Stability - Stable & Unstable Structures & Members
The resistance offered by a structure to undesirable movement like sliding, collapsing and over turning etc is called stability.
A stricter is said to be stable if it can resist the applied load without moving OR A structure is said to be stable if it has sufficient number of reactions to resist the load without moving.
A structure which has not sufficient number of reactions to resists the load without moving is called unstable structures.
Stability of Structures
STABILITY OF TRUSS
A truss is said to be stable if it is externally and internally stable
EXTERNAL STABILITY OF TRUSS:
Externally a truss is said to be stable if
INTERNAL STABILITY OF TRUSS:
Internal stability of truss depends upon the arrangements of members and joints as
* If m + r = 2j internally stable
Where m = number of members, J = number of joints, R = number of unknown reactions.
For complete stability the should be both internally and externally stable
Stability of Structural Members
A beam is said to be stable if it satisfy the following conditions.
STABILITY OF FRAME
A frame is said to be stable if it satisfy the following condition.