The design concept of bridge railings has evolved from the early simple "blocking" to a modern, sophisticated safety system emphasizing buffering, guidance, occupant risk control, and vehicle attitude control. In addition to concrete, metals such as steel are now widely used, with metal beam-column railings, such as corrugated beam railings, becoming the mainstream. The protection level needs to be set based on factors such as the design speed, traffic composition, and degree of danger of the road section where the bridge is located, and verified through full-scale vehicle crash tests and computer simulations.
Based on structural characteristics, bridge railings can be divided into beam-column (metal and concrete) railings, reinforced concrete wall railings, and composite railings; based on crashworthiness, they can be divided into rigid railings, semi-rigid railings, and flexible railings. Common railing types include concrete railings, corrugated beam railings, and cable railings.
The design of transition sections is an important detail. For example, the transition section railings for SB-grade bridges without wing walls can smoothly transition directly to the roadside corrugated beam railings, featuring high protection levels and short construction time.