The New Storstrøm Bridge - Nonlinear Dynamic Ship Impacts

The New Storstrøm Bridge in Denmark is a 3800m long concrete girder bridge with 44 standard spans of mostly 80m and two navigational spans of 160m which are stay cable supported. The foundations are constructed as direct pad foundations, i.e. with the ability of the caissons to slide and rotate on gravel beds. The bridge supports two high-speed railway tracks and two lanes of road traffic. The waters of Storstrømmen are prone to high naval activity and this, in combination with relatively flexible foundations and high dynamic sensitivity of the girder due to train runability requirements, implies that ship impact scenarios are a critical design parameter. In the present paper, nonlinear dynamic ship impacts performed for the detail design are presented. The simulations include nonlinear representation of soil stiffnesses as well as ship indentation properties. Also, nonlinear geometric effects and strongly nonlinear bearing uplift effects are considered. Detailed descriptions of the complex structural response mechanisms occurring during critical ship impacts are provided and the influence of girder/pier tie-down cables on uplift magnitudes are presented.