 Figure 1. Elevation diagram of wind forces affecting a concrete dome. Figure 1. The elevation profile of wind forces affecting a concrete dome. Concrete dome wind analysis Example 1 Commercial dome building 30 feet high in exposure C — the most severe exposure in open, flat terrain. Using wind design pressure from UBC 1985 Edition, section 2311.d, of 70 MPH. p = Ce Cq Qs I I = 1.0 (commercial building) Qs = 13 psf (pressure from wind) Ce = 1.3 (building height 30-feet, exposure C) Cq = 1.3 (method 2) Therefore, p = 1.3 × 1.3 × 1.3 psf × 1.0 = 22 psf Example 2 Assume same building from Example 1 and same exposure but with a wind speed of 300 MPH. (Reference: Fine, Mark, Handbook of Concrete Engineering; Nan Nostrand Reinhold, 1974.) p = ½ Cs Ca Cg P Vh2 (H/h)2/φ Assume everything is constant except the wind speed. P = C Vh2 = 22 psf for V = 70 MPH (example 1) Therefore, C = 22 / 702 = 0.00449 Then, p = 0.00449 Vh2 for V = 300 MPH; p = 404 psf The maximum concrete stress in a dome 100 feet in diameter by 30 feet high with p = 400 psf is 1,098 psi compression. From the “Concrete dome seismic analysis” example (below) we see the allowable stress is significantly higher at 2,394 psi. Image by Drawing by Dave South Posted to Building Survivability: A Guru's Analysis of Monolithic Dome Tornado and Earthquake Resistance © All Rights Reserved