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Operating CMOS circuits at cryogenic temperatures offers advantages of higher mobility, higher ON-current, and better subthreshold characteristics, which can be leveraged to realize high-performance CMOS circuits. However, an ultra-low-voltage operation is necessary to minimize the power consumption and to offset the cooling cost overheads. The MOSFET threshold voltages (Vt) increase at cryogenic temperatures making it challenging to achieve high performance while operating at very low voltage. Ultra-thin body and buried oxide silicon-on-insulator (UTBB-SOI)-based MOSFETs can modulate the transistor threshold voltage using the back-gate bias, unlike conventional FinFETs. This unique UTBB-SOI technology attribute has been leveraged to realize compact pseudo-static storage circuits, namely, embedded dynamic random access memory (DRAM) bitcell and a flip-flop operating at 0.2 V and 77 K. This article presents UTBB-SOI device fabrication details and calibrate experimental device characteristics with BSIM compact models. SPICE simulations suggest the feasibility of three-transistor gain-cell embedded DRAM (eDRAM) capable of reliably storing three distinct voltage levels (1.5 bits/cell) and exhibiting retention time of the order of 104 s. Furthermore, a unique pseudo-static flip-flop design is presented, which can lower the clock power by 50%, transistor count by 20%, and static power consumption by 20%.

The use of geosynthetic reinforcement to enhance the ultimate load-bearing capacity and reduce the anticipated settlement of the shallow foundation has gained sufficient attention in the geotechnical field. The improved performance of the shallow foundation is achieved by providing one or more layers of geosynthetics below the foundation. The full wraparound technique proved to be efficient for the confinement of soil mass and reduction in settlement of foundation however lacks the literature to ascertain the performances of such footing under dynamic loading. In view of the above, the present study examines the effect of geosynthetic layers having a finite length with full wraparound ends as a reinforcement layer, placed horizontally at a suitable depth below the foundation using the finite element modeling (FEM) and evaluates the ultimate load-bearing capacity of a strip footing resting on loose and dense coarse-grained earth beds under seismic loading and further compared to those of footing resting on unreinforced earth bed. Moreover, the effect of horizontal seismic acceleration coefficient (kh) on the ultimate load-bearing capacity has been investigated by varying kh from 0.1 to 0.6 at an interval of 0.1, for both reinforced and unreinforced earth bed having loose and dense soil strata. Furthermore, this study demonstrates that by adopting the new practice of using the geosynthetic reinforcement with the full wraparound ends in foundations, it is possible to support relatively heavier structures under static as well as dynamic loading without allowing large footing settlements. From the outcomes of the present study, it is noted that the ultimate load-bearing capacity of footing resting on loose and dense sand bed found to be improved by 60% and 18% for soils having friction angle of 25° and 40°, respectively compared to respective unreinforced earth beds under static condition.

Based on investigation of rural buildings in china, there are more than 20% of the masonry structures constructed in 1970s. Thus, the old blue bricks (OBB) and old red bricks (ORB), which demolished from the typical brick masonry structures was built in 1970s, was chosen in the test. During demolishing the OBB and ORB, the original mortar was destroyed. Thus, the 1:7.8 cement mortar was chosen instead of original mortars and the 1:5 cement mortar was chosen as the reinforcement mortar. In order to know the performant of the reinforcement methods, there are three-level test plan was put forward in the study. Firstly, the mechanical properties of OBB and ORB and mortars was tested; Secondly, the experiment tested the shear strength of the reinforced and unreinforced masonry specimens along mortar joints; Thirdly, there are four walls (OBB reinforced wall and unreinforced wall, ORB reinforced wall and unreinforced wall) have been made for the pseudo-static tests. This research conducted physical performance tests on masonry bricks, masonry components, and masonry walls of typical masonry structures. Through experiments, the shear capacity of the masonry structure reinforced by high-strength mortar and steel bars can be obtained.

Metal magnetic memory (MMM) testing is a nondestructive approach for evaluating the stress concentration and early damage of ferromagnetic components. However, research on the MMM testing of large steel structures has been limited. Thus, this study investigates the suitability of MMM technology for monitoring the damage in steel structures exposed to complex stresses. The normal components of magnetic signals Hp(y) on the beams and columns of a portal frame are obtained through pseudo-static testing. The signal increment ΔHp(y) and its absolute value |ΔHp(y)| under different loads are analyzed. The relationship between the equivalent stress and magnetic signal is investigated through numerical simulation. The results show that the ΔHp(y) curves are similar during the elastic stage but change abruptly during the plastic phase. Moreover, the differences in the magnetic signal directions caused by the varying detection directions cannot be ignored. In the elastic stage, with the increase in the load, |ΔHp(y)| curves initially increase and then decrease. The formation of the ΔHp(y) curve is similar to the distribution of the equivalent stress. The mutation of ΔHp(y) can determine whether a specimen is entering the plastic phase, and can warn against structural failure. The magnetic signal distribution qualitatively reflects the stress distribution.

