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The Use of Demand-to-Capacity Indexes for the Iterative Design of Rigid Structures for Wind



Filmon Habte, Arindam Chowdhury, Sejun Park


Estimates of wind effects on rigid buildings by database-assisted design (DAD) methods can be more accurate than those based on information available in standards. An upgraded version of DAD was developed that streamlines the wind engineering/structural engineering components of the design process by allowing the direct computation of Demand-to-Capacity Indexes (DCIs). Although the basic procedure described in this report is applicable to any rigid building, the focus in this work is on simple buildings with gable roofs, portal frames, and bracing parallel to the ridge. The procedure makes use of the two largest building aerodynamics databases available worldwide; large simulated extreme wind databases for hurricane- and non-hurricane- prone regions; a novel interpolation scheme allowing the design of buildings with dimensions not covered in the databases; an effective multiple-points-in-time algorithm for estimating peaks; and parameter-free methods for estimating DCIs with specified mean recurrence intervals. In addition to a brief description of the procedure, the report contains the following link to the software developed for the implementation of the procedure:, and a user's manual. Detailed additional material on the procedure is being provided in a companion paper.
Technical Note (NIST TN) - 1908
Report Number


Aerodynamics, database-assisted design, demand-to-capacity indexes, parameter-free statistics, structural engineering, wind climatology, wind engineering.


Habte, F. , Chowdhury, A. and Park, S. (2016), The Use of Demand-to-Capacity Indexes for the Iterative Design of Rigid Structures for Wind, Technical Note (NIST TN), National Institute of Standards and Technology, Gaithersburg, MD, [online],, (Accessed July 21, 2024)


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Created February 1, 2016, Updated October 12, 2021