Explanation - The alignment offset for the member is large enough to move the alignment wire (insertion line) outside of the section bounding box.

How to resolve -

It would be useful to read the Analysis model features section at this point for you to gain an understanding of how the analysis model is constructed and an appreciation of the alignment wire (insertion line), analysis wire and rigid offsets.

Example - If we hover over the Alignment offset validation warning or an item listed within the branch, a tooltip is displayed “Alignment offset moves the member out of the section bounding box”. This indicates that the alignment wire (insertion line) does not lie within the section perimeter.

We can double click the “Alignment offset” warning or an individual item listed under the branch. If the items exist in the active view they will be highlighted. If they do not exist in the active view then Tekla Structural Designer will automatically switch to the 3D Structure view regime and highlight the item. Alternatively, you can right click and choose Highlight Items from the context menu. The selected item(s) are also displayed in the Properties window for review and editing.

The Alignment section of the Properties window allows you to adjust the location of the physical element with respect to the alignment wire (insertion line).

To resolve the issue, adjust the Alignment section of the Properties window to ensure that the alignment wire (insertion line) sits within the physical cross section.

After making the amendments above. No validation warnings of type Alignment offset are reported.

Explanation - The physical model is split into separate analysis elements where members connect. This message triggers if an analysis element is shorter than the limit set in Home > Model Settings > Validation.

How to resolve -

Alternatively, you could adjust the limit to greater than the length of the analysis element; however, having very small analysis elements can cause ill-conditioning of the matrix during analysis.

Example - In the example below, there is a brace on gridline A, which is intended to connect to the top of the column on gridline A/1. In the Structure scene view it would appear to be connected at the intended point.

If you Validate the model, an error is reported.

Double clicking the validation error will switch the active Scene view to the Solver view and highlight the location of the issue for further investigation.

In the Properties window it reports the length of the analysis element. In this example it is 8mm, which is less than the error limit of 10mm.

To resolve the issue you need to re-position the brace so that it connects to the node at the top of the column.

You could also have adjusted the limit to greater than 8mm, however, having very small analysis elements can cause ill-conditioning of the matrix during analysis.

If you choose to it ignore the warning, to prevent it from being displayed in future right click on it and select Disable this warning from the context menu.

How to resolve - Double click the validation error. This switches the active view to a Structure view and highlights the beam for further investigation.

Review the beam alignment/slab edge and adjust one or other to suit.

If you choose to it ignore the warning, to prevent it from being displayed in future right click on it and select Disable this warning from the context menu.

How to resolve -

If you choose to it ignore the warning, to prevent it from being displayed in future right click on it and select Disable this warning from the context menu.

How to resolve - Double click the validation warning. This will open (or switch to) a Structure 2D view and highlight the construction/grid line(s). Check the construction line or grid line and either modify it or delete it if it is not required.

Explanation -

This warning occurs when more than one diaphragm is identified on the same level and the second smaller diaphragm is greater than 5% of the wind profile width.

How to resolve - Review your wind profile, panel, and diaphragm configuration to ensure the current setup matches your design intent.

Example - To clarify what the message text "More than one diaphragm at a level has at least 5% overlap with the wind profile or panel - decomposition will be applied to these diaphragms" means we will consider a model with both Wind in X and Wind in Y applied.

Wind in X direction

The wind profile width is 4m. Level 1 has two separate diaphragms - one behind the other. The second diaphragm has a width of 100% of the wind profile width. This is greater than 5% and hence the validation warning is provided.

Wind in Y direction

The wind profile width is 24m. Level 1 has two separate diaphragms - side by side. The smaller second diaphragm has a width of 25% of the wind profile width. This is greater than 5% and hence the validation warning is provided.

The method of applying wind load using the simple wind load command to diaphragms is discussed here. It is imperative that you refer to this to understand the limitations of the method when you have disconnected diaphragms.

So, the above explains why you get the warning, what about how to resolve it?

We will look at the two scenarios identified above:

Wind in X = Wind load parallel to disconnected diaphragms

If the second diaphragm is behind the first when resisting simple wind load then the applied loads are shared between both diaphragms. The diaphragm locations are beyond the scope of the intended use of the Simple wind load command and it is recommended that you manually input the loads instead of using the simple wind command.

