Ductile iron manhole covers are generally divided into round and square ones. In urban road administration, they are generally round, because round manhole covers are not easy to tilt, which can better protect the safety of pedestrians and vehicles. When using a circle, it is mainly considered that each diameter of the round well cover passing through its center is the same length. In this way, if the well cover is rolled up by passing vehicles, its diameter will be slightly wider than the lower wellhead no matter how it is rolled up, and the well cover will not fall into the wellhead. But how to distinguish the bearing grade of Hubei ductile iron well cover?
Group I: (select A15 type): green belt, sidewalk and other areas where motor vehicles are prohibited.
Group II: (B125 type is selected): sidewalk, non motor vehicle lane, car parking lot and underground parking lot.
Group 3: (C250 type): residential area, back streets and alleys, and areas only driven by light vehicles or cars, within 0.5m of curbs on both sides of the road.
Group 4: (D400 type is selected): urban trunk roads, highways, high-grade highways, expressways and other areas.
Group 5: (select E600 type): freight station, wharf, airport and other areas.
Group 6: (F900 type is selected): airport runway and other areas.
Each grade of manhole cover is applicable to different places. For example, the D400 ductile iron manhole cover is mainly used in urban trunk roads, highways, highways and other areas, and its bearing capacity is about 40 tons.