Objective To reduce tram construction disturbance on existing road traffic and to shorten construction periods, some regions have begun to adopt prefabricated pile-slab subgrade structures. However, current research on such structures remains limited, and the dynamics characteristics of piles, slabs, and key connection nodes of the prefabricated pile-slab structures have not yet been clarified. Therefore, it is necessary to analyze the dynamics characteristics of the load-bearing slabs and piles in both tram cast-in-place and prefabricated pile-slab structures.

Method Using Jiaxing Tram (phase I) project as the research background, multiple sensors are installed on-site to obtain data on subgrade soil pressure beneath slabs and soil stratification settlement for both cast-in-place and prefabricated pile-slab structures. Finite element numerical models of the above two subgrade types are established to investigate and clarify the dynamics characteristics of their load-bearing slabs, piles, and connection nodes under tram dynamic loading.

Result & Conclusion  Compared with the cast-in-place pile-slab structure, the prefabricated pile-slab subgrade exhibits larger values in certain dynamics response parameters of its load-bearing slabs, piles, and connection nodes. Regarding the dynamics characteristics of the load-bearing slabs, the peak vibration acceleration at the mid-span section of both structural types is greater than that at the pile-top section, while the peak tensile and compressive stresses at the mid-span section differ significantly. In terms of pile dynamics characteristics, the peak acceleration of piles in both structural types decrease with the increasing depth. As for the connection node dynamics characteristics, the stresses experienced by the bolts connecting the load-bearing slabs and piles in the prefabricated pile-slab subgrade corresponds to the tramway load and exhibits periodic variation.