Seismic limit states for reinforced concrete bridge pile in sand

Lateral responses of a pile are governed by its mutual interaction with the supporting soil, known as the Pile-Soil Interaction (PSI), which in turn influences its structural limit states. The present study evaluates the seismic limit states for bridge pile in sand, while incorporating the parametric influences of pile and soil assessed through PSI. Such influences have not been dealt with in the past, except for the p (soil-pile reaction) - y (pile deflection) responses (though with only few pile parameters). Pile cross sectional size, grades of concrete and reinforcement, longitudinal and transverse reinforcement ratios, axial load ratio and the sand effective friction angle are observed to affect the PSI and consequently the limit states. Thus, limit states are proposed as parameterised expressions, generated through regression on the limit state data obtained by analysing the damage model (developed herein) for the pile-soil system samples generated over wide ranges of the influential parameters. These expressions, validated through the compliance with the expected trends and a fair agreement with a test result, can be readily used to obtain the expected values of the limit states over a broad range of parametric combinations and without requiring analysis repetition. These, in turn, can contribute to reliable estimation of fragility of a bridge system with the given properties for its pile foundation.

Automated summary

The study evaluates the seismic limit states for bridge piles in sand, considering the parametric influences of pile and soil through PSI. The results show that various parameters affect the lateral response of piles, influencing the expected values of limit states and the fragility of bridge systems.