Effect of Shell Spacing on Mechanical Behavior of Multi-Span Soil-Steel Composite Structure

This paper analyses the effect of lateral shells on the central shell at a different spacing in a multi-span soil-steel composite structure subjected to live loads. The displacements and internal forces of the central shell during consecutive truck passages over the structure are investigated by finite element (FE) analysis. The results of a field measurement on the structure located in Niemcza, Poland, are used to calibrate the input parameters. Next, the simulations for different spacing between the shells are investigated. The constitutive model for the backfill soil is elastic-perfectly plastic and linear elastic for the shell and sheet piles. The analysis shows that both vertical and horizontal displacements are significantly increased when the ratio between shell spacing and span length is less than 0.5. Maximum stress is observed when the shells are assumed adjacent to one another, i.e., without spacing. The stress is almost doubled in this position compared to that in the reference case, that is, the single-span structure. The shifting of extreme deflections and stress is observed in the direction of the vehicle movement. Nevertheless, the effect of the lateral shell on the performance of the central shell under moving load is almost negligible at a spacing-to-span ratio of not less than 0.5.