General Provisions of Temporary Subgrade Guardrail
On-site planning, road isolation, channel management, route guidance for large-scale celebrations, large-scale exhibitions, conferences, large-scale sports meets and temporary activities.
General requirements for subgrade guardrails.
1. Design guiding ideology.
(1) Tolerant design concepts should be adopted. Properly handle the obstacles in the roadside safety clear zone.
(2) When the width of the safe clear area on the roadside of the highway cannot be satisfied, the safety treatment should be carried out according to the principle of guardrail setting.
(3) Transition treatment should be carried out between different types of subgrade guardrails or between subgrade guardrails and bridge guardrails.
2. Design sequence.
(1) Collect highway horizontal and vertical alignment, fill and excavation data, and data on the composition of operating vehicles, traffic volume, operating speed, and design speed.
(2) Collect or investigate the distribution of various obstacles in the safe clean area on both sides of the highway and the data on the intersection with other highways and railways.
(3) Determine the anti-collision level of the guardrail and select the guardrail type.
The principle of setting the three-way side guardrail.
(1) Roadside guardrails must be installed on the road section where the vehicle driving out of the road may cause a second major accident.
(2) Roadside guardrails must be installed on road sections where one of the following conditions is met, and the vehicle driving out of the road may cause a single-vehicle accident or a second major accident:
① The road section within the specified range of the side slope slope and embankment height of the second and above grade highway.
② Roads with rivers, lakes, seas, swamps, navigation channels and other waters along the road.
(3) Where one of the following conditions is met, and the road section where a vehicle may cause a major accident when driving out of the road, roadside guardrails should be installed.
① The road section within the specified range of the side slope slope and embankment height of the second-class and above roads.
② There are facilities such as lights, cameras, variable information signs, traffic signs, cutting support walls, sound barriers, piers or abutments of upper span bridges, etc., in the safe clean area on the roadside of expressways and first-class highways that cannot be safely traversed by vehicles. Section of the road.
③ Excavation sections where the side ditch of the second-class and above roads has no cover and cannot be safely traversed by vehicles.
④ Sections of roads with cliffs, deep valleys, and deep trenches on the side of the third and fourth-level highways.