土木人

一
`A_(X)=90.82KN(larr)`
`D_(X)=90.82KN(rarr)`
`D_(y)=34.058KN(uarr)`
`F_(y)=34.058KN(darr)`

二
`M_(AB)=-29.067KN-m
`M_(BA)=-22.267KN-m
`M_(BC)=22.267KN-m
`M_(CB)=16.4KN-m
`M_(CD)=-12.7KN-m
`M_(CE)=-3.7KN-m

三
略

四
`Delta_(A,x)`=0.005028m`(larr)`
`Delta_(A,y)`=0.0125m`(darr)`
`S_(AB)=-16.76KN
`S_(AC)=13.966KN
`S_(AD)=-13.966KN

以上供參考

補充
第三題
第二小題
`M_c`影響線
A->B: `M_c(X)=(X^3)/(7200)-X/8`
B->D:
X=0~15m, `M_c(X)=-(X^3)/(7200)+(X^2)/(80)+X/4
X=15~30m, `M_c(X)=-((X-15)^3)/(7200)+((X-15)^2)/(160)-(15(X-15))/(32)+(195)/(32)`
`M_(C,max)=168.75KN-m`