Relative Stiffness Research Articles

Controlling the mechanical behaviour of stochastic lattice structures: The key role of nodal connectivity

Additive manufacturing has enabled the fabrication of lattice structures with controlled micro-architectures and mechanical properties. These structures are particularly attractive in the orthopaedic industry where their osseointegration capability and bone-matching mechanical properties are ideally suited for use in implants and bone scaffolds. The broad range of mechanical properties required for this application is a challenge – it typically requires a range of periodic lattice structures, each of which require separate characterisation. An alternative approach is to use a stochastic lattice structure, where a single relationship between the lattice design parameters (connectivity, strut density and strut thickness) and resulting mechanical properties should be possible. To investigate this, we manufactured stochastic lattices in pure Titanium with connectivity from 4 to 14, strut density from 3 to 7 [struts/mm3] and strut thickness of 230 and 300 µm. Specimens were compression tested in quasi-static and fatigue loading. In static loading, the low connectivity structures displayed bend-dominated deformation while the high connectivity structures displayed stretch-dominated deformation. The structures had a stiffness ranging from 0.1 to 8 GPa and different Gibson-Ashby stiffness/relative density relationships were required for high and low connectivity structures. A unified multivariable linear regression model was found to predict relative density from the connectivity, strut density and strut thickness of the structure. In fatigue loading, increasing the connectivity from 4 to 14 increased the fatigue strength by 60% for a fixed relative density. These findings provide important design information when creating structures using stochastic lattices to maximise strength for a desired relative density or stiffness. The single integrated model presented in this study can define a structure to achieve a broad range of design requirements, even as gradient within the same component. To achieve the same with periodic lattices would require different unit cell, with individual regression models for each unit cell used.

Deformation prediction and compensation of a dual-machine riveting system for aircraft assembly

Automatic riveting systems play a crucial role in the field of aircraft manufacturing. In the riveting process, the machine tool bears a large axial squeezing force, and the resulting deformation will inevitably affect the riveting quality. In this paper, a dual-machine riveting system is developed first, the kinematic chain model and the lower-numbered body of the system structure are constructed sequentially. Then, considering the interaction and coupling effect of the two machines in the actual riveting process, the relative stiffnesses of the dual machine in the resisting state are identified by loading tests. Based on the stiffness data at a combination of postures within the workspace, a Kriging prediction model is established to describe the relationship between stiffness and postures. According to the prediction results, the influence of rotational and translational axes on the spatial stiffness distribution of the riveting system is revealed. Finally, the online deformation compensation is realized by modifying the displacement of the feed axis on both sides. A riveting experiment is carried out, and the results demonstrate that the riveting quality is significantly improved after compensation.

Transverse seismic response of end‐bearing pipe piles to S‐waves

AbstractThis paper presents a method for the seismic analysis of open‐ended pipe piles subjected to vertically propagating S‐waves, that considers kinematic interaction between the pipe pile and its external and internal soil. Following the presentation of the elastodynamic continuum model, which is based on the assumptions of linear elastic soil response and uniform soil conditions, we employ the derived solution to investigate the sensitivity of the seismic response of pipe piles to certain key problem parameters, such as pile slenderness or the relative stiffness of the pipe pile compared to its surrounding soil. We demonstrate that the bending stiffness of pipe piles is governing their seismic response, and that thin‐walled pipe piles offer the best material usage versus seismic performance ratio. The presented solution offers a low‐cost alternative to complex numerical simulations for preliminary seismic design purposes, such as the selection of optimal pipe pile section geometry.

Effect of Pile-Soil Relative Stiffness on Deformation Characteristics of the Laterally Loaded Pile

Laterally loaded piles are widely used in structural foundations under horizontal loads such as wave load, wind load, seismic load, and traffic load. Based on the complexity of pile-soil interaction, a test simulation of single pile through the indoor 1 g model test was conducted, in order to study the influence of different loading heights and relative stiffness of pile and soil on the bending moment, soil resistance, and horizontal displacement of pile. It is found that the shear modulus of soil from large to small is arranged as dry fine sand, dry coarse sand, saturated fine sand, and saturated coarse sand. The shear modulus of dry fine sand, dry coarse sand, and saturated fine sand are close under the same loading height and horizontal displacement of pile top, while the shear modulus of saturated coarse sand decreases sharply. Under the condition of water saturation, the particle size has a significant effect on the shear modulus of soil. The relative stiffness of pile soil is found to be the main influencing condition of pile horizontal displacement. Compared with the displacement and bending moment of the pile, the loading height has more influence on the soil resistance, and the main influence area is the soil resistance of the pile toe.

