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This work presents the numerical simulations of shaking table tests of a full-scale masonry cross vault. The boundary conditions simulate the presence of a continuous lateral wall and of a colonnade-between-naves condition. The seismic action is applied along the longitudinal direction of the specimen, with increasing amplitude. The model used for the simulations allows for the elastic finite element modelling of masonry units and the discrete element modelling of the interfaces between them. A tension cut-off governs the interface: no tensile stress can be transmitted once this strength is exceeded. The shear response is defined by cohesion and friction: once the former is exceeded the interface reacts according to Coulomb's behaviour. The simulations are related to the blind predictions, according to the scheduled tests, and the post-dictions, according to the actual testing sequence. The prediction model overestimates displacements and does not catch the actual crack distribution. Therefore, a post-simulation model was implemented, revising the masonry elastic modulus as well as the stiffness and boundary conditions of the supporting piers. Simulations are improved both in terms of displacement predictions and damage mechanism. Finally, the sensitivity to finite-element size, damping ratio and block discretisation was explored. [ABSTRACT FROM AUTHOR]

Due to several advantages, including controllable tolerance, accelerated construction and environmental friendliness, the grouting sleeve connections has been widely used in precast concrete pier structures. However, the seismic capacity of precast concrete piers would be significant impaired under the marine or deicing-salt environment. This article presents an experimental investigation on the seismic behaviour of corroded precast concrete piers with grouting sleeve connections. Five specimens with different corrosion levels were tested under cyclic loads. Seismic capacities of specimens with different corrosion levels, including hysteretic behaviour, stiffness degradation and energy-dissipation capacity, were analysed. The results showed that corrosion of reinforcements and grouting sleeve connections would significantly affect the seismic behaviour of the piers. The crack load, yield load and peak load decreased gradually with the increase of corrosion ratio, with the effect of corrosion on peak load being slightly greater than that on yield load. An approximate exponential decrease in yield displacement and peak displacement was observed as the corrosion ratio increased, and the decline rate in yield displacement and peak displacement gradually decreased. A numerical method for simulating the seismic behaviour of corroded precast concrete piers with grouting sleeve connections is proposed, and agreement between simulated and experimental results is observed. [ABSTRACT FROM AUTHOR]

This work presents the simulations of the non-linear dynamic response of a three-dimensional finite-discrete element model. The model simulates a half-scale masonry building aggregate tested on a shake table by other Authors. The aggregate is made of two un-connected building units having different heights and slightly different wall thicknesses. The floors are made of timber beams and boards. The modelling approach accounts jointly for in-plane and out-of-plane responses, which can be expected given the high flexibility of the floors, and for the separation between the two building units. The simulations are related both to the blind predictions, according to a scheduled testing sequence, and to the post-dictions according to the actual testing sequence and some model calibrations. The prediction model overestimates displacements, underestimates base shear and fairly predicts the damage pattern of comparable experimental runs. The use of the recorded shake table motion improves the accuracy of the post-diction simulations, while still delivering beam unseating. A higher Young's modulus of the blocks improves markedly the predictions. The strengthening intervention with steel angles connecting floors to walls is only approximately modelled and does not improve the outcomes of the simulations. In summary, the adopted modelling approach is capable of accounting for the pounding between the two building units, predicting the most significant damage as well as estimating approximate average of peak values of base shear and displacements, while individual time histories are less accurately estimated. [ABSTRACT FROM AUTHOR]

Liquefaction is a catastrophic phenomenon that poses a serious threat to lifelines during an earthquake. To assess the seismic behaviour of a well casing buried in saturated sand, a series of 1-g shaking table model tests were performed. The present study aims to investigate the impacts of the relative density and groundwater level on the base case as well. The responses of the models, including accelerations, pore water pressure changes, settlements, and strains induced along the well casing at various locations, were measured during the shaking. The outcomes illustrated that the groundwater level has a significant effect on the position of maximum strain. A rise in relative density leads to a 40.7% reduction in strains and moments caused along the well casing, while the rate of strain permanence in denser soils is considerable compared to looser soils. Moreover, experimental results indicated that the maximum shear force caused at the bottom of the well casing grows about 67% with increasing groundwater table. [ABSTRACT FROM AUTHOR]

