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ABSTRACTTopographic influences of the ground motions in 3D geological configurations have been addressed using Spectral Element Method as implemented in SPECFEM3D code developed to simulate seismic wave propagation. Hexahedral mesh model was constructed to which the 1987 Jinka earthquake source characteristics were applied. The simulation results have shown that topography has significant effects on ground motion and changes PGA values by ± 55% compared to the flat topography. PGA amplification variation between valley and hill/ridge top is observed to be in the order of 1.6. The study indicates that there is PGA amplification on top of hills and de-amplifications occur at the base. Valleys and flat areas generally show low and negative amplification factors. It is observed that topographic features play significant roles in concentrating or diffusing seismic energy. This was confirmed by observing the behaviour of PGA values along selected profiles and by comparing PGA maps with and without topography. The study shows that topography has serious consequences and must be taken into account to minimise damage to infrastructures and safeguard human lives and suggests the importance of incorporating the effects of topographic features in any seismic hazard analysis schemes in densely populated mountainous regions.

Topographic influences of the ground motions in 3D geological configurations have been addressed using Spectral Element Method as implemented in SPECFEM3D code developed to simulate seismic wave propagation. Hexahedral mesh model was constructed to which the 1987 Jinka earthquake source characteristics were applied. The simulation results have shown that topography has significant effects on ground motion and changes PGA values by ± 55% compared to the flat topography. PGA amplification variation between valley and hill/ridge top is observed to be in the order of 1.6. The study indicates that there is PGA amplification on top of hills and de-amplifications occur at the base. Valleys and flat areas generally show low and negative amplification factors. It is observed that topographic features play significant roles in concentrating or diffusing seismic energy. This was confirmed by observing the behaviour of PGA values along selected profiles and by comparing PGA maps with and without topography. The study shows that topography has serious consequences and must be taken into account to minimise damage to infrastructures and safeguard human lives and suggests the importance of incorporating the effects of topographic features in any seismic hazard analysis schemes in densely populated mountainous regions. [ABSTRACT FROM AUTHOR]

Wilayah Kemiling yang terletak di Kota Bandar Lampung sering kali mengalami gempa lokal dengan magnitudo kecil. Gempa ini terjadi secara berulang dan dirasakan di daerah Kemiling dan sekitarnya. Hal tersebut dapat menimbulkan kekhawatiran bagi warga dan dapat merusak bangunan. Fokus utama pada studi ini adalah untuk memahami bagaimana karakteristik tanah dan indeks kerentanan seismik di daerah tersebut. Untuk meminimalisir dampak kerusakan akibat gempa, perlu dilakukan mikrozonasi pada wilayah rawan gempa. Parameter mikrozonasi yang digunakan untuk mengetahui karakteristik tanah antara lain amplifikasi (A0), frekuensi natural (f0), indeks kerentanan seismik (Kg), periode dominan (T0), dan kecepatan gelombang geser hingga kedalaman 30 meter (VS30). Sebanyak 65 titik pengukuran mikrotremor telah diukur di Kecamatan Kemiling dan sekitarnya meliputi kota Bandar Lampung, Kecamatan Gedong Tataan, dan Kecamatan Natar. Pada penelitian ini digunakan analisis metode Horizontal to Vertical Spectral Ratio (HVSR) dan didapatkan bahwa frekuensi natural berkisar antara 0,5-31,47 Hz, periode dominan 0,03-2,0 sekon, amplifikasi 0,76-7,67 kali penguatan, indeks kerentanan seismik 0,05-76,31, dan VS30 49,61-777,80 m/s. Hasil penelitian menunjukkan bahwa wilayah barat daya hingga utara Kemiling memiliki risiko kerentanan yang lebih tinggi dibandingkan wilayah lainnya dengan tipe tanah berupa tanah lunak. Oleh karena itu, diperlukan tindakan mitigasi yang tepat, termasuk pengembangan rencana mitigasi risiko, pemantauan lanjutan, dan keterlibatan aktif masyarakat dalam perencanaan darurat.

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The position of Bengkulu Province, which is flanked by the subduction zone between the Euro-Asian and Indian-Australian plates to the west, and the Sumatra Fault zone to the east, makes Bengkulu City one of the areas prone to earthquake disasters. Muara Bangkahulu District is one of the sub-districts in Bengkulu City. Muara Bangkahulu sub-district is an area that functions as a government centre, trade and service centre, and one of the education centres in Bengkulu City. This study aims to determine the ground response in the Muara Bangkahulu sub-district area during an earthquake. The wave propagation method used in this study is a one-dimensional equivalent of linear and nonlinear modelling that propagates earthquake waves from bedrock to surface. The results of this study are Peak Ground Acceleration (PGA), amplification factor, earthquake acceleration time history, and acceleration spectra response. The results of this analysis will be compared between equivalent linear and nonlinear values. The results of this study can also help us realise and further consider the value of seismic design in the Muara Bangkahulu sub-district area, mainly if a stronger earthquake occurs in the future.

AbstractThis study, conducted in the Banarli district of Tekirdag Province, Turkey, focuses on soil reaction analysis and liquefaction potential in an area where a landfill and an associated power plant are planned. The research was examined with a one-dimensional ground response analysis to understand seismic behaviour, revealing the varied responses of soil categories to seismic waves. Soft soil layers were found to lengthen the dominant period of oscillation rather than significantly enhancing peak acceleration during seismic events. Earthquake records specific to the region were crucial for accurate assessments. The study comprehensively assessed liquefaction potential using various estimation methods, including the probability of liquefaction (PL), liquefaction potential index (LPI), and liquefaction risk index (IR). Moreover, this study examined liquefaction potential based on Standard Penetration Test (SPT) results, identifying susceptibility in the clayey sand layer at a depth of 3 to 12 meters. Recommendations for soil improvement measures are made to mitigate the risk. This research highlights the need for “customized seismic protocols” and emphasizes the importance of “site-specific assessments” in construction projects. By addressing susceptibility to liquefaction and proposing targeted ground improvement strategies, we contribute to safer and more resilient infrastructure development.

Local soil conditions play a significant role in the intensity variations of seismic waves during earthquakes. These variations can be either amplified or de-amplified depending on the specific soil conditions. This study aimed to assess the impact of different soil profiles on seismic site responses. The study considered four types of site profiles: sand (Sa), clay (Cl), sand overlying clay (SaCl), and clay overlying sand (ClSa) profiles. To simulate the ground motion, we selected seven sets of strong earthquake records from the European Strong-Motion Database. These records were selected according to Eurocode-8 with a peak ground acceleration (PGA) of 0.24 g, site class A using REXEL computer program. The records were then applied to the bedrock at a depth of 30 meters. Subsequently, a series of 1-D equivalent linear (EQL) response analyses were performed using the STRATA. Amplification factors (AFs) and surface acceleration time histories provided quantitative evaluations for our analysis results. The results demonstrated that site profiles with clay overlying bedrock (SaCl and Cl profiles) exhibited higher seismic amplification and peak ground acceleration in comparison to site profiles with sand overlying bedrock (Sa and ClSa profiles). The maximum median AF is calculated from the SaCl site profile, while the minimum median AF was calculated from the ClSa profile. The relative difference between the maximum and the minimum median AFs was about 33.7%. Based on these results, we can conclude that soft local soils have a pronounced effect on the amplification of seismic waves compared to stiff local soils. [ABSTRACT FROM AUTHOR]

