Foundation Uplift Research Articles

Study on the pullout bearing characteristics of bio-inspired root piles in coral sand foundation under different root buried depths

Root foundation is a new type of bio-inspired foundation, which has a broad application prospect in the development and construction of China's South China Sea area due to its good bearing characteristics such as pullout bearing capacity. The effect of root buried depth on the uplift bearing characteristics of root piles is analyzed through the model test of uplift bearing of root piles with different root buried depths in coral sand foundation. The results show that increasing the root buried depth can improve the ability of the root pile to control the uplift displacement, and there exists an optimal buried depth or range of buried depths that can effectively improve the pile foundation's uplift bearing capacity and control the ultimate displacement. The attenuation of axial force at the root is in the form of a step; with the increase of root buried depth, the maximum value of lateral friction resistance develops from the lower part of the pile body without root to the upper part of the pile body without root. The range of the bearing ratio of the root section of the pile with root buried depth of 260mm, 340mm and 420mm is 12.33%-15.68%, 9.98%-17.82% and 7.61%-21.65%, respectively; the smaller the root buried depth is, the higher is the ratio of the bearing ratio of the root section at the beginning of loading, and the bigger the root buried depth is, the bigger is the ratio of the root's final bearing ratio. The change of soil pressure around the pile increases and then decreases, and the densest point of soil compacting moves upward with the increase of root buried depth. The research results provide scientific basis for the design of root pile buried depth and root arrangement in actual projects.

Numerical model for suction anchor under vertical impact loading

In marine engineering, suction anchors are widely employed as the supporting foundation for many types of fixed or floating structures. One of the important control conditions for the service of marine foundations is the impact loading in extreme environments. This study proposes a numerical model to predict the dynamic behavior of suction anchors under impact loading. A mass module is added to the numerical model to quantify the effect of anchor inertia. The t-z springs are positioned along the depth to reflect the soil layer stress and accurately calculate the skirt wall friction. Considering the seepage effect, the differential pressure development, internal soil stress loss and external soil stress enhancement are also reflected. Subsequently, the influence of anchor aspect ratio and loading history are investigated. As the foundation uplift movement is further pronounced, the friction resistance gradually works, resulting in the weakening of inertial force. The existence of pretension loading makes friction resistance take effect earlier, and accelerates its attenuation during the impact loading stage.

Study on Arching Mechanism of Bridge Pile Foundation: Taking the Shiyangtai No.1 Bridge as an Example

The structure of a bridge has certain peculiarities, and its pile foundations are susceptible to uplift or settlement deformation due to various factors. This can result in bridge deck cracking, structural instability, tilting, and even irreversible damage, which significantly impacts the bridge’s stability and driving safety. This study focuses on the Shiyangtai No.1 Bridge and aims to investigate the factors that cause abnormal rise and fall deformations of bridge pile foundations. The study combines macro and micro analysis, physical characteristic testing of the overlying soil under the bridge pile foundation, and numerical simulation of the bridge pile foundation in the goaf. The study discusses in-depth the formation mechanism of the abnormal uplift of some pile foundations of the Shiyangtai No.1 Bridge based on the analysis of the factors influencing the abnormal rise and fall deformation of the bridge pile foundations at home and abroad. The expansive soil beneath the pile foundation is weak, and the force generated by the water expansion is insufficient to cause the pile foundation to rise to 309 mm. The results indicate that the pile foundation of the bridge is not affected by the expansion characteristics of the overlying soil. The collapse of the goaf roof generates double lateral thrust from the accumulation body at the bottom of the goaf and the upper collapse arch. This causes staggered bending uplift of the sandstone soil layer, resulting in upward squeezing pressure that causes the bridge pile foundation to rise. Therefore, the coal mining area is the main factor influencing the abnormal uplift of the pile foundation of the Shiyangtai No.1 Bridge.

