Question

Classify each of the structures shown in Figure 1 as statically determinate, statically indeterminate, stable or unstable. If indeterminate, specify the degree of indeterminacy. The supports or connections are to be assumed as stated.

Pin Fixed Roller Pin Pin

Answer 1

Solution - to m A Here, External andelenminacy - Pse :: Pse = fe-3 = ( 3+1+2)-3 = 3. Inverndl indetemingus : Psi Psi = 3m - (3)-3) - V mo number a members. = 4 j: number of joints. reaction released 2 .: Ds; = 3x4 - (345-3) - 2 = 12-12-2=-2 total. Indeterminacy = Ds = Pse + Psi =). Ps = 3-2 - 1 So, structure in Indelerminate with 1 degree. and Stable. is

B Degree q stan'e Indeterminacy - Pse. Pse a re-3 = 3-3=0. Degree of Intemal Indeterminacy - Psi Dsi - m-123-3) Ds;= 11- (2x7-3) = 11-11 - 0 so total. Degree q Indererminacy = Dj = Dse + Ps; = 0 to 20 Q = 0 So, structure is dererminate with zero degree. and structure to stable.