Premixed hydrogen-air laminar flames with equivalence ratios ranging from 0.32 to 2.68 adopt different shapes during propagation in a gap (from 1. 5 mm to 4. 2 mm) between two plates. Thermodiffusive and Darrieus–Landau instabilities are visible for lean mixture while Darrieus–Landau is visible at higher equivalent ratio. Using for the first time simultaneous schlieren visualisation in this configuration, we were able to make two important observations: (i) either symmetric or asymmetric shapes are observed and quantified within the gap as a function of equivalence ratio and gap thickness; (ii) 3D flame surface for unstable laminar flame was estimated. These results validate (or invalidate) the quasi-2D assumptions made in Hele-Shaw cells. Linear stability analysis allowed us to find an a priori criteria differentiating symmetric and asymmetric cases. Finally, curvature effect on flame speed enhancement relative to surface amplification is estimated for unstable hydrogen-air laminar flames. This experimental 3D amplification factor provides means to take into account instabilities effect on large scale turbulent models. • The first quantification of the asymmetry factor in Hele-Shaw cells is presented. • Asymmetric cases may occur when the channel gap exceeds the cut-off wavelength. • The curvature between the plates results in an increase of the 2D flame surface by 25%–50% • For the first time, we have estimated the 3D wrinkling factor for unstable flames. • Amplification factor measurements show values greater than one for lean H2 mixture. [ABSTRACT FROM AUTHOR]

The Integrated Laboratory Building of Political and Social Science Faculty, located in a seismic-prone area, has been the subject of a comprehensive study of its performance using seismic response analysis. This research has yielded significant findings, gathering crucial secondary data, such as soil layers, bedrock depth, building structure, and earthquake wave information. The seismic response analysis, conducted by referencing the synthetic earthquake wave from the Bengkulu–Mentawai earthquake in 2007, with a magnitude of Mw 8.6, has provided a comprehensive overview of the earthquake waves at the foundation soil layers. The data, analysed using the finite element method to understand the structural response, revealed that the Peak Ground Acceleration (PGA) and amplification factor at the surface soil layer are 0.220g and 1.429, respectively. The most critical PGA and amplification factors at the foundation soil layer are 0.147g and 0.955. Structural analysis has revealed internal forces and beam elements experiencing over-strength, necessitating retrofitting the affected structural elements to reduce the impact. One practical and highly effective method of retrofitting involves increasing the beam dimensions by 53.12%. With retrofitting, the impact of structural deformation can be minimised, enhancing the building’s resilience in case of an earthquake of equal or greater magnitude. These findings underscore the importance of our research and highlight the significant role of engineers, architects, and researchers in ensuring the safety and longevity of structures in seismic-prone areas.

A computational methodology is presented for calculating the spatial evolution of Tollmien–Schlichting (T–S) waves and their amplitude growth-rate factor in substantially nonparallel compressible flows, based on a global stability analysis of stationary solutions of the full Navier–Stokes (N–S) equations. Three stages of this methodology (obtaining a stationary solution, as well as carrying out a global stability analysis and its postprocessing) are described, and the results are presented of its validation based on the comparison of the results of calculating the characteristics of T–S waves on a flat plate with the corresponding results of the classical stability theory in the parallel approximation. An example of calculating the flow around a plate with a rectangular cavity is presented to illustrate the possibility of applying the proposed methodology to nonparallel flows. [ABSTRACT FROM AUTHOR]

As an important part of nonstructural components, the seismic response of indoor water supply pipes deserves much attention. This paper presents shaking table test research on water supply pipes installed in a full-scale reinforced concrete (RC) frame structure. Different material pipes and different methods for penetrating the reinforced concrete floors are combined to evaluate the difference in seismic performance. Floor response spectra and pipe acceleration amplification factors based on test data are discussed and compared with code provisions. A seismic fragility study of displacement demand is conducted based on numerical simulation. The acceleration response and displacement response of different combinations are compared. The results show that the combination of different pipe materials and different passing-through methods can cause obvious differences in the seismic response of indoor riser pipes. [ABSTRACT FROM AUTHOR]

Conventionally, Ground Response Analysis (GRA) is carried out using a discrete approach in which a layered soil column is idealized as a multidegree of freedom lumped mass system. In this approach equivalent-linear or nonlinear soil model is used and the soil layers are assumed to be horizontal and infinitely extended. However, when these conditions are not met, the continuum approach to model soil column using finite elements is more realistic. Further, depending on the soil test data availability, the soil model may be chosen as linear, equivalent-linear or nonlinear. When the phenomenon of ground response analysis is numerically simulated, the boundary conditions of the numerical model and the input ground motions play an important role. The present study, aims to compare the results of 1D GRA using discrete and continuum approach. For this purpose ten different real Indian sites are considered and modeled in DEEPSOIL and ABAQUS. The results show a good agreement between the approaches adopted for 1D GRA. This study is a step forward to use continuum approach to carry out 1D and 2D ground response analysis. [ABSTRACT FROM AUTHOR]

It is shown that the vibration transfer and working medium pressure pulsations through vibration-isolating pipeline junctions of various plants may increase by two or three orders of magnitude with an increase in the vibration frequency and in the presence of incompressible working fluid. The results of research of the found physical models that determine this phenomenon are presented. The experimental results for a spatial three-component broadband active vibration-protection system (AVS) for vibration damping beyond the vibration isolation junction with liquid are considered. An experimental plant scheme for studying the simultaneous spatial active damping of dynamic forces, vibrations and pressure pulsations downstream from the junction has been given. Calculated dependences of the maximum efficiency of considered AVS on frequency are obtained. Efficient active damping of forces is shown to be attainable in an open loop without feedback. While damping in an open loop at the experimental plant, the efficiency of active damping of dynamic forces is obtained in three directions up to 10 dB or more in the frequency range from 5 to 800 Hz (more than seven octaves). The analysis of scientific publications reveals the uniqueness of this result. In this case, there are no zones of negative efficiency outside the active damping frequency range, which appear while using other methods of active damping. [ABSTRACT FROM AUTHOR]

Currently, the buffeting analysis for transmission lines (TLs) only involves the excitation of horizontal turbulence, while numerous investigations have proven that significant vertical turbulence exists in many wind fields. Additionally, overhead conductors generally exhibit nonlinear behavior, rendering the conventional multidimensional wind-excited model based on linear theories no longer applicable. To address these challenges and avoid relying on the extremely time-consuming nonlinear finite-element method, this paper proposes a closed-form solution (CFS) for predicting time-frequency buffeting responses of TLs excited by two-dimensional turbulent wind. First, the static response is determined through nonlinear static analysis. Then a two-dimensional influence line method, employed to evaluate the turbulent wind effect, is developed by decoupling the buffeting responses in two directions. Power spectral density functions for various responses are further derived, considering the cross-correlation between horizontal and vertical turbulence. Moreover, the impact of wind attack angle on various responses is revealed through parametric analyses. Finally, an amplification factor is introduced to modify the vertical wind effect on equivalent static wind load (ESWL), and the corresponding fitting formula is provided to facilitate the design. Numerical verification illustrates the high accuracy and efficiency of the CFS. Although the wind attack angle is time-varying, it is controlled by the mean wind. As it increases, the RMS of transverse and longitudinal reactions decrease, while the RMS of the vertical reaction increases. Neglecting vertical turbulence underestimates the horizontal ESWL, with the amplification factor exceeding 1.35 when a wind attack angle of 50° is considered. [ABSTRACT FROM AUTHOR]

Penelitian respons dinamik dan indeks kerentanan seismik sangat penting untuk memperkirakan dampak kerentanan lapisan permukaan dan kerusakan bangunan ketika terjadi gempa bumi. Penelitian ini bertujuan untuk mengidentifikasi respons dinamik Kecamatan Nambo, Kota Kendari serta menentukan area-area dengan perlapisan tanah yang sangat rentan. Data mikrotremor diolah menggunakan Geopsy 2.0.5 untuk memperoleh kurva HVSR (Horizontal to Vertical Spectral Ratio) serta parameter respons dinamik tanah berupa frekuensi dominan dan faktor amplifikasinya yang digunakan untuk menghitung indeks kerentanan seismik. Nilai frekuensi dominan Kecamatan Nambo berkisar antara 0,7 Hz- 3,63 Hz yang termasuk dalam kategori tanah Tipe II dan III. Area dengan frekuensi rendah menunjukkan penebalan lapisan alluvial yang merupakan produk sedimentasi permukaan. Interpolasi nilai indeks kerentanan seismik (kg) menunjukkan area Kecamatan Nambo yang memiliki kerentanan tinggi meliputi Kelurahan Pentoahan dan Nambo.

