Chinese Standards
In China, there are many national standards for manhole covers, including single-layer, double-layer, cast iron, ductile iron, composite, concrete, magnesium oxide, etc.
According to the latest national standard GB/T 23858-2009, Manhole cover load capacity can be divided into the following categories:
It's important to note that manhole cover load capacity and the ability of a manhole cover to withstand vehicle traffic are not the same concept.
Manhole cover load capacity refers to the pressure test conducted on a unit area using a pressure testing machine, typically 40 tons for heavy-duty covers. However, if considering vehicle traffic, the calculation for a 5-axle heavy-duty truck is: 5 axles x 40 tons = 200 tons. Under a total vehicle weight of 200 tons, this heavy-duty manhole cover can withstand the load.
Some manufacturers claim a technical parameter of 80 tons for vehicle load. If divided by 5 axles, the manhole cover load capacity from that manufacturer is: 80t/5 = 16t, which means the manhole cover itself only has a load capacity of 16 tons.
According to Article 4 of GB/T23858-2009 "Inspection Manhole Covers," manhole covers are divided into six grades based on their load-bearing capacity:
Group 1: (Minimum selection A15 type): Green belts, sidewalks, and other areas where motor vehicles are prohibited.
Group 2: (Minimum selection B125 type): Sidewalks, non-motorized vehicle lanes, small car parking lots, and underground parking lots.
Group 3: (Minimum selection C250 type): Residential areas, back streets and alleys, areas where only light motor vehicles or small cars travel, and within 0.5m of the curb on both sides of the road.
Group 4: (Minimum selection D400 type): Main urban roads, highways, high-grade roads, and expressways.
Group 5: (Minimum selection E600 type): Freight stations, docks, and airports.
Group 6: (Minimum selection F900 type): Airport runways.
Japanese Standards
Engineering Level
In 1958, Japan established mandatory standards for manhole covers, specifying key indicators such as thickness, material, and load-bearing capacity. Current industry standards require manhole covers to be cast from high-strength ductile iron, with a thickness of at least 17 centimeters and a weight of at least 40 kilograms.
