Bridges are structures erected over rivers, lakes and seas to enable the smooth passage of vehicles and pedestrians. In order to adapt to the modern high-speed development of the transportation industry, bridges are also extended to cross mountain and streams, poor geology or to meet other transportation needs and erected to make the passage more convenient buildings.
Bridges are generally composed of superstructure, substructure, bearings and appurtenant structures, superstructure is also called bridge span structure, is the main structure across the barrier; substructure includes abutments, piers and foundations; bearings for the bridge span structure and piers or abutments at the support set by the force transfer device; appurtenant structures refer to the bridge head lap, tapered berm, bank protection, diversion works, etc.
According to the structure:
There are Beam Bridge, arch bridge, truss bridge, suspension bridge, combined system bridge (cable-stayed bridge) five basic types
According to the length of:
Special bridge (L>1000m); bridge (100m?L?1000m); bridge (30m