Although the numerical models can estimate the significant influence of local site conditions on the seismic propagation characteristics near the surface in many studies, they cannot feasibly predict the seismic ground motion amplification in regular engineering practice or earthquake hazard assessment due to the high computational cost and their complex implementation. In this paper, the scattering problem of trapezoidal sedimentary basins, one of the representatives of local complex sites with a relatively small model size, and simplified by practice in this type of study, was selected as the basin model. A series of standard basin models were built to quantify the relationship between the site condition parameters and the site amplification parameters (the peak ground acceleration and the hazard location). In addition, the factors that influence seismic ground motion amplification, such as the basin shape ratio, the soil depth, the basin edge dip angle, the ratio of shear wave velocity between the bedrock and the soil layer, the damping coefficient, and the fundamental frequency, were selected to investigate the sensitivity. A convolutional neural network (CNN) algorithm based on deep learning replacing traditional recursive algorithms was explored to establish a prediction model of basin amplification characteristics. By the Bayesian optimization method, the structural parameters of the CNN predicting model were selected to improve the accuracy of the prediction model. The results show that the optimized CNN models could predict the amplification characteristics of the basin better than the un-optimized CNN models. Three prediction models were established with the site condition parameters as the input parameters and their output parameters were the maximum amplification value of the peak ground acceleration (PGA), the hazard location, and their combination for each basin. To analyze the CNN's prediction ability, each CNN model used about 80% of the data from the seismic model repose results for training and the remaining data (20%) for testing. By comparing the CNN prediction results with the FE simulation results, the accuracy and rationality of each prediction model were studied. The results show that, compared to a single numerical model, the CNN prediction results of the site amplification features could be quickly obtained by inputting the relevant parameters. Compared to recursive class models, the established CNN prediction model can directly establish the relationships among multiple input and multiple output parameters. A comparison of the three kinds of CNN models shows that the prediction accuracy of the joint parameter model was slightly lower than that of the two single-output models. [ABSTRACT FROM AUTHOR]

Site response estimates from one-dimensional (1D) site response analyses (SRAs) carry inaccuracies due to modeling and parametric errors. Modeling errors are due to the condensation of the three-dimensional (3D) wave propagation phenomenon to the vertical propagation of a horizontally polarized wave through a soil column, and parametric errors are due to the incomplete knowledge of the distributions of soil parameters, leading to the selection of nonoptimal input parameters for a site of interest. While parametric errors are traditionally handled using different soil parameters (e.g. alternative shear-wave velocity profiles), modeling errors are generally neglected. This paper proposes an approach for conducting linear elastic 1D SRAs to improve site response predictions and account for modeling errors. First, ground-motion data from borehole array sites are collected, processed, and screened for appropriateness (e.g. expected shear strains lower than 0.01%, signal-to-noise ratio higher than 3). Second, 1D SRA predictions in terms of transfer functions and amplification factors are compared against observations, and the discrepancies are quantified as residuals. Finally, the residuals are partitioned into a model bias term (c 3 D SRA) , a site term (δ S 2 S s SRA) with standard deviation ϕ S 2 S SRA , and a event- and site-specific remaining residual (δ AMP es SRA) with standard deviation ϕ AMP SRA . Values for c 3 D SRA and ϕ S 2 S SRA for forward predictions are recommended. The sensitivity of the site response residuals to region, site type (1D- or 3D-like), and the applicability of findings to outcropping applications are discussed, and an example application for a hypothetical project site is presented. [ABSTRACT FROM AUTHOR]

One-dimensional site response analysis (1D SRA) remains the state of practice to estimate site-specific seismic response, despite the ample evidence of discrepancies between observations and 1D SRA-based predictions. These discrepancies are due to errors in the input parameters, intrinsic limitations in the predicting capabilities of 1D SRAs even for sites relatively compliant with the 1D SRA assumptions, and the inability of 1D SRAs to model three-dimensional (3D) wave propagation phenomena. This article aims at reducing 1D SRA mispredictions using small-strain damping profiles factored by a damping multiplier (D mul) and randomized shear-wave velocity (VS) profiles. An approach for conducting 1D SRAs for site-specific site response assessment is developed to reduce the 1D SRA errors in magnitude and variability. First, sites from a database of 534 downhole sites are classified as 1D- or 3D-like, depending on the substructure conditions inferred from observed transfer functions. Second, data from the 1D-like sites are compared against predictions from 1D SRAs conducted using various trials of D mul and VS standard deviations (σ ln V S ) for VS randomization. Third, D mul and σ ln V S are selected based on their combined ability to reduce the root mean square error (RMSE) in SRA predictions. Results indicate that 1D SRAs conducted with D mul = 3 and σ ln V S = 0. 25 lead to an overall minimum RMSE and thus provide more accurate site response estimates. The use of these parameters in forward SRA predictions is discussed in a companion paper. [ABSTRACT FROM AUTHOR]

Microtremor recording tests using an accelerometer were carried out in this paper with the aim of characterizing the effects of seasonally frozen soil on the seismic site response, including the two-direction microtremor spectrum, site predominant frequency, and site amplification factor. The study selected eight typical seasonal permafrost sites in China for site microtremor measurements during both summer and winter seasons. Based on the recorded data, the horizontal and vertical components of the microtremor spectrum, HVSR curves, site predominant frequency, and site amplification factor were calculated. The results showed that seasonally frozen soil increased the predominant frequency of the horizontal component of the microtremor spectrum, while the effect on the vertical component was less noticeable. It indicates that the frozen soil layer has a significant impact on the propagation path and energy dissipation of seismic waves in the horizontal direction. Furthermore, the peak values of the horizontal and vertical components of the microtremor spectrum decreased by 30% and 23%, respectively, due to the presence of seasonally frozen soil. The predominant frequency of the site increased by a maximum of 35% and a minimum of 2.8%, while the amplification factor decreased by a maximum of 38% and a minimum of 11%. Additionally, a relationship between the increased site predominant frequency and the cover thickness was proposed. [ABSTRACT FROM AUTHOR]