Building with rammed earth has become increasingly popular in recent years because it is highly sustainable and has little environmental impact. More than half of the world's population lives in earthen houses, many of which are located in earthquake-prone areas such as Croatia. However, their seismic performance still needs to be researched, especially considering local construction techniques. One of the first steps in this process is the experimental testing of such walls. Four models of rammed earth walls were constructed using traditional local building techniques and experimentally tested under in-plane cyclic loading to investigate their seismic behaviour. The model walls were built using locally available soil material. The new particle size distribution envelope for determining the suitability of soil material for rammed earth construction was proposed for the first time. The building material was chosen according to the envelope. Moreover, walls were made using two different material compositions—i.e., natural soil from eastern Croatia and "man-made" soil with the addition of fine gravel. The main objective, the seismic performance of the RE walls, was evaluated in terms of their bearing capacity, behaviour after yielding, failure mode, stiffness degradation, initial elastic stiffness, and energy dissipation capacity. [ABSTRACT FROM AUTHOR]

Assessing the seismic vulnerability of existing buildings is an essential task for the management of earthquake disasters. For this purpose, the seismic behaviour of buildings is usually determined under the assumption of isolated conditions, although aggregate structures are one of the most common typologies found in urban centres. This study aims to investigate the nonlinear static behaviour of aggregate dwellings consisting of grouted reinforced concrete block configurations commonly observed in San José, Costa Rica. This research investigates the use of several strategies to model connections between adjacent buildings which are typically found in modern building practises in this country. The methodology used here to analyse the seismic behaviour of isolated and row-aggregated dwellings reveals significant differences in their response under seismic loads, especially when acting perpendicular to the aggregate. The study reveals that the type of interaction considered between adjacent buildings has a very important impact on the seismic capacity and failure mechanisms of the aggregated structures. This procedure can also be applied to the vulnerability assessment and retrofit of existing aggregates. [ABSTRACT FROM AUTHOR]

Out-of-plane (OOP) damage is one of the main failure modes for infill walls in frames during earthquakes, which can result in significant economic losses, injuries, and fatalities, and is difficult to repair. This paper investigates the effect of in-plane(IP) damage on the out-of-plane performance of infill walls using recycled concrete blocks with the finite element software ABAQUS and t was used to model and analyse the infill walls with recycled concrete block frames, and the modelling method is verified by the test results. The out-of-plane performance of 20 infill walls with recycled concrete block specimens of different aspect ratios and block sizes was investigated under various inter-story drift damage conditions. The results indicate that in-plane damage has little effect on the out-of-plane bearing capacity when the inter-story drift is 0.15%, and the initial out-of-plane stiffness of the infill walls increases by 5.4%. However, when the in-plane inter-story drift reaches 0.5%, the out-of-plane bearing capacity decrease by more than 50%, and the initial stiffness and ductility also decrease significantly. The study found that the thickness-to-diagonal length ratio of the infill walls has a prominent effect on the out-of-plane strength reduction, and an empirical formula for the in-plane damage and the out-of-plane strength reduction coefficient was proposed and fitted to the data obtained from the finite element analysis with a root mean square error of 0.18. [ABSTRACT FROM AUTHOR]

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Fixed pile-founded offshore platforms require careful consideration during their analysis, design, and assessment because uncertainty in design variables can decrease the reliability of the structures. The present study investigated the sensitivity of seismic engineering demand parameters to stochastic and epistemic modelling variables for a fixed pile-founded jacket platform. Tornado diagram analysis and the first-order second-moment techniques were employed to examine the effects of 11 variables on engineering demand parameters under real earthquake loads and the importance of each variable was determined. As the nonlinear response of the pile foundation is a crucial source of nonlinearity in offshore platform response, a robust model considering soil–pile–structure–fluid interaction was employed. This study varied from previous research as it employed a three-dimensional model, fluid environment modelling, and earthquake actions in perpendicular directions. These differences resulted in more realistic approximations of the seismic behaviour of the platforms. It was found that the effects of different variables, especially water depth, should be considered in order to produce better performance evaluations of a structure for a more efficient and cost-effective design. [ABSTRACT FROM AUTHOR]

