TRUSSING: is a method for making weak structures more rigid. It works because the triangle is the only figure that cannot be deformed. Therefore, structures that have a triangular shape are rigid.
BRACE: is a part that is positioned diagonally between two bars to connect them by forming a right angle.
STAY CABLES: are used to help support the tensile stresses in other components of a structure by distributing the weight to the supports or the terrain where they are anchored.
SECTIONS: the other strengthening elements that we have already seen are beams and columns.
FORCE: is an influce that can deform a body.
STRESSES: are the physical demands that a body or object must withstood.
STRENGHT: it is a material that ability to withsand external forces without breaking.
The strength of a structure depends on:
The types of forces applied and the points where they act.
The shape of the structure and the elements that form it, as well as the type of material that they are made from.
So how do we obtain strong structures?
By making them more stable.
By making them more rigid.
STABLE: when it remains in equilibrium even when a force is applied to it.
CENTRE OF GRAVITY: is the point where the weight of an object is considered to be concentrated.
RIDIGITY: it does not change shape when force is applied to it.
EQUILIBRIUM: when its structure remains stationary.
STABILITY: equilibrium if it does not move when a force is applied to it.
COMPRENSSION:
This is caused by forces acting on a body that tend to flatten it or reduce its length or thickness. It happens in structures that need to support weights.
TENSION (or traction): This is caused by forces acting on a body that tend to stretch it.
BENDING: This is caused by forces acting on an element that make it curve or bend. It is done by supporting the two ends and applying force in the centre, as shown in the figure to the right.
TORSION: This is caused by forces acting on a body that make it twist.
SHEAR: This is caused by two equal forces applied in opposite directions that act on lines of action close to each other. Shear stress will tend to cut the material if it cannot twist or bend.