Medial packing and elastic asymmetry stabilize the double-gyroid in block copolymers

Triply-periodic networks are among the most complex and functionally valuable self-assembled morphologies, yet they form in nearly every class of biological and synthetic soft matter building blocks. In contrast to simpler assembly motifs – spheres, cylinders, layers – networks require molecules to occupy variable local environments, confounding attempts to understand their formation. Here, we examine the double-gyroid network phase by using a geometric formulation of the strong stretching theory of block copolymer melts, a prototypical soft self-assembly system. The theory establishes the direct link between molecular packing, assembly thermodynamics and the medial map, a generic measure of the geometric center of complex shapes. We show that “medial packing” is essential for stability of double-gyroid in strongly-segregated melts, reconciling a long-standing contradiction between infinite- and finite-segregation theories. Additionally, we find a previously unrecognized non-monotonic dependence of network stability on the relative entropic elastic stiffness of matrix-forming to tubular-network forming blocks. The composition window of stable double-gyroid widens for both large and small elastic asymmetry, contradicting intuitive notions that packing frustration is localized to the tubular domains. This study demonstrates the utility of optimized medial tessellations for understanding soft-molecular assembly and packing frustration via an approach that is readily generalizable far beyond gyroids in neat block copolymers.

Deformation estimation of a circular tunnel from a point cloud using elliptic Fourier analysis

In recent years, light detection and ranging technology has been applied to tunnel engineering. Although more accurate than traditional measurement techniques, estimating the tunnel deformation from the light detection and ranging point cloud remains challenging. This paper proposes a deformation estimation method using elliptic Fourier analysis, whereby the tunnel deformation is estimated from the difference in the Fourier series representations of the tunnel outline before and after deformation. The applicability of the proposed method for a circular tunnel cross-section is theoretically considered. Numerical results show that there is almost no error in the estimation of radial displacement, regardless of the measurement conditions. In contrast, there is an error in the estimation of circumferential displacement because this does not modify the circular tunnel outline. Therefore, tunnel deformation cannot be accurately estimated using point cloud data obtained only from distance measurements. As a special case, when the full-slip condition is imposed on the ground–lining interface and the estimated circumferential displacement of the inner surface is regarded as that of the middle surface, circumferential displacement can also be accurately estimated. Moreover, the difference in the deformation patterns under the full-slip and no-slip conditions decreases as the relative stiffness of the lining with respect to the ground increases. As a result, the deformation estimation accuracy is expected to be high for tunnels with a high possibility of deformation. When the distance measurement error is considered, the estimation accuracy of the displacement decreases, especially that of the circumferential displacement. Smoothed data significantly improve the accuracy, and high-precision estimation can be achieved when the measurement error is small compared with the tunnel deformation. However, small displacement errors produce significant stress errors in the higher-order terms of the Fourier series. Therefore, only the lower-order terms can be used for stress estimations.

Predicting pituitary adenoma consistency with preoperative magnetic resonance elastography.

Pituitary adenoma is one of the most common primary intracranial neoplasms. Most of these tumors are soft, but up to 17% may have a firmer consistency. Therefore, knowing the tumor consistency in the preoperative setting could be helpful. Multiple imaging methods have been proposed to predict tumor consistency, but the results are controversial. This study aimed to evaluate the efficacy of MR elastography (MRE) in predicting tumor consistency and its potential use in a series of patients with pituitary adenomas. Thirty-eight patients with pituitary adenomas (≥ 2.5 cm) were prospectively evaluated with MRI and MRE before surgery. Absolute MRE stiffness values and relative MRE stiffness ratios, as well as the relative ratio of T1 signal, T2 signal, and diffusion-weighted imaging apparent diffusion coefficient (ADC) values were determined prospectively by calculating the ratio of those values in the tumor to adjacent left temporal white matter. Tumors were classified into three groups according to surgical consistency (soft, intermediate, and firm). Statistical analysis was used to identify the predictive value of the different radiological parameters in determining pituitary adenoma consistency. The authors included 32 (84.21%) nonfunctional and 6 (15.79%) functional adenomas. The mean maximum tumor diameter was 3.7 cm, and the mean preoperative tumor volume was 16.4 cm3. Cavernous sinus invasion was present in 20 patients (52.63%). A gross-total resection was possible in 9 (23.68%) patients. The entire cohort's mean absolute tumor stiffness value was 1.8 kPa (range 1.1-3.7 kPa), whereas the mean tumor stiffness ratio was 0.66 (range 0.37-1.6). Intraoperative tumor consistency was significantly correlated with absolute and relative tumor stiffness (p = 0.0087 and 0.007, respectively). Tumor consistency alone was not a significant factor for predicting gross-total resection. Patients with intermediate and firm tumors had more complications compared to patients with soft tumors (50.00% vs 12.50%, p = 0.02) and also had longer operative times (p = 0.0002). Whereas other MRI sequences have proven to be unreliable in determining tumor consistency, MRE has been shown to be a reliable tool for predicting adenoma consistency. Preoperative knowledge of tumor consistency could be potentially useful for surgical planning, counseling about potential surgical risks, and estimating the length of operative time.