This study of West Nile virus (WNV) examined the possibility of avian transmission to explain synchronicity in the year‐to‐year variability of WNV case numbers from Texas northward to the Dakotas, and reasons for the large case numbers on the northern Great Plains. We determined correlation coefficients between annual disease incidence per 100,000 people among states within the Great Plains Region, as well as the Central Flyway. There was spatial and temporal synchronicity, as evidenced by Pearson "r," with values along the core of the Central Flyway (Oklahoma, Kansas, Nebraska, and South Dakota) varying between 0.69 and 0.79. Correlations for North Dakota (r = 0.6), however, were affected by local conditions. The concept of relative amplification is helpful in explaining why northerly states along the Central Flyway have larger annual case numbers per 100,000 than Texas but preserve the temporal signal. States differed in their capacity for amplifying the temporal signal in case numbers. For example, Nebraska, South Dakota, and North Dakota case numbers were commonly amplified relative to Texas, with Oklahoma and Kansas deamplified. Relative amplification factors for all states increased as a function of increasing case numbers in Texas. Thus, increased numbers of initially infected birds in Texas likely led to the rapid intensification of the zoonotic cycle as compared to more typical years. The study also confirmed the importance of winter weather in locally modulating disease cases. North Dakota appeared most impacted by these factors to the extent of reducing WNV case numbers in colder years and years with deep snow. Plain Language Summary: This study examined factors controlling broad patterns of transmission of West Nile virus (WNV) on the Great Plains of the United States. We found that yearly human case numbers are correlated both temporally and spatially from Texas northward. These findings support the idea that each year migratory birds were important in retransmitting WNV along the Central Flyway with Texas as the source of WNV and North Dakota and South Dakota as sinks. However, states differed in their capacity to enhance the temporal signal. In Oklahoma and Kansas, deamplification in case numbers relative to Texas was common except for the worst WNV years in Texas. For Nebraska, South Dakota, and North Dakota case numbers were commonly amplified relative to Texas. Relative amplification factors for all states increased as a function of increasing case numbers per 100,000 in Texas. These patterns are likely controlled by virulence of the dominant Culex species and local habitat. In North Dakota, the winter climate may also affect human case numbers. Cold conditions reduce populations of over‐wintering mosquitoes and large snow accumulations modulate the springtime return of migratory birds. Such correlations between the local WNV disease cases and these factors may provide a robust, early screening tool for WNV. Key Points: Spatial and temporal synchronicity in human West Nile virus cases was observed along the Central FlywayA consistent pattern of amplification and deamplifications in human case numbers is evident along the Central Flyway as compared to TexasKey factors controlling trends include avian spread, vector competence, and local winter conditions, especially in North Dakota [ABSTRACT FROM AUTHOR]

In the present study, the seismic performances of gravity retaining walls having both inclined back side and inclined backfill were investigated under sinusoidal acceleration excitations using series of shaking table tests on 750 mm height physical model. The effects of input peak ground acceleration (PGA$PGA$), inclination angle of backfill material (α) and inclination angle of back of the gravity retaining wall (β) on acceleration amplification factor (RMSA$RMSA$), maximum peak lateral relative (Smaxpeak(rel)${S}_{{\rm{maxpeak}}({rel})}$) and maximum residual lateral displacement (Smax(res)${S}_{{\rm{max}}({res})}$) of the wall, surface settlement (Sset${S}_{set}$) of the backfill material, inertial force (PI${P}_I$) and horizontal dynamic active force (Pdynh${P}_{dynh}$) were assessed. It was observed that higher values of the RMSA$RMSA$ were obtained from the experimental results as compared the ones from current seismic design codes. Moreover, the six results of shaking table tests revealed that the phase difference was appeared between the inertial force and dynamic earth pressures. Pseudo‐static limit equilibrium methods resulted in over conservative Pdynh${P}_{dynh}$ results and could not truly reflect the seismic behavior of gravity wall due to the inertial forces and phase difference not taken into consideration. [ABSTRACT FROM AUTHOR]

San Salvador Metropolitan Area (MASS) is an urbanized territory in the country of El Salvador, located between the San Salvador volcano and the Ilopango caldera, in a sub-flat area called "Valle de las Hamacas" (Valley of the Hammocks). The high seismicity of this area is due to the subduction zone of the Cocos plate that causes strong seismic events such as the earthquakes that occurred on 13 January (7.6 Mw) and 13 February 2001 (6.6 Mw). As part of the international cooperation project between Italy (AICS) and El Salvador University, the CASTES project focussed on natural hazards in the territory of El Salvador was launched. Therefore, 2D simulations are carried out along two sections to evaluate the Local Seismic Response (LSR) in the Southeast part of MASS territory. Results show spatially variable amplifications (from 3 to 6.5) in the period ranging 0.1–0.7 s and evidence of lateral FA variations that can be calculated only through 2D numerical analyses. Two amplified periods are recognised, 0.1–0.5 s and 0.4–0.8 s, due to the presence of two types of subsoil volcanic deposits: the shallow and soft Tierra Blanca deposits and the deeper and stiffer Volcanic ash and Tuff. [ABSTRACT FROM AUTHOR]

This review paper discusses the procedures for evaluating the design displacement given in various design codes from seismically prone countries around the world (the United States, New Zealand, Chile, Japan, Greece, Italy, Iran, India, Turkey, and Romania). The limit displacements and the corresponding limit states are also presented and analyzed in this study besides the importance class factors considered in the selected seismic design codes. A presentation of the behavior factors necessary for evaluating the design value of the seismic action is also shown in this study. One of the observations of this review paper is that there are significant similarities in terms of the approach to the displacement check in the analyzed codes. In addition, it was observed that the displacement check is generally associated with the serviceability limit state (e.g., damage limitation). However, differences in terms of the mean return period for the serviceability check action were observed among the analyzed seismic design codes. Several aspects which have to be further adapted in the future versions of seismic design codes are also discussed in this review paper. One of the main aspects which must be further discussed is the enforcement of displacement limits, which are dependent on the structural system and on the importance of the class/height regime for the ultimate/serviceability limit state. In addition, the dependence of the TD control period on the probabilistic seismic hazard ordinates should be further discussed. Moreover, the pulse effects, which can affect both the acceleration and the displacement design of response spectra, should be accounted for as well in future generations of seismic codes. Finally, it appears necessary to perform a harmonization of the behavior factors employed in seismic design codes. [ABSTRACT FROM AUTHOR]

The Liwa area is near the active shear fault of the Sumatra Fault Zone (SFZ), with a right lateral mechanism where the Kumering segment crosses this area. The geodynamic simulation results based on the pre-seismic modeling using the slip rate input of a recent study, Liwa, and its surroundings show a comparatively high compression level. The seismic moment rate estimation based on the present-day surface strain data shows alignment and consistency with the pre-seismic modeling result and the previous correlation dimension (DC) analysis. The high DC indicated that the Kumering segment indicates a relatively high-stress level. The finding also aligns with the suggestion based on the previous result that more frequent large strike-slip earthquakes occur since the recent study found that the slip is faster than the previous one. And it is consistent with the historical records; Liwa has a minimum of 3 times experienced destructive earthquakes, which occurred in 1908, 1933, and 1994. Although based on a deterministic hazard analysis point of view, the zone around the SFZ will experience the most significant ground shaking since it is close to the source. However, the Probabilistic Seismic Hazard Analysis (PSHA) studied around the southern part of Sumatra Island, especially in areas close to the coast boundary, shows that the shaking caused by the source of the subduction and intermediate depth is more frequent than that of the SFZ source. As the city of Liwa is located near the Kumering Segment and relatively close to the shoreline, evaluating the Seismic Hazard Function (SHF) by integrating megathrust, SFZ, and medium depth sources is necessary. The amplification analysis in the previous study using Liwa's HVSR method showed the most considerable amplification value. Thus, this study intends to evaluate the potential for earthquake hazards based on the probability of integrated sources of megathrust, SFZ, and intermediate depth to deep and deterministic based on SFZ sources around the city of Liwa. The earthquake intensity (MMI) estimation at the surface based on the probabilistic to deterministic point of view is in the range of VI to XI. Therefore, it has the potential to reach the maximum MMI scale. The result of this study might be very beneficial in better understanding the future seismic hazard study and mitigation analysis. [ABSTRACT FROM AUTHOR]