Confined masonry (CM) is a construction system that consists of loadbearing masonry wall panels enclosed by vertical and horizontal reinforced concrete confining elements. The presence of these confining elements distinguishes CM from unreinforced masonry systems, and makes this technology suitable for building construction in regions subject to intense seismic or wind activity. CM construction has been used in many countries and regions, and has performed well in past earthquakes. The purpose of this paper is to review experimental research studies related to the seismic in-plane and out-of-plane behaviour of CM structures. The authors identify the key design and construction parameters considered in previous research studies and perform statistical analyses to establish their influence on the seismic performance of CM walls. For the purposes of this study, the authors compiled databases of previous experimental studies on CM wall specimens, which were used for statistical analyses. Finally, the paper discusses research gaps and the need for future research studies that would contribute to the understanding of seismic behaviour and failure mechanisms of CM walls. [ABSTRACT FROM AUTHOR]

This paper focused on the behavior of the dam when exposed to seismic loading and ability of the dam to withstand the applied loads from various seismic events. The chosen concrete dam to be referred to in the twodimensional analysis is Beris Dam located in Kedah, Malaysia. A nonlinear dynamic analysis is chosen to analyse the behavior of Beris Dam under selected ground motion. Analysis of the dam is performed using the finite element method by utilizing ABAQUS software. From the cracking analysis pattern, a crack appeared at the upstream face of the dam caused mainly by the excessive tensile stress. Based on the results, the displacement of the dam is increased with the increasing of ground motion data where the displacement occurred in the horizontal direction. The maximum stresses exerted by the dam structure do not exceed the allowable capacity of concrete dams. The stress behaviour of the dam was satisfactorily acceptable as the maximum normal stress and shear stress of the dam when numerous seismic loadings are applied do not exceed the allowable stress capacity which is 800 kN/m2. [ABSTRACT FROM AUTHOR]

A novel precast concrete (PC) frame with an innovative assembly pattern and optimised connection locations was proposed and evaluated. The PC column components were connected by extrusion sleeves and/or U-type reinforcement ferrules to realise cost-effective, efficient, and reliable assembly. Quasi-static cyclic loading tests and finite element analyses were conducted on a cast-in-place (CIP) frame and three PC frames with different connection types. The PC frames exhibited higher lateral stiffness and load bearing capacities than the CIP frame, as well as similar energy dissipation capacities. The PC frames employing the extrusion sleeve connections in the beam exhibited the best seismic performance. [ABSTRACT FROM AUTHOR]

The conservation of modern architectural heritage in seismic contexts must consider the analysis of more complex pathological processes than those traditionally associated with reinforced concrete deterioration. The behaviour of 21 school buildings built in Chile between 1937 and 1965 was comparatively analysed using the pathological diagnosis method. The documentation, in-situ observation, and measurements with non-destructive testing show that mechanical damages are more severe than physical–chemical damages. The levels and classification of deterioration are affected by accumulated damage due to the property's age and the characteristics of the architectural and structural design, which evolve from models of resistance by rigidity to flexible behaviour, which have lower levels of damages. In turn, the physical–chemical damage in the envelopes will depend mainly on the construction quality of the enclosures and the maintenance processes, rather than on the variation of the period's designs. An adequate pathological diagnosis of this architectural heritage allows the generation of appropriate conservation action guidelines to prolong the durability of these heritage works. [ABSTRACT FROM AUTHOR]

