Incorporating cyclic degradation into pile design for the Gull Wing Bridge, Lowestoft-PPT Presentation

PPT Presentation

Pdf Summary

The Gull Wing Bridge in Lowestoft was designed between 2018 and 2020, with construction completed in 2024. Its pile design considered how repeated loading can reduce pile resistance over time.<br /><br />Cyclic pile behaviour depends on the range and amplitude of loading. Under some conditions, repeated cycles can cause progressive failure, so designs must remain within a cyclic limit state (CLS), as well as satisfy conventional ultimate limit state requirements.<br /><br />The presentation describes a simplified calculation method for incorporating cyclic degradation into pile design. For a defined pile length, designers identify the maximum, minimum, cyclic and mean loads, then calculate the ultimate shaft and base resistances. They compare the cyclic and mean loads with the ultimate shaft resistance and plot the resulting ratios on a stability diagram. The diagram is used to assess cyclic stability and derive a cyclic reduction factor, which reduces the static ultimate shaft resistance to account for cyclic effects.<br /><br />Static design partial factors are then applied to shaft and base resistance. The design also checks shaft-only CLS utilisation, using a resistance factor of 1.2.<br /><br />The method provides a structured way to account for cyclic loading alongside standard pile-design checks. The supplied material refers to the Gull Wing Bridge design outcome but does not provide its specific numerical results.

Keywords

Gull Wing Bridge

Lowestoft

pile design

cyclic loading

cyclic pile behaviour

cyclic limit state

ultimate limit state

shaft resistance

base resistance

cyclic reduction factor