Based on the nonlinear Barton-Bandis (B–B) failure criterion, this study considers the system reliability of rock wedge stability under the pseudo-static seismic load. The failure probability (Pf) of the system is calculated based on the Monte–Carlo method when considering parameter correlation and variability. Parameter analysis and sensitivity analysis are carried out to explore the influence of parameters on reliability. The relationships among the failure probability, safety factor (Fs), and variation coefficient are explored, and then stability probability curves of the rock wedge under the pseudo-static seismic load are drawn. The results show that the parameter correlation of the B–B failure criterion has a significant influence on the failure probability, but correlation increases system reliability or decreases system reliability affected by other parameters. Under the pseudo-static seismic action, sliding on both planes is the main failure mode of wedge system. In addition, the parameters with relatively high sensitivity are two angles related to the joint dip. When the coefficient of variation is consistent, the probability of system failure is a function of the safety factor.

Anchored retaining walls are structures designed to support different loading applied in static and dynamic cases. The purpose of this work is to design and study the stability of an anchored retaining wall loaded with different seismic actions to obtain minimal anchor lengths. Mononobe-Okabe theory has been applied for the evaluation of seismic earth pressures developed behind the anchored wall. Checking the dynamic stability of anchored retaining walls is usually done using the classic Kranz model. To take into consideration the effects of the internal forces developed during failure, we have proposed a new model, based on the Kranz model, which will be used as the Kranz model to find the critical angle failure performed iteratively until the required horizontal anchor length is reached for a minimum safety factor. The results of this study confirm that the effect of the seismic load on the design of an anchored retaining wall, and its stability, has a considerable influence on the estimation of anchor lengths. To validate the modifications made to the new model, a numerical analysis was carried out using the Plaxis 2D software. The interpretation of the obtained results may provide more detailed explanation on the effect of seismic intensities for the design of anchored retaining walls.

One of the major reasons for the popularity of reinforced soil structures is their ability to perform better under seismic loading conditions. This could be attributed to the conservatism associated with the design procedure that considers only the axial direction of the pullout force rather than an appropriate seismic design. The kinematics of failure, however, suggests that the direction of the pullout force is not axial, and it is inclined to the horizontal direction. This paper presents the pseudo-static stability analysis of a reinforced soil wall considering the obliquity of the pullout force, where the backfill soil is idealized as a two-parameter Pasternak model. The effect of various controlling parameters such as horizontal seismic coefficient, material properties of the backfill and the wall geometry on the pullout response is also studied under the seismic loading conditions. The results are compared with the conventional methods of analysis. The comparisons show that the present analysis removes the extra degree of conservatism prevailing in the conventional methods and thus gives a better estimation of the pullout capacity. A typical design of reinforced soil wall is also shown to demonstrate that the present analysis can be easily integrated with the existing methods.

In the previous chapter we discussed ways how to characterize DML cells into several libraries and use these with standard EDA tools. In this chapter we outline an optimized synthesis procedure for DML design. In a nutshell, this methodology involves changing certain steps within the tools. We present an algorithm for DML-optimized synthesis and show the implementation of this algorithm in Perl language. The synthesis results indicate that while this approach still has a significant room for improvement, it can boost performance gains and reduce the energy consumption of a design.

Pseudo-static approaches often become handy due to their simplicity compared to the complex coupled continuum dynamic analysis and yield satisfactory results. A pseudo-static approach is employed herein to evaluate the response of a pile-supported structure located in a highly active seismic zone in northeast India. Pseudo-static approach essentially involves two main steps: estimation of maximum ground deformations and surface accelerations from a free field ground response study, combined with static analysis considering the surface acceleration and superstructure mass. In the present study, dynamic behavior of underlying soil strata was investigated using two high-quality element testing techniques—resonant column and dynamic simple shear tests. The dynamic soil properties were established and site-specific ground response study was conducted for the chosen site, using the artificially generated ground motions for the region. Equivalent static load was estimated from the surface acceleration obtained from free field ground response study. A three-dimensional finite element model has been developed and validated against the field lateral load test results. An increased magnitude of displacement and bending moment was observed with increased ground motion intensity. The peak bending moments induced for the scenario ground motions is higher than the plastic moment capacity of the pile section, displaying the probable failure of considered pile-supported structure.

