Wind loading on cylindrical structures as per IS 1875 part 3

It is a matter of concern that, in staad pro, the features available for applying wind load is not fully automatic (unlike other design softwares) , but there is much more lacking in it, which is briefly described as below, There is automatic application of wind load only for few types/shapes of roofs/structures ,like rectangular building,pitched roof, mono slope roofs. For many other types of roofs, like saw toothed roof,cantilever roof,multispan pitched roof, combined roof, inverted pitched roof, inverted mono slope roofs, cylindrical shaped structures etc, the automation of wind load is not available, (or available partly). Moreover, automatic wind load for all types and shapes of "ROOF PURLINS", "COMMUNICATION TOWERS", wind load on circular or elliptical shaped column is not available in staad, local wind coefficient (for corner pressures) is not available, automatic calculated solidity ratio/ shielding factor is not available. It is very demanding that wind load in staad should be available for all types of roofs and purlins with Full automation and can be applied with few clicks, For illustration, refer "TABLE NO. 04 to 24" of IS 875 part -3", refer following PDFs 1st PDFs: wind load on frames 2 nd PDFs: wind load on roof purlins. In short, wind load in staad should be available for all types/shapes of of roof/building, purlins and not only for global X and Z directions ,but it should also available for 45⁰,135⁰,225⁰,315⁰,270⁰ etc.

According to my View, the Wind Pressure is acting on the Circumference of the Cylindrical Structure like Chimney/Silo/Shaft Mounted Over Head Water Tank etc. The External Pressure Coefficients are given in Table 19 from 0 degree angle to 180 degree angle . That means the pressure distribution coefficients are given half of the Cylindrical Surface and the Wind Direction in +X direction as per Staad Pro. The Wind Coefficients are positive from 0 to 30 degree and negative from 45 to 180 Degree angle. The Positive Sign of the Coefficients indicate the wind force is pushing the Structure and the Negative Sign indicates the Structure is Pulled by the Wind. That means Negative sign indicates Drag or Suction Pressure on the structure. The same wind pressure will be acting in other orthogonal directions as per Staad i.e -X , +Z , -Z. The Force Coefficient for Solid Shapes mounted on the a Surface i.e fixed foundation is given in Table 27. You can refer even fig-5 to calculate the Force coefficients. Refer also Appendix -D of the code for Force Coefficient, Viscosity, roughness etc.

For clarity here are you looking at structures created as finite element cylinders and thus the load is that perpendicular to the finite element that makes up the wall of the cylindrical chimney/silo? From the image associated with table 19, can you confirm that the external wind pressure up to 30 degrees is parallel to the wind direction, but 30 to 180 degrees, the wind cause suction pressures which are perpendicular to the surface?

Thank you for posting your idea. I have used the title to provide a suitable description of your idea (rather than make it an instruction, which is not an idea)