Point-Supported Glass Calculator

Fitting layout and glass thickness from panel size and load.

Panel width (mm)

Panel height (mm)

Design wind load (Pa)

Support points

Glass type (1-2)

Tab to move between fields

Selected thickness (mm)

Stress utilization (%)

20,816,532.3

Min. thickness (mm)2.7

Actual stress (MPa)19,359,375

Deflection (mm)2.5

Deflection limit (mm)25

Bolt hole dia. (mm)26

Min edge distance (mm)60

Load per fitting (N)1,130

Panel weight (kg)45

Stress Ratio20,816,532.26%

Defl Ratio0.1%

How to Use This Calculator

Enter the glass panel dimensions and glass type (tempered, laminated).
Set the wind pressure design load in psf or kPa.
Input the number of point supports and their layout pattern.
Review the maximum glass stress and deflection at design load.
Verify stress is below the glass allowable strength and deflection is below span/60 limit.

What each input means

Panel width (mm): Width of the glass panel between support points.
Panel height (mm): Height of the glass panel between support points.
Design wind load (Pa): Design wind pressure per ASCE 7 or local building code.
Support points: Number of point fixings (spider arms). Typically 2, 4, or 6.
Glass type (1-2): 1 = Heat-strengthened (45 MPa), 2 = Fully tempered (93 MPa). Tempered required for bolt holes.

Min. thickness (mm): Minimum glass thickness from stress analysis with bolt-hole stress concentration.
Selected thickness (mm): Nearest standard glass thickness meeting the stress requirement.
Actual stress (MPa): Maximum bending stress at bolt hole with selected glass thickness.
Stress utilization (%): Ratio of actual stress to allowable stress. Must be below 100%.
Deflection (mm): Maximum centre-of-panel deflection under wind load.
Deflection limit (mm): Allowable deflection (span/60 for point-supported glass).
Bolt hole dia. (mm): Recommended bolt hole diameter for countersunk fitting.
Min edge distance (mm): Minimum distance from bolt hole centre to glass edge (≥ 2.5t or 60 mm).
Load per fitting (N): Combined dead + wind load per spider fitting for structural sizing.
Panel weight (kg): Glass panel weight for dead-load design of support structure.

Identify Input Parameters
4 parameters
Panel width (mm) = 1500, Panel height (mm) = 2000, Design wind load (Pa) = 1500, Support points = 4 = 5 input(s) provided
Calculate Selected thickness
6 = 6
Calculate Stress utilization
Stress utilization = round((actualStressMpa / sigmaAllow) * 1000) / 10
20816532.3 = 20816532.3
Calculate Min. thickness
Min. thickness = sqrt(
2.7 = 2.7
Calculate Actual stress
Actual stress = actualStress * 1e6
19359375 = 19359375