Well foundation is commonly used in India for road and railway bridges over rivers. It is a massive structure and hence it is generally considered to be safe under laterally loaded condition. Indian Roads Congress Codes (IRC:45-1972 and IRC:78-1983) suggests limit equilibrium approach to determine lateral load capacity of well foundation. It considers well foundation as a rigid body and surrounding soils as elastic in design state and plastic in limit state. Design procedure stated in Indian standard codes determines ultimate lateral load capacity of Well-Soil system. However, it does not yield the magnitude of lateral displacement of a well foundation at the ultimate load. Because of this, it is difficult to decide whether the lateral displacement at estimated ultimate lateral load capacity of a well foundation is allowable or not. Over the years, few methods to analyze the lateral response (both force and displacement responses) of well foundation are developed. These methods consider surrounding soil as linear elastic material which is modeled by linear elastic springs, and well foundation as a rigid body. Recently developed methods consider lateral stiffness as well as rotational stiffness of the surrounding soil and represent soil by parallel combination of lateral linear springs and rotational springs. Some of these methods also consider flexibility of well foundation and model well foundation by Euler-Bernoulli beam element. In this article, we present a comparative study of the available methods of analysis of laterally loaded well foundation. This study indicates significant differences in the response of Well-Soil system obtained from different methods. Validation of existing methods is done with two-dimensional continuum model to identify accuracy in existing models. It highlights the need for proper evaluation of available methods of analysis with realistic incorporation of foundation stiffness and interface effect in modeling the Well-Soil system for pseudo static loading conditions.

International audience; Dry stone retaining walls (DSRWs) are vernacular structures which can be found all over the world. Most of them have been built in the 19 th century but they can be as old as two hundred years. Because of decades of neglect, many of these walls are highly damaged; however, in the absence of national rules for this peculiar heritage, any intervention on these constructions is made difficult. A number of former studies in France have tried to settle the bases for a standard aimed at designing slope DSRWs. This paper complement those works in order to give clues for a seismic design of slope DSRWs following the simplified approach proposed by the Eurocode 8 and denoted pseudo-static approach. Firstly, scaled-down experiments have been carried out using a mock-up composed of a wall made of clay bricks retaining a sandy backfill. This mock-up was then tilted and the characteristics of the system at failure were reported and analysed. A particularity of failure in DSRWs is that the failure surface crosses the wall leaving a part of it intact. Secondly, an analytic method based on the limit equilibrium using the Coulomb wedge theory has been designed to predict the tilting angle and validated on the basis of these experimental results. Finally, some preliminary implications for the seismic design of DSRWs have been proposed for walls built in moderate seismicity areas which is typical of mainland France. In low seismicity zones, the extra width required to bear the seismic motion does not exceed 25% of the width identified through the static design. Results are also given for more critical cases associated to zones of higher seismicity as well as for different wall configurations.

Existing ancient Chinese timber buildings are frequently subjected to seismic or strong wind loads throughout their lifetime, hence their lateral structural performance can undergo significant changes. It is essential to employ tests in the laboratory to study these variations to protect these existing timber buildings. In this paper, a single-layer model of a timber building with a geometrical ratio of 1:2 was fabricated according to the pre-Ming dynasty construction method. Six pseudo-static tests were conducted under three levels of vertical loads. The timber structure displayed visible rocking characteristics during the tests, and the column feet and mortise-tenon joints were the weak links in the structure. The features of hysteresis curves, envelope curves, strength reduction, energy dissipation, and lateral stiffness of the timber structure were obtained, and their variations associated with loading courses were discussed. Moreover, a simplified restoring force model was built for this type of timber structure.

Although deformation along a weak joint under a strong seismic event can seriously damage the tunnel, the effect of joint has not yet been well understood or quantified. We perform a series of pseudo-static discrete element analyses to evaluate the effect of deformation along rock joint on the seismic response of circular tunnels. We also perform parallel continuum analyses to compare and quantify their differences. A comprehensive set of joint parameters are considered in this study. The results illustrate that the joint significantly increases the moment demand in the tunnel lining, whereas it has a secondary influence on the thrust. The joint stiffness and shear strength have critical influence on the tunnel response. Widely spaced joint set produces a larger tunnel response. The tunnel response is highest for vertical and horizontal joints, and the lowest when the joint dips at an angle of 45°. The moment in jointed rock may be 20 times higher than that in intact rock. The pronounced deviation from continuum analyses highlights the need to estimate the influence of discontinuities on the seismic response of underground tunnels from discrete element analyses. This may be of concern for critical structures such as nuclear facilities.

