top of page

GSA Analysis


Footfall analysis





Footfall response is of interest to clients concerned about vibration in their structures, whether they are laboratories, bridges, hospitals, airports, offices or retail buildings. Sensitivity to vibration is becoming increasingly significant as advances in structural design result in lighter structures; the lighter the structure the more sensitive it is to induced vibration.


What is the solution?


In the past it has proved difficult to calculate footfall response on irregular floor or staircase structures; that is until now. GSA Building and GSA Bridge analyse the footfall response of structures to the Arup method (as adopted by the Concrete Centre CCIP-016), the Steel Construction Institute P354, and AISC SDGS11. Not only that, but because they can predict absolute vibration levels at all locations on a floor, they enable the engineer to advise on the positioning of sensitive equipment and services or to improve problem areas in a cost-effective way.


GSA Footfall analysis is the best way to predict the footfall response of any structure (see our footfall whitepaper for a more in-depth look) and is included in GSA Buildingand GSA Bridge.


Product benefits


  • GSA is the only program available that allows you to analyse any structure for footfall analysis, whether an irregular floor, a bridge or a staircase, whether concrete, steel, or composite.

  • Quick and accurate predictions of resonant and transient response to footfall vibrations, including response factors, peak accelerations, and peak, RMS and RMQ velocities.

  • Define areas of interest on a floor; e.g. the effect of running down a corridor next to an operating theatre




Modal analysis


  • Choice of vibration analysis: Modal, Modal P-delta, Ritz, Ritz P-delta

  • Chose number of vibration modes and start mode

  • Include additional horizontal or vertical restraints

  • Specify mass or derive mass from loads and self weight

  • Include stiffening effects of loads


Footfall analysis


  • Quick or full excitation methods

  • Check full model or specified areas

  • Damping by user input values, modal damping or table

  • Vary number of footfalls for resonant response

  • Vary weight of walker

  • Choice of excitation force methods: Arup / Concrete Centre or Steel Construction Institute for floors or stairs

  • Adjust minimum and maximum walking frequencies

  • Detailed chart views of results


Footfall weighting curves


  • BS 6841:1987

  • BS 6472-1: 2008

  • User defined

Footfall analysis methods


  • Arup / Concrete centre method - Concrete Centre CCIP-016

  • Steel Construction Institute - P354

  • American Institute of Steel Construction – Steel Design Guide 11

  • Staircase method - CCIP-016 & SCI P354




  • Resonant analysis

Maximum resonant response factor

Peak acceleration

Resonant critical nodes

Resonant critical frequency

  • Transient analysis

Maximum transient response factor

Peak velocity

RMS velocity

RMQ velocity

Transient critical node

Transient critical frequency

  • Overall Maximum and minimum response factors


Chart views


  • Resonant analysis

Response factor v walking speed

Acceleration v harmonic forcing frequency (including criteria of response factor: R, BBN or ASHRAE)

Dynamic load factor v forcing frequency

Participation factor v modes

  • Transient analysis

Velocity response v walking frequency (including criteria of response factor: R, BBN or ASHRAE)

Velocity v time

Participation factor v modes

bottom of page