Scientific Theorem
A major consideration when constructing a bridge is the forces that act upon them.
The forces on a bridge are the weight of the bridge and the opposite reaction from the materials that support it.
A force is a push or pull exerted by particles. Isaac Newton created the three laws of motion that helps to describe movement.
His First Law-
"When the sum of the forces acting on a particle is zero, its speed is constant. In particular, if the particle is initially stationary, it will remain stationary."
Basically when an object is stationary (still) it will stay still unless acted upon by a force.
His Second Law-
A net force on an object will accelerate it—that is, change its speed. The acceleration will be proportional to the magnitude of the force and in the same direction as the force. The proportionality constant is the mass, m, of the object.
Therefore this is saying the overall force on an object with either increase or decrease speed. The amount of force is exerted on it determines the change in the speed of the object will travel.
His Third Law-
"The forces exerted by two particles on each other are equal in magnitude and opposite in direction"
Which means for every action force, there is an equal and opposite reaction force - a very common saying.
This relates to bridges as one force is exerted but another has to oppose it for the physics to work and the bridge not to fall down. There has to be a correct ratio of forces and opposing forces in correctly designing & constructing a bridge.
For example this truss bridge diagram demonstrates the force compression and tension opposing each other and reacting equally for the bridge to stand.
The forces on a bridge are the weight of the bridge and the opposite reaction from the materials that support it.
A force is a push or pull exerted by particles. Isaac Newton created the three laws of motion that helps to describe movement.
His First Law-
"When the sum of the forces acting on a particle is zero, its speed is constant. In particular, if the particle is initially stationary, it will remain stationary."
Basically when an object is stationary (still) it will stay still unless acted upon by a force.
His Second Law-
A net force on an object will accelerate it—that is, change its speed. The acceleration will be proportional to the magnitude of the force and in the same direction as the force. The proportionality constant is the mass, m, of the object.
Therefore this is saying the overall force on an object with either increase or decrease speed. The amount of force is exerted on it determines the change in the speed of the object will travel.
His Third Law-
"The forces exerted by two particles on each other are equal in magnitude and opposite in direction"
Which means for every action force, there is an equal and opposite reaction force - a very common saying.
This relates to bridges as one force is exerted but another has to oppose it for the physics to work and the bridge not to fall down. There has to be a correct ratio of forces and opposing forces in correctly designing & constructing a bridge.
For example this truss bridge diagram demonstrates the force compression and tension opposing each other and reacting equally for the bridge to stand.
Truss bridges are commonly used because of their simple design yet immense strength. They are easy to construct with effective materials.
It is made up of lots of triangles, large and small. Triangles are the strongest shape you could use, and this assists the bridge in its strength. It is very efficient in how it distributes weight and force. |
Suspension bridges are effective due to their intricate design. The basic design is a strip connected to two or more vertical strips. Then a cable is attached from either side of the vertical strips and numerous cables going vertically down to the horizontal strip. However, suspension bridges have been proved to sway in extreme forces and therefore become unsafe.
|
Arches are the oldest type of bridge. An arch bridge consists of one or many arches supporting a horizontal strip above it. This bridge is effective because the arches spread the force outwards, putting less pressure in one spot which would make the bridge weaker. Materials such as steel and concrete are used more commonly today, as they enable us to build far larger arches than structure using stone. Stone was used in Roman aqueducts back in 321 BC.
|