The static and dynamic performances of historical masonry churches are closely related to the behaviour of each substructure, as well as to the mechanical properties of the constituent materials. Information on damage location and extent, collected after recent violent Italian earthquakes, highlighted that masonry vaults are among the most vulnerable elements. The investigation of their dynamic behaviour under earthquake excitation (stress and deformation states) is a fundamental issue for effective structural interventions. During an earthquake ground motion, cross vaults are basically subjected to two phenomena: (i) the "shaking"/dynamic response of the vault system itself, vibrating above the lateral walls and piers, and (ii) the response of the vault to imposed displacements at its springings, accommodating the significant movements of the lateral walls and piers. Within this context, this paper aims at improving the knowledge of the structural behaviour of cross vaults under static shear deformation at the springings, by means of an experimental test representative of a Gothic cross vault from the aisle of the Holyrood Abbey in Edinburgh (UK). The experimental test was performed on a 1:4 scaled specimen built with timber and lime mortar. The shear displacement was applied by moving two abutments until failure. The deformation of the vault was recorded in space with a Total Station. The results of the tests are reported in this paper in terms of crack pattern evolution, vertical displacements of the transverse ridge, identifying the shear displacement levels corresponding to significant damages in the vault.

The identification of a single global model for a stochastic dynamical system operating under various conditions is considered. Each operating condition is assumed to have a pseudo-static effect on the dynamics and be characterized by a single measurable scheduling variable. Identification is accomplished within a recently introduced Functionally Pooled (FP) framework, which offers a number of advantages over Linear Parameter Varying (LPV) identification techniques. The focus of the work is on the extension of the framework to include the important FP-ARMAX model case. Compared to their simpler FP–ARX counterparts, FP–ARMAX models are much more general and offer improved flexibility in describing various types of stochastic noise, but at the same time lead to a more complicated, non-quadratic, estimation problem. Prediction Error (PE), Maximum Likelihood (ML), and multi-stage estimation methods are postulated, and the PE estimator optimality, in terms of consistency and asymptotic efficiency, is analytically established. The postulated estimators are numerically assessed via Monte Carlo experiments, while the effectiveness of the approach and its superiority over its FP–ARX counterpart are demonstrated via an application case study pertaining to simulated railway vehicle suspension dynamics under various mass loading conditions.

Este artículo presenta una estimación del riesgo en edificaciones por deslizamientos causados por lluvias y sismos en la ciudad de Medellín, empleando una plataforma de Sistemas de Información Geográfica (SIG). Para esto se implementó un modelo que considera las propiedades topográficas, geológicas, geotécnicas e hidrológicas de la zona en estudio. El modelo de cálculo usado para la valoración de la amenaza por deslizamiento, está fundamentado en el Método seudoestático de NewmarN para el cálculo de estabilidad de laderas y usa un enfoque probabilista el cual se basa en el método de primer orden y segundo momento —FOSM— para estimar la varia- ción de los parámetros geomecánicos del suelo. El abordaje para la valoración de la vulnerabilidad de las construcciones en el área de estudio se realizó mediante índi- ces de fragilidad estructural que consideran la definición de niveles de daño a través de árboles de decisión haciendo uso de la información catastral de la ciudad. El modelo calcula la probabilidad de que ocurra un deslizamiento dado que se presente un sismo que produzca una aceleración (Ah), considerando la incertidumbre de los parámetros geotécnicos y las condiciones de saturación del suelo, y multiplica tales valores con los índices de debilidad estructural para estimar los índices de daño de las construcciones, las cuales se asocian con el riesgo al considerar la variable eco- nómica correspondiente al costo de reposición de tales construcciones.

International audience; A pseudo-static study on dry-joint brick retaining walls has been carried out as part of a preliminary work aiming at designing actual dry stone retaining walls located in seismic areas. First, scaled-down dry-joint brick retaining walls have been tilted towards failure and the influence of the wall geometry has been analysed. Then, numerical simulations have been performed using the Distinct Element Method to complement the observations made in the experimental tests. From both approaches, we found that the more slender the wall is, the less resistant to a pseudo-static action it results. Using the numerical model, it has also been found that the assemblage plays a significant role in the stability of dry-joint structures, with a particular emphasis on the critical role played by the headers. Moreover, the simulations brought to light complex features when failure is triggered in large walls.

The problem of identifying a single global model for stochastic dynamical systems operating under different conditions is considered within a novel Functionally Pooled (FP) identification framework. Within it a specific value of a measurable scheduling variable characterizes each operating condition that has pseudo–static effects on the dynamics. The FP framework incorporates parsimonious FP models capable of fully accounting for cross correlations among the operating conditions, functional pooling for the simultaneous treatment of all data records, and statistically optimal estimation. Unlike seemingly related Linear Parameter Varying (LPV) model identification leading to suboptimal accuracy in this context, the postulated FP model estimators are shown to achieve optimal statistical accuracy. An application case study based on a simulated railway vehicle under various mass loading conditions serves to illustrate the high achievable accuracy of FP modelling and the improvements over local models employed within LPV–type identification.

