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Sustainability has emerged as a paramount concern in the construction and development of built infrastructure. This study delves into the environmental impact and vulnerability of an idealized bridge–foundation–ground system using stone columns as a liquefaction countermeasure, focusing on the seismic response in the transverse direction. For that purpose, a nonlinear three-dimensional (3D) finite element framework is established, exploring the influence of stone columns on the vulnerability of the bridge–foundation system. To enhance the reliability of the analysis outcomes, an optimal intensity measure is identified through comprehensive evaluations of efficiency, correlation, coefficient of variation, and sufficiency. Further, systematic assessments of total cost and carbon emissions associated with ground improvement are performed using three different life-cycle assessment (LCA) approaches, including process-based LCA (P-LCA), economic input–output LCA (EIO-LCA), and a hybrid approach that combines P-LCA and EIO-LCA. The results demonstrate that stone columns noticeably reduce liquefaction-induced damage to pile foundations, proving their effectiveness in improving seismic resilience. While several factors influence overall ground improvement design (such as material availability and demobilization), the overall analysis techniques and derived insights systematically quantify sustainability, thereby offering an additional dimension in decision-making when implementing such liquefaction mitigation techniques in seismic-prone regions. [ABSTRACT FROM AUTHOR]

PREdiction of NOn-LINear soil behavior (PRENOLIN) is an international benchmark aiming to test multiple numerical simulation codes that are capable of predicting nonlinear seismic site response with various constitutive models. One of the objectives of this project is the assessment of the uncertainties associated with nonlinear simulation of 1D site effects. A first verification phase (i.e., comparison between numerical codes on simple idealistic cases) will be followed by a validation phase, comparing the predictions of such numerical estimations with actual strongmotion recordings obtained at well-known sites. The benchmark presently involves 21 teams and 23 different computational codes. We present here the main results of the verification phase dealing with simple cases. Three different idealized soil profiles were tested over a wide range of shear strains with different input motions and different boundary conditions at the sediment/bedrock interface. A first iteration focusing on the elastic and viscoelastic cases was proved to be useful to ensure a common understanding and to identify numerical issues before pursuing the nonlinear modeling. Besides minor mistakes in the implementation of input parameters and output units, the initial discrepancies between the numerical results can be attributed to (1) different understanding of the expression “input motion” in different communities, and (2) different implementations of material damping and possible numerical energy dissipation. The second round of computations thus allowed a convergence of all teams to the Haskell–Thomson analytical solution in elastic and viscoelastic cases. For nonlinear computations, we investigate the epistemic uncertainties related only to wave propagation modeling using different nonlinear constitutive models. Such epistemic uncertainties are shown to increase with the strain level and to reach values around 0.2 (log10 scale) for a peak ground acceleration of 5 m=s2 at the base of the soil column, which may be reduced by almost 50% when the various constitutive models used the same shear strength and damping implementation.

Due to seismic response, accumulation of permanent ground deformation (lateral spreading) is an important mechanism of much practical significance. Such deformations typically occur near a ground slope, behind retaining structures such as sheet-pile and quay walls, and in mildly sloping ground. In conducting a shake table test, the generation of permanent deformations further elucidates the underlying mechanisms and allows for related ground-foundation-structure response insights. In this paper, an approach for development of accumulated ground deformations is presented, in which asymmetric inertial loading results in a biased dynamic one-dimensional shear state of stress. As such, the proposed approach allows for further insights into the soil cyclic response and pore pressure build-up, with deformations accumulating in a preferred direction. To permit a virtually unlimited number of such loading cycles, focus is placed on motions that do not cause the shake-table actuator to accumulate displacement, in view of its possible limited stroke. Using this approach, representative experimental response is outlined and discussed. This experimental response can be used for calibration of numerical models to emulate the observed permanent strain accumulation profile and associated mechanisms. In addition to liquefaction-induced lateral spreading, this asymmetric shaking approach might be beneficial for a wide class of earthquake engineering shake table testing applications. Key words: asymmetric, seismic, earthquake, shake table, lateral spreading, liquefaction. En raison de la reponse sismique, l'accumulation de deformations permanentes du sol (propagation laterale) est un mecanisme important qui revet une grande importance pratique. Ces deformations se produisent generalement pres d'une pente du sol, derriere des structures de retenue telles que des palplanches et des murs de quai, et dans un sol legerement incline. En effectuant un test de table de secousses, la generation de deformations permanentes permet d'elucider davantage les mecanismes sous-jacents et d'obtenir des informations connexes sur la reponse de la structure du sol. Dans cet article, une approche pour le developpement des deformations accumulees du sol est presentee, dans laquelle le chargement inertiel asymetrique resulte en un etat de contrainte de cisaillement dynamique unidimensionnel biaise. Ainsi, l'approche proposee permet de mieux comprendre la reponse cyclique du sol et l'accumulation de pression dans les pores, les deformations s'accumulant dans une direction privilegiee. Afin de permettre un nombre pratiquement illimite de ces cycles de charge, l'accent est mis sur les mouvements qui n'entrainent pas de deplacement cumulatif de l'actionneur de la table vibrante, compte tenu de sa course eventuellement limitee. Cette approche permet de decrire et de discuter des reponses experimentales representatives. Cette reponse experimentale peut etre utilisee pour l'etalonnage des modeles numeriques afin d'emuler le profil d'accumulation de contraintes permanentes observe et les mecanismes associes. En plus de l'etalement lateral induit par la liquefaction, cette approche de secouage asymetrique pourrait etre benefique pour une large classe d'applications de tests de tables de secouage en genie sismique. [Traduit par la Redaction] Mots-cles : asymetrique, sismique, tremblement de terre, table a secouer, etalement lateral, liquefaction., Introduction Liquefaction-induced lateral ground deformation due to earthquake excitation is a main mechanism that results in major damage to embedded structures and foundation systems worldwide (Andrus and Youd 1987; Cetin [...]

