Wind Loads per ASCE 7-05

Executive Summary

For the past four years I have been working for the engineering company FLSmidth CEntry in Sandy, UT that specializes in industrial engineering. I’m a structural engineer and am responsible for the structures and equipment supports for the various projects that we perform. As part of the design of a structure, the loads for that structure need to be determined, this can be a very lengthy and in many cases, the most difficult part, of any project. For this project I have decided to take the current code governing the design of wind loads (ASCE 7-05) and automate it into an excel spreadsheet that can easily determine the necessary design criteria.

.

Over the past 20 years, wind load design in the United States has become progressively more complicated. There currently are so many variables and different options in the design, that experienced professional engineers, will have difficulty coming up with the correct loads in many situations. The engineer must first choose a design method to use; Method 1, which is a simplified approach, Method 2 which is an analytical approach or Method 3 which relies on results from wind tunnel tests. After determining the method type, the engineer needs to determine the structure type, roof type, roof angle, roof height, enclosure type, occupancy category, exposure category, gust factor, and Effective wind area. With this information, the engineer then needs to find the corresponding figure and tables within the code (48 to choose from) to find the external pressure coefficient, internal pressure coefficient, basic wind speed, topographical factor, directionality coefficient, and importance factor. To make things more complicated, the factors change depending on whether the Main Wind Force Resisting System (MWFRS) is being designed, or Components and Cladding are being designed.

.

With all the pertinent factors and design criteria on hand, the engineer then needs to find the applicable equation for the particular structure being designed. These equations vary based on the type of structure, the roof type, and the enclosure type.

.

The Spreadsheet that I built includes all the necessary tools in which an engineer can quickly input the required wind data into a userform and all the associated calculations, and resources are generated into a printable calculation that can be put into the formal calculation book for each project.

.

To see a copy of how this is implemented and a some sample code click here.

.

To see a copy of an example printout click here.

.

This excel file will not be made public due to privacy issues with the data. Sorry for the inconvenience.

.