Mechanical properties and energy absorption of bio-inspired hierarchical circular honeycomb

This study proposed a new bio-inspired hierarchical circular honeycomb (BHCH), mimicking the hierarchical structures from wood. The mechanical properties and energy absorption characteristics of the proposed structures were investigated by means of quasi-static compression tests and finite element (FE) analysis. Subsequently, the influences of geometric parameters and material selections on the energy absorption capacity were investigated. The experimental results and parametric study indicated that the BHCH outperformed the conventional circular honeycomb (CH) in terms of energy absorption capacity. Specifically, the BHCH had a higher specific energy absorption (SEA) than the corresponding CH with the same wall thickness (i.e. 45.3%) and the same volume of honeycombs (i.e. 71.2%). Furthermore, the relative stiffness, relative strength, and relative energy absorption of the BHCH were significantly higher than other popular cellular structures. Finally, a theoretical model was developed to estimate the mean crushing stress (MCS) and interaction effect of the proposed structure, which further demonstrated its enhanced energy absorption mechanisms. A good correlation between the predicted values and the numerical results proved the reliability of the proposed analytical models. With its excellent performance, the proposed BHCH provided a promising solution for the enhanced energy absorption of the honeycomb structure used in a wide range of applications from structural components of defence structures to protection systems in vehicles.

Non-invasive measurement of nuclear relative stiffness from quantitative analysis of microscopy data

The connection between the properties of a cell tissue and those of the single constituent cells remains to be elucidated. At the purely mechanical level, the degree of rigidity of different cellular components, such as the nucleus and the cytoplasm, modulates the interplay between the cell inner processes and the external environment, while simultaneously mediating the mechanical interactions between neighboring cells. Being able to quantify the correlation between single-cell and tissue properties would improve our mechanobiological understanding of cell tissues. Here we develop a methodology to quantitatively extract a set of structural and motility parameters from the analysis of time-lapse movies of nuclei belonging to jammed and flocking cell monolayers. We then study in detail the correlation between the dynamical state of the tissue and the deformation of the nuclei. We observe that the nuclear deformation rate linearly correlates with the local divergence of the velocity field, which leads to a non-invasive estimate of the elastic modulus of the nucleus relative to the one of the cytoplasm. We also find that nuclei belonging to flocking monolayers, subjected to larger mechanical perturbations, are about two time stiffer than nuclei belonging to dynamically arrested monolayers, in agreement with atomic force microscopy results. Our results demonstrate a non-invasive route to the determination of nuclear relative stiffness for cells in a monolayer.Graphic abstract

