Pipe Support Trunnion & Dummy Leg Stress Calculator

Model localized longitudinal, circumferential, and shear stresses at pipe-to-trunnion welded junctions under deadweight, thermal friction, and lateral loads.

Run Pipe & Trunnion Geometry

Run Pipe Outside Diameter D_p (in):

Run Pipe Wall Thickness t_p (in):

Trunnion Outside Diameter d_t (in):

Trunnion Wall Thickness t_t (in):

Vertical Sustained Load F_v (lbf):

Axial / Thermal Friction Load F_ax (lbf):

Trunnion Projection Length L_t (in):

Basic Allowable Stress S_h (psi):

Localized Stress Results

Max Local Combined Stress:

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Stress Utilization Ratio:

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Bending Moment at Attachment (M):

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Weld Shear Stress (τ):

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Reinforcement Pad Required:

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Support Adequacy Status:

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Piping Trunnion Support Stress Verification

Trunnions and dummy supports (welded pipe stubs) are commonly used to support vertical pipe risers and long horizontal runs. Because the trunnion transmits deadweight and thermal friction cantilever bending moments directly into the thin-walled pipe shell, localized circumferential bending stresses can induce fatigue or local buckling.

Reinforcement Pad Criteria

When localized combined stresses exceed $1.5 cdot S_h$, an integral reinforcement wrapper plate (repad) with a minimum thickness equal to the run pipe wall is welded around the pipe before attaching the trunnion to distribute radial loads across a broader circumference.

Pipe Support Trunnion & Dummy Leg Stress Calculator

Run Pipe & Trunnion Geometry

Localized Stress Results

Piping Trunnion Support Stress Verification

Reinforcement Pad Criteria

Frequently Asked Questions