Note, however, that it is possible to apply manual loads in conjunction with the simple wind load command to obtain your final applied loads. To resolve, you could manually apply panel in-plane point loads to correct the loading. In the screenshot below the incorrectly applied 9kN load to the second diaphragm is applied in the opposite direction to cancel it and is applied to the first diaphragm location to increase the load at this location.

Note also that manually applying loads to modify the simple wind load distribution will not remove the validation warning. This will only disappear if the simple wind load command is not used in this direction and the load applied manually.

Wind in X = Wind load parallel to disconnected diaphragms

If the diaphragms are side by side when resisting simple wind load then you could redefine the simple wind load so that separate simple wind loads are applied to each diaphragm. In this way only one diaphragm acts with the wind profile width. Since a second diaphragm does not exist within each individual wind profile width the warning does not appear.

If you choose to it ignore the warning, to prevent it from being displayed in future right click on it and select Disable this warning from the context menu.

Explanation - A grid line is not quite aligned with the model Building Directions.

By default the Building Directions follow the global X and Y directions, but can be set via the Project Workspace > Structure window by selecting the Structure branch.

The warning will result if a gridline is placed into the model which is less than 0.01 degrees out of alignment with the Building Directions. This is most commonly seen after importing a document exchange format (DXF) file into Tekla Structural Designer in order to establish an architectural grid system. You may think that the imported DXF is a rectilinear system of gridlines, however, due to potentially poor DXF modelling this may not be the case. Tekla Structural Designer checks that any imported gridlines are not less than 0.01 degrees out of alignment within the Building directions. If they are then the Validation warning is reported. You can select individual gridlines and review the properties window to verify the angle.

How to resolve - You may choose to ignore the warning. To resolve, you could either correct the DXF file and import again (if it came from a DXF import), or amend the problem gridline in Tekla Structural Designer by selecting the grid line end node and repositioning to ensure that it is rectilinear (and parallel with the appropriate Building direction).

If you choose to it ignore the warning, to prevent it from being displayed in future right click on it and select Disable this warning from the context menu.

How to resolve - Double click the validation warning. This will open (or switch to) a Structure 3D view and highlight the inclined pile.

Review the support reactions and edit the pile restraint data as required.

If you choose to it ignore the warning, to prevent it from being displayed in future right click on it and select Disable this warning from the context menu.

How to resolve - Double click the validation error. This will open (or switch to) a Structural inclined plane view and highlight the slab and mid-pier wall.

Change the mid-pier wall to be a meshed wall.

Explanation - A member is in a group but no longer meets the group rules.

How to resolve - Double click the warning to locate the members in the active scene view. If the member is not in the active scene view then the Structural 3D view is opened and set active. The selected member properties are also displayed in the Properties window for review and editing. You can determine the Group the member is in via the Properties window.

To resolve the warning, an investigation is not necessary, since the issue is quickly resolved by right clicking the problem item in the Status window and via the context menu choosing the option Regroup Member(s).

When this command is run the item is automatically placed in a valid existing design and detailing groups or new groups are created as necessary.

Rerun the validation to clear the warning.

If you choose to it ignore the warning, to prevent it from being displayed in future right click on it and select Disable this warning from the context menu.

Explanation - Tekla Structural Designer uses the theory of isotropic linear elasticity so the modulus of elasticity, E is related to the shear modulus, G by way of Poisson's ratio, v.

Poisson’s ratio is the ratio of lateral strain to longitudinal strain in a material subjected to loading.

The Poisson's ratio for a wide range of materials fall within a lower limit of -1.0 and an upper limit of +0.5. Since most common materials become thinner in cross section when stretched, the Poisson's ratio is positive and hence in Tekla Structural Designer we only allow values within this positive range [> 0 < 0.5].

You will obtain this error if any element has been assigned a material with a Poisson’s ratio specified outside the range [> 0 < 0.5].

How to resolve - On the Home ribbon click Materials. Then, on the Material page of the Materials dialog locate the problematic material grade and click Edit. Adjust the Poisson's ratio so that it lies within the range [> 0 < 0.5].

Concrete typically has a Poisson’s ratio in the range of 0.1 to 0.2.

Explanation - Two members have a common length along which the centerlines clash.

How to resolve - Either delete one of the members or alter the end node positions of the members to prevent the collision.

Example (beams) - In the screenshot below, the Status window is reporting two members colliding. SB 1/A/1-1/B/1 -1 : SB 1/A/1-1/1/'29 -1

Double clicking this branch highlights both members in the active Scene view.