Shaking table tests on fault-crossing tunnels and aseismic effect of grouting

Tunnels crossing inactive faults may experience large differential deformations along their lengths during earthquakes, resulting in damage. Faults always have inferior material properties for historical geological reasons. Grouting is an auxiliary construction measure in fault-crossing tunnels and has the potential to be an economical and effective aseismic measure. However, the feasibility and seismic mitigation mechanisms of grouting in fault-crossing tunnels have not been sufficiently studied. In this study, large-scale shaking table tests were conducted to verify the aseismic effect of grouting in a tunnel crossing an inactive fault and to explore the seismic mitigation mechanism behind it. On this basis, verified numerical models were developed to determine the optimized design parameters. The test results indicate that grouting reduces the acceleration response of the tunnel within the fault and reduces the differences in the acceleration responses in the longitudinal direction of the tunnel induced by the fault. As grouting increases the shear strength and stiffness of the strata around the tunnel within the fault, the strain of the tunnel invert is effectively reduced by over 80%, and the potential damage of the invert uplift is reduced simultaneously. Meanwhile, grouting effectively reduces the diameter deformation of the tunnel within the fault and reduces the differences in tunnel deformation in different areas of the fault site. By reducing the resonance caused by the frequency components of the input seismic wave that is close to the natural frequency of the strata, which contributes most to the tunnel response, grouting effectively reduces the seismic responses of the fault-crossing tunnels. Increasing the stiffness of the grouting zone is an effective approach to improve its seismic mitigation performance. In the example of this study, adjusting the relative stiffness ratio to approximately 100 between the grouting zone and the fault resulted in a favorable condition for aseismic effects, which could be deemed to be a suitable parameter for grouting. The above results can provide a reference for the seismic design of mountain tunnels crossing inactive faults.

Elucidating the effect of cohesive zone length in fracture simulations of particulate composites

The influence of the cohesive zone length on the crack driving force is quantified and analyzed in a representative system of particles dispersed in a matrix of a composite material. For heterogeneous material systems, e.g. particulate composites, it is known that as a crack approaches the particles, the crack driving force may increase (shielding) or decrease (anti-shielding) depending on the relative stiffness of the particles. These results have been established in numerous studies using the classical linear elastic fracture mechanics approach (LEFM). The cohesive zone method (CZM) introduces a length scale parameter, referred to as the cohesive zone (or fracture process zone) length scale, into the formulation of fracture mechanics. It is generally established that fracture mechanics predictions using the CZM are similar to those obtained using LEFM in the limit case where the process zone is very small relative to a suitable characteristic dimension of the problem. However, the influence of the length scale parameter has not been clearly demonstrated for crack propagation in a heterogeneous material system, especially when the cohesive zone length is not negligible. By considering a simple crack-particle-matrix system, it is shown that, in addition to the elastic properties, the process zone length scale parameter exhibits a critical influence on the crack driving force. For this study, the concept of configurational forces is utilized and the eXtended Finite Element Method (XFEM) is employed as a tool to simulate crack propagation. Through numerical simulations, it is shown that (i) the magnitude of the driving force vector directly depends on the length scale parameter and (ii) the direction of the driving force is largely influenced by the presence of a cohesive zone. This, in turn, alters the crack trajectory in the particulate system if the criterion for the direction of crack propagation depends on the orientation of the driving force vector. Towards this end, two different criteria for direction of crack propagation, namely maximum principal stress and maximum energy dissipation, are compared in the presence of a cohesive zone and the results are reported. The study reveals the crucial influence of the inherent length scale associated with the cohesive zone method when applied to crack propagation in particulate composite systems and elucidates important differences when comparing predictions from distinct theories of fracture mechanics.

Fatigue behavior of hybrid continuous-discontinuous fiber-reinforced sheet molding compound composites under application-related loading conditions

Hybrid continuous-discontinuous sheet molding compound (SMC) composites are considered suitable candidates for structural automotive applications, due to their high mass-specific mechanical properties combined with high geometrical flexibility and low costs. Since structural automotive parts are subject to repeated loading, profound knowledge of their fatigue behavior is required. This paper presents an experimental study on the bending fatigue behavior of hybrid SMC with discontinuous glass fibers in the core and unidirectional continuous carbon fibers in the face layers. Effects of hybridization on the S-N behavior and stiffness degradation have been analyzed in constant amplitude fatigue tests under 3-point bending load at different temperatures and frequencies. Microscopic investigations on polished specimen edges were used to study the damage behavior. The ultimate flexural strength at quasi-static (UFSS) and fatigue strain rate (UFSF) of the hybrid composite was 54 % and 59 % higher than that of discontinuous SMC, respectively. In contrast, the flexural fatigue strength at 2.6⋅106 cycles increased by 258 %. The relative stiffness degradation of the hybrid composites was smaller during most of their fatigue lives due to the continuous carbon fiber reinforcement. The carbon fiber ply on the compression loaded side was the first ply to fail. Fatigue stress significantly decreased at 80 °C due to early kinking of the continuous carbon fiber-reinforced ply on the compression loaded side. Variation of frequency had no significant effect on the fatigue behavior of both discontinuous and continuous-discontinuous SMC.

