Structural Strength and Stability
A structure is stable if it remains on its base, undamaged when acted on by force. All structurs have mass when is acted on by gravity. There is a point where this gravity is concentrated, it is called the center of gravity. When the object is supported at the center of gravity, it is perfectly balanced.
Magnitude of Force
Every force has magnitude, it is the description of the force.
Direction of Force
The direction of force affects how a structure will react to it. If a door says "push", it will not open if you use a pulling force.
Point and Plane of Application of a Force
Where and how a force is applied to a structure affects the result.
Loads
Static load is caused by the forces of gravity.
Dynamic load is caused by forces other than gravity.
Pressures
Live force: Something moving/alive/active.
Dead load: It is caused by a live force acting upon a suspension causing compression and tension.
Eg. A car in the middle of an arch bridge causing the ends in tension. Thus, ontop of each end (the suspensions), a dead load occurs also because of gravity.
Planned Obsoloscence
It doesn't always make sense to design a product to be used forever. It makes sense to design a product so that it lasts as long as it needs to. The term that is often used to describe this concept is planned obsolescence. A product has an expected life, or amount of time it will last under coditions of reasonable use.
Bridges
Beam bridges: Supported mostly at the ends but sometimes by additional columns. Literally, it is a strict beam from one end to another.
Suspension bridges: Supported mostly at the ends but sometimes by additional columns. LIterally, it has suspensions to suspend the bridge.
Truss/frame bridges: Relies on a system of triangular structures to support the load.
Arch bridges: A bridge used over spans where supports would be difficult to place. Literally, there is an arch on the lower plant (bottom) suspended at the ends of the arch.
Cantilever bridge: The mass on either end supports the mass of a middle span.
Deck bridges: A roadway built on top of a frame.
Through bridges: A roadway inside of the frame.
next »