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The use of nonlinear, large-deformation, dynamic finite element analysis (FEA) has become a cornerstone in crash test simulations, playing a pivotal role in evaluating the safety performance of critical civil infrastructures, including soil-embedded vehicle barrier systems. This review paper offers a detailed examination of numerical modeling methodologies employed for simulating dynamic soil–structure interactions in crash test simulations, with a particular focus on dynamic impact pile–soil interaction. This interaction is a critical determinant in assessing the effectiveness of soil-embedded barrier systems during vehicular impacts. Our extensive review methodically categorizes and critically evaluates four prevalent modeling methodologies: the lumped parameter method, the subgrade reaction method, the modified subgrade reaction approach, and the direct or mesh-based continuum method. We explore each methodology's underlying philosophy, strengths, and shortcomings in accurately simulating the dynamic interaction between soil and piles under impact loading. This technical review aims to provide a thorough understanding of the critical and distinctive aspects of modeling soil's dynamic responses under impact loading conditions. Moreover, this paper is envisioned to serve as a foundational reference for future research endeavors, steering the advancement of innovative simulation techniques for tackling the dynamic impact soil–structure interaction problem. [ABSTRACT FROM AUTHOR]

Understanding the dynamic interaction between piles and the surrounding soil under vehicular impacts is essential for effectively designing and optimizing soil-embedded vehicle barrier systems. The complex behavior of pile–soil systems under impact loading, attributed to the soil's nonlinear behavior and large deformation experienced by both components, presents significant simulation challenges. Popular computation techniques, such as the updated Lagrangian finite element method (UL-FEM), encounter difficulties in scenarios marked by large soil deformation, e.g., impacts involving rigid piles. While mesh-free particle and discrete element methods offer another option, their computational demands for field-scale pile–soil impact simulations are considerable. We introduce the erosion method to bridge this gap by integrating UL-FEM with an erosion algorithm for simulating large soil deformations during vehicular impacts. Validation against established physical impact tests confirmed the method's effectiveness for flexible and rigid pile failure mechanisms. Additionally, this method was used to examine the effects of soil mesh density, soil domain sizes, and boundary conditions on the dynamic impact response of pile–soil systems. Our findings provide guidelines for optimal soil domain size, mesh density, and boundary conditions. This investigation sets the stage for improved, computationally efficient techniques for the pile–soil impact problem, leading to better pile designs for vehicular impacts. [ABSTRACT FROM AUTHOR]

This study investigated the multi-hazard resistance of highway bridge piers retrofitted with carbon-fiber-reinforced polymer (CFRP) and polyurea coating against the combined collision–blast loads and evaluated their effectiveness. Detailed finite element models of CFRP- and polyurea-retrofitted dual-column piers that considered the blast-wave–structure interactions and the soil pile dynamics were developed using LS-DYNA to simulate the combined effects of a medium-size truck collision and close-in blast. Numerical simulations were conducted to examine the dynamic response of bare and retrofitted piers under different levels of demands. The numerical results indicated that using CFRP wrapping or polyurea coating effectively mitigated the combined collision and blast effects and increased the pier's resistance. Parametric studies were performed to identify an in situ retrofit scheme to control the parameters and determine the optimal schemes for the dual-column piers. For the parameters that were studied, the results showed that retrofitting at half the height of both columns at the base was identified as an optimal scheme to improve the multi-hazard resistance of the bridge pier. [ABSTRACT FROM AUTHOR]

Highway bridge piers could be underdesigned for a multihazardous condition involving vehicle collision and air blast based on the current design code. The piers are often positioned in such a fashion that it is neither possible nor economically feasible to place protective devices around them. This paper numerically investigated two potential strengthening techniques, the placement of a fiber-reinforced polymer (FRP) wrap and polyurea coating onto the column surface, to improve column resistance against the extreme demands from combined collision and blast loads. Finite-element models of isolated reinforced concrete (RC) columns with an FRP wrap and polyurea coating were developed using a commercial software, LS-DYNA. The modeling techniques were validated separately against impact and blast experimental results. Collisions were supplied from a medium-size F800 single-unit truck at various velocities, and air blasts of varying magnitude were represented using the arbitrary Lagrangian–Eulerian approach. Bare and strengthened column response to various collision and blast demands was compared to assess the effectiveness of strengthening. The results indicated that using the FRP wrap and polyurea coating on columns could effectively mitigate the effects of combined vehicle collision and air blast. The effectiveness of each scheme differed as a function of geometric and material properties and column demands. Parametric studies were then conducted to evaluate the influences of various design parameters on column performance and identify optimal strengthening schemes. [ABSTRACT FROM AUTHOR]

