A comprehensive explanation of structural calculation methodology for facade systems, from load analysis to final section approval.
Wind Load Analysis on the Facade Pane
The calculation begins by determining the wind pressure acting on each facade pane based on its height, location, and the building's shape, and a wind tunnel study may be used in high-rise or complex-shaped buildings instead of relying on simplified equations in the general code. This pressure is later translated into a distributed force on each pane's surface, the starting point for all subsequent calculations in the system.
Calculating Glass Deflection and Breakage Resistance
Glass is calculated under wind load per equations accounting for its behavior as a brittle material fundamentally different from metal, with no gradual "yielding" — only sudden fracture once the strength limit is exceeded. Codes such as American ASTM E1300 or European EN 16612 define how to calculate the maximum allowable deflection and maximum allowable stress for glass based on its thickness, type (tempered or laminated), and aspect ratio, and any calculation not grounded in these codes is considered unreliable.
Analyzing Composite Aluminum Sections Under Load
Aluminum sections in facade systems are often composite sections (combining two or more pieces mechanically or thermally connected), and their analysis requires calculating the composite section's actual moment of inertia rather than treating each piece separately. This analysis determines the section's capacity to resist bending under wind load without exceeding the allowable stress limits for the alloy used, per values approved in specifications such as EN 755 or ASTM B221.
Calculating Structural Silicone Performance Where Applicable
In structural glazing systems, the structural silicone bead's width and depth are calculated based on the pane's weight and wind load with an additional safety factor per the European EOTA guideline or American ASTM C1401, since the silicone here carries the role of an actual structural element rather than a mere gap-filling material. Any shortfall in this calculation risks the pane fully detaching under high wind pressure — one of the most severe failure modes in modern facade systems.
Reviewing and Approving Calculations Before Fabrication
Every structural calculation package must undergo an independent review by a qualified structural engineer other than the one who prepared it, a standard practice known as an "independent check" that catches errors the original calculator may have overlooked due to familiarity with their own work. Formal approval of the calculations by the consulting authority responsible for the project is a mandatory step before authorizing fabrication start, and it cannot be bypassed even under the tightest schedule pressure.
