Bridges are assets that are subject to not only varying loads on a daily basis but are also highly susceptible to seismic loading in the event of an earthquake. Additionally, bridges tend to be post-disaster structures and need to be operational at all times.

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Since many bridges in North America were constructed prior to modern seismic codes and need to be assessed in order to determine their compliance and, if needed, be retrofitted to conform to codes. In order to assess a bridge, the bridge needs to be modelled to varying degrees. Once modelled, the model can be analyzed to extract the critical structural characteristics. ​The principal objective of modelling and analysis tools is the quantification of the seismic response of bridges in terms of structural displacements and member forces and deformation. (Ref. Priestly, M.N., Seible, F. and Calvi, G.M., 1996. Seismic design and retrofit of bridges. John Wiley and Sons)