Double clicking the individual members listed under this branch highlights each in turn. This perhaps provides a little more detail on the issue. One member extends between the columns while the other member only extends for part of the length. Both, however, have a common length such that they share the same physical space. This is impossible to achieve in reality.

In a slightly different example shown in the screenshot below, the Status window is reporting two members colliding. SB 1/A/1-1/B/1 -1 : SB 1/A/1-1/B/1 -1

Note that the references are identical and hence this tells us that both individual members share exactly the same physical space in the model. This is because the reference relates to the intersection of the start and end locations of the member.

To resolve the Member collision validation error you need to select one of the two members and use Delete to remove it from the model. This ensures that only one member occupies the physical 3D space.

Once the member is removed from the model, if you run the Validate command again the issue should not be flagged.

Example (walls) - The Member collision validation error will also occur if any type of beam is placed along the top of and in the plane of any kind of wall. Though this is not prevented during modelling, it is not allowed and will cause the Member collision validation error. This applies to all wall types; bearing, concrete (meshed and mid-pier) and general.

The reason for this is that all wall types already have elements automatically created along their top in the solver model, so adding another member along the top of the wall (either partially or entirely) will cause a collision with these existing elements. For more about the solver models for walls see the following topics:

Meshed walls representation in solver models

Mid-pier walls representation in solver models

Shear only walls representation in solver models

Bearing walls representation in solver models

To resolve this error, the beam along the top of the wall must be removed as this situation of beam lying along the top of a wall - which we believe is uncommon - is beyond the current scope of the program.

If you really must model this kind of geometry, some manual modelling will be required e.g. if the beam is along the top of a bearing wall, a bearing wall cannot be used. You could alternatively retain the beam you wish to lie along the wall top, then manually replicate the bearing wall solver model vertical elements - we would suggest by using regularly spaced columns of a general material with appropriate releases.

How to resolve - Double click the validation warning. This will open (or switch to) a Structure 3D view and highlight the crossing members.

Example - In the screenshot below, the Status window is reporting two members with an intersection issue. SB 1/~15-1/1/'29 : SB 1/A/2-1/B/2

Double clicking this branch highlights both members in the active Scene view.

Double clicking the individual members listed under this branch highlights each in turn. This perhaps provides a little more detail on the issue. Since "members intersect", one member must extend beyond the other and hence they cross each other.

To understand the issue further we need to look at the location where the two members meet.

We can see in the screenshot below (rotated view), that the highlighted member passes through the other. This secondary member should be supported on the primary member. Hence, to resolve the issue, we need to relocate the end of this secondary member so that the end support is at the intersection with the primary member.

Note that the view above displays the physical shape, it may be easier to use Scene Content and turn off Geometry to display only the center wire.

To resolve the Member intersection validation error you need to click on the end node to pick it up and then click on the intersection point with the primary beam.

The example below also moves the adjacent beam to the correct support location.

Once the member is removed from the model, if you run the Validate command again the issue will be resolved and no longer be flagged.

Double click the validation warning. This will open (or switch to) a Structure 3D view and highlight the unsupported member.

If required, add a support to the member and reanalyze.

Alternatively, if you are happy to accept that the member may be unsupported and no longer want to be notified about the issue, right click the validation warning and select Disable this warning from the context menu.

How to resolve - Whilst this is a warning rather than an error it can have design implications and could also cause problems with analysis. We recommend that this error is never ignored and that the engineer review their model to ensure that both the connectivity and design model are as they intend.

In all cases, double click the warning and the problem members will be highlighted in the Structural View.

Tip - use Scene Content > Members. Uncheck “Geometry” so that you can see just the 'wires' of members - this makes it easier to see the member connection - or lack of it. Also zoom into each end of the problem element(s) as shown in the picture below. Then check - are both ends connected as intended?

Example 1 - Members not connected as intended

This can result from errors in modeling and can also occur with models imported via Structural BIM (e.g. from Tekla Structures or Revit) if the analytical wires were not correctly connected in the BIM Application.

After making amendments to the model, undertake a Validate command again to see if the issue is resolved.

Example 2 - Cantilevers not set correctly

Another situation where this Validation Warning may occur is for cantilevering beams that do not have their releases set correctly as cantilever.

This is most common on cantilevering concrete beams but can occur with steel beams also.