The arrangement scheme of the sensors in a pseudo static test for an immersed tunnel joint was revealed in this paper. To achieve this target, the pushover analysis of the two immersion joint models were studied by using numerical calculation. The mechanical characteristics of the immersed tunnel joint under horizontal loading condition were carefully observed. According to the numerical results, shear keys and connecting part in tunnel elements are the key observation sections, the stress development, the shear capacity and the deformation features of the immersion joint should be measured. Furthermore, a loading system of pseudo static test for immersion joint is also developed. Based on the loading system and numerical funding, the locations for deploying sensors were determined. The scheme of sensor positions played a crucial role in guaranteeing the successful completement of the experiment, and also can offer some reference opinions for similar experiments.

This paper deals the analysis of the behavior of an underground saline cavity under the cyclic load due to traffic landing gear from the Boeing 747-400 airplane using the pseudo static approach. This cavity was located at a depth of 2.5 m from the free surface of the second runway at Es-Senia airport in Oran (Algeria). Where, this airstrip is built in very complex geotechnical conditions, which several cavities are formed by dissolution of gypsum, have been observed during the geological investigations. In-situ geotechnical studies and experimental tests carried out in the laboratory have permitted to identify the hydromechanical behavior parameters of the great Sebkha soil of Oran city. The Oran airport base is composed of a mixture of clay and silty gypsum sand with an overconsolidated behavior.

Green high performance fiber reinforced cementitious composites (GHPFRCC) are a new class of sustainable cementitious composites, employing a high volume of fly ash to replace cement. In addition to increasing the sustainability of the construction environment, GHPFRCC exhibits a high tensile ductility and multiple cracking behaviors in the strainhardening state. These materials can effectively improve the structural energy dissipation capacity and structural durability. In this study, the optimum mixture ratio of GHPFRCC is presented established using an orthogonal experiment for a specific engineering application. The described GHPFRCC sustains the mechanical performance of concrete and is employed as the outer cladding to strengthen concrete columns. The finite element analysis of the material was based on the software ABAQUS and pseudo static experiments were conducted to exhibit retrofitting of GHPFRCC applied in the rehabilitation of seismic-damaged concrete columns. The computed and experimental results showed that GHPFRCC, while incorporating high volume fly ash, can retain significant multiple cracking behaviors. The energy dissipation capacity of the GHPFRCC reinforced concrete (RC) column is better than the comparable unreinforced column.

This paper presents an experimental study on a full-scale two-storey, two-bay by one-bay steel-concrete composite slim floor that was subjected to horizontal pseudo-dynamic and cyclic pseudo-static loadings. The primary objective of this test is to investigate the bearing behavior and load bearing capacity of the composite slim floor under horizontal loads. The time-history load-displacement curves, hysteretic curves, skeleton curves, structural deformation and the failure mode were obtained from the tests. The test results indicated good load bearing capacity and good ductility of the test structure and also required improvement of the construction of the beam-column connection. At the end of this paper, some suggestion on the improvement of composite beam-column connection has been proposed.

In this present paper, a circular failure surface passing through the toe is assumed for a homogeneous soil, and the Fellenius line is used to locate the centre of the most critical circle. Using limit equilibrium analysis under the influence of static forces such as weight of potential slide mass and surcharge along with the pseudo-static seismic forces are considered to obtain the factor of safety of the slopes. Factor of safety is found through the application of force equilibrium. The effects of variation of different parameters like slope angle (i), soil friction angle (F) and seismic acceleration coefficients both in the horizontal and vertical directions (kh and kv respectively) on the factor of safety are presented. Finally, the present results are compared to the existing solutions available in literature and found to give minimum values of factor of safety using the present approach for seismic slope stability analysis.

This paper presents a limit equilibrium method, based on the approach of Mononobe and Okabe, for calculating the active thrust on fascia retaining walls, where common methods cannot be used owing to the narrowness of the backfill which does not permit the development of the thrust wedge in the shape and sizes predicted by these methods. The proposed method examines three distinct failure mechanisms, called Mechanism 1, Mechanism 2 and Mechanism 3, where the thrust wedge is formed by one, two or three blocks, respectively; separated by plane slip surfaces. The seismic forces have been simulated with the pseudo-static method. For all three mechanisms, the active thrust is obtained in closed form: in particular, with a cubic equation for Mechanism 2, and with a system of two equations, one cubic and the other quartic, for Mechanism 3. Mechanisms with more than three blocks cannot have analytical solutions. The study is completed by an examination of some significant cases from which the higher attenuation of the seismic thrust, with respect to the static, emerges as the backfill width reduces.

