In two-hinged arch, how many unknown forces exist?
In two-hinged arch, how many unknown forces exist? Correct Answer Four unknowns
Explanation:
Three hinge arch :
- In the case of a three-hinged arch, we have three hinges, two at the support and one at the crown and there are four reaction components in the three-hinged arch.
- One more equation is required in addition to three equations of static equilibrium for evaluating the four reaction components.
- Taking moment about the hinge of all the forces acting on either side of the hinge can set up the required equation, making 3 hinge arch determinate.
Two hinge arch :
- In the two hinge arch, we have 2 hinges at two support of the arch and have four reaction or unknown components, as in a 3 hinge arch.
- But here we don't have an additional equation to solve the structure and hence our 2 hinge arch is indeterminate by degree 1.
Hinge less/ Fixed arch :
- In the fixed arch, both the support are fixed. So, in a fixed arch six reaction forces ( One moment extra on each support ).
- But, we have only 3 equilibrium equations. So, the degree of indeterminacy of fixed arch becomes 6 - 3 = 3.
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Feb 20, 2025