Beam Bridge
This is the most common bridge
It is a flat bridge that is supported at each of its ends
A longer beam bridge may be supported by additional supports
Truss Bridge
This bridge is light but strong
It has triangle shaped frames called trusses, on either side
Suspension Bridge
Suspension bridges, like beam bridges, have supports on each of their ends
They have tall towers on either side
The main cables (lines) are anchored at each end of the bridge
The smaller cables are attached to the main cables vertically on one end and the other is connected to the roadway. They support the roadway.
Arch bridge
These were made to hold heavy loads
The dynamic load of people and other traffic causes each piece of wood or stone in the arch to push against the piece next to it
This push is eventually transferred to the end supports that are embedded in the ground
The ground pushes back and the resistance is passed back through all the pieces creating an arch