Download and open the tutorial model

Download the tutorial model zip file Footfall - EC UK CCIP-016.zip from here.
Extract the following tutorial model from the zip:
- Footfall - EC UK CCIP-016.tsmd
Open the model in Tekla Structural Designer.

Open a footfall analysis view

Open a Structure 3D Scene view.
In the Status bar at the bottom of the main window, click the Footfall Analysis View regime button.

The Footfall Analysis ribbon becomes available, and the active view switches to a Footfall analysis view.

Tip:
In any view you can simply right-click a slab item and select Create Floor Analysis Model from the context menu in order to begin creating a new FAM. It is not essential for you to switch to the Footfall Analysis View regime first.

Confirm the floor analysis model settings

On the Footfall Analysis ribbon, select Settings

The available settings sets for each design guide are displayed.
In the left hand pane, select CCIP 016 > CCIP 016 settings > Analysis Settings
It is anticipated that most users will not need to adjust the default analysis settings which are as shown above.
In the left hand pane, select CCIP 016 > CCIP 016 settings > Analysis Model Options

These options allow you to configure the FAM to your requirements.
In the left hand pane, select CCIP 016 > CCIP 016 settings > Concrete Modification Factors

Note that by accepting the defaults shown above the static concrete modulus of elasticity will be factored by 1.1 to account for the greater stiffness under dynamic loading.

For more information on the different settings, options and factors, see: Footfall assessment settings
In the left hand pane, select Settings Sets Management

Although It is anticipated that the previously displayed settings will be appropriate in most cases, you can add further sets to investigate different configurations if you require. This would be achieved after selecting the CCIP 016 design guide using the Add or Copy buttons shown below.
We don't need to add a further set so click OK to exit.

Create a floor analysis model

On the Footfall Analysis ribbon, in the Design Guide list, ensure CCIP-016 is selected.
On the Footfall Analysis ribbon, select New
Select the slab item shown below.

A new Floor Analysis Model (FAM) view opens in Edit mode and the Floor Analysis Model (FAM) properties are displayed in the Properties window.

When in Edit mode, editing commands are available at the top of the Properties window.

Additional slab items (and attached members) could be added either by clicking slab items individually, or by box selecting. Note that the Selection Mode in the Properties window, which defaults to ‘Add or Remove’ can also be set to ‘Add Only’ or ‘Remove Only’ to assist this process.

For this example no more slab items are required.

Add and edit facade restraints

Facade restraints can be used to vertically restrain specific slab edges.

Select Generate Facade Restraint in the Properties window

Facade restraints are added around the entire perimeter of the selected slabs.

Restraints can also be added or removed from individual slab edges. We will now remove one of the restraints applied above.
In the Properties window, change the Entity type to 'Facade Restraint'.
Set the Selection Mode to 'Remove Only'.
Click on the right hand slab edge at the position shown.

The FAM should now look as follows:
The FAM model is now complete, so press ESC to exit Edit mode.

Confirm the design guide, settings and meshing

Review the following properties located at the top of the Properties window.

Ensure the Design Guide 'CCIP 016' is selected.
Ensure the Settings set 'CCIP 016 settings' is selected.
In a real model you could have created multiple FAM Settings sets, in which case you could then choose which set to apply.
Review the meshing properties.
The mesh defaults are reasonable and will be left unchanged.

Create a footfall mass combination

On the Footfall Analysis ribbon, select Footfall Mass Combinations.

Any existing combinations for static design will be listed in this dialog followed by a Footfall Mass combination which is selected as shown above. Two loadcases have automatically been included in this combination.

At this point you complete the Footfall Mass combination by making appropriate selections from the list of available loadcases.
Include the Dead and the Services loadcases.

In real models engineering judgment will be required as the list of available loadcases can potentially be very long.
Set the Services loadcase factor to 0.500.
Click the Applied mass tab in the dialog.

No changes are required here, but note that for Footfall mass combinations, the applied mass defaults to being applied in the Z direction only.
Click OK to save the footfall mass combination.

Analyse the model and view the results

On the Footfall Analysis ribbon, there are two analysis choices:

Analyse Current - this runs a first-order modal analysis of the currently selected FAM for all active footfall mass combinations.
Analyse All - this runs a first-order modal analysis of all FAMs for all active footfall mass combinations.

As only one FAM has been created at this stage, it doesn’t actually matter which of the above two options is selected.

Click Analyse Current

Note:

The FE results you see may vary slightly depending on your installed service pack and may not exactly match the documentation.

View the mode shapes

To view mode shapes graphically for the footfall mass combination:

Select the Footfall Mass combination in the Loading list.
On the Footfall Analysis ribbon, select Mode Shape View.
Select the next mode from the Mode list.
To adjust the amplitude of the mode shape, drag the Deflections slider in the ribbon as required.
To animate the mode shape, right-click in the view, and select Animate from the context menu.
To end the animation, close the Animation dialog.

