Seismic finite element method simulation of a soil-steel bridge with a gravel-rubber mix

Soil–steel complex bridges have been applied for many years in transport infra-structure. They are widely used in North America, Europe and Australia. The design codes and calculation methods related to soil–steel complex bridges and culverts specify, among others, the requirements for backfill. The typical backfill should be well-granulated sands and well-compacted gravels of harsh, coarse, or round grains. The behaviour of these bridges under static loads is relatively well understood. However, the response of these bridges to dynamic loads, especially seismic loads, is not fully known. Examples from the United States and Australia show that earthquakes damaged such bridges. Therefore, new solutions for the backfill are currently being sought to increase damping properties to minimize dynamic influences. The present study deals with a numerical simulation of a soil-steel complex bridge using a gravel-rubber mixture from end-of-life tire recycling as the backfill. A nonlinear model with El Centro records and the time history method was used. Using the DIANA program, numerical calculations were performed for two cases, i.e., the bridge shell covered with a traditional backfill and the gravel-rubber mix. The bridge has two closed pipe arches in its cross-section. The load-carrying structure was constructed as two shells assembled from corrugated steel plate sheets (depth = 0.05 m, pitch = 0.15 m, plate thickness = 0.003 m, shell span = 4.40 m, shell height = 2.80 m). The results suggest that the gravel-rubber mix can be used in soil-steel complex bridges as an alternative to traditional backfill. This results in better absorption of the seismic energy by the gravel-rubber mix than the conventional granular backfill. An indirect effect is the use of tire recycling, which is part of the sustainable development of the construction industry.