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Three-hinged arches2D

Settlement and temperature compatibility

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.

Visualize downward settlement and free thermal change in an unloaded ideal three-hinged arch.

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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Thermal coefficient
12.0 µ/°C
µ/°C
5.025.0

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Temperature change
35 °C
°C
-5080

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Downward support settlement
0.030 m
m
0.0000.100

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Three-hinged arch equilibriumPin supports A and B plus the moment-releasing crown hinge C form a determinate system.ACBUNLOADED IDEAL HINGE-COMPATIBLE MODELDownward settlement = 30 mmFree thermal change = 8.400 mmSecondary restraint force = 0Loaded reactions require reanalysis in the changed geometry.
Free thermal change
8.400 mm
Downward settlement
30 mm
no unloaded secondary force
hinge-compatible movement model verified

Concept question: Predict αΔTL for the unloaded hinge-compatible model.

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.