Note that if a cantilever beam does not have the releases set as cantilever, but another beam connects to it, this warning will not appear. This is illustrated in the example below using the same layout as above, but with a beam connecting the cantilever ends. The engineer should always review their model for such situations and use the cantilever end setting as appropriate.

This issue can be more problematic for steel structures where beams are commonly not continuous. In this case, not using releases and the cantilever end setting correctly can result in cantilevering beams being pinned to the supporting member producing mechanisms as illustrated below. Setting the cantilever end correctly will both set the appropriate end to 'free' and fix both ends ensuring that the analytical model is stable (providing the rest of the structure is) and that the design is appropriately for a cantilever.

Explanation - A Model coordinates too large validation error occurs if the nearest model node to the 0,0 origin is located greater than a radius of 1 km away.

If you hover over the Model coordinates too large validation error a tooltip is displayed “Model further than 1.0 km from the origin”. Since this is a validation error you are unable to proceed to an analysis or design until it is rectified.

How to resolve: method 1 - To prevent this issue from occurring in the first place, when you run the Structural BIM import command, the Relocate Import Model page indicates the range for imported coordinates. If you amend the Move import model by values such that values are input so that the nearest node is relocated within a radius of 1 km of the origin then the validation error does not appear. In the screenshot below the column intersection point A/1 has been relocated to the origin.

How to resolve: method 2 - If we had not adjusted the Move import model by coordinates during the Structural BIM Import (screenshot below) then it is likely that you have progressed the modelling such that it is too late to start again. The issue can be resolved another way.

To resolve, you can use the Move Model command on the Edit ribbon.

For further details and an explanation of the Reference Point options contained within the Move Model command please refer to this page in the Tekla Structural Designer product guides.

Clicking Move, relocates the model to the specified Target X and Y coordinates. Provided the closest node is located within the 1 km radius of the origin then the issue is removed. The screenshot below shows the Target X and Y set at 707m as an example. (998.84m from origin).

Explanation - This warning indicates that elements have been defined in the model as non-linear i.e. able to withstand either tension or compression only, (which requires non-linear analysis) but a linear analysis has been undertaken. Linear analysis cannot cater for non-linear behavior, and so non-linear elements are automatically adjusted to be linear for linear analysis. It is likely the analysis results would be incorrect for this analysis.

How to resolve (if running the analysis from the Design ribbon) - The Design ribbon > Settings > Analysis page controls the analysis to be performed when you undertake a Design command.

There is a note on this page that advises that should non-linear members/supports exist then a non-linear analysis will be automatically run during the design.

As part of its design routine, Tekla Structural Designer will always run a linear analysis, this is used for a number of operations including the calculation of equivalent horizontal forces / notional loads. Since a linear analysis cannot deal with tension or compression only elements, then the warning is raised - and for this type of analysis the element is set as linear i.e. able to take both compression and tension. The warning is displayed against this analysis type to bring this to your attention. The non-linear elements in the model have however, been identified so a non-linear analysis is ALSO carried out on the model and reported just below the warning. When designing the elements in the model the non-linear results are used. You can therefore ignore the warning in this situation.

How to resolve (if running the analysis from the Analysis ribbon) - If you are only interested in analysis, but not design, the non-linear characteristics will be considered if you run a non-linear analysis from the ribbon.

Running a linear analysis would result in the warning and hence the elements are converted to linear elements and able to take both tension and compression.

If you opted to run Analyze All, this has the same effect as running a Design (Static) command, albeit without running the final phase code checking (design) phase. It follows the Design ribbon > Settings > Analysis page so would run both a linear and non-linear analysis if non-linear elements were encountered.

Explanation - This warning indicates that springs have been defined in the model as non-linear, (which requires non-linear analysis), but a linear analysis has been undertaken. Linear analysis cannot cater for non-linear behavior, and so non-linear springs are automatically adjusted to be linear for linear analysis. It is likely the analysis results would be incorrect for this analysis.

How to resolve -

Explanation - This message is self explanatory. No supports exist in the model (i.e. under columns), and hence the structure is unsupported. Applied loads cannot go to ground and hence the structure is not in equilibrium.

We have seen this appear after a mat foundation has been modeled. In this scenario, the supports that are automatically placed under columns are manually deleted to ensure the columns are supported on the mat foundation (with a specified ground stiffness).

Alternatively, the error may also be triggered if the Engineer unselects Use Ground Bearing Springs in the mat properties. Because the springs are removed, the model is once again unsupported.

