Program Abstract

1
Program Abstract

• The CASE Center is developing a program for the
  design of steel antenna towers and supporting
  structures based on the TAI/EFA-22-F Standard, as
  reaffirmed March 27, 2003. This new program is
  designed to give the steel antenna tower and
  supporting structure design engineer and
  easy-to-use program to construct a tower and
  appurtenance model, analyze the model, review the
  results and code check the structural components.
  The model is constructed by entering data into
  spreadsheet-like tables. Models may be saved
  into neutral files and retrieved at a later date
  for adjustment or further refinement. Supported
  towers include monopoles, 3- or 4-sided latticed
  towers, with or without guys.

2
Program Goals

• Simplified modeling of tower and monopole
  geometry
• Simplified appurtenance input
• Automatic ice and wind load calculations
• Nonlinear analysis for guyed towers and monopoles

3
Program Goals (cont)

• Concise result reporting including twist, sway
  and displacement for antennas
• Code check by ASD9 along with TIA/EFA-222-F
  adjustments

4
Program Limitations

• No light gauge or cold-formed components (AISI)
  are code checked or have tables provided.
• Connections (bolts or welds) are not checked or
  designed.

5
Program Layout

• - Tabbed spreadsheet-like input
• Graphical display of current model
• Menu selections for
• File input
• GTSTRUDL processing
• Results review

6
Program Usage

• Modeling
• Input file creation
• Results

7
Usage Modeling

• Basic Geometry
• Tower type Monopole, 3- ro 4- sided
• Tower height
• Base and top widths
• Additional inflection (slope change) points

8
Usage Modeling
Basic geometry data entry
9
Usage Modeling

• Constants
• Wind speed
• Section 16, County listings of wind speeds
  available as drop-down lists
• Ice thickness
• Ice density
• Wind ice reduction factor

10
Usage Modeling
Constants entry sheet
11
Usage Modeling
State and county drop-downs for wind speed
12
Usage Modeling

• Section data
• Length of section
• Number of panels
• Bracing type (X, C or K)
• Existence of girts
• Properties

13
Usage Modeling
Data entry sheet for Section Geometry
14
Usage Modeling
Data entry sheet for Section properties
15
Usage Modeling

• Appurtenances
• Type
• Flat
• Round
• Dish
• Properties
• Width / Diameter
• Height
• Weight

16
Usage Modeling

• Appurtenances (cont)
• Elevation
• Mount
• Number of mounts
• Weight of single mount
• Equivalent projected area of single mount
• Legs (1 or more)

17
Usage Modeling

• Appurtenances (cont)
• Feed line(s)
• Number of feed lines
• Feed line diameter
• Face(s) feed lines are attached to
• Description
• 128 character description/note about appurtenance

18
Usage Modeling

• Guys
• Tower attachment location
• Anchor
• Torque arms

19
Usage Input File

• Job name and description
• Geometry
• Loads
• Code check
• Analysis
• Additional GTSTRUDL commands
• Notes and comments

20
Usage Input File
A GTSTRUDL input file is created upon request
once the model data is entered or read from a
neutral file. This file is used to get analysis
results and code check information from GTSTRUDL
and is not deleted. You can use this file to go
beyond the limits of the Antenna Tower program
and add your own GTSTRUDL commands to do dynamic
analysis, support pad modeling, etc. Note that
you can add these extra commands to the .gta file
(Antenna Tower program neutral file) so they will
be automatically be added to the generated
GTSTRUDL input file the next time you use the
.gta file. You can also add comments that will
be added to the GTSTRUDL input file as NOTES.
21
Usage Input File

• Job name and description
• STRUDL name description
• Geometry
• JOINT COORD, MEM INC, MEM PROP, etc.
• DEFINE GROUP (by types legs, braces, girts and
  by section)

22
Usage Input File

• Loads
• Wind and ice loads are generated on a
  panel-by-panel basis to take advantage of feed
  line termination within a section
• Self weight
• Ice (if specified) applied as joint loads at the
  top of each panel.

23
Usage Input File

• Loads (cont)
• Wind loads are applied as joint loads at the top
  of each panel.
• As many wind directions as are needed created.
• Design loads are created by FORM LOAD to allow
  nonlinear analysis.

24
Usage Input File

• Paramters
• CODE ASD9, maybe TOWER for single angles to do a
  second code check.
• ALSTRINC to account for increased allowable
  stress for towers under 1200.
• KY, KZ, LY, LZ as needed to satisfy Section
  3.1.14 for single angles in compression.

25
Usage Input File

• Parameters (cont)
• Possible new parameter TIA to keep code check
  complete in GTSTRUDL.
• Analysis
• Static for self supporting towers
• Nonlinear for monopoles and guyed towers.

26
Usage Input File

• Additional GTSTRUDL commands
• You can add extra commands to adjust the
  generated input file or add loads that the Tower
  program doesnt support. Once the additional
  commands are created, they can be added to the
  neutral file so they will be automatically
  appended each time an input file is created.

27
Usage Input File

• Notes and comments
• You can also add non-executable information which
  will be added to the input file as NOTES. This
  data could include file names, explanations for
  unusual values such as extra high wind speeds,
  etc.

28
Usage Results

• Base reactions
• Displacement of tower joints
• Twist, sway and displacement of antennas
• Member end forces
• Code check results
• Printed reports

29
Neutral File

• .gta extension
• Text file human readable and editable
• Easy to manage