2 5 points each State whether the following structures are s

2. (5 points each) State whether the following structures are stable or unstable, and statically determinant or indeterminant. If they are indeter- minant, state the degree of indeterminancy. b) a) e) d) t)

Solution

a) This strucutre is stable. This structure is statically determinate. Degree of indeterminacy is {(3+1-1)-3} = 0. Hence this is statically determinate.

b) This strucutre is un stable because of two internal hinges. This structure is statically determinate. Degree of indeterminacy is {(3+1-2)-3} = -1. Hence this is statically determinate.

c)This strucutre is stable. This structure is statically indeterminate. Degree of indeterminacy is {(3+3-1)-3} = 2. Hence this is statically indeterminate.

d) This strucutre is stable. This structure is statically indeterminate. Degree of indeterminacy is {(3+3-2)-3} = 1. Hence this is statically indeterminate.

e)This strucutre is stable. This structure is statically indeterminate. Degree of indeterminacy is {(2+2+1+1-3} = 3. Hence this is statically indeterminate

f) This strucutre is unstable. If load apllied horizontally, right side structure move away. This structure is statically indeterminate. Degree of indeterminacy is {(3+1)-3} = 1. Hence this is statically indeterminate.