The error may then be triggered later in the modelling process if the Engineer decides to delete the mat foundation (as they no longer wish to model it), but forget to reinstate the supports.

How to resolve - To reinstate the supports, use the Model ribbon tab > Support command. Define the degrees of freedom required in the Properties window and then place the supports by either clicking at the base of each column, or by boxing a window in a 2D plan view.

Alternatively, if the error occurred due to Use Ground Bearing Springs being unselected in the mat properties, reselect Use Ground Bearing Springs, then define the spring type and set the spring stiffness accordingly.

How to resolve - Double click the warning, or an individual wall reference listed underneath it to highlight the selected wall(s) with the issue. Alternatively, you can right click and choose Highlight Items from the context menu. If the wall is not visible in the current view then the view will automatically switch to the Structure 3D scene view with the selected wall(s) highlighted.

Review the wall and change it from a mid-pier wall to a meshed wall.

Explanation - If you hover over one of the problem items a tooltip is displayed “No panels have been set as unloaded in this pattern case”.

This means that you have opted to consider pattern loading by checking the option “Patten load” in the Load ribbon > Loadcases dialog but you have not looked at the loaded/unloaded arrangement of slab panels to define the patterns you wish to consider for this load case. All slabs are currently fully loaded so the warning is displayed.

Explanation - A raised support is a support that occurs on a higher (raised) level than the lowest support in the model.

A couple of situations where this warning can arise are listed below:

• Where we have multiple foundation levels in the model.
• Where we are trying to model support from an adjacent building - without physically modelling the adjacent building.

How to resolve - Review the slab opening and the member and adjust as necessary.

Double click the “Raised support provides lateral restraint” warning or an individual support listed under the branch to highlight the supports or support in the model. Alternatively, you can right click and choose "Highlight Items" from the context menu. The supports or supports are highlighted in the active scene view and their properties are displayed in the Properties Window to allow review or editing.

Note. In the screenshot above, the supports cannot be seen clearly due to the member geometry of the beams and columns obscuring the supports. To display the supports we could access Scene Content > Members and ensure that Geometry is unchecked. This ensures that the member wires are displayed and not the physical member.

The question then is… “Are these highlighted supports intended to be modeled at these locations and if so do you want them to provide lateral restraint?”Obviously if they are not intended to be modeled and have been created in the model by mistake then they should be deleted using the Delete command.

The supports located to the right of the model, cover situation 1) where multiple foundation levels exist in the model. The side view below clearly shows the step change in the foundation levels.

The supports to the left of the model on the upper levels, cover situation 2) where supports are provided to model an adjacent building.

Each support has 6 degrees of freedom, translational F_x, F_y and F_z and rotational M_x, M_y and M_z. A typical pinned support is shown below.

You can view the Solver view regime to see the supports and the degrees of freedom.

Each support fixity is color coded. Blue is X, Green is Y and Red is Z. A single arrow denotes translational fixity. A double arrow denotes rotational fixity.

So what support fixity do you require?

The warning “Review supports to ensure that lateral restraint is provided as intended - set as “free” if not” appears if the F_x (blue single arrow) and/or F_y (green single arrow) translational fixity or the rotational M_z (red double arrow) is set to Fixed. This is because the identified supports are constraining the model from moving laterally (horizontally). If you do not want the support to constrain the model horizontally, then set the F_x and/or F_y translational support and/or M_z rotational fixity to Free. For the case of situation 1) multiple foundation levels - providing a translational restraint could introduce a large proppoing force that is not wanted.

Note that the warning will only be removed if F_x and F_y and M_z are set to Free. You may have a situation where you need to provide a lateral support in one direction only. In this situation the warning will still display.

Clearly the engineer is responsible for defining the appropriate support fixity, since all six degrees of freedom need to be considered. The Results view can be used to verify the results following an analysis or design.

Example. Deflection results assuming upper supports are “Fixed”

When all highlighted upper level lateral supports are fixed translationally, the deflection in the direction of the applied wind load is zero and a horizontal support reaction (not shown) exists.

Example. Deflection results assuming upper supports are “Fixed”

When all highlighted upper level lateral supports are set as translationally Free, then deflection in the direction of the applied wind load exists since no resistance to lateral movement is provided by the support.

Explanation - This error occurs when a slab is defined on a sloped plane and the Diaphragm option is set to Rigid.

