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We would like to make some comments on the paper by Hamidatou et al. (2019). Initially, these comments are motivated to reveal that, previous results on probabilistic seismic hazard analyses, some of them computed and published by our research group, are wrongly quoted in the paper by these authors. In our opinion, some other points are worthy of debate, mainly, but not only, the used seismic source zone model, the used logic-tree, and also the comparison of estimated values of peak ground horizontal acceleration (PGA) with previous results. [ABSTRACT FROM AUTHOR]

10.1007/s10950-014-9468-6 13 Lyubushin A.A. Coherence between the fields of low-frequency seismic noise in Japan and California, Izv. 10.1134/S1069351314030069 11 Lyubushin A.A. Dynamic estimate of seismic danger based on multifractal properties of low-frequency seismic noise. It is the analysis of multifractal properties of low-frequency seismic noise that made it possible to predict the mega-earthquake in Japan of March 11, 2011 well in advance (Lyubushin, 2009; 2010a; 2010b). This was initially established in (Sobolev et al., 2005; 2008; 2010; Lyubushin and Sobolev, 2006; 2007; Sobolev and Lyubushin, 2006; 2007; Lyubushin, 2008). [Extracted from the article]

We have kindly received the comments by Hamdache and Pelàez on our published paper (Hamidatou et al. 2019); This article will give us the opportunity to provide more explanation and clarifications on the methodology followed during our work. We find these comments and critiques helpful for our future works. However, most of them were generated from the misapprehension of the paper by the comment authors. These remarks were mainly based on (1) the misjudging of the seismic source zone model used in relation to the active faults in the study area, (2) suspecting that the probabilistic seismic hazard PGA values were wrongly quoted from their analyses in our work, and (3) the logic tree usage , for which we here provide further general clarifications. [ABSTRACT FROM AUTHOR]

Kavitha and Raghukanth (Acta Geod Geophys 1-33, 2015) proposed an algorithm to forecast the earthquake energy release for the global seismogenic zones. They concluded that 'the developed model is efficient in forecasting the annual earthquake energy release of most of the seismogenic zone'. However, for several representative case studies their predictions not only are significantly smaller than the observations but also have unreasonable uncertainty. This commentary discusses some of the problems associated with the earthquake data selection for the input of modeling, which may improve the accuracy of the earthquake energy prediction. [ABSTRACT FROM AUTHOR]

Travertine and calcareous tufa are types of continental carbonates that form in subaerial environments near groundwater seepages, springs, and rivers. These deposits exist on all continents and can provide valuable information about past climates, environmental changes, and geological activity. A recent special issue of the journal Minerals focuses on the geochemistry of travertines and calcareous tufas, with contributions from researchers studying deposits in various locations around the world. The articles cover topics such as the formation processes, depositional environments, and diagenesis of these carbonate deposits, as well as their use as paleoclimate records and indicators of geothermal resources. The studies employ a multidisciplinary approach, combining techniques such as geochemistry, mineralogy, petrography, and isotopic analysis to gain a comprehensive understanding of these complex systems. Overall, the contributions highlight the importance of geochemical tracers in enhancing our knowledge of travertines and calcareous tufas. [Extracted from the article]

Earthquake sequencing studies allow us to investigate empirical relationships among spatio-temporal parameters describing the complexity of earthquake properties. We have recently studied the relevance of Markov chain models to draw information from global earthquake catalogues. In these studies, we considered directed graphs as graph theoretic representations of the Markov chain model, and analyzed their properties. Here, we look at earthquake sequencing itself as a directed graph. In general, earthquakes are occurrences resulting from significant stress-interactions among faults. As a result, stress-field fluctuations evolve continuously. We propose that they are akin to the dynamics of the collective behaviour of weakly-coupled non-linear oscillators. Since mapping of global stress-field fluctuations in real time at all scales is an impossible task, we consider an earthquake zone as a proxy for a collection of weakly-coupled oscillators, the dynamics of which would be appropriate for the ubiquitous Kuramoto model. In the present work, we apply the Kuramoto model to the non-linear dynamics on a directed graph of a sequence of earthquakes. For directed graphs with certain properties, the Kuramoto model yields synchronization, and inclusion of non-local effects evokes the occurrence of chimera states or the co-existence of synchronous and asynchronous behaviour of oscillators. In this paper, we show how we build the directed graphs derived from global seismicity data. Then, we present conditions under which chimera states could occur and subsequently, point out the role of Kuramoto model in understanding the evolution of synchronous and asynchronous regions. [ABSTRACT FROM AUTHOR]