Configure the footfall checks

Default CCIP-016 footfall check parameters for all models (predefined on the Footfall Assessment > CCIP-016 > Footfall Checks page in global settings) are automatically copied into the Footfall Checks section of the Properties window for each FAM that is created.

The copied values can then be adjusted as required to suit the individual FAM.

For a detailed explanation of the above parameters, refer to CCIP-016: A Design Guide for Footfall Induced Vibration of Structures. (Ref. 3)

In this example we shall initially accept all the defaults. Note that the default Target response factor is 4.0 so any nodes in the FAM with a greater response will be deemed to have failed.

If you were to change any of the above values, the Footfall Assessment results would update automatically - there is no need to re-perform the analysis.

View the footfall check results

Overall status

The overall status is displayed in the top left corner of the FAM view.

Note that the status takes into account any Mass Combination or Response Type filters applied in the Overall Status & Envelopes section of the Properties window.

By default, all active footfall combinations are considered, and all (i.e. both resonant and transient) responses are considered.

As the overall status is 'Fail', this indicates that the target response factor has been exceeded for the resonant or the transient response at one or more pacing frequency.

View resonant and transient response factors at specific pacing frequencies

On the Footfall Analysis ribbon:
1. Select Response Factor, Rf
2. Ensure the response type is set to Resonant
3. Ensure Envelope is unselected
In the above view, the text below the overall status confirms the current response type and pacing frequency selected in the ribbon. The critical node number for this selection is also shown along with its response factor.

An arrow indicates the location of the critical node.

Initially the response is displayed for the lowest pacing frequency.

Because a range of pacing frequencies has been requested, the list in the ribbon can be used to move between them.
Zoom in to the critical node, then hover the cursor over the node to display the tooltip.

The tooltip shows that the resonant response factor at this node for the selected pacing frequency. As this is less than the target response the ‘Current Selection Status’ is Pass.

Note: Node numbers are regenerated when a solver model is remeshed, so it is ok if the critical node's number that you see is not the same as the node number shown above.
To examine the transient response for the selected pacing frequency, select Transient on the ribbon.
Hover the cursor over the critical node to display the tooltip.

The resonant response factor for the selected pacing frequency is less than the target response, so once again the ‘Current Selection Status’ is Pass.

View response factor envelope

Note that envelopes take into account any Mass Combination or Response Type filters applied in the Overall Status & Envelopes section of the Properties window.

So by accepting the default filters as shown above, the response factor envelope allows us to locate the most critical response factor of either type (resonant or transient), for all pacing frequencies and all mass combinations (if more than one has been defined).

Select Envelope on the ribbon.

The above envelope reveals that the resonant response is critical at a pacing frequency of 2.16Hz with a response factor of 4.8.

View Pass/Fail Status

To gain a better understanding of how wide an area is failing, the Pass/Fail status can be examined for the enveloped results.

On the ribbon:

Ensure Envelope is still selected.
Select Pass/Fail Status

Nodes that exceed the Target response factor at any pacing frequency are shown as failed.

View acceptable hotspots

Acceptable hotspots can be used to investigate areas that fall between a general limit and the Target response factor.

In the Properties window:

Select Acceptable hotspots.
Leave the General limit as 2.0

Regions with Rf values between the General limit and the Target response factor are shown with a warning status.

Perform a VDV assessment

If the response factor fails you may be able to make a variable dose value (VDV) assessment instead. VDVs are always calculated, but by default they are not considered when determining the overall status.

For ease of use the VDV calculation procedure is ‘inverted’ so that the number of events (per period) equates to the number of times the walking path would need to be executed in order to generate an adverse response.

Is a VDV assessment applicable for this example?

It is important to note that when working to CCIP-016 a VDV assessment is only allowed for the resonant response - it cannot be used to assess the transient response. So before proceeding, it makes sense to determine the overall status for the individual response types.

This can be done as follows:

In the Properties window, under the Overall Status & Envelopes heading, change the Response Type to 'Resonant'
Review the overall status.
The overall status should still be failing.
In the Properties window, under the Overall Status & Envelopes heading, change the Response Type to 'Transient'
Review the overall status.
The overall status should be passing.

Therefore in this example a VDV assessment is applicable as it could potentially improve the resonant response status. It won't affect the transient response status, but as this is passing already, that is not going to be a problem.

View the number of events at each node

We want to display the number of events for the 'Resonant' response type enveloped for all pacing frequencies.

This is achieved as follows:

In the Properties window, under the Overall Status & Envelopes heading, change the Response Type to 'All'
On the Footfall Analysis ribbon:
1. Ensure Envelope is unselected.
2. If the response type is set to 'Transient' change it to 'Resonant'
On the ribbon, select No. of Events (per period).

The number of events at each node is displayed on a logarithmic scale.
Select Envelope on the ribbon.
The enveloped number of events will now be displayed for all pacing frequencies and all footfall mass combinations, (only one mass combination has been defined in this example).

