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Menu: Tubes

menu-tubesThis menu is active only in the state of Analysis. In form finding and patterning, it is not important to know the tubes which make up the structure, since neither the form finding nor the patterning depend on the existing tube.


The menu of Edit tubes displays a window in the form of a table with a series of buttons at the top.
The following data are found in the table:


  • Num
    Tube number (not the number of the bar!)
  • Bar
    Bar number
  • Rig
    If it is a rigid bar, an “X” is placed in the corresponding row of the tube. If it’s a double-jointed tube it is left blank.
  • Code
    It is the code of the tube as defined in the database of the tubes.
  • Axial (t)
    Axial force on the bar in t.
  • Stress (N/mm²)
    Maximum stress on the bar due to tensile, compressive forces taking into account the effects of buckling, deflection by self weight and bending calculation if it is a rigid bar.
  • Ratio
    Value that indicates if the stress exceeds the value of the permissible stress on the tube, taking the safety factor used into account. The permissible maximum value is 1. If this value is exceeded the box appears in red. If the value is close to or equal to zero, then the box is blank. In other cases it is in green.

In this table the only editable thing is column 4 (Code). When you click on any box of this column,  a drop-down menu opens to let us change the type of tube by any other available in the database. Other values are read-only.

Above the table there is a row of buttons:

  • OK
    All the data including all the changes we have made will be saved in the structure and the editing window will be closed.
  • Setup
    This is a drastic operation: removes all tubes of the structure (not the bars!) and re-define. Each tube is searched in the database in an order (*) so that the new selected tube gives a ratio < 1.
    This button is useful when you have made changes in the structure and have been added or removed tubes. It must not be used when we are in a state of analysis in which we have already decided what tube of the database we will use for every tube of the structure, since everything previously selected will probably be modified.
    WARNING: This action cannot be overridden by pressing on the Cancel button. The only way to cancel this action is to leave this window with the Cancel button and run an Undo through the button Desfer.
    (*)NOTA: This rule is very important, because it requires setting up a database with an order of preferences as WinTess3 always starts with the first tube of the database and will be looking for from the following to find the one that serves your needs. If there is a tube of smaller resistance capacity behind another of greater capacity, the first one will never be chosen automatically, although obviously we can choose it manually.
  • Ratio > 1
    This is the most helpful button in the state of analysis, since it modifies only the tubes that are not strong enough. The way of choosing a new tube which can resist is the same as already commented in the previous Setup paragraph. Anyway you should check what changes has done, as sometimes we want two tubes to be equal for cosmetic reasons or for reasons of symmetry in the another load combination or for any other reason, and change the tubes the program suggests with different tubes since it always proposes the minimum requirements that support the current loads.
  • Print
    See the comments made in this manual about tables.
  • Save
    See the comments made in this manual about tables.
  • F=1,50
    With this button, we can modify the safety factor for the tubes. By default the value is 1.65.
    As it’s a steel bar, there are always rules in this regard in any country.
    Therefore the user should modify this value according to the local rules. The modified value is saved by the program in the user preferences file until a new modification.
    To change this value, the program goes to the window of safety factors.
  • Export Excel
    See the comments made in this manual about tables.
  • Cancel
    The editing window for tubes is closed and none of the changes are saved.


This menu is active only in the Analysis state. In form finding or patterning, it is not important to know which tubes form the structure, since neither the form nor the pattern depend on the existing tube.
However, we can open this window in any state if you select a Rigid Bar or a Tube type bar using the right mouse button.


In this screen, we can compare the section and the inertia of a single tube and a lattice (truss) of tubes formed by three or four longitudinal bars which are connected by transverse tubes and, if necessary, by diagonal tubes, as shown on the window given above.

If we have come to this window by selecting the tube type bar or rigid bar, we see:

  • the bar data reflected in the left side of the window
  • the upper button, arrow from left to right, is active (with pink background)
  • the data on the right correspond to a lattice that has a few features equal to or higher than the tube

We can modify the data of the lattice:

  • number of bars
  • lattice diameter
  • diameter and thickness of the longitudinal tubes

We check using the traffic light semaforo if the combination of data is correct. In addition, at the bottom you will find information on the length and type of tube we must use in the transverse structure and diagonal of the lattice. The way to understand these data is given below:

d = 147.9 cm (128.2 cm) ø26.3 mm
147.9 cm = distance between the axes of the longitudinal tubes (in the sense of the transverse or diagonal tube)
128.2 cm = distance between the inner faces of the longitudinal tubes (transversal or diagonal tube length)
ø26.3 mm = diameter and thickness of transverse or diagonal tubes

In the bottom left, we have the following text: “Generally, lattice diagonal elements are only necessary in bars under bending forces“. Obviously it is an informational text that the user must confirm through the analysis of the particular case. In the image above right, we see a typical example of double-jointed mast where we do not see any diagonals.
The help button BotonAyuda leads to the same page of the manual.

If we press the arrow button on the bottom (from right to left), the traffic light indicates if the single-tube (the one on the left) is sufficient to match the lattice which is defined on the right. This can be important if we want to use a fictitious tube (that does not exist in the market) of equivalent to a lattice. For example a tube equivalent to a lattice of 4 longitudinal bars which form a lattice of 1 m in diameter, as shown in the image below.



A Polytube is a set of contiguous rigid bars. This st of bars behaves as a single object. If we modify a bar of the PolyTube, all bars belonging to this PolyTube will be modified as well. This object is very useful to manipulate arches, divided masts and other complex rigid structures.

By activating the menu, window of PolyTubes appears:


In this window we can create, edit or delete PolyTubes.

To do this click the Create button and the left box of the last row is activated. There, we enter the name of the PolyTube we want.

We can edit the name of the PolyTube (box on the left), the bars that form the PolyTube (by directly typing in the center box or by clicking on the bars in the main screen) or the type of tube that form the PolyTube. To change the type of tube, click in the box on the right to open the dropdown list of the tube types.

Clicking on this button displays a message indicating that we must erase its name (the box on the left) to delete a PolyTube.

This button closes the window without saving any of the changes that we have done.

This button closes the window and saves all the changes we have made.
ATTENTION: If we modify bars or types of tube, on having closed the window, these changes will become true in the structure for all those bars that belong to each PolyTube.


All matters relating to the database of the tubes have been discussed in the section Introduction – Tubes of this manual.

Create a new tube

This menu opens the window that allows you to create tubes to add them to the database and can be used later with the program.


  1. We indicate the type of tube in the column on the left that we want to create: circular, square, hollow or solid.
  2. We set the dimensions D, B, t of the tube.
    We will observe how the mechanical values of the pipe appear on the right.
  3. We choose the material: steel, stainless steel, aluminum, wood, concrete, other…
  4. According to the material, choose the type (drop-down on the right)
  5. We note the values generated for the modulus of elasticity, the elastic limit, the density and the code.
    If any of these values is not appropriate we modify.
  6. We point out where we want to keep this tube in the database: at first or at the end.
  7. Finally, we keep the tube in the database. If the tube (code) already exists, an information notice will appear.
    We can manually change the code or modify the tube.