Determine the forces using virtual work(unit force method)

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daphnelee-mh
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Summary:: Require to determine the designated forces using principle of virtual work ( unit force method )

I have no idea how to determine the multispan beam using virtual work, if I start to analyse the subsidiary portion BC member, the Yc can be calculated and following by the Ma... it seems don’t involve the unit force method
Handwritten free-body diagrams with a beam problem: a fixed-end beam A to C with a 2 kN/m distributed load, points D and B, and spans of 1.5 m, 1.5 m and 3 m; a 6 kN downward load on segment BC with Yc = 3 kN, and segment AB with Ya = 9 kN, MA = -18 kN·m.
 
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I use the Principle of Virtual Work quite often, but I have to say that I do not see a simple way to employ it here. Is this a homework problem? If not, who cares what method is used?
 
Yes, this is a homework problem, I know how to solve it if don't use virtual work method, but now I only can find the Yc
 
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  • Handwritten unit-load method solution: a beam with a 2 kN/m uniform load over a span, M_p = Y_c x - x^2 and m-bar = Y_c x, with the deflection integral set to zero and the result Y_c = 3 kN.
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