Tectonic position of the Ukrainian shield

Statement of the general problem. The analysis of the geological structure of Europe indicates a wide development of Laramian (post-Cretaceous - pre-Cenozoic) deformations in non-Alpine regions. They are traced by the regional angular unconformity between the folded Mesozoic and non-folded Cenozoic from the Caspian Sea to Great Britain. The area of development of the Laramie folding of Europe also covers the Ukrainian shield. An unsolved part of the overall problem. The Ukrainian crystalline shield is described as "uplift of the crystalline foundation of the East European platform", where Precambrian rocks come to the surface. But the same rocks can also be traced far beyond its borders. The question arises - what structural position does the Ukrainian shield occupy in the structure of the Laramie folded region? Analysis of recent research and publications. On the geological maps of the pre-Cenozoic formations of Ukraine, the northern border of the Laramie folded region can be traced along the Chernihiv-Lysychansk line. Mesozoic folds and an angular unconformity in the Cenozoic basement disappear further north. To the south, the Laramie deformations intensify, but unevenly. The purpose of the article is identification of modern structural position of Ukrainian crystalline shield. Research materials and methods. Were involved more than 120 geological maps of Ukrainian regions and author's digital geological model of East Ukraine. Presentation of the main research material. A band of Mesozoic folds and NW vergence thrusts tens to hundreds of kilometers long is developed immediately south of the border of the folded region. The amplitude of the folds is 1.5–2 km. The band of development of these folds and thrusts with a width of about 100 km limits the Ukrainian shield from the northeast. To the south of the Ukrainian Shield, on the shelves of the Black and Azov Seas and in Northern Crimea, a sub-latitude band of Laramie thrusts and folds with a width of 150–200 kilometers has been established. Amplitudes of thrust folds reach 1–2 km, amplitudes of separate thrusts reach 8–10 km. This band of folds and thrusts limits the southern slope of the Ukrainian shield from the south. These Laramie folds and thrusts are overlain by Cenozoic sediments. To the south, in the Mountainous Crimea, the deformations are still intensifying. Folds and thrusts are replaced by wide and extended mélange zones of northwestern vergence. The Ukrainian shield is bypassed by the development of folds and thrusts from the northeast, east, and south. On the slopes of the Ukrainian shield, Mesozoic fold deformations subside, and the Mesozoic there lies gently sloping and monoclinally. Such poorly deformed blocks within folded regions are called middle massifs. This middle massif of the Laramie fold region within Ukraine has an anteclise structure. In the core of the anteclise, Precambrian metamorphic and igneous rocks emerge from under the sedimentary cover. The western wing of the anteclise is overlain by younger thrusts of the Carpathian folded structure of Attic (post-Miocene) age. Scientific novelty. In the modern geological structure, the Ukrainian shield is the core of the anteclise of the middle massif in the Laramie folded region. Conclusions. As a tectonic uplift, shield was formed in the Paleocene. In the Late Cretaceous, it was still buried under shelf carbonate deposits. Erosion of this uplift formed the Cenozoic deposits of Ukraine with a specific mineragenic specialization. Taking into account the Laramian folding allows us to reconcile the diverse geological phenomena of the region into a single system without contradictions.

Improvement of soil plate-bearing test of drilled pile foot during bridge support construction

Purpose: The aim of this work is the construction of bridge structures on a soil foundation with physical and mechanical characteristics, often differing from survey activity parameters. Technical regulations of bridge supports envisage plate-bearing test of drilled pile foot.Design/methodology/approach: The quality improvement of not only plate-bearing test preparation, but also requirements for structural reliability, the approximated Ritter-Rassokhin method with different soil behavior under normal conditions with regard to foundation uplift, which allows calculating the maximum draft and other design parameters of soil.Practical implications: The obtained results make it possible to clarify the work regulations for plate-bearing test.

Experimental and numerical investigations of eccentric uplift capacity of mat foundation on marine clay seabed

The mat foundation is a new type of jack-up wind power installation platform suitable for clay seabed. Because of the large size of the mat foundation, a large suction force must be overcome during the uplift process. In this study, the eccentric uplift of a mat foundation was experimentally and numerically investigated. The effects of the eccentric distance, eccentric position, and foundation shape on the suction force of the mat foundation were discussed. The results revealed that the breakout force of the mat foundation mainly comprised the foundation weight and suction force. Both the uplift position and eccentric distance affected the suction force; however, the effect of the uplift position was considerably smaller than that of the eccentric distance. The dimensionless suction force for the eccentric uplift tended to decrease linearly as the eccentric distance increased. When the dimensionless eccentric distance was 0.5, the suction force was 0.35–0.5 times that in the case of central uplift.

