III. The guardrail in the triangular zone of traffic diversion should be constructed in accordance with the corrugated beam on the roadside. It should be laid out according to the line and topography of the triangle zone. The minimum length set is: Strengthened type (S-class) should be adopted within 8m on both ends of the main line of the expressway and within 8m of both ends of the ramp side. In the middle of the reinforced guardrail, 6-span A-grade guardrail is installed. The guardrails on both sides of the triangle area are connected by a round head. Anti-collision pads should be installed in the dangerous triangle area.
The center height of the cross beam of the corrugated beam
is 60 cm from the road surface to the center of the connecting bolt hole. When there is a curb stone, the distance from the top of the curb stone to the center of the connecting bolt hole is 60 cm. When the corrugated beam has anti-blocking blocks, and its central height remains unchanged, the pillars of the corrugated beam guardrail are generally buried in the soil foundation, and the burial depth is stipulated as follows:
I. When the guardrail column is buried in soil and there is no roadside stone, the depth of the column should not be less than 110 cm. When the guardrail column is buried in soil and there are roadside stones, the depth of the column should not be less than 125 cm. When the composite corrugated beam is used in the central partition zone, and the column is buried in the soil, its burial depth should not be less than 110 cm.
II. When the guardrail column meets the following circumstances, concrete foundation embedding method can be used:
1. Pillars are placed in places where bridges, passages, culverts, etc. cannot be penetrated.
2. There are underground pipelines and stone sections under the pillars.
3. Other special cases.
The depth of the column embedded in concrete should not be less than 40 cm. For the convenience of maintenance, flange assembling connection mode can be adopted. The size of concrete foundation and the connection strength of flange should be determined by calculation according to different conditions. When conditions permit, displacement guardrail column should be adopted.