PROBLEM TO BE SOLVED: To further increase fracture strength of a reinforced plastics manhole cover with variations in kinds of passing cars. SOLUTION: When heating pressure molding having a specific form is applied to unsaturated polyester resin by a main material layer 11 such as bulk molding compound or the like of base metal to manufacture a manhole cover 1, strand mats 12 are laid around the whole surface of the cover, and at least two cord robing cloths 13 are overlapped in the phase at right angles to each other on the inside surfaces of them. Cross parts of warps and wefts of the cord robing cloths are coated with polyester resin and are formed together as a unit, and slippage and loosening of threads are eliminated in the case of heating pressure molding. Long glass fibers are not woven by combining them in the shape of a lattice, but glass fiber nonwoven nets 17 combining them with adhesives are overlapped to lay, and great reinforcement can be realized in the best form at a slightly high cost.
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