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Three-hinged arches2D

Arch section N-V-M

Solve reactions, horizontal thrust, section resultants, shape effects, and imposed-movement compatibility for determinate arches.

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Advanced engineering statics simulation

Three-Hinged Arch Engineering Suite

Reactions, crown thrust, section resultants, shape effects, and imposed-movement compatibility.

Cut the arch normal to its tangent and resolve internal resultants with an explicit discontinuity convention.

Horizontal span
20.0 m
m
10.050.0

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Arch rise
5.0 m
m
1.512.0

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Point load
100 kN
kN
1250

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Load position
5.0 m
m
0.020.0

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Section coordinate
6.0 m
m
0.020.0

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Three-hinged arch equilibriumPin supports A and B plus the moment-releasing crown hinge C form a determinate system.ACBP 100.0 kNtnx = 6 mLOCAL SECTION RESULTANTSN = 37.14 kN compressionV = -41.78 kNM = 140 kN·mCoincident load uses the right face.
Normal compression
37.139 kN
θ = 21.8°
Local shear
-41.781 kN
Bending moment
140.000 kN·m
section equilibrium and transform verified

Concept question: Predict M = Mbeam − Hy at the selected section and selected cut face.

Model scope and verification

Scope: Planar, equal-elevation, pin-connected three-hinged arch unless the imposed-movement scenario is selected. Normal force is positive in compression. A section coincident with the point load uses the explicitly selected left or right face. Circular comparison is restricted to a single-valued minor arc with h ≤ L/2. The UDL acts vertically and is uniform per horizontal metre.

Acceptance check: Solve the equivalent simply supported beam reactions, enforce zero crown moment for H, use M_arch = M_beam − Hy, draw the cut normal to the arch tangent, and reconstruct global section-force components from N and V.