Abstract This study of West Nile virus (WNV) examined the possibility of avian transmission to explain synchronicity in the year‐to‐year variability of WNV case numbers from Texas northward to the Dakotas, and reasons for the large case numbers on the northern Great Plains. We determined correlation coefficients between annual disease incidence per 100,000 people among states within the Great Plains Region, as well as the Central Flyway. There was spatial and temporal synchronicity, as evidenced by Pearson “r,” with values along the core of the Central Flyway (Oklahoma, Kansas, Nebraska, and South Dakota) varying between 0.69 and 0.79. Correlations for North Dakota (r = 0.6), however, were affected by local conditions. The concept of relative amplification is helpful in explaining why northerly states along the Central Flyway have larger annual case numbers per 100,000 than Texas but preserve the temporal signal. States differed in their capacity for amplifying the temporal signal in case numbers. For example, Nebraska, South Dakota, and North Dakota case numbers were commonly amplified relative to Texas, with Oklahoma and Kansas deamplified. Relative amplification factors for all states increased as a function of increasing case numbers in Texas. Thus, increased numbers of initially infected birds in Texas likely led to the rapid intensification of the zoonotic cycle as compared to more typical years. The study also confirmed the importance of winter weather in locally modulating disease cases. North Dakota appeared most impacted by these factors to the extent of reducing WNV case numbers in colder years and years with deep snow.

In this study, dynamic centrifugal model tests for two homogeneous saturated soft clay sites are designed to analyze the influence of overlying sea water on ground motion. We obtain the response spectrum value and amplification coefficient from the acceleration sensor records. Through comparative analysis, we conclude that with the increase in input peak ground motion, the acceleration response spectrum value at the same depth gradually increases. When the input peak value is small, there is no significant difference between the response spectra with and without water; when the input peak value is large, there is no significant difference in the high-frequency part of the response spectrum value. In the middle- and low-frequency part, the response spectrum value with water is obviously smaller than that without water. The amplitude of the response spectrum of the water-free model gradually moves in the long-period direction, but the water model tends to the short-period direction. In the long-period part, the amplification coefficient of the water model is obviously smaller than that of the water free model. [ABSTRACT FROM AUTHOR]

Radiotherapy is an important modality for the treatment of cancer, e.g., X-ray, Cs-137 γ-ray (peak energy: 662 keV). An important therapy pathway of radiation is to generate the double strand breaks of DNA to prohibit the proliferation of cancer cells. In addition, the excessive amount of reactive oxygen species (ROS) is induced to damage the organelles, which can cause cellular apoptosis or necrosis. Gold nanoparticles (GNPs) have been proven potential as a radiosensitizer due to the high biocompatibility, the low cytotoxicity and the high-Z property (Z = 79) of gold. The latter property may allow GNPs to induce more secondary electrons for generating ROS in cells as irradiated by high-energy photons. In this paper, the radiobiological effects on A431 cells with uptake of 55-nm GNPs were studied to investigate the GNPs-enhanced production of ROS on these cells as irradiated by Cs-137 γ-ray. The fluorescence-labeling image of laser scanning confocal microscopy (LSCM) shows the excessive expression of ROS in these GNPs-uptake cells after irradiation. And then, the follow-up disruption of cytoskeletons and dysfunction of mitochondria caused by the induced ROS are observed. From the curves of cell survival fraction versus the radiation dose, the radiosensitization enhancement factor of GNPs is 1.29 at a survival fraction of 30%. This demonstrates that the tumoricidal efficacy of Cs-137 radiation can be significantly raised by GNPs. Because of facilitating the production of excessive ROS to damage tumor cells, GNPs are proven to be a prospective radiosensitizer for radiotherapy, particularly for the treatment of certain radioresistant tumor cells. Through this pathway, the tumoricidal efficacy of radiotherapy can be raised. [ABSTRACT FROM AUTHOR]

In this work, we used three finite difference schemes to solve 1D and 2D convective diffusion equations. The three methods are the Kowalic–Murty scheme, Lax–Wendroff scheme, and nonstandard finite difference (NSFD) scheme. We considered a total of four numerical experiments; in all of these cases, the initial conditions consisted of symmetrical profiles. We looked at cases when the advection velocity was much greater than the diffusion of the coefficient and cases when the coefficient of diffusion was much greater than the advection velocity. The dispersion analysis of the three methods was studied for one of the cases and the optimal value of the time step size k, minimizing the dispersion error at a given value of the spatial step size. From our findings, we conclude that Lax–Wendroff is the most efficient scheme for all four cases. We also show that the optimal value of k computed by minimizing the dispersion error at a given value of a spacial step size gave the lowest l 2 and l ∞ errors. [ABSTRACT FROM AUTHOR]

Based on numerous observations, local soil site conditions can significantly affect the formation of seismic responses. In this paper, we examine seismic responses caused by shear waves propagating through a two-layered soil deposit. The aim of the research is to study the phenomenon of amplification of shear waves due to the resonant properties of the soil deposit and the nonlinear characteristics of partial layers, which are assumed to be the cubically nonlinear continuous media. The target problem relates to a nonlinear boundary value problem, the solution of which is carried out using a semi-analytical approach. According to the approach, the problem's solution is sought using the method of separation of variables, while the solution to the corresponding spectral problem is derived in the form of a power series. Additionally, good agreement is shown between theoretical studies and numerical simulations. The developed approach allows one to evaluate the amplification factor for a nonlinear two-layered soil deposit and to detect changes in the shape of amplification factor profiles when the frequency of an incident wave on a rigid bedrock is varied. • amplification factor of nonlinear two-layered soil deposit is evaluated. • semi-analytic procedure for amplification factor calculation is developed. • comparison of theoretical and numerical studies of soil response is presented. [ABSTRACT FROM AUTHOR]

This article presents a finite difference method of order two for stiff differential equation that will overcome the effects of stiffness since it is A-stable. And, reflect the asymptotic behavior of the solution of the stiff problem since it is L-stable. The classical explicit Runge–Kutta methods of order two are not suitable for stiff problems since the numerical solution will not overcome the effects of stiffness and will not reflect the asymptotic behavior of the solution of the stiff problem (for example, Dahlquist problem). And, they are not both A-stable and L-stable. On applying Euler's implicit method, the numerical solution will overcome the effects of stiffness and will reflect the asymptotic behavior of the solution of the stiff problem. And hence, it is both A-stable and L-stable. But it is of order one method. A new numerical method which is both A-stable and L-stable and of order two for the numerical solution of a stiff differential equation is presented in this article. It will overcome the effects of stiffness and reflects the asymptotic behavior of the solution. The new method works well for large values of step size and works well in large domain. The new method is a modified form of the mid-point rule for the stiff problems. The rate of order of convergence is proved to be two both theoretically and numerically. Experimental results show the performance of the method based on the metrics such as stability function, stability region, order star fingers, the rate of order of theoretical and numerical convergence, absolute and relative errors, percentage of numerical solution accuracy and local and global truncation errors both numerically and graphically. [ABSTRACT FROM AUTHOR]