An earthquake is one of the most significant and shocking natural disasters ever documented anywhere on the planet. Throughout history, it has claimed millions of lives and wreaked devastation on infrastructure. Because earthquake forces are spontaneous and unpredictable, engineering methods must be honed to investigate buildings under the impact of these forces. The dynamic and static computations of four RC multistory structure prototypes with various elevations in a high seismic zone are compared in this paper. The project under review is modeled as a 3, 6, 12, and 18-story establishment, and it is analyzed employing ETABS vs. 2019. The Equivalent Lateral Force (ELF) Procedure is used for static experimentation, while the Response Spectrum (RS) Procedure is employed for dynamic investigation. Both calculations are performed as per the EUROCODE 8-2004 recommendation. The ELF seismic load practice utilized was for the country of Norway, which has similar parameters to the ES-EN 8-15 seismic regulation Type I target RS, with ag/g = 0.1, spectrum type = I, soil factor S = 1.3 ground type, spectrum period (Tb, Tc, and Td) 0.1 s, 0.25 s, and 1.5 s. For the RS investigation, the parameters employed are as per ESEN-2015, ag/g = 0.1, and the spectrum type = I and ground type = B parameters were involved in the same manner for the RS analysis. The soil factor was set to 1.35; the spectrum period was set to (Tb, Tc, and Td) 0.05 s, 0.25 s, and 1.2 s. The behavior factor = 3.8, the lower bound factor = 0.2, and the damping ratio = 0.05. The results are then compared by employing different components such as displacement, story drift, story stiffness, base story shear, and story moment. Ultimately, a comparison of static and dynamic investigations has been carried out. Compared to the RS approach, the ELF technique produces more additional displacement, total drift, and base shear. As per the findings of this paper, for high-rise and tall buildings, dynamic analysis such as RS should be used rather than static analysis (ELF). [ABSTRACT FROM AUTHOR]

In the Split City area, with an air distance of approximately 18 km, the survey of land surface temperature (LST) and urban heat islands (UHI) was detected. It also shows how local geomorphology, especially the density of urban areas (especially densely built high-rise buildings and urban canyons) and the amount of greenery and water surfaces, affect the UHI of the observed area. The paper uses a known method of classifying local climatic zoning (LCZ) and its coincidence with the zones of the highest urban temperatures. The paper highlights the critical areas and suggests possible solutions to reduce the UHI. [ABSTRACT FROM AUTHOR]

Aiming at the problem of excessive vertical vibration caused by seismic primary waves in jacket structures located in seismic zones in China, a new type of shear plate metal damper with upper and lower elliptical openings (SPA) is proposed in this paper. The seismic model test is carried out to compare the shear plate metal damper with three traditional opening forms, central elliptical opening, single row opening, and double row opening, and the hysteretic curve, skeleton curve, and cyclic hysteretic energy dissipation capacity are analyzed. The results show that the energy dissipation performance of the new shear plate metal damper with upper and lower elliptical openings proposed in this paper is better than that of the other three types of dampers. [ABSTRACT FROM AUTHOR]

Alexandria is the second biggest city in Egypt as regards population, is a key economic area in northern Africa and has a very important tourist activity. Historical catalogues indicate that it was severely affected by a number of tsunami events. In this work we assess the tsunami hazard by running numerical simulations of tsunami impact in Alexandria through the Worst-case Credible Tsunami Scenario Analysis (WCTSA). We identify three main seismic sources: the Western Hellenic Arc (WHA - reference event AD 365, Mw = 8.5), the Eastern Hellenic Arc (EHA - reference event 1303, Mw = 8.0) and the Cyprus Arc (CA - hypothetical scenario earthquake with Mw = 8.0), inferred from the tectonic setting and from historical tsunami catalogues. All numerical simulations are carried out by means of the code UBO-TSUFD, developed and maintained by the Tsunami Research Team of the University of Bologna. Relevant tsunami metrics are computed for each scenario and then used to build aggregated fields such as the maximum flood depth and the maximum inundation area. We find that the case that produces the most relevant flooding in Alexandria is the EHA scenario, with wave heights up to 4 m. The aggregate fields are used for a building vulnerability assessment according to a methodology developed in the frame of the EU-FP6 project SCHEMA and further refined in this study, based on the adoption of a suitable building damage matrix and on water inundation depth. It is found that in the districts of El Dekhila and Al Amriyah, to the south-west of the port of Dekhila over 12 000 buildings could be affected and hundreds of them could incur in consequences ranging from important damage to total collapse. It is also found that in the same districts tsunami inundation covers an area of about 15 km2 resulting in more than 150 000 residents being exposed. [ABSTRACT FROM AUTHOR]

This paper analyzes and reviews the rapid uplifts of the Earth's crust in the Caucasus that occurred over the last century. The uplifts were registered by precise repeated state leveling and reflected on officially published maps of vertical movements of the Earth's crust. This study summarizes information on the region's vertical movements over more than a century. The present study describes the technology for creating maps of recent vertical movements of the Earth's crust using precision leveling data. This paper summarizes cases of recording uplifts of the Earth's surface in other regions of the world in connection with seismic activity. The authors carried out intercomparison of vertical movements with tectonics, seismicity, and geophysical fields, which discovered their apparent mutual correspondence. This indicates the deep tectonic nature of the observed uplifts of the Earth's crust. Spatial and temporal agreement with the distribution of strong earthquakes showed a natural relationship. It has been shown that strong earthquakes are confined to the boundaries of zones of rapid uplift. They occur predominantly in areas of transition between uplifts and subsidence. The results obtained demonstrate the role of the study and observations of vertical movements of the Caucasus in assessing periods and areas of increased seismic hazard. [ABSTRACT FROM AUTHOR]

