This mode is similar to the Continuous Purlins mode. The differences are that in the General tab you only have to specify the length of a standard span (all standard spans are assumed to have the same length), and you can specify the arrangement of hinges to provide equal moments or equal deflections. If the other option is selected, you have to specify the distance from the support to the hinge.
It should be noted that this mode can be used to analyze simply supported purlins if you specify the zero distance between the support and the hinge.
Only two types of loads can be specified for cantilever purlins: a uniformly distributed load on all spans, and the dead weight.
The purlins are checked for the following factors:
Check |
Reference to SNiP II-25-80, KMK 2.03.05-97 |
Reference to |
Reference to |
Reference to |
Reference to |
|---|---|---|---|---|---|
Strength of the member under the bending moment My |
Sec. 4.9 |
Sec. 6.9 |
Sec. 7.9 |
Sec. 9.4.1 |
Sec. 6.1.6 |
Strength of the member under the bending moment Mz |
Sec. 4.9 |
Sec. 6.9 |
Sec. 7.9 |
Sec. 9.4.1 |
Sec. 6.1.6 |
Strength under the lateral force Qz |
Sec. 4.10 |
Sec. 6.10 |
Sec. 7.10 |
Sec. 9.4.2 |
Sec. 6.1.7 |
Strength under the lateral force Qy |
Sec. 4.10 |
Sec. 6.10 |
Sec. 7.10 |
Sec. 9.4.2 |
Sec. 6.1.7 |
Strength under combined action of My and Mz |
Sec. 4.12 |
Sec. 6.12 |
Sec. 7.12 |
Sec. 9.4.3 |
Sec. 6.1.6 |
Stability of in-plane deformation |
Sec. 4.14, 4.15, 4.18 |
Sec. 6.14, 6.15, 6.20 |
Sec. 7.14, 7.15, 7.20 |
Sec. 9.4.4 |
Sec. 6.2.4 |
Deflection |
Sec. 4.33 |
Sec. 6.35 |
Sec. 7.35 |
|
|
Formula (50) of SNiP, KMK (formula (55) of SP 64.13330.2011, formula (61) of SP 64.13330.2017) is not used when calculating the maximum deflection because purlins are assumed to have a constant height, and Table 3 of Annex 4 to SNiP, KMK (Table F.3 of Annex F of SP 64.13330.2011, Table F.4 of Annex F of SP 64.13330.2017) requires that k=1, с=0 (the first line in the table is the most frequently used case).
The analysis is based on the assumption that the end span has a recommended length (~ 0.85 of the standard span length). The maximum values of bending moments, shear forces, and deflections cannot appear in the end span, therefore it is excluded from the analysis.