A Step-by-Step Probabilistic Seismic Soil–Structure Interaction Analysis with Ground Motion Incoherency for a Bridge Pier on Bored Pile Foundations

Marius Florin Botiș,Dan Crețu,Dan Mircea Ghiocel,Mircea Conțiu

doi:10.3390/app12041828

Abstract

In current design practice, typical seismic design of bridges tends to use simplified approaches. On the opposite side, the most advanced seismic analyses currently used in practice in all the fields of structural engineering are probably the ones used for the design of nuclear facilities, which include soil–structure interaction and motion incoherency effects. From that category, the most modern methodology is the probabilistic approach, which has been added to the new ASCE 4 standard. This type of state-of-the-art analysis is carried out in ACS SASSI software on a typical concrete bridge structure with deep foundations. A comparison of the results with the deterministic SSI approach and the typical Eurocode design from previous studies is presented at the end. Major differences in behavior are highlighted, which impact the overall safety of the structure.

Highlights

Soil–structure interaction refers to the influence that the ground has on the behavior of a structure placed on it, when subjected to different types of loads
This paper aims to perform a complete probabilistic seismic soil–structure interaction analysis of a highway bridge per ASCE 4-16 [50] recommendations, including motion incoherency effects, with a clear, step-by-step explanation of the probabilistic inputs and outputs
In order to highlight the differences between them, the probabilistic approach model

Summary

Introduction

Soil–structure interaction refers to the influence that the ground has on the behavior of a structure placed on it, when subjected to different types of loads. The SSI effects were usually neglected, and the structure was designed with a fixed (or very stiff) base. This would probably be acceptable for light and small structures on relatively stiff soil, such as houses or retaining walls, where there is no loss of coherency across different points of the foundation and a reduced dynamic amplification. The SSI effects on weaker soil become important with heavier and larger structures, such as nuclear facilities, high-rise buildings and large bridges, where the ground motion incoherency and local variations of the soil profile may influence the behavior of the structure to a large degree [1]

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