In the above display it can be seen that the critical number of events is 228. The arrow identifies the critical node where this occurs.

Activate the VDV assessment

For the purpose of the example we will assume the client has specified the target number of events as 200.

To perform a VDV assessment on this basis:

In the Properties window, select Consider VDV for Pass/Fail.
Set the Target number of events in a period as 200.

With the above settings, because the critical number of events is higher than the target, an overall pass status is achieved.

Output the calculations

To create a footfall analysis report:

On the ribbon, go to the Report tab.
Click Model Report.
In the Report Contents dialog, click Add and then under Active Style, enter a Name for the report
In the list of chapters and options, select Footfall Analysis and drag it across to the Report Structure area.
Click OK
On the ribbon, in the list on the left side, select the report name you just created.
Click Show Report.

Additional display and review options

Several tabular data views are available, each of which can be exported to Excel.

To display the Floor Analysis Model Data ribbon from where the tabular data views can be accessed:

Make the Floor Analysis Model (FAM) view active once more.
On the Footfall Analysis ribbon, select Tabular Results

The Floor Analysis Model Data ribbon is displayed and an FAM tabular data view opens.

Modal Frequencies

To view modal frequencies, on the Floor Analysis Model Data select Modal Frequencies

This table lists the period, frequency, mass participation, and modal mass for each mode.

Mode Shape by Node

To view mode shapes by node:

On the Floor Analysis Model Data ribbon, select Mode Shape by Node
Select the required Mode from the list.

The mode shapes are listed for the selected mode.

Response Parameters

To view response parameters:

On the Floor Analysis Model Data ribbon, select Response Parameters
Select the Resonant or Transient response type
Select the Pacing Frequency from the list
In the Properties window, ensure the Footfall Checks parameters are specified as required.

Note in particular:

If Consider VDV for Pass/Fail is unchecked in the Properties window, the response factor is compared to the target response factor to determine the status.
If Consider VDV for Pass/Fail is checked and the response type is Resonant, the number of events are compared to the target number of events to determine the status.
If Consider VDV for Pass/Fail is checked and the response type is Transient, the transient response factor is compared to the target response factor to determine the status.

Accelerations and Velocities

To view accelerations:

On the Floor Analysis Model Data ribbon, select Accelerations
Select the Resonant response type
Select the required Mode from the list
Select the required Pacing Frequency from the list
Select the required Harmonic from the list
Select the required Node from the list

To view velocities:

Select Accelerations
Select the Transient response type
Select the required Mode from the list
Select the required Pacing Frequency from the list
Select the required Node from the list

Base Data

To view Resonant base data:

On the Floor Analysis Model Data ribbon, select Base Data
Select the Resonant response type
Select the required Mode from the list
Select the required Harmonic from the list
Select the required Pacing Frequency from the list

To view Transient base data:

Select Base Data
Select the Transient response type
Select the required Mode from the list
Select the required Pacing Frequency from the list
Select the required Node from the list

SRSS Acceleration and SRSS Velocity

To graphically display SRSS Accelerations, return to the Floor Analysis Model (FAM) view and:

On the Footfall Analysis ribbon, unselect Envelope (if selected)
Select Resonant
Select SRSS Acceleration
The resonant acceleration is shown and the critical node identified for the Footfall Mass combination selected in the Loading list.
To consider all pacing frequencies and mass combinations (if more than one is defined), select Envelope

To graphically display SRSS Velocities:

On the Footfall Analysis ribbon, unselect Envelope (if selected)
Select Transient
Select SRSS Velocity
The velocities are shown and the critical node identified for the Footfall Mass combination selected in the Loading list.
To consider all pacing frequencies and mass combinations (if more than one is defined), select Envelope

FAM solver model

After the analysis has been performed, if you require you can examine the solver model used for the Footfall Analysis model as follows:

Ensure that the required Floor Analysis Model (FAM) view is active.
To change the view type of the FAM view, do one of the following:
- Right-click the FAM view tab and in the context menu, select Solver view
- Or, in the Status bar at the bottom of the window, click Solver View.
The FAM view changes to an FAM solver view.
Right-click anywhere in the solver view.
In the context menu, select Solver models.
In the submenu, select Solver Model used for Footfall Analysis.
Tekla Structural Designer opens the selected solver model. You can then select individual elements in the solver model to display their section and material properties in the Properties window.

Create additional floor analysis models, edit or delete models

When the Structure 3D view is active and set to the Footfall Analysis View regime it will display all the floor analysis models that have been created so far.

You can continue to define as many FAM’s as you wish in a similar manner, on the same or other levels. Slab items can be in more than one FAM. For example you might create a single FAM for a very large floor area which will expose areas of interest which might then be investigated with other more localized FAMs.

The following options are available:

Click on an existing model in order to edit it in a FAM view.
Select New in the ribbon to start a new model
Select Delete in the ribbon, then click on an existing model in order to delete it.

Footfall analysis basic workflow - CCIP 016