Cyclic Lateral Responses of Monopiles Considering the Influence of Pile—Soil Relative Stiffness in Sand

Cyclic Lateral Responses of Monopiles Considering the Influence of Pile—Soil Relative Stiffness in Sand

Seismic behavior of hollow-core infilled steel frames; an experimental and numerical study

This study describes an experimental program designed to investigate the influence of the presence and orientation of hollow-core wall panels as well as beam to column connection rigidity on the seismic performance of steel frames infilled with hollow-core wall units. For this purpose, four half-scale, single-story, and single-bay specimens, including three infilled steel frames and one bare moment frame, were subjected to cyclic lateral loading. The bare steel frame and two infill specimens had rigid connections, while the last one had pinned connections. One of rigid connections specimen was constructed with hollow-core wall panels placed vertically, whereas the other was fabricated with wall panels with the horizontal core. The experimental results indicated that the vertical placement of hollow-core wall units controlled structural damage and improved the seismic performance through the rocking mechanism within the steel frame. In addition, the strength, stiffness, and energy dissipation capacity of the infilled pinned connections frame were less than those in rigid connections specimen. In another part of this study, a parametric study was conducted with finite element method using ABAQUS software. The parametric nonlinear analyses study revealed that the infilled frames with hollow-core wall panels placed vertically had less initial stiffness and more strength than those with horizontal core panels. On the other hand, the initial stiffness and strength of the infilled steel frame, bare steel frame, and infill contribution were reduced by the decrease in the rigidity of the steel frame connections, regardless of infill aspect ratio and the relative stiffness of the hollow-core panels to the surrounding steel frame.

Scaled Modeled Tests and Finite Element Numerical Study on Lateral Responses of PRF System under V-H-M Loading

ABSTRACT Considerable research has been endeavoured to examine the responses of piled raft foundation (PRF) under gravity load. In reality, PRF often encounters combined vertical (V), horizontal (H) and moment (M) load simultaneously due to wind, earthquake and wave load along with dead load of the structure, and vertical soil pressure. Present study aims at a scaled-model test on the PRF subjected to V-H-M loads to investigate the lateral responses of PRF due to the interaction of loadings. The scaled model tests are conducted in Agartala sand with a relative density of 30%. Effects of relative stiffness raft with respect to soil, the length and spacing to diameter ratio of the pile, number of piles in a group and non-uniform pile length configuration on the lateral response of PRF are studied. Results indicate that the V load in V-H-M loading has a significant influence on the lateral response of PRF. Further, a substantial influence of other parametric variations on lateral response is also observed. Furthermore, a numerical model is also developed and validated based on experimental results that substantiate investigation on prototype foundation. Finally, the load-sharing behaviour of prototype PRF is also studied through the validated numerical model.

Impact of soil‐structure interaction on the effectiveness of Tuned Mass Dampers

AbstractTuned Mass Dampers (TMDs) can represent an attracting solution to mitigate vibrations of a structure under seismic excitation, but their effectiveness can be considerably altered by the dynamic interaction with the foundation soil. The available design criteria for TMDs do not account for these effects and can therefore lead to a non‐optimised structural performance. In this paper an investigation on the dynamic interaction of the TMD with the whole soil‐structure system is presented, with the objective of highlighting the system parameters governing the response and the effectiveness of the device as seismic protection. An interpretative model of the soil‐structure‐TMD system expressed in a rigorous non‐dimensional form is proposed, and an extensive global sensitivity analysis on its performance under harmonic loading is carried out. The identification of the typical performance regions shows that the seismic effectiveness of a TMD is mainly controlled by a limited number of parameters describing the structural behaviour and the soil‐structure interaction, such as the structure‐to‐soil relative stiffness and those governing foundation rocking. The non‐dimensional system parameters leading to either a favourable or detrimental effect on the TMD performance due to soil‐structure interaction are also identified, and two design methodologies proposed in the literature are critically assessed in light of the framework proposed.

