Test HTML – Lonsdale Form

Section Property Calculator

Aluminium Rooflight Mullion — Box Bar Design Sheet

Prepared by

Date

Job No.

Inputs

Span (m) Mullion Centre, L1 (m) Mullion Centre, L2 (m) Roof Angle, α (degrees) Positive Wind (kN/m²) Negative Wind, Uplift (kN/m²) Snow Load (kN/m²) Maintenance Point Load (kN) Total Glass Thickness, t (mm) Double Glazed Unit? Selected Box Bar

Box Bar Dimensions–

Ixx of Box Bar (cm⁴)–

Zxx of Box Bar (cm³)–

Output

Positive Wind Line Load (kN/m)–

Negative Wind Line Load (kN/m)–

Snow Line Load (kN/m)–

Self Weight Line Load (kN/m)–

Maintenance Point Load (kN)–

Positive Combined Load (kN/m)–

Negative Combined Load (kN/m)–

Maximum Deflection (mm)–

Deflection Limit (mm)–

Utilization–

Maximum Stress (N/mm²)–

Utilization–

–

Please note

1) Design for CWCT Class 3 – Fragile roof.
2) The minimum point loads refers to access for maintenance only according to BS 6399: Part 3:1997 clause 4.3.1, spreader boards for cleaning and maintenance assumed.
3) Aluminium grade 6063 T6 or higher (ρo = 160N/mm², ρv = 95N/mm²) in accordance with BS 8118: Part 1:1991 Table 4.1.
4) Mullions assumed to be simply supported.
5) Does not include the effect of HAZ (caused by welding); this is likely to increase the Zxx required — for heat affected mullions a Structural Engineer’s input is recommended.
6) Clear Structures recommend that this spreadsheet is used by a suitably competent person and takes no responsibility for the figures entered.
7) It is recommended that wind and snow loads are calculated in accordance with BS 6399 or another approved method.
8) This calculator is licensed for use by Lonsdale Metal Company Limited only; Clear Structures Ltd takes no responsibility for unauthorised use.