Rigid diaphragms have infinite in-plane stiffness and zero out of plane stiffness properties and therefore they neither exhibit membrane deformation nor report the associated forces. When a rigid diaphragm is specified, nodal constraints are automatically applied to all nodes within the diaphragm plane and thus they move together as a single unit. Since they do not move relative to one another no axial force can develop within any member within the plane of the diaphragm. In Tekla Structural Designer a rigid diaphragm is only permitted on horizontal levels. They are not permitted on a sloping plane since it will constrain the nodes on all horizontal levels that it interacts with.

If you hover over one of the problem items a tooltip is displayed “A slab is sloping and is set to have a rigid diaphragm. Rigid diaphragms cannot be defined on sloping slabs.”

How to resolve -

Double click the “Rigid diaphragms on sloping slabs” error or an individual item listed under the branch to automatically switch to the Solver view regime and highlight the slabs or slab in the an inclined plane view. Alternatively, you can right click and choose Highlight Items from the context menu.

Now we have identified the slab with the validation error, we can switch back to the Structure view regime and select the slab to display the slab properties in the Properties window.

To resolve the validation error you can either set the Diaphragm option to None or Semi-rigid.

How to resolve - Review the modelling of the core and consider if the model of the structure needs to be changed to ensure rigid section behavior.

If you choose to it ignore the warning, to prevent it from being displayed in future right click on it and select Disable this warning from the context menu.

Explanation - To obtain this validation error you will have created your own user defined section within the Material Section database but incorrectly defined the cross sectional area property and then subsequently used the section in the model. Following an analysis the validation error would be displayed.

If we hover over the Section area is invalid validation error or an item listed within the branch, a tooltip is displayed “A member has an invalid or zero area”.

We can double click the “Section area is invalid” error or an individual item listed under the branch. If the items exist in the active view they will be highlighted. If they do not exist in the active view then Tekla Structural Designer will automatically switch to the 3D Structure view and highlight the item(s). Alternatively, you can right click and choose Highlight Items from the context menu. The selected item(s) are also displayed in the Properties window for review and editing.

You may wish to use Scene Content and turn off items such as Wall and Roof panels to declutter the view.

Whilst you can review and edit some properties within the Properties window it is not possible to Edit the custom material section properties. We can however, clearly see the invalid entry for the cross sectional area.

How to resolve - To rectify the validation error we need to use the Home ribbon > Materials command to be able to Edit the section.

In the Sections dialog, the Edit… button is available, where we can now correct the invalid section property.

Explanation - To obtain this validation error you will have created your own user defined section within the Material Section database but incorrectly defined the major axis moment of inertia property and then subsequently used the section in the model. Following an analysis the validation error would be displayed.

If we hover over the Section major axis moment of inertia is invalid validation error or an item listed within the branch, a tooltip is displayed “A member has an invalid major axis inertia”..

You may wish to use Scene Content and turn off items such as Wall and Roof panels to declutter the view.

How to resolve - To rectify the validation error we need to use the Home ribbon > Materials command to be able to Edit the section.

In the Sections dialog, the Edit… button is available, where we can now correct the invalid section property.

Explanation - To obtain this validation error you will have created your own user defined section within the Material Section database but incorrectly defined the minor axis moment of inertia property and then subsequently used the section in the model. Following an analysis the validation error would be displayed.

If we hover over the Section major axis moment of inertia is invalid validation error or an item listed within the branch, a tooltip is displayed “A member has an invalid minor axis inertia”..

You may wish to use Scene Content and turn off items such as Wall and Roof panels to declutter the view.

How to resolve - To rectify the validation error we need to use the Home ribbon > Materials command to be able to Edit the section.

In the Sections dialog, the Edit… button is available, where we can now correct the invalid section property.

Explanation - To obtain this validation error you will have created your own user defined section within the Material Section database but incorrectly defined the torsional moment of inertia property and then subsequently used the section in the model. Following an analysis the validation error would be displayed.

If we hover over the Section torsional moment of inertia is invalid validation error or an item listed within the branch, a tooltip is displayed “A member has an invalid or zero torsional moment of inertia”.

We can double click the error or an individual item listed under the branch. If the items exist in the active view they will be highlighted. If they do not exist in the active view then Tekla Structural Designer will automatically switch to the 3D Structure view and highlight the item(s). Alternatively, you can right click and choose Highlight Items from the context menu. The selected item(s) are also displayed in the Properties window for review and editing.

You may wish to use Scene Content and turn off items such as Wall and Roof panels to declutter the view.