Extremely stiff and lightweight auxetic metamaterial designs enabled by asymmetric strut cross-sections

Negative Poisson’s ratio has been shown to enhance packing efficiency, impact absorption, indentation resistance, fracture resistance and acoustics attenuation in auxetic materials, making them useful for applications such as protective cases and stents. However, these benefits are usually realized at the expense of a low specific modulus and poor loading efficiencies, as auxetic structures rely on ‘soft’ strut bending and/ or joint rotation deformation modes to reach perceptible levels of negative Poisson’s ratios. Here, a general 3D Anti-Tetrachiral (3ATC) structure was analyzed and shown that, in the limit of low relative density (i.e lightweight structure), the trade-off between specific relative stiffness and auxeticity is linear and the maximum attainable specific relative stiffness is 1/3. If the strut cross-section is symmetric, the maximum attainable Poisson’s ratio is -0.5, while that for an asymmetric cross-section depends on the specific geometry of the cross-section. Importantly, our analysis shows that the non-zero product of inertia for asymmetric cross-sections can lead to an additional twist of the joint, thereby increasing the auxeticity of the 3ATC structure. This allows the 3ATC lattice to exhibit a large specific relative stiffness for a given Poisson’s ratio, which can be more than an order of magnitude higher when compared to other auxetic designs in the literature. Our analysis was validated by finite element simulations and experiments on 3ATC lattices with strut cross-sections that were square (symmetric) and L-shaped (asymmetric).

Sports Training's Effects on Muscle and Tendon Characteristics at Different Stages of Development

This study aimed to investigate the influence of sprint training on muscle and tendon properties across different developmental stages, specifically focusing on pre-adolescent children, adolescent boys, and young men. It is well-established that adults show higher force production, rate of force development, and effective re-use of elastic energy during the stretch-shortening cycle (SSC) compared to children due to different muscle and tendon properties. Thus, it is important to classify the interaction between age and the training process on muscle-tendon system. Participant’s tendon properties were assessed using two 10 seconds ramp isometric contractions(increasing the force level every 2’’) with an ultrasound probe stabilized on muscle-tendon junction. Moreover, two maximal isometric plantar flexions were performed to evaluate maximal isometric force. Both force capacity and tendon stiffness was evaluated. Our results showed significant increases in height, body mass, and strength levels through maturation (p<0.05). Moreover, significant changes were found in tendon stiffness and produced force in athletes compared with non-athletes groups (p<0.05). On the other hand, significant differences were found in relative stiffness and force between young adults and non-athletes with the athletes (p<0.05). Our results revealed that both maturity and sprint training imposes the tendons to a greater mechanical load through the higher produced force and strain. These stimuli lead to adaptive responses and changes in Achilles tendon properties. Moreover, our data support the importance of training in young adults to maintain tendon properties at the level of adolescence. This study provides valuable insights into the interaction between age, sprint training, and tendon adaptations to prevent tissue imbalances in male individuals engaged in sports activities

Numerical Solution for Electronic Assemblies Subjected to Mechanical Bending

This work introduces high-accuracy numerical solution for the two elastically coupled beams subjected to mechanical bending problem. Finite difference method (FDM) was considered to solve the governing equations along with the boundary conditions of the structure. The validity of this solution was ensured and tested with literature data. Finally, the influence of the key structural parameters of the problem, such as the relative stiffness between the beams as well as the elastic layer, was thoroughly discussed with the specific attention on its application in electronic assemblies subjected to mechanical bending. The numerical findings showed that for stiffer beams and compliant layer, the axial deformations of the layer are lower which can be reflected as lower solder stresses and hence more reliable designs of electronic devices.

Extent and hierarchy of seismic induced inelastic demands in the substructure system of bridges on piled foundation crossing waterways

The effect of the exposed length of piles supporting bridges crossing waterways on the spread of inelasticity along the pile shaft compared with the extent of plasticity in the body of the column, and hence on the precedence of the formation of plastic hinges in the substructure system is of paramount importance. Plastic hinges may form ideally and preferably at the bottom of the column just above the pile cap, or undesirably either at the pile’s head or at any other section within the pile be it along its free/exposed length immersed in water or its embedded part in soil. A set of bridges are designed according to Eurocode for multiple configurations with various relative stiffness between the column and the group of piles featuring partly exposed shaft. Pushover as well as time history inelastic analyses under a set of ten earthquake records are performed accounting for soil-structure interaction. Results demonstrate that it is likely in some cases characterized by a remarkable increase in the flexural stiffness of the column relative to the group of piles to have spread of inelasticity and plastic hinges forming in piles prior to the column. This is undesirable for a robust, reliable and resilient seismic design as devised by universal design standards for bridges on piled foundation. While there is no clear consensus on the most effective corrective measure to such undesirable response, a few proposed remedial design actions have been formulated in order to preclude (or at least improve the behavior for the case featuring) plastic hinges deplorably forming in the piles prior to the base of the column.