A.70% B.80% C.85% D.90%
A.0.75fptk B.0.80fptk C.0.85fptk D.0.90fptk
A.混凝土構(gòu)件本身 B.預(yù)應(yīng)力張拉臺座 C.張拉千斤頂 D.其他固定設(shè)備