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Minimizing Moment Reactions: Roller supports restrain translation (movement along the support) but do not resist rotation (moment forces). By incorporating roller connections, we aim to minimize the moment reactions or eliminate bending stresses in the structure, which can simplify design calculations.
Stability Considerations: In structures, particularly tall or slender columns or frames, the possibility of buckling, a sudden failure due to excessive compression, must be carefully considered. By using roller supports instead of pinned connections at critical points, the structure's stability can be improved. Roller supports restrict lateral translations, providing an enhanced resistance against buckling.
Static Indeterminacy: A structure is termed statically indeterminate if the analysis of equilibrium alone is insufficient to determine all reactions and internal forces. Incorporating roller supports, which have fewer reaction components compared to pinned connections, can help reduce the number of unknowns and simplify the analysis.
Realistic Representation: In certain scenarios, roller supports provide a more realistic representation of actual conditions compared to pinned connections. For example, in bridges, the expansion joints between segments act as roller supports, accommodating thermal expansion and contraction.
Simplified Analysis: In structural analysis, roller supports can facilitate the calculation of reactions and internal forces using simpler equilibrium methods, such as the method of sections or moment distribution method, as they eliminate or reduce the number of unknown moments.
Economy and Constructability: Roller supports may be more economical in specific applications. They can be easier to install and maintain than pinned connections, especially in larger-scale structures. However, the cost-effectiveness analysis should be done for each project.