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KB 001649 | Stability Analysis of a Purlin With I-Section Without Lateral and Torsional Restraint
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Description
Due to this structural design, a lateral and torsional restraint cannot be assumed here when determining the ideal elastic critical moment during the stability analysis. This reduces the structural resistance and therefore has to be considered. On the other hand, the ultimate load increasing capacity effect of the rotational restraint from the trapezoidal sheeting is taken into account.
Keywords
Dlubal Knowledge Base Lateral and torsional restraint Purlin Lateral-torsional buckling Stability Rotational restraint Dlubal KB Knowledge Base Technical Contribution
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Videos
Models to Download
Knowledge Base Articles

Stability Analysis of a Purlin With I-Section Without Lateral and Torsional Restraint
This technical article deals with the stability analysis of a roof purlin, which is connected without stiffeners by means of a bolt connection on the lower flange to have a minimum manufacturing effort.
Screenshots
The model is constructed by means of parameters for geometry and loads and regenerates when the parameters are changed.
RF-/STEEL Cold-Formed Sections Module Extension | Design of cold-formed sections according to EN 1993-1-3
3D model of the butadiene storage sphere in RFEM (left) and the mode shape from RF-DYNAM Pro (right)
Product Features Articles

SHAPE-THIN | Cold-Formed Sections
SHAPE-THIN determines the effective cross-sections according to EN 1993-1-3 and EN 1993-1-5 for cold-formed sections. You can optionally check the geometric conditions for the applicability of the standard specified in EN 1993‑1‑3, Section 5.2.
The effects of local plate buckling are considered according to the method of reduced widths and the possible buckling of stiffeners (instability) is considered for stiffened sections according to EN 1993-1-3, Section 5.5.
As an option, you can perform an iterative calculation to optimize the effective cross-section.
You can display the effective cross-sections graphically.
Read more about designing cold-formed sections with SHAPE-THIN and RF-/STEEL Cold-Formed Sections in this technical article: Design of a Thin-Walled, Cold-Formed C-Section According to EN 1993-1-3.
Frequently Asked Questions (FAQ)
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