The extreme multihazardous event involving a truck collision and an air blast is a low-probability, high-consequence event for bridge piers. This study aimed to numerically investigate the performance and failure modes of multicolumn piers under a medium-sized truck collision combined with an air blast. Full-scale, finite-element models of multicolumn piers with three configurations were developed using LS-DYNA software with a soil domain restraining the foundations. The accuracy of modeling approaches was verified by comparing tested and simulated results. The collisions were simulated using a single-unit truck (SUT) at velocities ranging from 65 km/h to 120 km/h and combined with air blasts at different scaled distances. Analyses were completed to examine damage propagation and dynamic response during the extreme multihazards. The results showed that after the SUT collision compromised pier capacity, further deterioration occurred from the subsequent air blast, resulting in severe damage and even failure of the pier. In addition, parametric studies were conducted to assess the effects of several load and design parameters on pier performance and identify the controlling parameters. Representative failure modes of multicolumn piers under truck collisions combined with air blasts were assessed. The findings from this study provided a comprehensive understanding of multicolumn pier response to the extreme multihazards and developed recommendations for the practical design and analysis of the multicolumn pier. [ABSTRACT FROM AUTHOR]

Distributed temperature sensing (DTS)-based fiber optic sensors are widely used for monitoring spatially continuous temperature distribution in structures. In this research, hydro-thermal (H-T) coupled analysis is used to monitor seepage conditions in an embankment dam. Variably saturated two-dimensional heat transport (VS2DHI), a computer code developed by the U.S. Geological Survey, was used for this coupled analysis. From the coupled analysis, the temperature profile for a dam with an artificially generated crack clearly showed the location of the crack. In addition, it turned out that the temperature change in the dam took much longer than the seepage time due to the additional time required for heat transfer. The study shows that temperature variation in the dam is comparable to the seepage condition with time delay for heat transfer. This study also shows the possibility that temperature data may serve as a tool to diagnose prior seepage conditions and past incidents of a dam. [ABSTRACT FROM AUTHOR]

The dynamic pile-soil interaction is one of the most important and challenging problem in geomechanics, especially when geometrical, material-related, and dynamic contact-related nonlinearities exist. Geometrical nonlinearity is a fundamental obstacle to the popular Lagrangian finite element methods (FEM) that have been utilized in other areas of geomechanics research. This paper introduces a Multi-Material Arbitrary Lagrangian-Eulerian (MM-ALE) model for predicting the pile-soil interaction and forces during lateral dynamic impact events. The study used the MM-ALE method in conjunction with an elasto-viscoplastic soil material model that included strain softening and an elasto-plastic steel material model that incorporated strain rate effects to examine pile response during lateral vehicle impacts. The model was validated using large-scale, dynamic impact test data for piles embedded in soil, thus confirming its capability to simulate the complex dynamic impact pile-soil interaction. The effects of impact velocity, embedment depth, and soil strength on impact forces, energy dissipation, and impulse response of a pile-soil system were subsequently investigated. It was determined that average impact force, F avg , and impact velocity, are proportional to one another as F a v g ∝ v 2 regardless of pile embedment depth. This relationship provides evidence for the existence of inertial or hydrodynamic drag forces in the pile-soil system during lateral impacts similar to a solid object passing through a fluid. • Novel computational modeling scheme for predicting impact dynamics of pile-soil systems at large deformations. • Validation of proposed model against a well-documented large-scale physical impact test data. • Evaluation of effects of impact velocity, embedment depth, and soil strength on impact forces and energy dissipation. • Investigation of dynamics of lateral impacts into various pile-soil systems. [ABSTRACT FROM AUTHOR]