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Extreme Winds Software: Along-Wind Response of a Tall Building Input Format (2015/11 Version)

Introduction This page describes the input format for the 2015/11 version of the along-wind response of a tall building subjected to a wind load with mean direction normal to a building face. This version makes a modification to the computation in the STILDA function. The input file is nearly identical to the 2009/10 version of the program. The exception is that micrometerological parameters input line has been modified.

As with the 2009/10 version of the program, this version has a less rigid format for the input file than the original program.

Specifically, input values no longer need to be entered in specific columns. Also, you may separate data values on the line either with one or more spaces, commas, or tabs. Note that you should only use a single comma or tab to separate data values (if multiple commas or tabs are encountered, the program treats these as "blank" fields). Although it is not recommended, you can mix the use of commas, tabs, and spaces as field separators. It will generally be easier to read the input file if you pick one style for separating fields.

The program will provide prompts for the input values. This can be helpful when running the program interactively.

One trade-off of using a less rigid format is that you can no longer specify default values by simply leaving a field blank. To specify that a default value be used, you can do one of the following.

  • You can explicitly enter a zero value for the field.

  • You can use multiple commas or tabs to indicate a missing field. For example, entering ",,," indicates that there are two empty fields.

  • If the fields to be omitted occur at the end of an input line, then simply leaving them blank will work. For example, if the line has five fields and field three is not using a default value, then you leave fields four and five blank. However, all fields up to field three must be entered.
Program Control Parameters The first line should contain the following input control parameters:

  • RLIM = The number of modes of vibration used in the calculations (between 1 and 8).

  • IPRINT = Selects one of two options for output printing by the main program as the approximate integration progresses from FTILDA = 0 to FTILDA = some cutoff value. Option 1, obtained by setting IPRINT=1, causes running information to be printed at each sample value of FTILDA in the quadrature. Option 2, obtained by entering a value of 0 or leaving IPRINT blank, suppresses this printing.
Both of these values should be entered on the same line.

If no more data is to be entered, you can either enter a value of zero for RLIM or enter a blank line.

Structural Parameters The next line of the input file contains the following structural parameters:

  • H = Height of building in meters

  • BCON = Width of building (i.e., horizontal dimension perpendicular to wind direction) in meters

  • DCON = Depth of building (i.e., horizontal dimension parallel to wind direction) in meters.
These parameters are required (i.e., there are no default values for these). Although these values are typically entered on the same line, this is not required.
Structural Control Parameters: Natural Frequencies The next section contains the following structural control parameters:

  • EN(I) = Natural frequencies of the building in modes 1, 2, ... in Hertz.
The number of values to be entered is given by the RLIM value entered in the Program Control section. Although these values are typically entered on a single line, this is not required. All RLIM values must be entered.
Structural Control Parameters: Damping Ratios The next section contains the following structural control parameters:

  • ZETA(I) = Damping ratios in modes 1, 2, ...
The number of values to be entered is given by the RLIM value entered in the Program Control section. Although these values are typically entered on a single line, this is not required. All RLIM values must be entered.
Structural Control Parameters: Ordinates of the i-th Modal Shape at Specified Elevations The next section contains the following structural control parameters:

  • XMUTAB(J,I) = the ordinates of the i-th modal shape at specified elevations. Specifically, for elevations 0, 1*H/14, 2*H/14, 3*H/14, 4*H/14, 5*H/14, 6*H/14, 7*H/14, 8*H/14, 9*H/14, 10*H/14, 11*H/14, 12*H/14, 13*H/14, and 14*H/14. The value for H is entered in the Structural Parameters section.

    If two or more vibration modes (specified by RLIM given in the Program Control section) are taken into account in the calculations, then 15 values need to be entered for each vibration mode (i.e., there will be 15*RLIM values in all).

There are 15 values to be entered for each vibration mode. For a given vibration mode, you can enter the 15 values on one or more lines (and there is no set number of values for a given line). However, the values for a new vibration mode should start on a new line.

Structural Control Parameters: Building Weight per Unit Mass The next section contains the following structural control parameters:

  • The weight of the building per unit height, XMASS, in Newtons/meter at elevations 0, 1*H/14, 2*H/14, 3*H/14, 4*H/14, 5*H/14, 6*H/14, 7*H/14, 8*H/14, 9*H/14, 10*H/14, 11*H/14, 12*H/14, 13*H/14, 14*H/14. The value for H is entered in the Structural Parameters section.

