Fpa/2FpFpa/2qaqa2aqqa22qa /8对称a2qa2aaaa(79)(78)PaPaqa2qa/24P3qa2aa2a6Pa-8Pa4Paaa2a(80)aaaq(81)80kN.m24kN.mq=10kN/m4kN.m12kN.m8kN.m2kN2m2m56kN.m2m2m4m(82)4ma
31
q=4kN/m20kN.m10kN1m1m8kN.m2m2m2m2m(83)5kN2.27kN-5kN-3.510N1k.65kN5kN2.27kNN1k3m2.27kN36kN2.27kN-3k36.5-5kN10.6a21.82kN.m-10kN-10kN21.82kN.m2qa22qa/4qaqqa/228maNa/2a/2(85)4X3m=12m(84)Pa2Pa2a4Pa2aaaaa(86)aPaP
32
100kN.m20kN40kN.m10kN.m40kN.m10kN/m20kN40kNm20kN.m60kN.m10kN/m10kN/m20kN.m80kN.m30kN.m70kN.m4m30kN.m2m2m2m2m2m2m2m2m(87)3PP40kNP4m20kN/m80kN.m80kN.m80kN.m4m2P24m2P2m2m(89)2m2m2m2m(88)P1.5mP/2P/2PP2m2m2m2m(90)
33
3qL/22L3003002/LqL/22qLPP2LL/LPL/2PL/2L(92)4P4P4P4Pm44PP4P4m4P2m2m4m(93)PPa/2aPa/2Pa/2aPa/2aPa/2aPa/2a(94)MMMMMaaaaaaaa(95)34
(91)
10kN/m20kN.m2Pa40kN.m20kN.m20kN.m2m20kNP2Pa60kNm60kN.m60kNm2m2m2aa2m2m2maaa(97)(96)3PL2m5kN.m100kN.m100kNmPL50kN4PL2mP5kN.m10kN/m2PLL2m2m2mLLL(99)(98)MaaMaa(100)a/2a/2L6P4P-2P
35