Seismic displacement ratios for soil-pile-structure systems allowed to uplift

In this paper, the soil-pile-structure interaction effects on seismic displacement demands are investigated using various dimensionless parameters. The code prescribed procedures for estimating seismic displacement demands are built upon fixed-base structure assumption and neglect the effect of foundation uplift. Tensile index, the ratio of the summation of the tensile strength of all piles to the weight of the structure, is introduced as a novel dimensionless ratio for the seismic assessments. The seismic behavior of the structures with a small tensile index is close to the structures with uplift-allowed shallow foundations. Structures with a large tensile index behave like tied foundation structures. The tensile index paves the path to cover the interaction effects from the soil-structure to soil-pile-structure interaction. The considered simplified structure in this study is a single degree of freedom model with a rigid foundation mounted on a group of piles simulated using the Winkler springs. The piles are simulated using nonlinear uniaxial springs with asymmetrical behavior under tensile and compressive forces. The accuracy of the model is verified by calculating the displacement ratios for four cases; The first three cases representing high tensile index (tied foundation), are verified with the code results, and Case 4, which represents low tensile index (uplift-allowed foundation), is compared to the literature. More than 150,000 nonlinear response history dynamic analyses are conducted for several dimensionless parameters and 20 ground motion records with various intensities and for each analysis, the displacement of the structure, linear and nonlinear hinge plastic rotation, and the foundation rotation and uplift are collected. The results, including elastic and inelastic displacement ratios, are finally compared with those of ASCE41 for shallow fixed-base foundations. It is concluded that for the cases with no pile slippage, the code prediction is accurate enough. However, in cases with high soil-pile-structure interaction effects and low tensile index, the displacement ratios are up to twice the code predictions. • Tensile index is developed to assess the soil-pile-structure interaction effects. • Simplified uplift-allowed SDOF model with piles simulated using Winkler springs. • Elastic and inelastic displacement ratios are compared with the code predictions. • Foundation uplift, tensile index and aspect and periodic ratios are investigated.

Soil-Structure Interaction Effects on Dynamic Behaviour of Transmission Line Towers

As inferred from earthquake engineering literature, considering soil structure interaction (SSI) effects is important in evaluating the response of transmission line towers (TLT) to dynamic loads such as impulse loads. The proposed study investigates the dynamic effects of SSI on TLT behavior. Linear and non-linear models are studied. In the linear model, the soil is represented by complex impedances, dependent of dynamic frequency, determined from numerical simulations. The nonlinear model considers the soil non-linear behavior in its material constitutive law and foundation uplift in a non-linear time history analysis. The simplified structure behavior of a typical lattice transmission tower is assessed. The analysis of frequency and time domain are followed through varying soil stiffness and damping values. Three different shock durations are investigated. The soil-structure system with equivalent dynamic properties is determined. The behaviors achieved utilizing a rigid and a flexible base for the structures is compared to estimate the impact of taking SSI into account in the calculation. The current mainstream approach in structural engineering, emphasizing the importance of the SSI effect, is illustrated using an example where the SSI effect could be detrimental to the structure. Furthermore, the non-linear analysis results are analyzed to show the linear approach’s limitations in the event of grand deformations.

Seismic analysis of reinforced concrete building accounting for local uplift, large rotation of the base and soil plasticity

This study provides an analysis of multistory reinforced concrete residential buildings to earthquakes considering local uplift of foundation, soil behaviour, site category and seismicity of area as suggested by the Moroccan seismic regulation. The superstructure was modeled as a flexible column with lumped mass placed at the top of the column under the hypothesis of large rotations or small rotations. The governing equations of the coupled system were obtained by expressing momentum conservation principle and were solved by means of adequate time integration numerical scheme. Then, the maximum seismic response of the coupled system was determined under El Centro ground motion for various configurations of the coupled mat-foundation system: elastic or elastic-perfectly plastic, as well as soil class and seismic magnitude. It was found that the nonlinear seismic demand of a reinforced concrete building, in terms of maximum values of horizontal and vertical displacements and rotation, depends considerably on the assumption regarding rotation magnitude. It is governed also by the height of the structure and the soil stiffness.