A reciprocating low-cycle pseudo-static loading test on three reinforced concrete (RC) piles was performed in the Structural Laboratory of Fuzhou University to study their failure modes and seismic behaviors. The modified calculations of lateral deformation and soil pressure along the piles were further verified based on the test results. In this article, a displacement-based simplified calculation for pile-soil interaction of piles was proposed based on the shear equilibrium and test results, and then it was compared with the traditional m method and p-y curve method. The test results show that m method overestimated the bearing capacity of piles, leading to a lower safety factor for the piles. Therefore, it was not suitable to calculate the internal force and lateral displacement under large displacement. Moreover, the ductility of prestress high-strength concrete pipe piles or RC piles would be overestimated by the p-y curve method. Although the p-y curve method took into account the nonlinearity of soil, the calculated force-lateral displacement curve still showed a significant difference with the test results under large deformation. The test results further show that the modified calculation of lateral displacement and soil pressure can be preferably validated by test results, which indicates that the displacement law of laterally loaded pile can be accurately assessed. Furthermore, the proposed displacement-based simplified calculation showed a good agreement with the test values in terms of internal forces and force-lateral displacement curve. Therefore, it was recommended for analyzing the cyclic behavior of laterally loaded pile foundations considering soil-pile interaction in integral abutments jointless bridges (IAJBs).

The horizontal pullout capacity of vertical anchors embedded in sand in the presence of pseudo static horizontal earthquake body forces has been determined by using the lower bound finite element limit analysis. The variation of the pullout factor Fγ with changes in embedment ratio of the anchor plate for different values of horizontal earthquake acceleration coefficient (αh) has been established. The effect of the anchor-soil interface friction angle on the results has also been examined. The pullout capacity decreases quite significantly with an increase in αh. The pullout capacity becomes higher for greater values of embedment ratio and interface friction angle. The normal pressure distribution along the front surface of the anchor plate and the development of failure patterns have also been examined.

The elasto-plastic analysis of reinforced concrete square columns was introduced to study the relationship between lateral force and curvature by using the open source program OpenSees. A pseudo static test on the inverted "T" shape reinforced concrete square column was conducted for the comparative analysis. The results indicated that the lateral force calculated by program agree with experimental data with an axial load ratio of 0.33. The calculated yield lateral force was 29.7 kN, the error was lower than 7% compared with experimental results. In addition, the cross-section curvature were obtained, which were difficult to obtain through the traditional experimental study, the calculated yield curvature was 1.825×10-5. The calculated results with different axial load ratios were presented in this paper, which showed that both the yield lateral force and curvature of reinforced concrete square columns were increased with low axial load ratio, and at the same time it could reduce some experimental work by using computer simulation.

The article puts forward a single-rammer energy calculation formula based on pseudo-static method which is to be applied in the dynamic compaction trials of saturated soft soil foundations. A comparison between the formula and the dynamic compaction effective reinforcement range formula is made. Then, data from actual engineering project are applied to the formula, and the calculated results are consistent with the testing results. That is to say, the formula can facilitate the forecast of single-rammer energy in dynamic foundation compaction.

Pseudo static method is a common method in the research of pile-soil interaction. In this paper pseudo static method was major introduced, the p-y relationship of saturated degraded soil was applied to Winkler foundation beam model to perform pseudo static calculations on the basis of previous studies. Through the practical calculation of test data in literature [1], the feasibility of this method was verified.

Discontinuity layout optimization (DLO) is a recent development in the field of computational limit analysis, and to date, the literature has examined the solution of static geotechnical stability problems only by this method. In this paper the DLO method is extended to the solution of seismic problems though the use of the pseudo-static approach. The method is first validated against the solutions of Mononobe–Okabe and Richards and Elms for the seismic stability of retaining walls, and then used to study the effect of a wider range of failure modes. This is shown to significantly affect the predicted stability. A framework for modelling water pressures in the analysis is then proposed. Finally an example application of the method is illustrated through the assessment of two quay walls subjected to the Kobe earthquake.

The paper deals with experimental activity on 4 scale-models of elevated pile cap foundation belonging to a real bridge. The foundation was composed of 9 piles, pile cap and pier and the special soil box was built to consider soil-pile-superstructure interaction. Two specimens were strengthened by steel protective pipe at each pile top. The tests consist of cyclically imposed displacement to 4 specimens, performed in the state key laboratory for disaster reduction in civil engineering of Tongji University. According to the test result, the peak strength of strengthening specimens is about 1.77 times of the others and the ultimate displacement is 1.66 times of the original models. Additionally, the dissipated hysteric energy capability of strengthening specimens is more than 2.15 times of the others as the equivalent viscous damping ratio is reduced by 50%. Other relevant phenomena are the pinching effect of original specimens is more obvious and the hysteretic loops of reinforced specimens are more plumpness. Moreover, the failure and collapse mechanisms of the elevated pile cap foundation were summarized. Finally, the measures to enhance the aseismic capability for elevated pile cap foundation were proposed.

