Determinate Structure Analysis

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In Structural Analysis, we analyze the structures with different methods based on its structures type. Two types of structures are determinate structures and indeterminate structures. Generally, it is actually not possible to perform an exact analyze of a structure. Hence, approximations for structure geometry, material limit and boundary, loading type and magnitude must be made. Determinate structure simply means that all the forces in the structure can be determined from the equilibrium equation. If there are more unknowns than the equation, the structure is indeterminate.
Determinancy=Reactions-Equilibrium

Statically determinate beam can be solved by the equilibrium equation consist of summation of horizontal force ∑fx=0, summation of vertical force ∑fy=0 and summation of moment ∑M at a point =0. One of the advantages of statically determinate beam is that it is easier to be analyzed. As one of the common statically simply supported beam with a pin support and a roller support, which results in three reactions- equilibrium = 0 hence determinate. Even though one of the supports has settled, there will be no stress caused due to the less of fit or settlement, this is because roller support allows rotation and hence it will be in equilibrium state. Besides, determinate structure that allows rotation at such will not be affected by the temperature reaction. For example, expansion due to hot weather and constraint due to cold weather will not influence the structure equilibrium. Besides, bending moment or shear at any point is independent and not relying on the material property. This is because the structure itself allows rotation from roller support and hence it will not cause any unnecessary stress to the material of beam i...

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...ave of water, wind loading and settlement of support. However, those situations stated will cause stress due to the ability of the beam to compact and redistribute the load among the beam. To overcome the disadvantage, the most suitable material, cross section and second moment area is required to be used to design the highest efficiency structure in real life application.
In conclusion, statically indeterminate beam’s most significant advantage is safety. All fundamental of structure is to withstand load and function to serve its designated purpose. Hence, real life structures are mostly indeterminate to brace the unknown external load or internal defect and yet still able to achieve stability.

References

Carpinteri, Alberto. Structural Mechanics: A Unified Approach. Taylor & Francis, 1997.
Wearne, Phillip. Collapse - Why Buildings Fall Down. TV Books , 2000.

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