Effect of shell spacing on mechanical behavior of multi-span soil-steel composite structure

This study analyses the effect of lateral shells on central shell at a different spacing in a multi-span soil-steel composite structure subjected to quasi-static moving loads. The displacements and internal forces of the central shell during consecutive truck passages over the structure are investigated by finite element (FE) analysis. Field measurements from a site in Niemcza, Poland, are used to calibrate input parameters. Next, the simulations for different spacing between the shells are investigated. The backfill soil is modeled as elastic-perfectly plastic, while the shells and sheet piles are linear elastic. The non-linear contact zone between the shell and the soil backfill is assumed to reflect an elastic-plastic constitutive model. The analysis reveals that both vertical and horizontal displacements increase significantly when the ratio of shell spacing to span length is less than 0.5. Maximum stress occurs when the shells are placed adjacent to each other, i.e., without spacing. The stress is almost doubled in this position compared to the reference case—a single-span structure. The shifting of extreme deflections and stress is observed in the direction of truck movement. Nevertheless, the influence of lateral shells on the central shell's performance under moving loads is nearly negligible when the spacing-to-span ratio exceeds 0.5.