A.15;4.5B.18;4.5C.15;6D.18;6
A.1/50~1/40B.1/40~1/30C.1/30~1/20D.1/20~1/10
A.跨度15m;柱高7.5mB.跨度18m;柱高4.5mC.跨度15m;柱高6.0mD.跨度24m;柱高4.5m