DOSI Example 1

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This is a frame. The DOSI is:

Reactions (r = 7)

There are one fixed and two pinned supports. A fixed support has three reactions (lateral, vertical, rotational). A pinned support has two reactions (lateral, vertical).

Joints (j = 6)

There is a joint at every reaction, free end, and intersection of elements.

Frame Members (n_frame = 5)

There are five segments.

Strut Members (n_strut = 0)

There are no strut members, because there are no members that only exhibit axial forces.

Equations of Condition (e_c = 2)

There is one roller connected to two members. Therefore, there are two equations of condition.

Degree of Static Indeterminacy (DOSI = 2)

r + 3n_frame + n_strut – [3j + e_c] = 7 + 3(5) + 0 – [3(6) + 2] = 2

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