Creep affects the long-term deformation of concrete structures. Nonlinear creep further overestimates the safety factor of structures and affects the safety service performance. The coupling of creep and a damage model considering the rate effect is conducive to accurate prediction of nonlinear creep, but the iterative process of strain makes the calculation method more complex. The purpose of this study is to propose a nonlinear creep explicit method that considers the damage evolution of concrete under compression. Two groups of axial compression members with compressive stresses of 0.2 fc and 0.4 fc were made. Considering the law of concrete damage evolution under uniaxial compression, coupled with elastic creep and damage incremental strain, the lower limit of the medium stress level that gives rise to nonlinear creep is analyzed. The concrete nonlinear creep amplification coefficient with a loading age of 28 days and loading duration of 360 days is studied with consideration for the uncertainty of relative humidity and the theoretical thickness of the component. On this basis, the explicit calculation formula of the nonlinear creep amplification coefficient related to the concrete axial compressive strength and stress level is given. The results indicate that the nonlinear creep amplification coefficient increases nonlinearly with an increase in the stress level, and, when the compressive stress level ratio is higher than 0.6, the nonlinear creep amplification coefficient increases significantly; when the stress level is determined, the creep amplification coefficient decreases gradually with an increase in the compressive strength of the concrete. It is suggested that a stress level range of 0.35~0.75 should be used for the study of a nonlinear creep amplification factor under the medium stress state. [ABSTRACT FROM AUTHOR]

The effect of uncertainty on the shear wave velocity (VS) profiles from the Korean soil conditions on the seismic site response analysis (SRA) was investigated by comparing the amplification factors (AFs) computed from 170 VS profiles to those from three (representative) statistically derived VS profiles (Approach 1: a constant standard deviation of VS, σln(Vs), Approach 2: a depth-dependent, σln(Vs), and Approach 3: 5% and 95% percentiles for generating lower and upper bounds). All of the VS profiles are divided into three site classes (B, C, and D) by the National Earthquake Hazards Reduction Program (NHERP) site classification system. Seven pairs of ground motion records (two horizontal components) that represent Korean bedrock conditions are entered into all of the three types of VS profiles to run the SRA with a single type of modulus reduction and damping curves. The root-mean squared difference (RMSD) of the mean and standard deviation, (μln(AF), and σln(AF)) of the AFs in natural log-scale between the three types of VS profiles is estimated, which results in Approach 3 with the smallest RMSD measure for all the site classes. Conventionally, characterizing the uncertainty of the VS profiles is typically assessed through the representative profiles of Approach 1; however, this practice suggests that the inclusion of the percentile bounds (Approach 3) can be supplemental to better describe the VS uncertainty while taking the Approach 1 as primary representative profiles. [ABSTRACT FROM AUTHOR]

Although the numerical models can estimate the significant influence of local site conditions on the seismic propagation characteristics near the surface in many studies, they cannot feasibly predict the seismic ground motion amplification in regular engineering practice or earthquake hazard assessment due to the high computational cost and their complex implementation. In this paper, the scattering problem of trapezoidal sedimentary basins, one of the representatives of local complex sites with a relatively small model size, and simplified by practice in this type of study, was selected as the basin model. A series of standard basin models were built to quantify the relationship between the site condition parameters and the site amplification parameters (the peak ground acceleration and the hazard location). In addition, the factors that influence seismic ground motion amplification, such as the basin shape ratio, the soil depth, the basin edge dip angle, the ratio of shear wave velocity between the bedrock and the soil layer, the damping coefficient, and the fundamental frequency, were selected to investigate the sensitivity. A convolutional neural network (CNN) algorithm based on deep learning replacing traditional recursive algorithms was explored to establish a prediction model of basin amplification characteristics. By the Bayesian optimization method, the structural parameters of the CNN predicting model were selected to improve the accuracy of the prediction model. The results show that the optimized CNN models could predict the amplification characteristics of the basin better than the un-optimized CNN models. Three prediction models were established with the site condition parameters as the input parameters and their output parameters were the maximum amplification value of the peak ground acceleration (PGA), the hazard location, and their combination for each basin. To analyze the CNN’s prediction ability, each CNN model used about 80% of the data from the seismic model repose results for training and the remaining data (20%) for testing. By comparing the CNN prediction results with the FE simulation results, the accuracy and rationality of each prediction model were studied. The results show that, compared to a single numerical model, the CNN prediction results of the site amplification features could be quickly obtained by inputting the relevant parameters. Compared to recursive class models, the established CNN prediction model can directly establish the relationships among multiple input and multiple output parameters. A comparison of the three kinds of CNN models shows that the prediction accuracy of the joint parameter model was slightly lower than that of the two single-output models.

Microtremor recording tests using an accelerometer were carried out in this paper with the aim of characterizing the effects of seasonally frozen soil on the seismic site response, including the two-direction microtremor spectrum, site predominant frequency, and site amplification factor. The study selected eight typical seasonal permafrost sites in China for site microtremor measurements during both summer and winter seasons. Based on the recorded data, the horizontal and vertical components of the microtremor spectrum, HVSR curves, site predominant frequency, and site amplification factor were calculated. The results showed that seasonally frozen soil increased the predominant frequency of the horizontal component of the microtremor spectrum, while the effect on the vertical component was less noticeable. It indicates that the frozen soil layer has a significant impact on the propagation path and energy dissipation of seismic waves in the horizontal direction. Furthermore, the peak values of the horizontal and vertical components of the microtremor spectrum decreased by 30% and 23%, respectively, due to the presence of seasonally frozen soil. The predominant frequency of the site increased by a maximum of 35% and a minimum of 2.8%, while the amplification factor decreased by a maximum of 38% and a minimum of 11%. Additionally, a relationship between the increased site predominant frequency and the cover thickness was proposed.

In combination with the moving train, track irregularities have a significant influence on the structural response of railway bridges. Compared to the ideal case of perfect track geometry without any irregularities, an amplification of the response is observed. This paper proposes a probabilistic model to predict this dynamic response amplification of railway bridges due to random track irregularities when subjected to high-speed trains. The developed regression model, based on a parametric numerical study, provides the mean and standard deviation of the dynamic response amplification separately for bridge deflection and acceleration, since large differences are found for these vibration variables. Depending on the span, mass, fundamental frequency, and damping coefficient of simply supported bridges, dynamic response amplification statistics are approximated for a range of train speeds and different track qualities. The proposed model estimates the dynamic response amplification due to random track irregularities at predefined exceedance probabilities, and a customized amplification factor is determined that is consistent with the semi-probabilistic safety concept used in structural design. An application example shows the superiority of this model compared to the commonly used code-based approach. [ABSTRACT FROM AUTHOR]

The seismic vulnerability index (Kg) is based on soil dynamic properties. To create a seismic vulnerability index map, horizontal-to-vertical spectral ratio (HVSR) microtremor measurements were taken at over 260 locations throughout the Makkah Al-Mukarramah urban region. The fundamental resonance frequency and accompanying maximum relative amplification maps have been developed based on the H/V results. According to these maps, portions of the wadis in Makkah have fundamental resonance frequencies ranging from 0.26 and 17.27 Hz and may amplify bedrock ground motion by up to 14 times with the estimated amplification factor of 0.87 to 14.68 for the studied sites. The vulnerability index reveals the structural damage before destructive earthquakes. The values of the vulnerability index range from 0.13 to 284, with a high value of vulnerability indicating that the area in this value is located on the thickest layer of soft soil, posing the greatest risk. In the Al-Sharai’a, Ar Rashidiyyah, Al Khadra, AN Nassem, Al Shoqiah, and AZ Zahir districts, in the An nuzah, Batha Quraish, and Umm Al Qura University districts, a moderate result of the vulnerability index indicates that the location is located in stiff soil, which poses a moderate risk. The Makkah Al-Mukarramah municipality’s civil engineers and urban designers will benefit from these findings. In addition, these results can be used to improve the Saudi Building Code. [ABSTRACT FROM AUTHOR]

