Crown-hinge horizontal thrust
Solve reactions, horizontal thrust, section resultants, shape effects, and imposed-movement compatibility for determinate arches.
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Three-Hinged Arch Engineering Suite
Reactions, crown thrust, section resultants, shape effects, and imposed-movement compatibility.
Enforce zero crown moment for a symmetric parabolic arch under a vertical UDL uniform over the horizontal projection.
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.