In order to analyse seismic behaviors of the haunched beam-shaped transfer floor, carried out the pseudo static testing, which were subjected to vertical loads and horizontal cyclic loads, respectively on two specimens, including the framed short-leg shear wall haunched beam-shaped transfer plane framework and the same dimension unhaunched beam-shaped transfer frame. The test shows that: 1) Haunched beam-shaped transfer structure can apparently improve the shear-bearing-capacity of the abutment section and reduce the beam dimension effectively, and it is easier to implement the aseismatic design principles, including “strong column and weak beam, strong shearing and weak bend”; 2) if the design is reasonable, haunched beam-shaped transfer structure can get better seismic behavior.

Korea has about 70% of its land classified as the mountain area, which has led to cut-slope being the result of substantial road and railway construction. However, there is currently a lack of research about the seismic retrofit design of a slope, even though many earthquakes have recently occurred at home and abroad. In this study, in order to investigate the stabilizing effect of piles against sliding during an earthquake, a series of 1 g shaking table tests and pseudo-static analyses were carried out. As a result, the stabilizing effect of piles against sliding during an earthquake was verified by the 1 g shaking table tests and the most effective result from the pseudo-static analyses was that the installation of the piles on the central part of the slope, where the failure surface included piles unlike the lower part and upper part of the slope. Furthermore, when the pile was installed on the central part of the slope, the change of the safety factor depending on the distance between the center of two piles was evaluated.

Composite construction’s performance depends greatly on shear effectively transfer between steel and concrete, we usually set shear connector between surface of the two different materials, the connector is a determining factor of combinable capability. Composite open-web plate frame is a new type of composite construction, has good performance in application of large span and large load floor or roof. This paper carries on research on two kind of new shear connectors of the composite open-web plate frame, the shell type shear connector and the block type shear connector, and carried on push-out test, also done vertical pseudo-static analysis on composite open-web plate frame which adapt new connector, study the hysteretic behavior ultimate bearing capacity and damage form. Study shows that, block type shear connector which set additional steel bars has good mechanical properties, it’s a shear only connector; Composite construction which adapt the connector has good capability of energy consumption and higher safety storage under vertical load.

Landfills constructed in the seismic zones can experience the seismic forces in both the horizontal and vertical directions. However, in most of the design, the vertical component of seismic acceleration is neglected, assuming that it does not have great impact on seismic performance of landfills, which is not true especially for landfills located in vicinity of active fault areas. To design any generalized shape of landfill, it is hence necessary to compute the non-dimensional yield acceleration for the seismic stability of landfill. In addition, the estimation of permanent seismic displacements requires the information about the yield acceleration induced in landfills during earthquakes. A simplified limit equilibrium method for different types of landfills is used in the present study to address the above issues for different landfill configurations and with sloping bases considering the pseudo-static approach for the seismic forces. In addition, the effect of vertical component of seismic acce...

A study on centrifuge modelling of geogrid reinforced soil walls was carried out through centrifuge tilting table tests. Special attention was focused on the effect of the properties of geogrid and backfill material, and the interaction between geogrid and backfill material on the seismic stability of geogrid reinforced soil walls using different types of model geogrids and backfill materials. As a result, it was found that the seismic stability of geogrid reinforced soil walls is highly influenced by the tensile stiffness of the geogrid and the deformation modulus of the backfill material. The geogrid reinforced soil walls collapsed after clear formation of slip lines in the reinforced area due to failure of the backfill material. The effects of disagreements about similitude in this test series on the behaviour of geogrid reinforced soil walls are discussed with results of centrifuge tilting table tests and stability analyses with the two-wedge method. It was found that the pullout resistance at the displacement corresponding to the failure of geogrid reinforced soil walls should be used in the seismic stability analysis rather than the peak pullout resistance.

The article deals with a brief description of methods of temperature measurements in a flowing water steam. Attention is paid to the measurement of pseudo static temperature by a single sealed thermocouple entering the flowing liquid through the flown-by wall. Then three types of probes for stagnation temperature measurement are shown, whose properties were tested using CFD calculations. The aim was to design a probe of stagnation parameters of described properties which can be used for measuring flow parameters in a real steam turbine. An important factor influencing the construction is not only the safe manipulation of the probe when inserting and removing it from the machine in operation, but also the possibility to traverse the probe along the blade length.

