SED navigation bar go to SED home page go to Extreme Winds page go to NIST home page SED Home Page SED Contacts SED Projects Extreme Winds Publications Search SED Pages

Extreme Winds Software: Fortran Code for the Along-Wind Response of a Tall Building

Introduction The purpose of this software is to estimate the along-wind deflections and accelerations of flexible buildings with rectangular shape in plan, subjected to the action of wind with mean speed normal to a building face. The across-wind and the torsional response are not calculated by this program.

This program supersedes the program listed in "The Buffeting of Tall Structures by Strong Winds," by E. Simiu and D. W. Lozier (NBS Building Science Series 74, Oct. 1975).

This program was authored by Dan Lozier of the NIST Mathematical and Computational Sciences Division. It consists of a main program called MAIN and eight subprograms, called INPUT, INIT, TRIPLE, F, UTILDA, XMU, STILDA, AND FISTAR.

We provide pre-built executables for the Windows XP/VISTA/7/8 platform. The Fortran source code is provided for other platforms (it should compile and run on any Unix/Linux system that has the gfortran compiler installed).

Updates to Program The following documents the updates that have been made to the original program.
  1. In 2005, Alan Heckert made a few minor updates to the code so that it would run under Fortran 77 and Fortran 90 compilers (it was originally written for Fortran 66 compilers).

  2. The program was further updated by Alan Heckert in 12/2007 in the following ways:

    • The original version of the program had a rigorous input format (i.e., input fields had to be entered into specific columns in a specified format). The program was modified to allow the data to be entered in free format. Note that the order of the data entered remains the same, but you are no longer required to enter the data in specific columns.

      However, there is one issue you need to be aware of if you have used the original version of the program. The original version of the program allowed many fields to be entered as "blank" (these "blank" fields would be read as "0" which the program interpreted to mean "use the default value") . In order to allow the more flexible input format, the option of leaving fields blank no longer works. For a few of the input lines, if the blank fields are all at the end of the line, you can still leave them as blanks. However, other input lines may extend over multiple lines and leaving fields blank will not work. You can specify default values by entering a zero value for the field.

      The main point is that if you have a run file setup to run the original version of the program, it may no longer work with the new version of the program. For this reason, the original version of the program is still available.

    • The program will print prompts for the input values. This should be helpful to those who are uncertain about what some of the input fields are suppossed to be.

  3. The program was further updated by Alan Heckert in 10/2009 in the following ways:

    • The input values entered by the user are automatically saved to the file "windload.echo". This makes it simpler to save and modify your interactive responses to the program in order to run the program in a batch mode (i.e., if you want to run the program with slight variations in the input parameters, you can copy "windload.echo" to a new file name, make the edits using any ASCII text editor, and then run the edited file in batch mode). You should move "windload.echo" to a new file since the next time you run the windload program it will overwrite the contents of "windload.echo".

  4. The program was further updated by Alan Heckert in 11/2015 in the following ways:
    • ...
Example under Windows 7 This section describes how to run the program under the Windows 7 operating system.

For the sake of discussion, let us assume that you have created the directory "C:\WINDLOAD" and that you have a sample input data file called "windload.input".

To run the program:

  1. Open a command prompt window.

  2. Enter

The program will then run. After it completes, the program output will be in the ASCII file WINDLOAD.OUT. This file can be viewed with any suitable editor (e.g., Notepad).

Alternatively, you can just enter

and the program will prompt you for the appropriate input.
Download You can download the following: You can download these files to whatever directory is convenient for you. These files require no additional installation.
Description of the Input File The following description of the input files is provided:

SED Home |  Extreme Winds Home |  Previous |  Next ]

Privacy Policy/Security Notice
Disclaimer | FOIA

NIST is an agency of the U.S. Commerce Department.

Date created: 12/01/2005
Last updated: 11/16/2015
Please email comments on this WWW page to