We illustrate the princimple here with boundary conditions, but also materials, eccentricities, … can be changed the same way.

• A model contains three bars with different boundary conditions.
  
  You want all bars to have the N = 100 kN/m boundary condition, without changing the other boundary conditions these bars already have.
• Select all bars and click on .
  The following dialog appears:
  
• Open the padlocks before N. Leave the other padlocks closed .
  Change the transfer of axial forces to 100kN/m.
  
• Hit “OK”.
  You now changed the boundary conditions for the transfer of axial force for all selected bars, whil not changing the boundary conditions for moment or shear.

In particular if your model contains soil layers and /or requires global imperfections and/or requires the calculation of the global buckling factor and/ or requires a modal, seismic or dynamic analysis. And there’s why:

1. Global imperfections

• A Diamonds project contains two columns. Both columns have the same geometry. All loads are the same except for the wind loads:
  
• We run a first order calculation with global imperfections.
  In the results, the bending moment My is not “mirror symmetric”. You expect to see the same absolute value in both columns. But that’s not the case.
  
• Reason: Diamonds applies the global imperfections using equivalent horizontal forces (example here). It will apply those equivalent horizontal forces in different directions. Of those directions, it shows the most severe in the results, not the envelope of all the directions! If two (or more) directions result the same |absolute maximum|, Diamonds shows one of them.In this particular example: if the equivalent horizontal forces are applied in the +X-direction, they will have a favourable effect on the bending moment of the left column and an unfavourable effect on the right column. If the equivalent horizontal forces are applied in the -X-direction, they will have a favourable effect on the bending moment of the right column and an unfavourable effect on the left column.
  The effect of the equivalent horizontal forces in the +X and -X on this structure is the same but the sign is opposite. Since the absolute value is the same, Diamonds only shows the results of one direction: +X in this case.
• Solution: create a separate Diamonds model for each structure.

2. Soil layers

• A Diamonds project contains two plates next to each other.
  Both plates have the same geometry and are supported by the same soil layer profile.
  
• In the deformations, you see that both plates affect each other. This is because of Boussinesq law More info in our webinar about Settlement calculations or in our e-learning course (only available in Dutch).
  
• Solution: place the plates far enough from each other. But what is “far enough”? In one model 50m might be enough, another model might require 100m. And does the model still remain pratical? Because comparing results won’t be so easy.
  For your own convenience, create a separate Diamonds model for each structure.

3. Global buckling factor

• Two frames have the same geometry, but they are loaded differently.
  
• We run a second order calculation.
  The lowest global buckling factor is 2,86. But from the table we cannot deduct to which frame that value applies. Oké, we could look at the first buckling mode and conclude the minimum factor is valid for the frame on the left.
  But what does it say about the global buckling behaviour of the frame on the right? Nothing!  
• Solution: create a separate Diamonds model for each frame.

4. Modal analysis

• A Diamonds project contains two independent beams.
  The right beam is significantly stiffer than the beam on the left.
  
• We run a modal analysis requesting 10 eigenmodes.
  In the results, 9 out of the 10 eigenmodes are found to the beam on the left.
  Only eigenmode 5, is related to the beam on the right.
  
• If these results are later used to describe the dynamic or seismic behaviour of these beams, how can you achieve sufficient accuracy in the right beam with only one eigenmode?
• Solution: asking 20 eigenmodes instead of 10? That’s not really a solution, because it doesn’t guaranteed that the next 10 eigenmodes will be in the beam on the right. Nor does it allow you to check if sufficient effective model mass is reached for each beam.
  The only reliable solution is to create a separate Diamonds model for each structure.

• If the transfer is between two (or more) bar elements, we use the name “hinge” or “joint”.
  Defined in Diamond using the button .
• If the transfer is between two (or more) surface element, we often use the name “hinge line”.
  Defined in Diamond using the button .

However, adding to many hinges will result in an arithmetic mechanism. Thus a structure that will not calculate or result in exaggerated deformations. We list the most common mistakes here together with their correct alternative.

BAD	GOOD	Why?
		A simple support cannot bear moments. By adding an internal hinge, you say that the column cannot transfer bending moment to the support. That’s saying the same thing twice. Remove the internal hinge.
		A built-in support can bear moments. By adding an internal hinge, you say that the column cannot transfer bending moment to the support. That’s saying the opposite thing. Remove the internal hinge and use a simple support.
		A simple support cannot bear moments. A tie rod is a hinged bar by definition (otherwise it cannot function as a tie rod). If you anchor a tie rod to the foundation, without any other bars meeting in that node, you should define the support as built-in. Because the simple support + hinged tie rod, is an arithmetic mechanism.
		N bars meet in a node (N=4 in this example). Neglect the tie rods, because internally in Diamonds, they will automatically be defined as hinged. You want the node to work as hinged (EN: truss, NL: vakwerk),  then you should apply a hinge to 3 bars, not all 4. If you apply a hinge to all 4 bars, you create an arithmetic mechanism. If bars 1 to 3 contain a hinge, the bending moment in bar 4 (which doesn’t contain a hinge) can’t go anywhere because every bar around it is hinged.

• C-Therm S100/S101 FD
• C-Therm S110/S111 FD
• Sherwin William paints: Firetex FC2002, FX2004, FX2007, FX5090, FX6002, FX6010
• Euroquimica paints
• Hempel paints
• Nullifire SC901/902

Other protective materials:

• Fibre-cement silicate boards
• Fibre-silicate boards
• Gypsum boards
• Mineral fibre
• Perlite
• Perlite and cement
• Perlite and gypsum
• Plaster
• Promalan_HT 150
• Rockwool Conflit P756

Note: in case of multiple layers of reinforcement, you enter the mean cover.

[Diamonds]

In Diamonds you define the gross coverage.

• Select the element for which you want to change the cover
• Click on and on the button “Reinforcement”.
  

[ConCrete]

In ConCrete you define the net coverage.  ConCrete will automatically add 10mm to the coverage.

So if you model a beam with a coverage of 35mm in Diamonds, and you want to model the same beam in ConCrete, you should set the coverage to 25mm. Because ConCrete will automatically add 10mm to the coverage.

Method 1

• Go to the geometry configuration.
• Select the relevant point(s) and hit DEL.
  If the line segments left and right of the selected point(s) are co-linear, the point(s) will be deleted.
  If they are not co-linear, the point(s) will remain present. In that case you should try method 2 to remove them.

Method 2

• Go to the geometry configuration.
• Double click the linge segment you want to delete. Pay attention to where you double click: the end point nearest to your double click will stay in place while the other one moves.
• Set the length of the line segments to zero.
  Example: delete point B. Double click the line closer to point A and set the length to zero.