V.03.6Biaxial Cantilever, BETA 30

Problem

Compare the second-order (P-Delta) response, including the bowed moment along the member, with STAAD.Pro.

Reference

• STAAD.Pro V8i SS6, the same input file run by Sutranet: linear analysis, PDELTA with SMALLDELTA, and the same model meshed into 10 members per member (for the moment along each member).

Model

• Horizontal cantilever 5 m long, fixed at the base, IY 4 × 10⁻⁵ m⁴ and IZ 10⁻⁴ m⁴, rolled by BETA 30
• Tip loads −30 kN in Y and 20 kN in Z, 10 kN/m downward, 157.9 kN axial compression
• Prismatic members: AX 0.01 m², IX 0.0002 m⁴, IY = IZ 0.0001 m⁴ unless stated; E 2 × 10⁸ kN/m²

Comparison

• First-order displacements, reactions and end forces equal STAAD's linear run to its print precision; P-Delta joint results and end forces are within 0.3% of STAAD's SMALLDELTA run. STAAD reports the moment inside an unmeshed member without the P-δ bow, so the moment along the member is compared with the meshed model.

Reproduce in Sutranet CAD

1. Open the project in the app (no sign-up needed), or download the file and open it with 📂 Import Job JSON in the File group.
2. Run Analysis (Static) with P-Delta Analysis ticked (unticked for the first-order result).

The app works in SI units; results in kip and inch are converted (1 kip = 4.448 kN, 1 kip-in = 0.1130 kN·m, 1 in = 25.4 mm).

Automated test: staad_pdelta.rs, run on every change.