element jonit 2d

[e.kian]

Hi dear fmk
I want To model RBS(reduced beam section) and I used element joint2D instead of hinge or RBS and gave central node the behavior of RBS connection . I thought that I could get the exact answer by this method but I dont know why frame be stiffener instead of be softer!
do you think using element joint 2d instead hinge is logical? if your answer is no please say me "how can I model RBS connection"?
sincerely
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Jalal kiani
MS student of Thehran univercity