The 2015 Nepal Earthquake (Mw7.8) affected more than 9000 schools in the country. Damage distribution in the 14 most-affected administrative districts shows that the construction practices were an important determent for the level of damage extended. The use of improper construction materials, lack of construction supervision, and non-compliance with the existing building codes during design and construction probably contributed to severe damage to most of the school buildings. Based on the damage analysis data and experience of the rebuilding process after the 2015 Nepal Earthquake, this paper highlights the steps to be considered during a rebuilding plan for school buildings after an earthquake disaster. Preliminary damage assessment results show that in the most-affected districts, about 86% of schools (locations) were affected by the earthquake and about one million students were out of their schools for a long time. The damage survey data indicate that about 30% of classrooms collapsed, about 13% of classrooms sustained major damage, and about 17% of classrooms sustained minor damage within the most-affected 14 districts. This damage report is largely based on the secondary data provided by the concerned government authorities. Such evidence of loss and damage in earthquake disasters provides an opportunity to learn lessons for future preparedness and to encounter disaster challenges. This work shares an experience on the rebuilding process of damaged schools and classrooms. It is expected that the experience reported in this paper will help in better planning of the seismic safety of school buildings in Nepal as well as in other similar seismically active regions. Most papers related to the 2015 Nepal Earthquake focus on overall building damage, but this paper addresses the issues of school buildings. As a case report, this paper probably lacks scientific originality, but the presentation of the damage data and the rebuilding process are the original work of the authors. [ABSTRACT FROM AUTHOR]

The paper describes the procedure employed for developing a new earthquake zone map of India as part of the seventh revision of the Indian Earthquake Standard IS 1893 (Part 1). This new zone map is based primarily on a probabilistic earthquake hazard analysis performed at a grid spacing of 0.1°×0.1° in longitudes and latitudes of the entire country. But, for grid locations with small probabilistic hazard estimates, a minimum level of hazard has been estimated deterministically for the most likely maximum magnitude of an earthquake on the nearest mapped fault. Based on the results, the Indian landmass is grouped into five zones, designated as ‘earthquake zones II, III, IV, V, and VI.’ The peak ground accelerations corresponding to a return period of 2475 yr in these zones are estimated as 0.15, 0.30, 0.45, 0.60, and 0.75g, which also include the site amplification effect. Common normalized response spectra are recommended for all five zones, one for each of the three different site soil conditions, as an interim measure. [ABSTRACT FROM AUTHOR]

Timber-framed masonry structures are widely used around the world, and their seismic performance is generally poor. Most of them have not been seismically strengthened. In areas with high seismic fortification intensity, there are great potential safety hazards. And it is urgent to carry out effective seismic reinforcement. However, due to the complicated construction process of the existing reinforcement technology, the poor durability of the reinforcement materials, and the significant disturbance to the life of the original residents, an efficient single-story timber-framed masonry structure reinforcement technology suitable for comprehensive promotion and application has not been explored. In this paper, a fiber-reinforced cement mortar (FRCM) material was proposed. A 1/2 scale model of a single-story timber-framed masonry structure was taken as the research object. The method of strengthening a single-story timber-framed masonry structure with FRCM layer was adopted. And the shaking table test of the model before and after reinforcement was carried out in turn. The dynamic characteristics, failure modes, acceleration response and displacement response of the FRCM layer-strengthened structure were analyzed through comparisons of the two cases. The experimental results showed that the FRCM layer significantly improved the seismic performance of the seismic-damaged single-story timber-framed masonry structures. The X- and Y-direction natural frequencies of the model structure were increased by 31.30% and 30.22%, respectively, after the structure was strengthened with FRCM. During a rare eight-degree earthquake, the inter-story displacement angles in the X- and Y-direction of the unreinforced model reached 1/98 and 1/577, respectively, and the structure was destroyed, while the inter-story displacement angle of the FRCM-reinforced model was only 1/2 of that the unreinforced model. During a rare nine-degree earthquake, the X-direction inter-story displacement angle of the model strengthened with FRCM reached 1/78 and the Y-direction inter-story displacement angle reached 1/178. At this time, the reinforced model structure was destroyed, but there was no collapse of the structural components, which met the seismic design objectives of "operational under the design minor seismic intensity, repairable damage under the design seismic precautionary intensity, and collapse prevention under the design rare seismic intensity", which proved that the FRCM layer was an effective and feasible way to strengthen the existing single-story wood-masonry rural building. [ABSTRACT FROM AUTHOR]

In this paper, we present a scenario-based approach for tsunami hazard assessment for the city and harbour of Sines - Portugal, one of the test-sites of project ASTARTE. Sines holds one of the most important deep-water ports which contains oil-bearing, petrochemical, liquid bulk, coal and container terminals. The port and its industrial infrastructures are facing the ocean southwest towards the main seismogenic sources. This work considers two diffierent seismic zones: the Southwest Iberian Margin and the Gloria Fault. Within these two regions, we selected a total of six scenarios to assess the tsunami impact at the test site. The tsunami simulations are computed using NSWING a Non-linear Shallow Water Model With Nested Grids. In this study, the static ellect of tides is analysed for three diffierent tidal stages MLLW (mean lower low water), MSL (mean sea level) and MHHW (mean higher high water). For each scenario, inundation is described by maximum values of wave height, flow depth, drawback, runup and inundation distance. Synthetic waveforms are computed at virtual tide gauges at specific locations outside and inside the harbour. The final results describe the impact at Sines test site considering the single scenarios at mean sea level, the aggregate scenario and the influence of the tide on the aggregate scenario. The results confirm the composite of Horseshoe and Marques Pombal fault as the worst case scenario. It governs the aggregate scenario with about 60% and inundates an area of 3.5 km2. [ABSTRACT FROM AUTHOR]

