CC0 1.0 , via Wikimedia Commons.

Half-timbered

Made up of vertical and horizontal elements.

Examples: Building structure. Chairs and tables. Ladder.

Gantry-shaped crane.

Richard Humphrey, CC BY-SA 2.0 International, via Wikimedia Commons.

Pendants

Made up of cables that support the loads.

Examples: Cable car. Cable-stayed bridge or suspension bridge. Construction crane. Zip line.

San Francisco Suspension Bridge.

Mikebhuang, CC BY-SA 4.0 International, via Wikimedia Commons.

Laminar

Formed by a thin sheet or wall.

Examples: Bowl. Turtle shell. Motorcycle helmet. Water tank.

Motorcycle helmet.

Stefania Anghelea, CC BY-SA 4.0 International, via Wikimedia Commons.

Movement in structures

Most structures are built so that they cannot be moved. However, some structures must allow movement in order to function correctly. These structures will continue to resist the forces and their own weight without breaking, but they will allow the movement of some of their parts.

Mobile structures

They can be moved or are articulated. They support loads while allowing movement.

Examples: Door with hinge. Drawbridge. Wheel chair. Crane.

Fixed structures

They do not move and cannot be moved.

Examples: Bridge. Building. High voltage tower. Bowl.

---

Exercises

1. List four natural and five artificial structures.

2. List four massive structures.

3. Lists four vaulted structures.

4. List four triangulated structures

5. List four half-timbered structures

6. List four hanging structures

7. List four laminated structures

8. Indicate the differences between triangulated and truss structures.

9. Classify the following structures:

   Aqueduct Turtle shell Computer case Helmet Mollusk shells Bowl Human skeleton Building structure Construction crane Church Table

   Chinese wall. Pyramid. Water dam. Cable-stayed bridge. Suspension bridge. Roman bridge Chair Cableway High voltage tower Eiffel Tower Tree trunk

10. Indicate what type of structure each of the following sentences refers to:

    • Made up of cables that support the loads.
    • Made up of vertical and horizontal elements.
    • Made up of arches and vaults.
    • Formed by a large mass of material with hardly any gaps.
    • Formed by a thin sheet or wall.
    • Made up of bars joined together in triangles.