Structural Properties

Loading

Wind loads are varied and factored by amounts determined by size and shape of structure, locational parameters, (open countryside will usually have lower wind speeds than sheltered inner city sites), and duration of installation. Surface pressures increase in proportion to the square of the wind speed. Therefore the pressures upon the surface of the structure are much greater than a small increase in the stated wind speed would first suggest.

Simulated pressures from two different angles

Surface pressures should be calculated for walled structures with the walls attached. Dominant openings such as sections of wall left open are not normally allowed for. Smaller openings such as large doors are catered for by allowances in the initial calculations. A major consideration can be uplift. Uplift is often the dominant part of wind loading considerations, as is the effect of suction. The illustrations show the representative mesh with simulated wind loads broken down, polygon by polygon.

Once the potential membrane loading estimates or pressure coefficients (CP) are confirmed, then attention must be made to the supports, lifting gear, ground anchors and other factors such as stiffening members such as webbing belts or spars.