Seismic regulations of developing countries are often grounded on rules of more experienced countries. The Lebanese regulations refer to four foreign codes, this excess of guidelines generating confusion and conflicting design choices. Moreover, the scarcity of earthquakes recorded in the Lebanese area makes it difficult to obtain suitable sets of spectrum-consistent accelerograms for dynamic analyses. Sorting through the reference regulations and the indications for their local application, this paper derives and compares all the design response spectra allowed by the Lebanese code. Consistent with the design response spectra of the two codes that are still in force (of the four referred to), some suites of spectrum-consistent accelerograms are derived. Based on the Arias intensity, a general procedure is also proposed to reduce the time duration of the accelerograms, while saving the earthquake energy content and, thus, the reliability of the results. Full-length and short-length spectrum-consistent accelerograms are thus made available for the Lebanese design. With reference to a two-dimensional model some comparisons between response-spectrum-based and earthquake-based analyses are provided, which showed that the Lebanese code allows different safety levels for earthquake-resistant buildings. The paper provides a very useful contribution to researchers and designers that are involved in the protection of the Lebanese building heritage from seismic hazards, and it also provides data and tools that can be more generally exploited in other seismic areas. [ABSTRACT FROM AUTHOR]

Purpose: This paper aims to develop preliminary damage scenarios for unreinforced masonry buildings located in low to moderate seismic hazard areas in Algeria, taking into account the specific site effects. Design/methodology/approach: Three soil types were considered in this analysis according to the definition of the Algerian seismic code (RPA99/2003). Peak ground acceleration values were assigned to each soil type issued from a probabilistic seismic hazard analysis (PSHA). To highlight the effect of soil conditions on the seismic vulnerability analysis of masonry buildings, a site vulnerability increment is carried out, and the macroseismic Risk-UE method has been adopted and applied by developing two main seismic scenarios according to both return periods of the PSHA, 100 and 475 years, respectively. Findings: Based on the preliminary results of rock site condition, it can be outlined that the significant damage obtained for different earthquake scenarios discovered a substantial worldwide seismic risk to the building stock of the study area. Once the site effect is integrated into the analysis, more high values of vulnerability indexes and expected damages are obtained. Moreover, it can be concluded that soft soil (S3) is a little bit more influential than stiff soil (S2) on the final vulnerability index compared to (S1). However, the difference between the soil effect S2 and S3 on the vulnerability index can be neglected. Research limitations/implications: Researchers are encouraged to test the mechanical approaches for more detailed outcomes of a specific building analysis. Practical implications: This research proves to the Algerian decision-makers that due to the site effects and the vulnerability of the masonry buildings, an urgent intervention program is required even for existing buildings located in low to moderate seismic hazard areas. Originality/value: Several seismic vulnerability types of research have been conducted in Algeria for the unreinforced masonry buildings in moderate to high seismic areas in which generally the soil effect is neglected. In this context, this research paper proves that due to the site effects and the vulnerability of the masonry buildings, special attention is required even for existing buildings located in low to moderate seismic hazard areas. With this conclusion, the requirement of taking into account the soli effect in the high seismic areas is even more pronounced and should be conducted. [ABSTRACT FROM AUTHOR]

On 6 February 2013 an Mw 8.0 subduction earthquake occurred close to Santa Cruz Islands at the transition between the Solomon and the New Hebrides Trench. The ensuing tsunami caused significant inundation on the closest Nendo Island. The seis- mic source was studied with teleseismic broadband P waves inversion optimized with tsunami forward modeling at DART buoys (Lay et al., 2013), and with inversion of teleseismic body and surface waves (Hayes et al., 2014). The two studies also use different hypocenters and different planar fault models, and found quite different slip models. In particular, Hayes et al. (2014) argued for an aseismic slip patch SE from the hypocen ter. We here develop a 3-D model of the fault surface from seismicity analysis and retrieve the tsunami source by inverting DART and tide-gauge data. Our tsunami source model features a main slip patch (peak value of ~ 11 m) SE of the hypocentre, and reaching to the trench. The rake direction is consistent with the progressively more oblique plate convergence towards the Solomon trench. The tsunami source partially overlaps the hypothesized aseismic slip area, which then might have slipped coseismically. [ABSTRACT FROM AUTHOR]