Whilst you can review and edit some properties within the Properties window it is not possible to Edit the custom material section properties.

How to resolve - To rectify the validation error we need to use the Home ribbon > Materials command to be able to Edit the section.

In the Sections dialog, the Edit… button is available, where we can now correct the invalid section property.

Explanation - Settlement loads are applied to an unfixed direction at a node - this is not permitted.

Before we look at how to resolve this error let us consider a support in more detail.

A support can have 6 degrees of freedom, Translational F_x, F_y, F_z and Rotational M_x, M_y, M_z. Each degree of freedom (DOF) can be either Fixed or Free.

When a degree of freedom is set as Free, it can either be Released or act as a Linear or Non-linear spring.

If you set the support as a spring then you define the Stiffness to be adopted in the analysis.

So, considering translation in the vertical direction (F_z) as an example. If the support is set as:

• Fixed - then the support acts as a knife edge support with no movement in that direction permitted.
• Free / Released - then the support does not act at all in that direction and it acts as though there is no support at all - allowing infinite displacement.
• Free / Spring - the stiffness is the slope of the load / deflection curve. Hence, assuming a specified stiffness (K) and applied force (F) the deflection (x) can be determined from F = K x

The Settlement Load command works differently to a spring support in that you are stipulating the absolute deflection required to occur at the support. For this reason when you assign a Settlement Load to a support the support must be set as Fixed. The support is then adjusted to allow the specified displacement in the analysis model.

If we hover over one of the problem items a tooltip is displayed “Settlement loads are applied in unfixed direction at a node.”

We can double click the “Settlement loads applied in unfixed direction” error or items listed under the branch to highlight the selected items with the issue. Alternatively, you can right click and choose Highlight Items from the context menu. The view will automatically switch to the Structure 3D scene view with the selected items highlighted and its properties displayed in the Properties window.

How to resolve - Review the Settlement load to determine the direction it has been applied and then select the support and ensure the same DOF is set as Fixed.

How to resolve - Double click the validation error. This will open (or switch to) a Structure 3D view and highlight the wall.

Either split the shear only wall panel at the crossing member or delete the crossing members

How to resolve - Double click the validation error. This will open (or switch to) a Structure 3D view and highlight the wall.

Add beams and columns to surround the shear only wall panel or change the shear only wall panel to be a different wall type.

If slab depth overrides have been applied they may need to be removed and separate parent slabs defined instead.

Explanation - Two supports have been defined at a single node.

How to resolve - Delete the duplicate support.

We can double click the “Support collision” error or items listed under the branch to highlight the selected items with the issue. Alternatively, you can right click and choose Highlight Items from the context menu. If the items are not visible in the active scene view then the view will automatically switch to the Structure 3D scene view with the selected items highlighted and their properties displayed in the Properties window ready for review or editing.

If we look at the support references in the Project workspace > Status window we can see that SUP A/1 collides with SUP A/1 - they both have the same reference and hence two supports exist at the same location in the model. This can be confirmed by hovering the mouse over the intersection point and reviewing the Select Entity tooltip. Both support references are shown in the list.

To resolve, select one of the supports, the Properties window will confirm that 1 support item is selected, and then either use the Delete key on the keyboard or the Delete command available via the Quick access toolbar or Edit ribbon to remove it from the model.

You can double click the “Supports exist within area of Mat Foundation” warning or items listed under the branch to highlight the selected items with the warning. Alternatively, you can right click and choose Highlight Items from the context menu. The view will automatically switch to the Structure 3D scene view with the selected items highlighted if they are not available in the currently active scene view.

When columns are defined in the model a support is automatically placed below them if a supporting element is not determined. You control the support degrees of freedom via the Properties window. In the screenshot below a pinned support (default) has been defined.

You may decide at a later stage of the design process to introduce a Mat foundation via the Foundations ribbon.

You can specify Soil Parameters that allow the ground stiffness to be modeled as a series of linear or non-linear springs by defining the Type, Stiffness and Horizontal Support options.

Existing supports within the boundary of the mat foundation are not automatically deleted when a mat foundation is created. For this reason the Validation warning is presented to you.

Your resolution depends upon what you wish to achieve:

• If you intend the column(s) to be supported solely by the mat foundation then you can select the support(s) under the columns and use the Delete key. Alternatively you could use the Delete command on the Quick access toolbar or Edit ribbon tab. Since no mat foundation and column support exist - the validation warning would be removed.
• If you intend the existing support(s) underneath the column to assist the mat foundation then you would keep the support(s). In this situation, the validation warning will still be reported to you.