In the ultrasonic vibration-assisted manufacturing method using complex vibration, the amplitude amplification factor of horn for each vibration is important. In this paper, we focus on longitudinal-torsional vibration as a complex vibration and propose a stepped horn with a hollow part as a horn that can design the amplification factors of these vibrations individually. The proposed equation for the amplification factor of the horn with a hollow part was derived from the equation of the conventional step horn without a hollow part, and the validity of the proposed equation was verified by the finite element method and experimental measurements. As a result, the validity of the equation was confirmed, and it was clarified that the proposed stepped horn with a hollow part can be individually designed for the amplitude amplification factors of longitudinal vibration and torsional vibration. [ABSTRACT FROM AUTHOR]

A mathematical model based on the three-dimensional (3-D) boundary element method (BEM), including porous and non-porous breakwaters, is developed to determine the wave trapping characteristics of porous breakwater over the partially reflecting walls with variable bathymetry. In this formulation, a special form of Green's function is utilized to solve the Laplace equation in the 3-D domain to enhance the numerical accuracy. The order of convergence of the present numerical scheme shows a better convergence rate than simple Green's function. The numerical scheme with and without the porous breakwater is compared with the analytical studies of Yu et al. (1994) and Lee (1969), respectively. In addition, the numerical simulation for sloping bathymetry is conducted and compared with the analytical results of Wang et al. (2011). The numerical validation exhibits good agreement with and without porous breakwaters. Based on validation, the current numerical scheme is implemented on the realistic Visakhapatnam Port, Andhra Pradesh, India, at four different synthetic key locations S1 to S4 to analyze the hydrodynamic performance of porous and non-porous breakwaters. Wave amplification is determined for different porosity parameters, including variable linear resistance and inertial coefficient, and different reflecting coefficients of the port wall. Moreover, the wave amplitude within the Visakhapatnam Port is also estimated through a contour plot with and without porous breakwaters to identify the safe location for the moored ship. Overall, the porosity of the breakwaters and partial reflection coefficient on the port wall plays a significant role in inducing or reducing the resonance inside the port. [ABSTRACT FROM AUTHOR]

This article aims to investigate seismic force demand on RC shear walls which are designed using direct displacement‐based design (DDBD) method. For this purpose, first 12 shear walls were designed using DDBD approach and then were modeled nonlinearly in OpenSees using fiber section elements. Each wall was subjected to 45 artificial ground motions and the seismic force demand, including the shear force and the bending moment, were determined along the wall height. The nonlinear dynamic analysis results indicated that the seismic force demand was significantly amplified relative to the design forces. This amplification, which was due to the higher mode effects, is mainly a function of structural period and ductility demand. To find new shear and moment envelopes for capacity design, two envelop shapes compatible with internal force pattern along the wall height were selected. Then, the required equations were presented for envelope parameters based on the regression analysis of the results. The comparison of seismic force demand with proposed and previous envelopes indicates the superiority of new proposed envelopes for DDBD approach. [ABSTRACT FROM AUTHOR]

An attempt has been made to estimate the site amplification factors of different geomorphological units in Shillong city, northeastern India, based on the distribution of peak ground acceleration (PGA) due to maximum credible earthquakes that originated in nearby major faults. Empirical relations are used to determine the amount of shaking at base rock as a function of the magnitude of the earthquake (Mw), source depth (km), fault dimension (intraplate/interplate), velocity structure of medium and the distance from the source (km). The computed PGA values are convolved with the average shear wave velocity (Vs30) values at various geomorphological units of Shillong to ascertain the degree of amplification while travelling from base rock to the surface. The amplification for the highly dissected land in the city is found to be the maximum within a range of 2.77–2.92, while the high plateau segment is characterized by least values (2.01–2.16). Simultaneously, the effective ground motion mapped on the surface indicates the maximum value of 0.6–0.94 g for a probable earthquake of Mw 8.1 due to Dauki fault. Similarly, Dhubri and Kopili faults might produce a ground motion of 0.05–0.08 and 0.22–0.33 g for a maximum credible earthquake of Mw~7.0, respectively. [ABSTRACT FROM AUTHOR]

This is the first study to quantitatively evaluate the local site effects in the most severely affected neighborhoods of Sarpol-e-Zahab city following the devastating earthquake of November 12, 2017, in Kermanshah province (Iran). The site's two-dimensional numerical simulation and its nonlinear dynamic analysis were conducted using Abaqus finite element software. The study's findings include determining the dynamic predominant period and the maximum amplification factor of the site. The results showed that under applying the near-field record, 2 to 3-storey buildings in Fooladi neighborhood and 1 to 4-storey buildings in Shahid Shiroodi Mehr housing neighborhood experience the resonance phenomenon. Moreover, the average shear wave velocity Vs 30 was calculated. The project site was classified into the III class in the Iranian code of practice for the seismic-resistant design of buildings (IRSt2800). Finally, the acceleration response spectra obtained from the numerical study were compared with the standard design spectra of IRSt2800 and the International Building code of practice 2015 (IBC 2015). The reported results of this paper can provide a useful and new database of local site effects for seismic designers and specialists to reconstruct existing buildings and future structures adequately. [ABSTRACT FROM AUTHOR]

A state-of-the-art review is presented on the design and research based on response amplification dampers. In recent years, energy-dissipation vibration-reduction technology has been extensively employed for seismic resilience in building structures. Indeed, during minor-to-moderate earthquakes, the displacement or deformation of structures is relatively small, and they cannot fully exert their energy dissipation capacities. Therefore, amplifying the dynamic responses transmitted to the damper is important. Taking the field of shock absorption of building structures as the research object, this article describes the amplification mechanisms of response amplification dampers and elaborates on the device structures and working mechanisms of these dampers, indicating areas that require improvement. Concurrently, it introduces the seismic performance of building structures integrated with response-amplification dampers. To enable full determination of the energy dissipation capacities of dampers based on the seismic design method, this paper elaborates on methods of optimizing the parameters, quantity, and layouts of response amplification dampers. The latest research progress, shortcomings, and prospects are analyzed and summarized. The main purpose of this article is to provide a comprehensive overview of the shock absorption technology of building structures based on response amplification dampers, thus offering valuable reference information for further research and engineering applications in this field. • An analysis of the amplification mechanism of response amplification-type dampers has been provided. • Elaborated on device structures, mechanisms, and areas needing improvement in such dampers. • Summarized experimental research, seismic design, and engineering applications on frame structures with such dampers. • The methods of optimizing the parameters, quantity, and layout position of these dampers have been described. [ABSTRACT FROM AUTHOR]

Proper representations of ground motion characteristics and prediction of rock-to-ground amplification factors (AFs) of intensity measures (IMs) are crucial in site-specific probabilistic seismic hazard analysis (PSHA). By using spectrally equivalent pulse-like and non-pulse-like ground motion suites within the convolution-based PSHA framework, this paper aims to (i) investigate the amplification patterns and AF prediction efficiency for 16 typical IMs; and (ii) evaluate the sensitivities of AF and PSHA to the pulse-characteristic, rock-IM type, and AF functional form. The results reveal that IMs are generally amplified, whereas de-amplification occurs at soft sites for IMs largely dominated by high-frequency content (e.g., Arias intensity). Specific rock-IMs for predicting AFs are recommended through efficiency criterion. The results for pulse-like and non-pulse-like suites are found to be not significantly different; hence, including pulse-like records is generally not essential in convolution-based PSHA as long as the bedrock spectra designed with pulse-type features have been matched. Meanwhile, the similar AF predictions from the linear and nonlinear models indicate that the choice of functional form is of secondary importance. Instead, the selection of rock-IM is of higher importance, especially for soft sites and high-frequency dominated IMs. This study could provide useful insights into ground motion selection and AF prediction for site-specific PSHA. • Site amplification patterns of sixteen typical ground-motion IMs are investigated. • Efficiency of various rock-IMs in predicting amplification factor is ranked. • Effect of rock-IM type is larger for high-frequency dominated IMs at softer sites. • Spectrally equivalent ordinary records are sufficient for considering site response in PSHA under pulse-like motions. • Linear and nonlinear models yield similar amplification factor distributions. [ABSTRACT FROM AUTHOR]