The effectiveness of the tuned mass damper inerter (TMDI) in reducing the vibration of building structures under site-specific earthquake excitation is investigated. The site is Guwahati, Assam, which lies in the most severe seismic intensity zone in India. In this paper, the optimization of the TMDI design parameters is carried out for the site-specific input derived for the building site by a modulated Clough-Penzien (C-P) spectrum fitted to the power spectral density function obtained from a strong motion model of the site. All possible topologies of the TMDI, with one terminal of the inerter being connected to the damper mass attached to the top storey of the example buildings, and the other terminal being connected to any other floor, are investigated. The structure-TMDI system is analyzed both in the frequency-domain and in the time-domain. A numerical study is conducted with two example building structures. Optimization of design parameters of the TMDI is carried out using the technique of simulated annealing in the frequency-domain using the site-specific modulated Clough-Penzien spectrum as input. The performance of the optimal TMDI cases is evaluated by subjecting the example structures to 10 site-specific synthetically generated accelerograms. Results indicate that the TMDI is superior to the TMD for all topologies of the TMDI in case of the 3-storieed structure; and for topologies of the TMDI in which the inerter spans more than 4 floors for the 8-storied structure, with improved reductions in top-floor displacement, acceleration, and stroke length. [ABSTRACT FROM AUTHOR]

Ensuring resilience through rapid buildings recovery in seismic zones has been placed at the forefront of recent studies. However, studies that compare the relative resilience of buildings constructed with different materials are lacking. This paper focuses on a comparative resilience analysis of concrete moment frames where beam-column connections are made with varying types of concrete mixtures. The connections are made with normal strength concrete (NSC), rubberized concrete (RbC), steel fiber rubberized concrete (STFRC), synthetic fiber rubberized concrete (SYFRC), and high strength concrete (HSC). Nonlinear static pushover and incremental dynamic analysis (IDA) are utilized to understand system response and the level of damage sustained following an earthquake. Subsequently, seismic fragility functions are constructed for the five considered frame types. The frames are subjected to different seismic scenarios, and the corresponding losses, recovery time, and resilience are quantified. A comparison between the five frame types is carried out to examine the optimal concrete mixture to be used to reduce damage probabilities, total direct losses, and recovery time and subsequently enhance resilience. The results show that rubberized concrete strengthened with steel and synthetic fibers can reduce economic losses by up to 19% and increase building resilience by up to 37% compared with the frames constructed with normal strength concrete. [ABSTRACT FROM AUTHOR]

Health assessment and preventive maintenance of structures are mandatory to predict injuries and to schedule required interventions, especially in seismic areas. Structural health monitoring aims to provide a robust and effective approach to obtaining valuable information on structural conditions of buildings and civil infrastructures, in conjunction with methodologies for the identification and, sometimes, localization of potential risks. In this paper a low-cost solution for structural health monitoring is proposed, exploiting a customized embedded system for the acquisition and storing of measurement signals. Experimental surveys for the assessment of the sensing node have also been performed. The obtained results confirmed the expected performances, especially in terms of resolution in acceleration and tilt measurement, which are 0.55 mg and 0.020°, respectively. Moreover, we used a dedicated algorithm for the classification of recorded signals in the following three classes: noise floor (being mainly related to intrinsic noise of the sensing system), exogenous sources (not correlated to the dynamic behavior of the structure), and structural responses (the response of the structure to external stimuli, such as seismic events, artificially forced and/or environmental solicitations). The latter is of main interest for the investigation of structures' health, while other signals need to be recognized and filtered out. The algorithm, which has been tested against real data, demonstrates relevant features in performing the above-mentioned classification task. [ABSTRACT FROM AUTHOR]

A dynamic analysis of the Makhool dam using Geo-studio software is presented in this paper for the purpose of investigating the seismic behavior of earth dams. With emphasis on the dam's height, soil characteristics, and input motion, this study examines the effect of earthquake excitation on the dam's behavior. With input from the SEEP/W program, the analysis was conducted using the QUAKE/W program. In this study, the horizontal component of motion was taken at three different values: 0.04g, 0.06g, and 0.08g. In addition to total stress in x-direction and y-direction, pore water pressure, and x-displacement, the results were presented in figures. Study findings showed that the horizontal displacement and shear strain of the dam increased with dam height, with the maximum displacement of the dam equal to 94 cm at the end of the earthquake. Besides the type of dam soil, the acceleration of the dam was also affected by the strength of the soil, since weaker soil reduced the acceleration of the dam. The pore-water pressure at the dam's base was the highest, with the horizontal movement increasing with depth. In earthquake zones, seismic evaluation is vital for dam construction, and the research provides valuable advice for designing and building earth dams. [ABSTRACT FROM AUTHOR]

Geological hazards caused by strong earthquakes have caused continuous social and economic losses and destruction of the ecological environment in the hazard area, and are mostly manifested in the areas with frequent occurrence of geological hazards or the clustering of geological hazards. Considering the long-term nature of earthquakes and geological disasters in this region, this paper takes ten earthquake-stricken areas in Wenchuan earthquake zone as examples to collect shallow landslide data in 2010, combined with the spatial location of landslides and other factors. Kernel density estimation (KDE) method is used to analyze the spatial characteristics of shallow landslide. Taking the space of shallow landslide as the characteristic variable and fully considering the regulating factors of earthquake-induced landslide: terrain complexity, distance to river, distance to fault, distance to road, lithology, normalized vegetation difference index (NDVI) and ground peak acceleration (PGA) as independent variables, based on KDE and polynomial logistic regression (MLR), A quantitative model of shallow landslide in the earthquake area is constructed. The results show that: (1) PGA has the greatest impact on landslide in the study area. (2) Compared with the two-category logistic regression (two-category LR) model, the susceptibility map of landslide prediction results based on the KDE-MLR landslide susceptibility prediction model is more consistent with the actual situation. (3) The prediction accuracy of the model validation set is 70.7%, indicating that the landslide susceptibility prediction model based on KDE-MLR can effectively highlight the spatial characteristics of shallow landslides in 10 extreme disaster areas. The research results can provide decision-making basis for shallow landslide warning and post-disaster reconstruction in earthquake-stricken areas. [ABSTRACT FROM AUTHOR]