A full-scale pile testing program was implemented using the large outdoor shake table at the University of California--San Diego. Nine steel helical piles with varying geometry were embedded in dense sand and tested individually and in 2*2 groups, comparing fixed and pinned pile head connections. The test piles were subjected to shake motions ranging from pulses and white noise to replicated earthquakes. Strain gauges attached to the exterior pile walls and accelerometers placed on the pile caps and within the soil provided data for analyzing the behavior of these piles. Foundation damping (herein soil-pile system) is a substantial parameter in seismic design of the foundation-structure. Therefore, the damping characteristics of the soil bed along with the combined soil-pile system consisting of single and grouped helical piles are discussed based on the experimental pulse, white noise, and shake excitations. Several methods, including logarithmic decrement, half-power bandwidth, and energy (equivalent) methods, were implemented to estimate the damping ratio over a range of strains. Based on the experimental data gathered from this study, the suitability and accuracy of different computational methods to determine damping ratio as well as the effect of type and location of instrumentation on the calculated damping ratio were evaluated. Key words: helical pile, seismic behavior, shake table, damping, soil-structure interaction. Un programme de test a grande echelle des pieux a ete mis en place a l'aide de la grande table a secousses en plein air de l'Universite de Californie a San Diego. Neuf pieux helicoidaux en acier de geometrie variable ont ete noyes dans du sable dense et testes individuellement et par groupes de 2*2 en comparant les assemblages de tetes de pieux fixes et epingles. Les piles de test ont ete soumises a des mouvements de secousses allant des impulsions et du bruit blanc aux tremblements de terre reproduits. Les jauges de contrainte attachees aux murs exterieurs des pieux et les accelerometres places sur les chapeaux des pieux et dans le sol ont fourni des donnees pour analyser le comportement de ces pieux. L'amortissement des fondations (ici systeme sol-pieu) est un parametre essentiel de la conception sismique de la structure de fondation. Par consequent, les caracteristiques d'amortissement du lit de sol ainsi que le systeme combine pieu-sol constitue de pieux helicoidaux simples et groupes sont discutes en fonction des excitations experimentales a impulsions, bruit blanc et secousses. Plusieurs methodes, notamment des methodes de decrement logarithmique, de reduction de la largeur de bande a demi-puissance et d'energie (equivalentes) ont ete mises en oeuvre pour estimer le rapport d'amortissement sur une plage de deformations. Sur la base des donnees experimentales recueillies dans le cadre de cette etude, l'adequation et la precision de differentes methodes de calcul permettant de determiner le coefficient d'amortissement ainsi que l'effet du type et de l'emplacement de l'instrumentation sur le rapport calcule ont ete evaluees. [Traduit par la Redaction] Mots-cles : pile helicoidale, comportement sismique, table de secousse, amortissement, interaction sol-structure., Introduction Determination of soil-pile dynamic parameters, such as damping, is required to accurately predict and analyze the dynamic behavior of pile foundations. For strong earthquake motions, damping of the soil-foundation [...]