Example - The implication of modelling localised supports and the mat foundation are best explained by way of a simple example. We will review the analysis results that come about from considering the following support arrangements:

1. local supports only,
2. local supports with a ground bearing mat foundation,
3. just a ground bearing mat foundation,

Local support only

Support reactions (F_z only) for gravity combination.

Local supports with a ground bearing mat foundation. (Note. An area load has been applied to the mat foundation).

Support reactions (F_z only) for gravity combination.

Close up where a localized support exists.

Bearing pressures under the mat foundation. Zero where local support exists.

Ground bearing mat foundation only. (Local supports under columns removed)

Support reactions (F_z only) for gravity combination.

Close up where a localized support has been removed.

Bearing pressures under the mat foundation. The localised support no longer exists resulting in an increase in the bearing pressure where the column is now resisted by the soil interaction under the mat foundation.

Summary

When the local support is retained, the mat bearing pressure will be zero at that point. If the local support is deleted then the intensity of the bearing pressure increases locally. Your construction details will determine which of these is more appropriate e.g is there a separate pad base for the column, is the mat isolated from the pad base or is the column supported directly off the mat?

Explanation - A temperature loading is applied to a rigid diaphragm in the 3D analysis - no effect will be seen in model.

This validation warning occurs when you have applied a temperature load to a slab panel but the slab panel is defined as a diaphragm with the Diaphragm option set to “Rigid”.

If you hover over the Temperature load defined on rigid diaphragm validation warning or an item within the folder branch a tooltip advises “A temperature loading is applied to an area of rigid diaphragm - no effect will be seen in model”.

A rigid diaphragm induces infinite in-plane stiffness, meaning any relative translation of nodes within the panel is prevented. The panel can translate/rotate as a rigid in-plane body.

In this scenario, Tekla Structural Designer does not apply a temperature load to the rigid diaphragm slab, hence no effect will be seen.

It should be noted that this validation warning is about temperature loads applied to slabs. If you were to apply a temperature load to the beams where a rigid diaphragm exists you will see the temperature effect as the strain builds up but elastic extension is prevented.

You can double click the Temperature load defined on rigid diaphragm or individual temperature load to locate it in the active scene view. If the load is not in the active scene view then the Structural 3D view is opened and set active.

How to resolve - Review the application of the temperature load to the diaphragm.

Select the slab panels under the temperature load and change the Diaphragm option to either None (in which case some other form of bracing system may be required) or to Semi-rigid. A semi-rigid diaphragm allows for in-plane stiffness properties to be modeled and hence in-plane deformation effects can occur. Temperature induced forces will then be more realistic - both the semi-rigid diaphragm and beams will experience temperature induced strain. Where full expansion (or contraction for a -ve temperature change) is inhibited - by connection to other members and/or supports - temperature strain induced forces will develop.

After making one of the above changes, revalidate to clear the warning.

Explanation - This warning occurs if a temperature load is applied to a slab and the 2-way slab is not meshed in the 3D analysis. This is because there are no elements modelling the slab behavior. Since there are no elements there will be no effect from the applied temperature load. If the intention is to include the temperature effect of the slab, then its stiffness behavior needs to be included in the model - i.e. it should be meshed.

How to resolve - You can double click the Temperature load defined on non-meshed slab warning or individual temperature load reference to locate it in the active scene view. If the load is not in the active scene view then the Structural 3D view is opened and set active.

You can now select the slab panels under the temperature load and determine the Plane upon which the slab resides.

You can then include the slab in the 3D analysis by switching to the Structure window, highlighting the level the slab exists on and ensuring a check against “Mesh 2-way slabs in the 3D analysis”

After making the above change, the validation warning will no longer be displayed since the slab is now included in the analysis.

How to resolve - Double click the warning to locate the two braces in the active scene view.

Convert the braces that share the node to be a braced pair. To do this, right click on the warning and select Create Brace Pair(s) from the context menu.

Rerun the validation to clear the original warning.

How to resolve - Double click the warning or individual wall panel reference to locate it in a Frame view.

Review the non-rectangular panel and modify to make it rectangular if possible.

If you choose to it ignore the warning, to prevent it from being displayed in future right click on it and select Disable this warning from the context menu.