Determine the force in members LK, KC, and CD of the Pratt truss and state if the members

Question

Determine the force in members LK, KC, and CD of the Pratt truss and state if the members are in tension or compression.

Accepted Answer

[latex] ⤹ +\Sigma M_{A}=0 ; \quad G_{y}(12 \mathrm{~m})-20 \mathrm{kN}(2 \mathrm{~m})[/latex]

[latex]-30 \mathrm{kN}(4 \mathrm{~m})-40 \mathrm{kN}(6 \mathrm{~m})=0[/latex]

[latex]G_{y}=33.33 \mathrm{kN}[/latex]

[latex]+\uparrow \Sigma F_{y}=0 ; F_{K C}+33.33 \mathrm{kN}-40 \mathrm{kN}=0[/latex]

[latex]F_{K C}=6.67 \mathrm{kN}(\mathrm{C})[/latex]

[latex] ⤹ +\Sigma M_{K}=0[/latex]

[latex]33.33 \mathrm{kN}(8 \mathrm{~m})-40 \mathrm{kN}(2 \mathrm{~m})-F_{C D}(3 \mathrm{~m})=0[/latex]

[latex]F_{C D}=62.22 \mathrm{kN}=62.2 \mathrm{kN}(\mathrm{T})[/latex]

[latex]\stackrel{+}{ o } \Sigma F_{x}=0 ; \quad F_{L K}-62.22 \mathrm{kN}=0[/latex]

[latex]F_{L K}=62.2 \mathrm{kN}(\mathrm{C})[/latex]

Question F5.8: Determine the force in members LK, KC, and CD of the Pratt t......