Dynamic behaviour of long jetty structures under seismic condtions

Jetty structures are relatively long structures. Codes applied to seismic engineering, e.g. eurocode 8, do not make a differentiation to relatively long structures. So, what is the effect of uneven excitation on relatively long structures? Is there an effect at all? Do the structural stresses increase/ decrease? The earthquake load, according to the eurocode 8, is modelled by a modal analysis spectrum. Consequently, this modal response spectrum is applied on a modal analysis. The only information a modal response spectrum contains, is the information about the maximum response of a single degree of freedom model during a design earthquake event. The modal response spectrum does not contain information about the time delay in excitation. Therefore it is not possible to implement the effect of uneven excitation when applying the modal analysis. inc a This research investigates the effect of uneven excitation on a jetty structure by the time history method. A model has been set up according the Euler- Bernoulli beam model. The calculation is done for the Alkion earthquake for variable angles of incidence. For particular angles of incidence does the maximum bending moment peak. The cause of this response amplification is discovered in the transfer functions. Time delay in excitation turns out to be important for the occurring maximum forces/ bending moments. Building codes should contain this information