The 15 values can be entered on one or more lines with no set number of values to be entered on a single line.

Micrometerological Parameters The next line of the input file contains the following micrometerological parameters:

  • ICODE = Selects parameters corresponding to standard micromereorological conditions for various types of exposure, as fololows:

    1. Option ICODE = 1 causes selection of parameters corresponding to exposure typical of open water.

    2. Option ICODE = 2 causes selection of parameters corresponding to exposure typical of open terrain.

    3. Option ICODE = 3 causes selection of parameters corresponding to exposure typical of suburbs at considerable distances from towns, sites in rural zones sparsely built-up, with trees, hedges, etc.

    4. Option ICODE = 4 causes selection of parameters corresponding to exposure typical of towns, densely built-up suburbs, wooded terrain.

    5. Option ICODE = 5 causes selection of parameters corresponding to exposure typical of centers of large cities.

  • Z0 = Roughness length in meters. The default value will be selected based on the value of ICODE.

  • ZPSP = Zero plane displacement in meters. The default value is ZPSP = 0.

  • CZ = Exponential decay coefficient for vertical separation in expression for cross-spectra of longitudinal velocity fluctuations. The default value is CZ = 10.

  • CY = Exponential decay coefficient for horizontal separation in expression for cross-spectra of longitudinal velocity fluctuations. The default value is CY = 16.

  • ZSUBG = (Height above ground beyond which it is assumed that the wind flow is laminar and uniform)/(Height of the building). This ratio should be in the interval 0 to 1. The default value is 0.
These values should all be entered on the same line. Although no specific format is required, the total line length is limited to 132 characters. See above for ways of specifying the default values.

References pertaining to micrometeorological parameters used in this program are:

  1. J. Bietry, C. Sacre, and E. Simiu (1978), "Mean Wind Profiles and Change of Terrain Roughness," Journal of the Structural Division, ASCE, pp. 1585-1593.

  2. B. J. Vickery (1970), "On the Reliability of Gust Loading Factors," Proceedings of Technical Meeting Concerning Wind Loads on Buildings and Structures held at the National Bureau of Standards 1969, Building Science Series 30, National Bureau of Standards.

  3. E. Simiu (1974), "Wind Spectra and Dynamic Along-Wind Response," Journal of the Structural Division, ASCE, pp. 1897-1910.
Climatological Parameters The next line of the input file contains the following climatological parameters:

  • JCODE = If the specified wind speed at 10 meters above ground in open terrain, U10, is given as a mean hourly speed in meters/sec., then set JCODE = 1. If U10 is given as a fastest-mile speed in miles/hour, then set JCODE = 2.

  • U10 = Specified wind speed at 10 m. above ground in open terrain.

  • T = Duration of storms in seconds. The default value of T = 3600 seconds.

  • P = Retardation factor (see reference 1 quoted above). The default value will be selected based on the value of JCODE.
These values should all be entered on the same line. Although no specific format is required, the total line length is limited to 132 characters. See above for ways of specifying the default values.
Aerodynamic Parameters The next line of the input file contains the following aerodynamic parameters:

  • CW = Mean pressure coefficient on windward side. The default value of CW = 0.8.

  • CL = Absolute value of mean suction coefficient on leeward side. The default value of CL = 0.5.

  • RHO = Specific weight of air. The default value of RHO = 12.258 newtons/meter3.

These values should all be entered on the same line. Although no specific format is required, the total line length is limited to 132 characters. See above for ways of specifying the default values.
Multiple Datasets If several sets of data are used, the above sequence of command lines can simply be repeated for each set of data. A blank line should follow the last line of data of the last set of data to indicate that there is no more data.
Sample Input File The following is a sample input file.
1  0
   4.0 10.0 1.0
   5.0
   0.5
   0.0  0.8  1.6  2.4  3.2  4.0  4.8  5.6
   6.4  7.2  8.0  8.8  9.6 10.4 11.2
   10000.0 10000.0 10000.0 10000.0 10000.0 10000.0 10000.0  10000.0
   10000.0 10000.0 10000.0 10000.0 10000.0 10000.0 10000.0
2  0   0   0   0  0.5
1  40.  0   0
0   0.00001 0

      
Note that this input file ends with 1 blank line. This blank line indicates that there are no additional datasets to process.
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Date created: 12/03/2015
Last updated: 10/03/2016
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