Causes of Failure and Strengthening Measures of a Pile Foundation Supporting Transmission Line Tower

The present paper describes the failure of an under-reamed pile foundation supporting a transmission line tower. Assessment of in-service pile conditions, i.e., in-built length, depth of bulb, uniformity of cross-sectional area, and length of the pile, are estimated through low strain integrity test. Integrity test results reveal that improper bulb formation and shorter as-built length than the designed are the leading causes of failure. Different performance criteria (uplift, compressive, and lateral capacities) of the in-service pile foundation are estimated through extensive finite element analysis and conventional approaches. Different geometric characteristics, i.e., straight shaft, different diameter of the bulb, and pile length, are simulated to represent the in-service pile conditions in the field. The estimated performance criteria are compared with the initial design values to evaluate the required degree of strengthening measures. The paper presents the initial design criteria of pile, soil condition, low strain integrity test, finite element modeling, and strengthening measures of the pile foundation to ensure the long-term stability of the transmission tower.

3D FEM Soil-Structure Interaction Analysis for Kashiwazaki–Kariwa Nuclear Power Plant Considering Soil Separation and Sliding

In the 2007 Niigataken Chuetsu-oki earthquake, soil settlement, considered to be a result of the relative displacement between the soil and the structure, occurred alongside buildings at Kashiwazaki–Kariwa nuclear power plant. The objective of this study is to evaluate accurately the influence of the nonlinear behavior of the soil-structure interface on the response of the reactor building using a three-dimensional finite element model. To achieve this, we modeled the separation and sliding from sidewalls during a severe earthquake using joint elements, and evaluated the effect on the horizontal response of the structure. Through the soil-structure interaction analyses based on the recorded seismic data on the foundation for unit 7 reactor building using the three-dimensional finite element model, it was confirmed that the simulated horizontal responses of the building corresponded to the recorded seismic data. In addition, the comparison of the cases with and without separation and sliding revealed that the separation and sliding of soil from sidewalls reduces the embedment effects of the structure and that the reduction causes an occurrence of the foundation uplift. Moreover, in this study, it was clarified that the increase of the foundation uplift affected both the soil pressure characteristics beneath the foundation and along the sidewalls, and the maximum acceleration response of structures. In this study, the separation and sliding of soil from sidewalls had only a limited influence on the structural responses; however, under severe seismic excitation, it is expected that the embedment effects will be significantly reduced due to the separation and sliding of soil. Therefore, a precise response evaluation of the building including the nonlinear behavior due to separation and sliding should be considered in the seismic response analyses under severe seismic excitation.

Determination of Ultimate Load and Stability Evaluation of Transmission Tower Foundation during Operation Period

500kV transmission tower foundation on the Yanzi landslide is taken as the research object this article. The extreme working conditions of the transmission tower foundation under different operating conditions, including maximum wind speed, icing and disconnection, are determined. Based on this, the stability of the tower foundation, including foundation uplift stability, foundation overturning stability, foundation bearing capacity, is initially evaluated according to the " Code for Design of 110kV ∼ 750kV Overhead Transmission Line " (GB 50545-2010). The results show that when the wind speed is greater than 20m/s, the maximum wind speed is determined as the extreme load condition of the tower foundation. Preliminary evaluation of the stability of the tower foundation shows that its stability is related to the wind speed and the buried depth of the tower foundation. Therefore, the research results can provide technical reference for related power departments.

Seismic performance of nonlinear soil-structure systems located on soft soil considering foundation uplifting and soil yielding

In most of researches on soil-structure systems, it is assumed that the foundation is bonded to the ground where no foundation uplift is allowed. Uplifting makes changes in force–displacement behavior of the soil-structure systems, which in turn alters structural demands. In this research, a set of non-dimensional parameters is considered which controls the behavior of uplifting systems. The effects of foundation uplift on response of soil-structure system are investigated parametrically through time history analysis for a wide range of systems subjected to harmonic excitation and also ground motions recorded on soft soil with predominant period. It is seen that the response of systems with more dominant soil-structure interaction effects will influenced more by foundation uplift. It is shown that the period of soil-structure systems to the predominant period of ground motion has an important rule on the response of uplifting systems. While this period ratio is greater than one, the total displacement of uplifting soil structure systems almost equals to elastic soil-structure system when uplifting is prevented but the drift of the structure as a part of soil-structure system while uplifting is permitted decreases in comparison with corresponding systems which foundation uplift is prevented. If the period ratio becomes smaller than one, systems which are allowed to uplift experience larger displacements in comparisons with corresponding case which foundation uplift is prevented. It is shown that neglecting the influence of foundation uplifting in seismic performance assessment procedure of stiff and squat structures located on soft soil is not conservative, because in this situation structures can experience larger drift due to foundation uplift in comparison with the case that uplifting is prevented while subjected to excitation with long predominant period. Also for nonlinear soil-structure systems it is shown that foundation uplifting and soil yielding can reduce the ductility of the structure as a part of soil structure system. It is observed that traditional structures with longer period of vibration which are designed based on conventional spectra will be influenced less by foundation uplifting and soil yielding.

