Structures part or parts of an object that actually hold it up and give it its shape TYPES: We call structure the
Natural structures: they are not made by human
beings (trees, skeletons, turtle´s shells…). Manufactured structures: Made by human´s hand.
What type of structure are they?
What type of structure are they?
Artificial structures Mass Structure: It is a simple structure which uses its
mass to support the load. Frame Structure: It is made of small parts joined together. It consists often in a skeleton made of bars and tubes. The elements of a frame structure are: pier, beam, column, pilaster, framework.
A triangulated structure is a kind of frame structure whose parts form triangles
Suspension structure: It is supported by cables. Shell structure: It is made of thin sheet material with not
internal frame.
Mass structures
Stone construction
Megalithic structures
Shell structure
made of thin sheet material
Pneumatic structure may be a shell structure
Frame structure Different elements such as beam, pillar, column, nodes‌
Suspension structure Its most important element is the suspension cable. Thick steel cables which hold the construction up.
Stress in a structure STRESS: The forces of gravity, wind, weight and other
things that push and pull on the structure. DEAD LOAD AND LIVE LOAD FORCES: may be static (loads) or dynamic A successful structure must be able to support all the forces it will experience without toppling over or collapsing.
Stress in a structure ď‚— A structure can fail by toppling, cracking,
crushing, or deforming (twisting out of shape).
FORCES: Depending on the direction Tension forces. Forces which can cause a member to stretch Compression forces: Forces which can cause a member to be
squashed. Shear forces: Forces that act across the material so that one part of the structure can be forced to slide over another. Torsion forces: When a turning force is applied to a member and it may twist. Bending forces: Forces which act making a member bend.
Forces lab
Name the stress it is bearing Tower crane
Name the stress it is bearing
Name the stress it is bearing
Name the stress it is bearing
Name the stress it is bearing
The self of a bookcase
Name the stress it is bearing
Name the stress it is bearing
Name the stress it is bearing Axes in machines
Name the stress it is bearing
Name the stress it is bearing
Name the stress it is bearing
Name the stress it is bearing
Name the stress it is bearing
Forces in a structure DEAD LOAD AND LIVE LOAD FORCES: may be static (loads) or dynamic
A successful structure must be able to
support all the forces it will experience without toppling over or collapsing.
Structural elements:
Pier or pillar:
is a vertical structural
element that transmits, through compression, the load and the weight of the structure above to the ground. Columns are a type of pier whose cross section is circular
Structural elements:
Beam:
is a structural element that is capable of withstanding load primarily by resisting bending.
Structural elements:
truss
A is a triangular structure formed by rigid bars. All elements (members) of the trusses are subjected only to
compression or tension stresses. We call struts the members which support compression forces, and ties the ones which are subjected to tension stress.
Types: ď śPlanar truss ď śSpace frame truss
PLANAR OR SPACE FRAME TRUSSES
triangles tetrahedron
Structural elements:
Truss
Trusses
skyscraper
pylon
Analyzing a truss “What would happen to the member if it broke, would the ends move apart or would they cross over one another?�
Ties and struts
Tie is the member which is being stretched Strut is the member that is being compressed
Tie is the member which is being stretched Strut is the member that is being compressed.
Tie is the member which is being stretched
Strut is the member that is being compressed.
SOLUTION FOR EXERCISE 4 Twice the nodes = members + 3 ïƒ 2 x nodes = members +3
Analyzing a truss
Twice the nodes = members + 3 ďƒ 2 x nodes = members +3
Remember to use trusses to avoid bending stress.
Remember to use trusses to avoid bending stress.
All materials are stronger under tension or compression and much weaker under bending forces
Structural elements:
Arch
All the forces in the arch are resolved into compression stresses
Archs
All the forces are resolved into compression stresses
Shell elements
Shell elements
Suspension cables
Suspension cables
Foundation elements
•Shallow foundations •Deep foundations
Drilled piers
Shallow and deep foundations Shallow Foundations
Deep foundations