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Static Analysis of Truss


New member
Jul 2, 2019
Below is a sketch of a truss in which external support reactions are given as R1 = 0 kN, R2 = 3.5 kN, R3 = 4.5 kN. Members (M) are labeled in boxes, joints labeled in circles, and forces R.

Draw 2 Free body diagrams, one for each joints C and E.
Define what direction represents a positive force, and write equations for all forces acting on that joint.

Screen Shot 2019-07-02 at 10.16.47 PM.png

For example, for joint D it's:
("SUM" is used for summation symbol)
SUMFy = 0
SUMFy = F4 sin(30) + R3 = 0
SUMFy = F4(1/2) + 4.5 kN = 0
F4 = -9kN
Screen Shot 2019-07-02 at 10.21.21 PM.png