Field Test on Uplift Bearing Capacity of Rock-Socketed Belled Piles

The thick sandstone with an upper layer of clay (2 m to 3 m) was identified at the transmission line projects in western China. Tower foundations are affected by extreme weather such as strong wind and snow all the year round, so the research of foundation uplift is very significant. Belled piles are widely used in the area due to its high uplift bearing capacity, however, further research studies regarding the uplift bearing capacity of the belled piles in this special scenario still need to be conducted. The uplift bearing characteristics of five rock-socketed belled piles were studied by field testing method. The load-displacement curves, fitting analysis of load-displacement curves, change rate of pullout stiffness, distribution of axial force alone the pile, and pile side friction were analyzed. Observation results show that the load-displacement curves of rock-socketed belled piles are steeply changed. Moreover, we find that the hyperbolic model can provide a good fitting result for load-displacement curves, and the ultimate uplift bearing capacity is suggested to be predicted by using a reduction parameter of 0.64–0.85. Both uplift bearing capacity coefficient Nu and utilization ratio of pile material η increase with the increase of L/d under a same diameter, while the growth rate decreases. In this paper, the significant size effect is observed with increasing of pile diameter. The change rate of pullout stiffness-displacement curves are consistent with the trend of the safety factor-displacement curves, and can be fitted by power function model. Additionally, the change rate of pullout stiffness at the limit state will decrease to around 154 in this study, which can be used as the instability threshold for the rock-socketed belled piles in a similar soil foundation.

A study of the effects of foundation uplift on the seismic loading of wind turbine tower and shallow foundation using a new dynamic Winkler model

In this study, the effects of foundation uplift on the seismic loading of wind turbine tower and shallow foundation are investigated. A dynamic Winkler model is proposed for the dynamic response analysis of shallow foundation supported structures and is named as QzSimple4, in which PySimple3 is applied to replace the elastoplastic component in QzSimple2 for the compression under the foundation and the gap model in QzSimple1 is assembled to capture the foundation uplift. The proposed model agrees well with the q-z experimental backbone curves and reasonably captures the acceleration responses of the bridge deck and the settlement-rotation responses of the shallow foundation under various excitation levels. However, QzSimple2 model strongly overestimates the q-z backbone curves in terms of linear range and ultimate bearing capacity, which leads to obviously overestimate some acceleration responses of the bridge deck and significantly underestimate the settlement responses of the shallow foundation. Finally, a systematical study is performed to investigate the effects of foundation uplift on the seismic loading by using the proposed Winkler model and the equivalent linear sway-rocking model. The foundation uplift occurs under severe earthquakes. Without considering the foundation uplift, the moment on the wind turbine tower is slightly overestimated, while that on the shallow foundation is significantly underestimated for the large soil stiffness. This is one reason why the shallow foundations at Aso-Nishihara wind farm were damaged during the Kumamoto earthquake.

A Macro-element for Modeling the Non-linear Interaction of Soil-shallow Foundation under Seismic Loading

This paper presents a macro-element for simulating the seismic behavior of the soil- shallow foundation interaction. The overall behavior in the soil and at the interface is replaced by a macro-element located at the base of the superstructure. The element reproduces the irreversible elastoplastic soil behavior (material non-linearity) and the foundation uplift (geometric non-linearity) at the soil- foundation interface. This new macro-element model with three degrees-of-freedom describes the force-displacement behavior of the footing center. The single element is restrained by the system of equivalent springs and dashpots. The footing is considered as a rigid body. It is solved by a suitable Newmark time integration scheme and implemented in Matlab to simulate the nonlinear behavior of soil-shallow foundation interaction under seismic loading. A reduce scaled soil-foundation system has been tested on a shaking table at the University of Transport and Communications, Hanoi, Vietnam. Five series of earthquake motions were used with maximum acceleration increased from 0.5 to 2.5 . The comparison of numerical results obtained from the simulation and experimentations shows the satisfactory agreement of the model. The proposed macro-element can be used to predict the seismic behavior of a wider variety of configurations.

