Statically determinate structure

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Explain with examples the statically determinate structures.
If the structure can be analyzed and the reactions at the support can be determined by using the equations of static equilibrium such as ∑Fx =0, ∑Fy=0, ∑Mp =0 then it is called as a statically determinate structure. Example: Simply supported beam, pin jointed truss or frame.

Differentiate Truss and Frame?
Truss is defined as number of members riveted together to carry the horizontal, vertical and inclined loads in equilibrium.

Frame is defined as number of members welded together to carry the horizontal, vertical loads in equilibrium.

What are the types of frames?
Frames are classified into two types.

  • a)   Perfect
  • b)   Imperfect
Imperfect frame may be classified into another two types
     i.                     Deficient frame
   ii.                  Redundant frame


Differentiate the perfect and imperfect frames?
I assume, n = number of members, j= number of joints.


Sl.No.
Perfect frame
Imperfect frame
1.



2.

3.
Perfect frames have sufficient or enough members to carry the load

It satisfies the formula n= 2j-3

Eg: Triangular frame n=3, j = 3
n= 2j-3
3 =2x3 -3,
3 = 3
Imperfect frames have less or more members to carry the load than the required numbers.

It doesn't satisfy formula n=2j-3

Eg: Square frame n=4, j = 4
n= 2j-3
4  = 2x4 -3,
4  Ç 5

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