Most backcalculation programs used to evaluate the pavement layer properties assume static deflections even though dynamic deflections are generated from the Falling Weight Deflectometer (FWD). This study aims to take into consideration the dynamic effects of the deflection basin from the FWD in the backcalculation procedure. A Pseudo-static backcalculation procedure, named DYN-BAL (Dynamic BALMAT), was developed to calculate the layer moduli after converting dynamic deflections into static deflections. In situ tests were carried out to evaluate the applicability and reliability of the backcalculation procedure, which can accommodate the dynamic effect. In situ tests included FWD tests at the site of a Multi-Depth Deflectometer (MDD) installation. From the test results, it was found that DYN-BAL gives the most reliable results when compared with several other computer codes in use.

Soil liquefaction during strong ground shaking results in almost a complete loss of strength and stiffness in the liquefied soil, and consequent large ground deformation. Characteristics of the liquefied soils and loads on piles are significantly different during the cyclic phase and in the subsequent lateral spreading phase. Thus, it is necessary to separately consider these two phases in the simplified analysis of piles. This paper describes a practical procedure for preliminary assessment of piles subjected to lateral spreading. Effects of a crust of non-liquefied soil at the ground surface, properties of liquefied soils and pile groups are discussed in relation to their modelling in the simplified pseudo-static analysis approach. Particular attention is given to the treatment of unknowns and uncertainties involved in the simplified analysis and the need for parametric studies.

Generalized solutions for uplift capacity of inclined shallow strip anchors embedded in general c–ϕ soils with inclined slope carrying a uniform surcharge is developed in this paper for seismic condition. The individual effects of unit weight, surcharge and cohesion components on the computation of uplift capacity of anchors are considered. Limit equilibrium method with logspiral failure surface is adopted in the analysis and the effects of seismic forces are considered as pseudo-static forces. The results have been presented in the form of seismic uplift capacity factors as functions of anchor inclination, ground inclination, embedment ratio, soil friction angle and seismic acceleration coefficients both in the horizontal and vertical directions. Both the seismic accelerations change significantly the uplift capacity of anchors. Effect of the vertical seismic acceleration coefficient has been found to always reduce the uplift capacity whereas the effect of horizontal seismic acceleration coefficient has been found to reduce the uplift capacity in most of the cases. Results are presented in graphical and tabular forms. Estimation of error while using the principle of superposition to compute the seismic uplift capacity is also conducted. A comparative study between the present theory and available results in literature shows the merits and requirement of the present analysis.

This paper describes an experimentally based procedure for building dynamic P–Y curves for clays from the Campeche sound in the Gulf of Mexico and for Mexico City clays. Cyclic triaxial and resonant column tests were used to derive hyperbolic stiffness–strain and damping–strain functions that depend on soil plasticity and on relative consistency. The dynamic P–Y curves incorporate these functions and also include hysteretical and geometrical damping characteristics of the pile–soil system; they can be used directly in dynamic interaction analyses of structure–pile–soil systems in the time or the frequency domains. Usual practice relies on pseudo static formulations and a simplified alternative to include P–Y curves in this kind of analysis is also proposed, which is essentially the same as the dynamic ones but does not include radiation or hysteretical damping.

We purpose to study the stability of reinforced earth walls subjected to seismic loading within the framework of conventional pseudo-static analysis applied to homogenous material. Firstly, we present a study of the stability of reinforced earth walls within the framework of the limit analysis. Secondly, we use the Newmark method for the determination of displacement field induced by seismic loading. Results of numerical simulations show a significant contribution of the reinforcement in the improvement of the resistance of reinforced walls to seismic loading.

In recent years, the seismic behaviour of structural systems composed of squat concrete walls has been the object of a renewed interest. This paper presents the results obtained in a large experimental campaign carried out as a joint effort between the University of Bologna and the Eucentre labs in Pavia. This effort aims at the assessment of the seismic performances of cellular structures composed of cast in situ sandwich squat concrete walls. In order to shed light upon the seismic behaviour (stiffness, strength, ductility, energy-dissipation) of such structures, a number of tests were performed upon two dimensional (3.0 m by 3.0 m) cast in situ sandwich squat concrete walls (with and without openings). In the experimental tests a number of horizontal in-plane loading cycles were imposed to the specimens, while the vertical load was kept constant. The results obtained have shown that the tested elements are characterized by: (i) high values of the maximum horizontal load applied to the structural systems (higher than the applied vertical load); (ii) residual bearing capacity with respect to the vertical loads, also when large lateral deformations are imposed; and (iii) high ductility.