STRUCTURES By: María García and Teresa Mendiola.
INDEX 1.DIFFERENT STRUCTURES 2.STRUCTURAL ELEMENTS 3. TYPES OF UNIONS 4.FORCES ON STRUCTURAL ELEMENTS 5.INTERNATIONAL AND LOCAL STRUCTURES
STRUCTURES: are groups of elements that are held or put together in a particular way to support a load with stability. Frame structures Shell structures Mass strucutures Arch structures Suspension structures
FRAME STRUCTURES: are structures made up of basic structures designed to support a light weight. The elements of frame structures are made of strong materials and the load is supported in one part of the structure. Advantages: easy to design and build. Disadvantages: they don't support big loads.
SHELL STRUCTURES: are structures with a thin outer layer of material that surrounds a empty space or a filled volume. The outer layer can be thin because the load is spread through the whole structure Examples of natural shell structure: Eggs and shellfish Examples of artificial shell structure: Balloons, boxes and helmets.
ARCH STRUCTURES: are structures that spans a space while they support a weight <ul><li>Arch structures are very strong and useful.
It's own weight is the main load and the geometry of the arch displaces the forces to the sides.
Arch structures are suitable for bridges. </li></ul>
MASS STRUCTURES: are structures made of clump material, filling the body completely . They are made up of low-quality materials. Advantages: they are held in a place for its own Disadvantages: they are heavy and is need a lot of material and space . Examples of natural mass structures: Mountains and coral reefs. Examples of man-made mass structures: Sandcastles, dams and pyramids.
SUSPENSION STRUCTURES: are structures that holds an element by cables that are held from the top of a column. Advantage: they are grate for covering a very large span Disadvantage: they are expensive to built.
STRUCTURAL ELEMENTS FOUNDATION: an element joined to the ground by fictrion. The foundation is also joined to the column. The column is joined to the fondation and to the primary beams. The beams and the column are joined by weldind. In some cases the beam can be laid on the column.
TYPES OF UNIONS: <ul><li>PERMANENT UNIONS: </li></ul><ul><li>NON- PERMANENT UNIONS </li></ul>Are made for structures that don't need to be disassembled Are made for structures that need to be assembled and disassembled as many times as necessary.
FORCES ON STRUCTURAL ELEMENTS <ul><li>TENSIONAL STRAIN
TENSIONAL STRAIN: is the strain that causes and element to stertch. It can be due to forces that pull an elemnt from its ends.
COMPRESSION FORCES: are the forces that make an element to squeeezed or buckled. When you sqeeze an elemt, it becomes shorter and thicker
SHEAR STRAIN: are forces that act across a material in such a way that they can force one part of an element to slide over another. One example is when you cut paper with a pair of scissors.
TORSION FORCES: are the forces that make an element twist when you apply a turning force. If the elemnt is fixed to a support at the oter end, th elemt twist If the element is not fixed, it wuld just turn without changing shape
BENDING FORCES: are the forces that act at an angles making it bend
LOCAL STRUCTURES Puente Real in Badajoz is a suspension structure that supports a beam by cables. It is used to allow transport cross the river.
INTERNATIONAL STRUCTURES The Eiffel Tower in Paris (France) is a frame structre because it is made Of strong material that support its load in one part of the structure. It is used for tourists attractions.