The effects of foundation uplift on seismic response of diagonally braced steel frames

The foundation of buildings commonly assumed to be fixed in practical seismic response analysis. However, in severe earthquake loadings, the uplift phenomenon would be occurred due to the lack of tensile strength in the subsoil. This research aims to investigate this nonlinear phenomenon to obtain the actual behavior of diagonally braced steel frames. For this purpose, four 4-, 8-, 12-, and 15-story X-braced frames are modeled in the software framework of OpenSees. Some key parameters such as the natural period of vibration, inter-story drift ratio, base-shear force, the axial force along with the plastic deformation of braces are examined in two cases consist of fully and partially restrained supports. In the latter case, gap link elements (no tension behavior) are employed to model the soil–structure interaction (SSI). Overall, the results showed that by occurring the uplift the first period and inter-story drifts of the structure are increased; while, the base-shear, axial force and plastic deformation of braces will be reduced.

Analysis of the seismic capacity of Chilean residential RC shear wall buildings

A very low percentage of reinforced concrete buildings subjected to the 2010 Chile earthquake suffered severe damage, even though they were affected by ground accelerations significantly larger than those prescribed by the Chilean seismic design code. This observation suggests that the seismic capacity of such buildings is actually much larger than that required by the seismic design code. In order to obtain insight into this issue, three actual building structures (of 5, 17 and 26 stories) that withstood the 2010 Chile earthquake with no observable damage are analyzed. A linear elastic concrete material model is adopted. In a first series of analyses, nominal procedures are used to calculate seismic demands and member capacities. In a second series of analyses, seismic demands are calculated by performing response history analysis, and member capacities are evaluated by state-of-the-art procedures. Results from nominal analyses are not consistent with the observed lack of damage in the 17- and 26-story buildings. Results from response history analysis are indeed consistent, but only when foundation uplift is accounted for. The suitability of linear concrete material models to assess the response of apparently undamaged reinforced concrete shear wall structures subjected to strong seismic demands is then discussed.

Load-bearing characteristics of fibreglass uplift anchors in weathered rock

Pull-out destructive tests on six fibreglass anchors and four steel anchors for resisting the uplift of foundations in medium-weathered granite were conducted. The test results revealed two modes of shear failure for the anchors: at the interface between the anchor rod and the mortar interface (the first interface) and at the interface between the mortar and surrounding rock (the second interface). With M32·5 mortar and a 2 m anchorage length, the ultimate pull-out bearing capacity of the fibreglass anchor rods and steel rods of 28 mm diameter was 225 kN and that of fibreglass anchor rods of 32 mm diameter was 250 kN, which satisfied engineering requirements. An exponential–power–linear function model was established that better described the load–slip curves of the anchor rods. The average bond strengths at the first and second interfaces were found to be 1·50–1·54 MPa and 0·32–0·37 MPa, respectively, which were slightly lower than those for steel rods. The average bond strength at the second interface of the fibreglass anchor rods increased with the rod diameter.

Displacement ratios for structures with material degradation and foundation uplift

In this paper, combined effects of material degradation, p-delta, and foundation uplift are incorporated in a soil-structure-interaction (SSI) framework to assess seismic response of a single-degree-of-freedom system. The considered phenomenological systems represent a column with a lumped mass on top is placed on a rigid foundation. The foundation is mounted on Winkler springs and dashpots to take account of soil-foundation compliance and material/radiation damping. The springs are tensionless to guarantee that uplift is properly modelled. The model is verified for two specific limit cases with the code and literature to make sure that the model is capable of capturing SSI and foundation uplift. Three sets of flexural degradations for capturing nonlinear performance of the column are defined to be categorized as low, moderate, and high degradation levels. The response of each system is then compared to the corresponding one with the elastic–perfectly plastic (EPP) material behavior. More than 150,000 analyses are conducted for several dimensionless parameters and twenty time history ground motions. The results including elastic and inelastic displacement ratios are finally compared with those stipulated by seismic codes for shallow foundations with the flexible-based condition. The results reveal that material degradation can significantly increase the displacement ratios of soil-structure systems and in some cases can lead to structural instability, which cannot be captured by conventional EPP models. More specifically, displacement ratios calculated in accordance with ASCE41-17 by assuming fixed-base model and incomplete data about level of material degradation might be underestimated, once compared to the results of more realistic conditions.