Many factors affect the earthquake vulnerability of reinforced concrete (RC) structures, constituting a large part of the existing building stock. Short column in RC structures is one of the reasons for earthquake damage. Significant damages may occur due to brittle fractures in structural elements when the shear resistances are exceeded under the effect of high shear stress in short columns formed due to architectural and topographic reasons. This study created structural models for three situations: the hill slope effect, band-type window and mezzanine floor, which may cause short column formation. The structural analyses by SAP2000 were compared with the reference building model with no short columns. Structural analyses were performed separately according to strength-based and deformation-based design approaches in the updated Türkiye Building Earthquake Code (TBEC-2018). Short column formation; the effects on soft-storey irregularity, the relative storey drifts, column shear force, plastic rotation in columns, roof displacement, base shear force and column damage levels were investigated. As a result of the analysis, it was determined that the relative drifts from the first floor of the building decreased significantly due to the band-type window and slope effect, which caused the second storey to fall into the soft-storey status. In addition, short-column formation caused a significant increase in both plastic rotation demand and shear force in short columns. [ABSTRACT FROM AUTHOR]

The Algerian seismic code assumes that the beam-column joints in monolithic reinforced concrete (RC) buildings are fully rigid. However, many experiments have proven the existence of relative rotations in these connections, and then the presence of relative transfer of bending moment. The present work aims to investigate the effect of beam-column joints modelling on the global seismic behaviour of reinforced concrete (RC) moment-resisting frame buildings, designed according to the Algerian seismic code recommendations. To consider the nonlinear deformation of the connections, an analytical model developed recently is used. This model includes two important deformation mechanisms; the first one covers the slippage of the continuous reinforcement within the column, whereas the second involves slippage caused by the creation of bending cracks at the extremities of the beams. Three multi-storey RC frames with different setback geometry, including a reference frame, are studied considering the connections as rigid/deformable. The nonlinear static procedure or pushover analysis is used to perform a nonlinear analysis of the studied structures and the results in terms of capacity curve, target displacement, storey drift, storey stiffness and the response reduction factor are presented. The results show the necessity of considering the beam-column connection flexibility when modelling this type of buildings

In the seismic risk assessment of structures, two main random variables are involved, namely the vulnerability of the structure and the seismic action. The aim of the study presented here is to analyze the seismic behavior of the jacket-type offshore platforms as an expensive and vital structure. Furthermore, the influence of the incidence angle of the seismic action is also investigated by using twelve ground motions, rotating the direction of both orthogonal components by 22.5° (from 0° to 180°). Three damage states have been used in result interpretation. The variability of structural response to the direction of seismic input becomes larger as the level of inelastic behavior increases. In the present study, the critical directions were determined and the vulnerability of jacket type offshore structure was examined by fragility curve based on methodology suggested by Pacific Earthquake Engineering Research Center (PEER) for three damage limit states by both multicomponent incremental dynamic analysis (MIDA) and directional multicomponent incremental dynamic analysis (DMIDA). Finally, it is found that structural behavior in the collapse zone is sensitive to directional uncertainty can change the results by up to 10%.

Featured Application: Practical engineers should gain confidence in base isolation as an alternative to stiffening, a possible design approach for new as well as for existing buildings even under rare seismic conditions (in large corner period areas and for pulse-type seismic records). This article presents the structural benefits of curved surface sliders on a specific, existing building application. Moreover, authorities should be encouraged by the information included in this article, to emphasize alternatives to the stiffening design approach even under such special seismic conditions. Southern Romania is a geographic region with alluvial deposits. This soil type leads to rather long corner periods and provides as a particularity of the response spectrum an enlarged plateau. These conditions produce large displacement demands. Moreover, pulse-type ground acceleration records make this seismic area more unique. Research on the seismic behaviour of structures built under such unusual conditions is limited and Romanian engineers are not confident to apply alternative solutions such as base isolation. Although capacity design is still the regular design method applied in Romania, modern base isolation solutions may overcome the large displacement demand expectation produced by seismic events and fulfil immediate occupancy requirements. This study presents the seismic performance of an existing hospital from Bucharest, for which two seismic design solutions were applied: (i) classical approach based on capacity design and (ii) base isolation. Both approaches are compared in terms of drift, acceleration and base shear values. Static as well as non-linear dynamic analysis methods were applied. [ABSTRACT FROM AUTHOR]

