Corner 90 degree butt glazed glass thickness calculation

[hans_freek]

Hi everyone,

I'm new to this community and would first like to thank you all for the incredible work you're doing in sharing your experience, expertise, and knowledge for the benefit of the engineering community. It's truly appreciated!

I'm currently working on a project involving a uPVC window with a 90-degree corner butt-glazed glass unit, and I’d love your input on the approach I’ve taken.

Window Specs:​

• Corner width: 72" x 72" (forming the 90° corner)
• Common height: 107"
• Wind load: 37.33 psf (1.78 kPa) .....factored wind load
• Glass requirement: Laminated from the inside
• Deflection limit: 40 mm (based on CAN/CGSB 12.20-M89)

My Calculation Approach:​

Using ASTM E1300, I analyzed:

• Interior glass: 4mm annealed + 0.030 PVB + 4mm annealed laminated
• Exterior glass: 6mm tempered
• Airspace: 7/16"
• Support condition: Three-side supported assumption (due to butt-glazed corner)

The combinations were selected based on graphs for 8.0 mm PVB laminated and 6 mm monolithic glass in ASTM E1300.

I do understand that I’m intersecting two different standards here (ASTM E1300 and CAN/CGSB 12.20-M89), but I’ve attempted to balance the stress resistance per ASTM E1300 with the deflection criteria from CGSB, especially considering this is a residential application.

​

My Questions:​

1. Does the glass combination I’ve selected seem adequate in terms of stress and deflection under the stated conditions?
2. Is it acceptable in practice to combine ASTM E1300 and CAN/CGSB 12.20-M89 in this way for a project?
3. Are there any other reference documents, formulas, or calculation methods that can be used (excluding FEA software)?
4. Can this method also be applied to 180° or other angular butt-glazed units, assuming similar or different edge support conditions?

Looking forward to hearing your thoughts, critiques, or recommended improvements. I’m always eager to learn from those with more field experience.


Thanks in advance!