***There are four types, as follows:

Electricity: underground cable line inspection well.

Sewage: Special pipeline inspection wells for domestic sewage and other urban sewage.

Rain: Special pipeline inspection well for rainwater drainage.

Water: Domestic water pipeline inspection well.

Technical parameters:

Technical parameters test load: heavy 400KN, common 250KN, light 125KN.

Bending strength: average 22MPa Impact strength: average 10J/m2.

Water absorption rate: 1.

Acid resistance: The sample is 20.

Soak in sulfuric acid solution for 48 hours.

No corrosion on the surface, quality loss 1.

Chinese standards:

There are many national standards for manhole covers in China, such as single-layer, double-layer, cast iron, ductile iron, composite, cement, magnesite, etc.

According to the latest standard requirements of the latest national standard GB/T 23858-2009,

The load capacity of manhole covers can be divided into the following types:

There is one explanation , The load capacity of the manhole cover and the ability of the manhole cover to pass vehicles are not the same concept.

The load capacity of the manhole cover refers to the pressure test performed by a pressure testing machine within a unit area, usually 40 tons in weight. And if it is a vehicle, the calculation formula for a 5-axle heavy-duty truck is: 5 axles x 40 tons = 200 tons. When the total vehicle weight is 200T, this heavy-duty manhole cover can ensure passage.

Reference for the above content: Baidu Encyclopedia-Manhole Cover