Large-scale shaking table tests were conducted to reveal the seismic instability mechanism of a sandy cutting slope under strong seismic action during the construction of the Sichuan‒Tibet railway. The input peak ground acceleration (PGA) was gradually increased to observe the spatiotemporal characteristics of the acceleration, dynamic strain and residual strain, dynamic displacement, and dynamic earth pressure of the cutting slope. Clarifying the dynamic stress and residual strain responses under different seismic excitations reveals the slope instability mechanism. The critical failure state analysis was analysed to examine the stress‒strain characteristics and the shear zone development under alternating compressive and tensile seismic loads. The delimitation of the critical state of the cutting slope from stability to instability under earthquake excitation was explained. The model test results show that the acceleration amplification factor defined by the positive PGA is more applicable for evaluating the amplification effect than that defined by the negative PGA (i.e. PGA ≥ 0.4 g). The evolution of the stage residual strain and shear strain reflects the shear zone development near the interface between the slightly dense and medium dense sand layers. The critical value of the normalized dynamic stress decreases from 2.1 at the back of the slope to 0.66 at the slope toe, showing a decreasing trend. As dynamic stress increases, the growth characteristics of residual strain exhibit stability and failure states. The results of this experimental study provide guidance for studying seismic instability mechanisms and improving retaining reinforcement technology of granular soil slopes along the Sichuan‒Tibet railway. [ABSTRACT FROM AUTHOR]

The assessment of the static and dynamic behaviour of historic masonry towers, together with the development of proper preservation strategies, has attracted in recent decades the interest of a plethora of scholars. Most of the studies focus on the assessment of their seismic behaviour since their slenderness exposes them to the dynamic effects induced by medium-to-severe earthquakes. This paper, which is framed in this background, discusses on a preliminary identification of the seismic behaviour of Giotto's bell tower in Florence, one of the iconic masonry towers ever built in Italy. In the first part of this paper, a summary of the available information on this bell tower is provided. Next, a refined numerical model, built through the finite element technique, and based on a recent laser scanning survey, is reported and employed to investigate its seismic behaviour. The numerical model accounts (in a simplified way) for the soil-structure-interaction, and scaled natural accelerograms selected based on the Florence seismic hazard are considered to develop linear and nonlinear time-history analyses. The results allow an initial assessment of the seismic behaviour of Giotto's bell tower suggesting both future in-depth investigations and analyses, together with proper preservation strategies. [ABSTRACT FROM AUTHOR]

The safety of the built heritage of our cities towards environmental factors and seismic actions is a pressing need for designers and researchers. The actual trend is to setup effective solutions to reduce thermal dispersions through the building envelope. Contrarily, combined systems able to enhance the resistance of constructions to earthquakes, on the one hand, and, on the other hand, to increase the energetic efficiency of existing buildings are scarcely diffused on the market and are rarely investigated in the scientific literature. In this framework, the seismic design of the new envelope DUO system for seismic-environmental requalification of existing masonry constructions is illustrated in the present paper with reference to a case study in the Neapolitan area. After the geometrical and mechanical characterization of the investigated building is performed, an FEM model of the masonry construction is setup by the SAP2000 analysis program, which has allowed performing pushover analyses. Based on the non-linear seismic response of the construction, an appropriate upgrading design mainly based on the innovative seismic envelope DUO system has been made. The static non-linear analyses applied to the upgraded FEM model of the building have shown a clear increase in performance in terms of strength, stiffness and ductility, thus confirming the effectiveness of the proposed envelope system.

The monumental complex consisting of the cathedral, tower and main square of Modena (Northern Italy) has been a UNESCO World Heritage Site since 1997. The visible tilting of the Ghirlandina tower has always generated concerns for its preservation, even more after the recent seismic events. This paper highlights the role of structural monitoring for the conservation of the site, with particular reference to the data acquired during the recent Emilia earthquakes. Unexpectedly, the inclination of this leaning tower decreased after the major seismic event. Some considerations are presented regarding the difficulty of modelling this kind of effects on buildings with complex historical stratifications and the application of the observational method, derived from geotechnical engineering, is proposed. The importance of structural monitoring is once again recalled, in order to preserve world heritage and comply with the principle of minimum intervention.