A new feature is added in for the United States Region (and others that utilize United States design codes and guides) to perform a rigorous analytical Footfall Analysis following the method of the AISC Design Guide 11 (DG11). In general this will be more widely applicable and accurate than the existing simplified floor vibration check. This feature was first introduced in release 2023 Service Pack 2.

For this new method the settings, input parameters and overall workflow are broadly similar to those for the existing SCI P354 and CCIP 016 options. For more in depth details and the general workflow see the Help Topic Footfall assessment handbook and eLearning Course Footfall assessment in Tekla Structural Designer.

With the new AISC DG11 option selected, in the Floor Analysis Model (FAM) view the “Footfall Assessment Results” group of the ribbon is configured specific to the new method, as shown in the picture below.

• Scope - we would note that the guidance in DG11 is generally based on steel buildings with composite or precast floors. However, the Footfall Assessment process in Structural Designer can be performed on models of any material with floors of any construction type. Where the structure is not predominantly a steel building with composite or precast floors, it is the engineer’s responsibility to determine the applicability of DG11, and thus the Footfall Assessment in Structural Designer which follows this, to their structure.

• New Settings - a new set of Footfall Assessment settings “AISC DG11” is added to Global Settings as shown below. These set the initial Footfall Assessment options and parameters for new models. The Analysis Settings, Analysis Model Options and Concrete Modification factors for AISC DG11 are generally the same as those for the existing methods and are not discussed further here.

  Note the “Footfall Checks” section features new settings and options specific to the DG11 method.
  

  Note also the new Analysis Model Options > “Spandrel Beam Properties” setting which is specific to the DG11 method shown below. For more about this setting and how it is applied in the FAM see the new Help topic Footfall analysis basic workflow - AISC DG11.

• Workflow - the workflow for the DG11 option is broadly similar to that for the existing options as detailed in the Footfall Assessment Handbook . Some notable aspects for the new method are as follows:

  • The new “AISC DG11” option can now be selected on the Footfall Analysis Ribbon prior to creating a FAM.
    
  • In the Footfall Analysis > Settings dialog there is now a new set of “AISC DG11” settings which can be selected, reviewed and edited.
    
  • The AISC DG11 and associated settings set can also be set in the Properties window when creating or editing a selected FAM.
    

  • Results - similar to the existing methods, the fundamental process of the DG11 method is the calculation of sinusoidal peak accelerations (at every node of the FAM slab 2D element mesh) resulting from footfall (walking) excitation, by a post-processing of the Modal analysis results for the FAM. For DG11, these are then compared to the design guide specified limiting accelerations (Figure 2-1 of DG11) to determine the Pass/Fail status.

    • Graphical Results - the Pass/Fail status can be graphically displayed in the FAM view in the form of a ‘heat map’ as shown in the picture below. You can also view a heat map of the sinusoidal peak accelerations. The FAM view heading text gives the overall status and the critical node which is identified in the FAM by a graphical arrow. The cursor tooltip for a selected node additionally gives the calculated sinusoidal peak and limiting accelerations which determine the Pass/ Fail status as shown below.
      

    • Tabular Results - although not strictly required as part of the general workflow/ output, to ensure the process is not an entire “black-box” there is comprehensive reporting of intermediate results in the Tabular Results View.

      • You can for example view a table of the Response Parameters giving the key results for each node, as shown below. This and all the other result tables can be exported directly to Excel should you wish, via the Floor Analysis Model Data ribbon “Current View” and “All Modal Results” buttons.
        
      • You can also view a plot of the Frequency Response Function (FRF) results for any specified node as shown in the picture below. This shows the calculated magnitude of response (in terms of a percent of acceleration due to gravity, g) for all frequencies (up to 20 Hz) and identifies the dominant frequencies for both the Resonant (< 9 Hz) and Transient Response (≥ 9 Hz) ranges.
        

  • Reporting - an automatically configured “Footfall Analysis” report chapter includes all the information you are likely to need to output for the Floor Assessment, as illustrated in pictures below; the Footfall Check settings, Pass/ Fail and sinusoidal peak acceleration heatmaps and a table of key result and status at the critical nodes for the enveloped assessment results.