There is a need for safer constructed medium in order to respond to the constant necessity for raising the security level of human society to earthquakes impact. In this respect the buildings monitoring in areas subjected to seismic site effects provides the possibility of getting immediate and reliable information on the status of certain structures, which enables decision makers to better allocate resources and to direct rescue operations. A procedure is implemented, which allows to perform real-time data acquisition, data exchange and data analysis from structures exposed to seismic excitation or under ambient vibration. The processed recordings are used to deliver information in real time about the seismic event. Engineering seismology parameters are computed: maximum acceleration, spectral acceleration, corresponding oscillation periods, etc., on both structures and free field. The output is conceived as a standard report on the characteristic response of the instrumented building. In the paper such an approach is described in an extended and thoroughly version, for two instrumented buildings, located in different areas, under the last year's strongest seismic event of 2022.11.03, Mw = 5 that hit the Romanian territory. [ABSTRACT FROM AUTHOR]

Soil plug formation in open-ended piles due to pile driving is a widely studied phenomenon in onshore applications. The narrow diameters of traditional onshore piles ranging from 0.5 to 1.5 m facilitate plug generation during installation and transfer of enhanced confining stresses across the whole body of the soil plug. Offshore wind monopiles with larger diameters and smaller aspect ratios may not enhance confining stress within the soil plug as effectively as their onshore counterparts. Monopiles are currently the most widespread foundation in the offshore wind sector including in seismic areas. Earthquake shaking can lead to accumulation of excess pore pressure and subsequent liquefaction of the soil retained inside the plug. This research investigates the influence of monopile diameter and confining stress on the development of earthquake-induced excess pore pressure within the soil plug using fully coupled time domain Finite Element Analysis. The results presented in this paper reveal lower accumulation of earthquake-induced excess pore pressure in soil plugs subjected to confining stress. However, the influence of additional horizontal stress caused by monopile driving on the generation of excess pore pressure within the soil plug diminishes as the monopile diameter is progressively increased. [ABSTRACT FROM AUTHOR]

Different catalogues of earthquakes are available for the Indian region besides regional catalogues for the Gujarat region. The limitations of these and other historical catalogues have been discussed in this paper for earthquake hazards and other studies. Keeping in view that these historical catalogues have been successful in explaining the recent occurrence of a few earthquakes like Coimbatore (1900), Hyderabad (1983), Bangaluru (1985) and Jabalpur (1997), the study has been extended to the Gujarat region. In this paper, therefore, an attempt has been made to correlate the historical data of the felt earthquakes in the Gujarat region from all the available sources with instrumental data to examine the recurrence of the earthquakes. It has been found that in addition to the seismically active Kutch region and Narmada and Cambay rifts, there is a tendency for earthquakes to recur in many districts of Gujarat for which felt data from historical times is available. The seismicity map prepared by the Institute of Seismological Research (ISR), Gandhinagar based on the Seismic Telemetry (2006–2020) shows scattered seismicity over the whole of Gujarat region besides active seismicity in the Kutch region. This data when combined with that from the catalogue prepared by the National Centre of Seismology provides greater confidence for earthquake hazard studies It has also been found that the coastal regions of Saurashtra and south Gujarat are more prone to swarm types of earthquakes. [ABSTRACT FROM AUTHOR]

Accelerated bridge construction (ABC) has attracted much attention in China as a new and efficient construction method. However, the seismic performance of the connections between precast piers and other structures limits the application of ABC in medium and high seismic zones. In this paper, a quasi-static test was conducted to investigate the seismic performance differences between a cap–column socket connection (PSC) specimen, which reinforced an embedded RC column-to-precast cap beam with a socket connection, and a cast-in-place (CIP) cap–column specimen. A fiber-based finite element model that considers bond slippage between the connection reinforcement and wet joint concrete is proposed. The numerical simulation results compared with the experimental results show an error of about 12% in peak bearing capacity and about 2% in initial stiffness. The experimental and numerical results show that the PSC specimen demonstrates comparable seismic performance to the CIP specimen. Experimental results verified that the finite element model in this paper is adequate to predict the seismic responses of a precast column with a reinforcement-embedded socket connection. A reinforcement-embedded RC column-to-precast cap beam with socket connection can be an effective solution for construction in medium and high seismic areas. [ABSTRACT FROM AUTHOR]

