A.鋼材的標(biāo)準抗拉強度下限值δb≤540MPaB.補強圈厚度小于或等于2δnC.殼體名義厚度δn≤28mm
A.1/3 B.1/4 C.1/2
A.α≤30° B.α≤45° C.α≤60°