Calculations

This list of topics includes some of our latest ponderings. Feel free to peruse these summaries, articles, and calculations.

Please use your own judgment in applying them elsewhere.

Roof Ponding

When a roof structure sags, it creates a depression where water can pond. This ponded water adds load to the roof, causing more sagging, a deeper pond, and even more load to the roof. If designed correctly, the roof stabilizes with enough residual carrying capacity to hold up the ponded water. Mr. Silver developed a design procedure for this effect - including caber and end-restraint - and published A Strength Design Approach to Ponding (pdf - 2715Kb) in AISC’s Third Quarter 2010 Structural Journal. For a sample calculation using the procedure click the following link: Roof Ponding Calculator