Probabilistic seismic hazard analysis (PSHA) has been recognized as a reasonable method for quantifying seismic threats. Traditionally, this method ignores the effect of the focal depth, in which the ground motion prediction equations (GMPEs) are applied to estimate the probability distribution associated with the possible motion levels induced by the site earthquakes, but it is limited by the unclear geological conditions, which makes it difficult to provide a uniform equation, and these equations cannot express the non-linear relationship under geological conditions. Hence, this paper proposed a method to consider the seismic focal depth for the PSHA with the example of California and used a back propagation neural network (BPNN) to predict the peak ground acceleration (PGA) instead of the GMPEs. Firstly, the measured PGA and unknown PGA seismic data applicable to this method were collected separately. Secondly, the unknown PGA data were supplemented by applying the BPNN based on the measured PGA data. Lastly, based on the full-probability equation, PSHA considering the focal depth was completed and compared with the current California seismic zoning results. The results showed that using the BPNN in the PSHA can ensure computational accuracy and universality, making it more suitable for regions with unclear geological structures and providing the possibility of adding other parameters to be considered for the influence of the PSHA. [ABSTRACT FROM AUTHOR]

Epistemic uncertainty offers alternatives on decision making and various possibilities of computing the hazard integral. Generally, the logic tree approach is used while treating the epistemic uncertainty. Logic tree weight calculation is a subjective decision based on the degree of belief of the analyst on the possible contributors to the epistemic uncertainty and often leads to a different set of values by different researchers. This paper aims to develop a framework of accounting for the epistemic uncertainty in probabilistic seismic hazard analysis (PSHA) by minimizing the subjectivity involved in weight calculation. Guidelines/rules are developed for the weight calculation at each node of the logic tree. Recurrence parameters, magnitude and distance probability distributions, maximum magnitude, and selection of ground motion predictive equations (GMPEs) are considered the possible sources of epistemic uncertainty. A GMPE rule is proposed to be used with the PSHA framework to account for the propagation of epistemic uncertainty. The north-east region of India is chosen for the purpose of illustration. The study region is divided into seven seismic source zones (five in the active crustal region and two in the subduction zone). Seismic hazard is characterized in terms of the weighted mean and fractile representation of hazards using the logic tree approach. Only one sample illustration of the results are reported in terms of weighted mean and fractile representation of hazard curves and uniform hazard spectra (UHS). Further illustration of the PSHA results with possible implications from the epistemic uncertainty is reported in the companion paper. [ABSTRACT FROM AUTHOR]

Today's earthquakes are the most direct manifestation of the latest tectonic activity and are the most powerful tool to understand the characteristics of nonrigid deformation within a continent. Particularly, the newly formed faults that have been active since the Late Pleistocene are characterized to have low development maturity, poor connectivity in geometric structure, and obvious difference in strike/depth dip in different sections. Therefore, earthquakes can reveal their three-dimensional space changes, especially the characteristics of brittle-ductile transition depth. Earthquakes can also promote the understanding of the preparation and earthquake generation process of newly formed active faults. The newly formed strike-slip active faults in the Bohai Bay Basin have experienced many strong earthquakes, including the Tangshan MS7.8 and the three Ninghe MS≥ 6.2 earthquakes. The crustal brittle-ductile transition depth revealed by these earthquakes has an important practical significance to understanding the seismogenic mechanism and activity of the region. In this paper, the new fault in the Baodi Miaozhuang uplift in the Bohai Bay Basin is taken as the target fault. In addition, the 2012 Baodi MS4.0 and MS3.5 earthquakes in the Baodi uplift and the 1976 Ninghe MS6.2 and MS6.9 and the 1977 Ninghe MS6.2 earthquakes in the Miaozhuang uplift are taken as the research objects. Finally, the CAP method is used to study the source mechanism solution and the source depth of the Baodi MS4.0 and MS3.5 earthquakes based on the waveform data from the Capital Circle Digital Seismic Network. The double difference method is used to locate the source positions of two earthquake sequences by employing the Sp converted wave of near earthquakes to accurately determine the source depth. Moreover, combined with other data, the seismogenic mechanism of earthquakes in this area and the brittle-ductile transition depth of new fractures are discussed. The following results were found. (1) The source properties of the Baodi MS4.0 and MS3.5 earthquakes are not completely consistent with the known faults on the exposed surface of the Baodi Miaozhuang uplift. Combining the research results of the source parameters of the three Ninghe earthquakes having an MS ≥ 6.2, it is inferred that they all occurred in the Baodi-Ninghe deep fault. (2) Based on the models of electrical structure and rheological structure in the focal area, the five significant earthquakes in Baodi Miaozhuang uplift reveal that the brittle-ductile transition depth of the Baodi-Ninghe deep fault is about 15 km. (3) Based on the dynamic evolution process of the Bohai Bay Basin and relevant deep geophysical exploration data, it is hypothesized that the seismic activity in this area is mainly the result of the Baodi-Ninghe deep fault and deep fluid actions. [ABSTRACT FROM AUTHOR]

