Bridge guardrail refers to the guardrail installed on the bridge. Its purpose is to prevent out-of-control vehicles from getting out of the bridge, and to prevent vehicles from breaking through, under-crossing, overpassing the bridge, and beautifying the bridge building. There are many ways to classify bridge guardrails. In addition to dividing by the installation location, it can also be divided according to structural characteristics, anti-collision performance, etc. According to the installation position, it can be divided into bridge side guardrail, bridge central partition guardrail and pedestrian and driveway boundary guardrail; according to the structural characteristics, it can be divided into beam-column (metal and concrete) guardrail, reinforced concrete wall-type expansion fence and combined guardrail ; According to the anti-collision performance, it can be divided into rigid guardrail, semi-rigid guardrail and flexible guardrail.

Standard Specification and Function of Bridge Guardrail

The selection of bridge guardrail form should firstly determine the anti-collision grade according to the highway grade, comprehensive consideration of its safety, coordination, characteristics of the object to be protected, and site geometric conditions, and then according to its own structure, economy, construction and maintenance. Factors such as the choice of structural form. The common forms of bridge guardrail are concrete guardrail, corrugated beam guardrail and cable guardrail.

Whether the bridge guardrail is for beauty or protection, after several vehicles broke through the guardrail and fell into the river, this problem was also indirectly placed under the “microscope”.

In fact, the guardrails on both sides of the bridge give more consideration to the safety of pedestrians, and the curb between the sidewalk and the roadway on both sides is the most important “line of defense” to block the traffic. On urban bridges, curbs are set at the junction of the sidewalk and the roadway on both sides. The main function of this line of defense is to intercept vehicles and prevent them from colliding with pedestrians or hitting the bridge. The guardrail on the outermost side of the bridge is mainly used to protect pedestrians and has a weak ability to resist collisions.

Standard Specification and Function of Bridge Guardrail

Why is the issue of guardrail safety easily overlooked? For a long time, bridge designers and managers in our country have paid more attention to the safety of the main structure of the bridge and whether the bridge will collapse, while ignoring how auxiliary structures such as curbs and guardrails ensure the safety of vehicles and pedestrians. There is a lot of room for improvement, and there is a lot of meticulous work to be done. In contrast, Western developed countries are more rigorous and meticulous. “They consider the design of guardrails and light poles on the bridge very well. For example, if a vehicle hits a light pole, they will consider how to ensure that the light pole will not fall down and hit the vehicle after being hit. To ensure the safety of people.

It is impossible for any bridge guardrail to block all accidental impacts. “The protective fence has a preventive and protective effect, but any bridge guardrail cannot be said to be able to withstand accidental collisions under all conditions.” That is to say, it is difficult to specify how many tons of vehicles hit the bridge guardrail at what speed. It is guaranteed that there will be no accidents falling into the river. If a large vehicle collides with the guardrail at high speed or at a large angle of attack (close to the vertical direction), the impact force exceeds the limit of the guardrail’s protective ability, and the guardrail cannot guarantee that the vehicle will not rush out of the bridge.

Generally, guardrails should be installed on both sides of the bridge in accordance with relevant codes or standards. However, for any bridge guardrail to perform its function, there must be corresponding preconditions. For example, the impact angle must be within 20 degrees. If the impact angle is too large, the guardrail will also be difficult to function.