In the hypersonic boundary layer, the streamwise instability modes are mainly the Mack first mode and the Mack second mode. After the Mach number exceeds 4.0, the Mack second mode becomes the dominant instability mode for boundary layer transition. Currently, there is no complete analytical method to establish an amplification factor transport equation for the second mode. In order to improve the application of the amplification factor transport (AFT) model in hypersonic boundary layer transition prediction, this paper employs boundary layer similarity solutions to conduct stability analysis on the second mode and introduces a function to calculate the growth rate of disturbances. Additionally, a transport equation for the amplification factor of the second mode is formulated. For the non-local variables appearing in the equation, a local calculation method is provided. Combined with the intermittency factor transport equation, a transition prediction model for the second mode is formed. Hypersonic flat plate, wedge, and flared wedge are selected for model validation. The computed results show good agreement with standard stability analysis or experimental results, demonstrating the rationality of the transition model and its high prediction accuracy and reliability. • Constructs an amplification factor transport (AFT) model for the second mode using analytical method. • Derive the functions in the source term using boundary layer similarity solutions. • Propose a method for determining the maximum value of variables in the boundary layer. [ABSTRACT FROM AUTHOR]

This research focuses on the Cathedral Church of Saint Mary in Murcia, Spain, which is located in a moderate-to-high seismic risk zone in the Spanish context. The study uses geophysical techniques and geotechnical investigation to characterise seismic ground models at the building's scale, aiming to understand the real amplification of the ground under seismic effect in historic buildings. Three soil layers (silt, sand with gravel, and gravel) were identified through core borings. Multichannel Analysis of Surface Waves (MASW) profiles and Mini-array profiles revealed Vs values of 305 ± 32 m/s, 296 ± 62 m/s, and 440 ± 38.5 m/s, respectively, for these materials. Seismic Refraction Tomography (SRT) showed Vp values of 586 ± 73 m/s, 700 m/s, and 1466 ± 489 m/s for the corresponding layers. The horizontal-to-vertical spectral ratio (HVSR) approach identified a ground predominant period ranging from 0.37 to 0.38 s. Another significant peak at 2.3 s is observed, probably associated to the Triassic basement. Three seismic events with magnitudes Mw between 4.9 and 5.1 were used as inputs to determine the amplification factor (AF). The results indicate a PGA amplification factor between 1.7 and 2.1. These results contribute to the conservation and mitigation of seismic risk of this cultural heritage generating input data that enables precise computation of the soil-structure interaction. • Seismic response of the soil underneath a historic building has been characterised. • Seismic characteristics of the ground are calculated using geophysical techniques and boreholes. • 3D velocity model of the subsoil of the Cathedral of Murcia is determined. • The PGA amplification factor is determined by using three seismic events as inputs. [ABSTRACT FROM AUTHOR]

This paper is aimed to discuss the conceptual troubles currently appearing in the codified rules to account for second-order effects in the seismic design of structures. First of all, starting from SDOF systems, the distinction between second-order effects in the elastic range and second-order effects in the plastic range is clarified. Moreover, the attention is focused on the conceptual difference occurring between a parameter measuring the structural proneness to second-order effects and a demand parameter measuring the safety level against the phenomenon of dynamic instability. Successively, the critical issues concerning the behaviour occurring in real MDOF structures when compared to SDOF systems is pointed out underlining the uncoupling between second-order effects in the elastic range and second-order effects in the plastic range, due to the influence of the collapse mechanism typology. The codified rules to account for second-order effects in Eurocode 8 are analysed showing why they are conceptually wrong giving rise to a lot of unjustified problems in the seismic design of steel MRFs. Recent proposals to improve Eurocode 8 are also analysed. Finally, it is shown how relevant studies already existing in the technical literature can be exploited in order to set up code provisions having a sound theoretical background. Finally, a new proposal, accounting for the influence of the collapse mechanism, for codification of P − Δ effects in seismic design is presented. ● In the case of SDOF systems, the stability coefficient is the only one parameter needed to measure the structural proneness to second-order effects both in the elastic range and in the plastic range. ● The stability coefficient adopted by Eurocode 8 is not a parameter measuring the structural proneness to second-order effects. ● Dynamic instability is a phenomenon related to the seismic displacement demand. ● In the case of real MDOF structures, the structural proneness to second-order effects in the plastic range of behaviour is dependent on the collapse mechanism. ● A new proposal for codification of effects in seismic design is proposed. ● The proposal novelty is that it accounts for the need of amplifying the seismic design forces, directly accounting for the influence of the collapse mechanism typology. [ABSTRACT FROM AUTHOR]

This review paper discusses the procedures for evaluating the design displacement given in various design codes from seismically prone countries around the world (the United States, New Zealand, Chile, Japan, Greece, Italy, Iran, India, Turkey, and Romania). The limit displacements and the corresponding limit states are also presented and analyzed in this study besides the importance class factors considered in the selected seismic design codes. A presentation of the behavior factors necessary for evaluating the design value of the seismic action is also shown in this study. One of the observations of this review paper is that there are significant similarities in terms of the approach to the displacement check in the analyzed codes. In addition, it was observed that the displacement check is generally associated with the serviceability limit state (e.g., damage limitation). However, differences in terms of the mean return period for the serviceability check action were observed among the analyzed seismic design codes. Several aspects which have to be further adapted in the future versions of seismic design codes are also discussed in this review paper. One of the main aspects which must be further discussed is the enforcement of displacement limits, which are dependent on the structural system and on the importance of the class/height regime for the ultimate/serviceability limit state. In addition, the dependence of the TD control period on the probabilistic seismic hazard ordinates should be further discussed. Moreover, the pulse effects, which can affect both the acceleration and the displacement design of response spectra, should be accounted for as well in future generations of seismic codes. Finally, it appears necessary to perform a harmonization of the behavior factors employed in seismic design codes.

San Salvador Metropolitan Area (MASS) is an urbanized territory in the country of El Salvador, located between the San Salvador volcano and the Ilopango caldera, in a sub-flat area called “Valle de las Hamacas” (Valley of the Hammocks). The high seismicity of this area is due to the subduction zone of the Cocos plate that causes strong seismic events such as the earthquakes that occurred on 13 January (7.6 Mw) and 13 February 2001 (6.6 Mw). As part of the international cooperation project between Italy (AICS) and El Salvador University, the CASTES project focussed on natural hazards in the territory of El Salvador was launched. Therefore, 2D simulations are carried out along two sections to evaluate the Local Seismic Response (LSR) in the Southeast part of MASS territory. Results show spatially variable amplifications (from 3 to 6.5) in the period ranging 0.1–0.7 s and evidence of lateral FA variations that can be calculated only through 2D numerical analyses. Two amplified periods are recognised, 0.1–0.5 s and 0.4–0.8 s, due to the presence of two types of subsoil volcanic deposits: the shallow and soft Tierra Blanca deposits and the deeper and stiffer Volcanic ash and Tuff.