Is there any relationship between the size and bearing capacity

From cast iron manhole covers to composite manhole covers, not only The Times are changing, the quality and characteristics of manhole covers are also changing. Does the size of the manhole cover have anything to do with its bearing capacity? The commonly used manhole cover sizes are round 500mm, round 600mm, round 700mm, round 800mm, round 900mm, bearing grades are A15, B125, C250, D400. The larger the size of the manhole cover, the more difficult it is to lift the load, so the larger the size of the manhole cover, the higher the load, the higher the price. Composite manhole cover based on unsaturated resin, glass fiber and other material and reinforced skeleton compounded by the special production craft, through high heat moulding a molding, using the continuous enhancement of silks, guarantee the filaments from the material and glass fiber cloth is an organic whole, make the product have enough carrying capacity, composite manhole cover due to its compressive resistance, flexural coefficient is strong, impact strength as well as good performance as manhole cover in today's market is very popular. With the development of international trade, manhole covers have also become a part of the export trade, to promote our products to the world, so that every country on the earth can use our manhole covers, this is our goal. The promotion and use of a new product cannot be separated from the efforts of the staff and the support and trust of every customer. It is very simple to make a good product, but it is very difficult to insist on making a good product. I hope every friend can stick to their own courage and go on.