The western coast of South America is a territory continually exposed to earthquakes, where architects had to experiment proposals that would allow them to maintain the safety of their buildings. Among the different solutions for earthquake-resistant constructions, planked timber vaults appeared in South American religious architecture during the 17th century. This paper explains how the construction technique of these vaults arose and developed in a context conditioned by earthquakes. For the study, architectural surveys of the different variants of South American vaults were conducted, which were confronted with data from archives and historical texts, to later be expressed graphically through the drawing reading method. This method is important to transfer textual information from historical documents to contemporary graphic language and permit to learn more about the architectural heritage, like the construction characteristics of the planked timber vaults and understand the structural criteria followed by the ancient master builders. [ABSTRACT FROM AUTHOR]

Buried water reservoirs are increasingly being built to replace open aboveground municipal water supply reservoirs in urban areas to enhance water quality and utilize their surface footprint for other purposes such as public parks or placement of solar arrays. Many of these lifeline structures are in seismically active regions and, as such, need to be designed to remain operational after severe earthquake shaking. However, evaluating their seismic response is challenging and involves accounting for the interaction of the structure with the stored fluid and the retained soil; in other words, accounting for fluid–structure–soil interaction (FSSI). This paper presents a combined experimental–numerical study on the seismic behavior of buried water reservoirs while considering FSSI. Two series of centrifuge model tests were performed at different reservoir orientations to investigate one-dimensional (1D) and two-dimensional (2D) motion effects under full, half-full, and empty reservoir conditions. Corresponding numerical models were developed whereby the structure and the soil were represented by continuum Lagrangian finite elements, while the fluid was modeled via Arbitrary Lagrangian Eulerian formulation. Soil–structure and fluid–structure interface parameters were calibrated using the experimental measurements. The simulations successfully captured the measured reservoir responses in terms of accelerations, bending moment increments, and water pressures. The study found that the common assumption of plane strain is not applicable for reservoirs because their behavior was found to be truly three-dimensional (3D) whereby stresses accumulated at the corners. Furthermore, the full reservoir resulted in the highest seismic demands in the reservoir walls and roof while the empty reservoir yielded the highest base slippage. The study demonstrates that the complex reservoir seismic response is best captured by carrying out a 3D FSSI numerical simulation. [ABSTRACT FROM AUTHOR]

Steel multitiered concentrically braced frames (MT-CBFs) not specifically detailed for seismic resistance with a response modification factor of R=3 are permitted in moderate seismic regions. Past research studies, however, have raised concerns regarding the seismic performance of MT-CBFs and CBFs designed using R=3 provisions, namely the stability of columns in MT-CBFs and connection limit states in R=3 CBFs. This paper examines the seismic response of R=3 MT-CBFs and proposes a design method to improve their seismic performance. A set of 16 prototype R=3 MT-CBFs, ranging from 8 to 20 m tall with two to five tiers and located in a moderate seismic area, was selected and designed in accordance with 2016 US design guidelines. Nonlinear response-history analyses were then performed to examine the seismic response of these frames using fiber-based numerical models. R=3 MT-CBFs designed to 2016 design guidelines are shown to experience premature fracture in brace-to-beam/column connections in a single tier, which imposes high in-plane bending demands on columns and in some cases, leads to column instability or a tier-sway mechanism. New seismic design recommendations, including requirements for intermediate struts, columns, and tier drift, are proposed. The design method aims to prevent column instability or a tier-sway mechanism and protect brace connections from excessive deformation. [ABSTRACT FROM AUTHOR]

The city of Zagreb, the national capital and economic hub of Croatia, is situated in a seismically active region and hosts a significant array of historical buildings, from the medieval to Austro-Hungarian periods. These buildings possess varying but generally high degrees of vulnerability to seismic loading. This was highlighted in the Zagreb earthquake of 22 March 2020, emphasizing the need for seismic retrofitting in order to preserve this architectural heritage. In this paper, the seismic capacity of one such unreinforced masonry building is considered through a number of analysis methods, including response spectrum, pushover, and out-of-plane wall failure analyses. Given the advantages and disadvantages of the individual methods, their applicability and value in a seismic analysis is considered. Ambient vibration measurements before and after the Zagreb 2020 earthquake, used for model calibration, are also presented. Conclusions are drawn from each individual analysis and later compared. In conclusion, no single analysis method considers all relevant failure modes, and a combination of nonlinear static or dynamic analysis and out-of-plane analysis is recommended. Due to the large volume of the material, it is published in two parts, with ground motion record selection, dynamic analysis, and a comparison of the results published in part two. [ABSTRACT FROM AUTHOR]

Nominated for Eurosteel 2021 Best Paper Award The introduction to the market of metal foams represents a significant opportunity to increase the use of metal in the construction market. In fact, the development of new products made of metal foams and steel could improve the performance of conventional buildings in terms of stiffness and resistance. The first structural applications of these materials have already shown the potential of composites made of foam and steel, and demonstrated the feasibility of producing mono‐dimensional and bi‐dimensional elements with a high resistance‐to‐weight ratio. Reducing the structural weight can be a significant advantage in many cases, such as infrastructures or buildings in seismic zones. Within this framework, the work presented in this paper aims to assess the response of composite sandwich panels made of steel and aluminium foam using a set of tests that will serve as the basis for developing a new system of dry‐assembled composite floors. The tests were carried out at the Strength laboratory (Structural Engineering Test Hall) at the University of Salerno, Italy and were designed to verify the mechanical properties of metal foam panels and double‐skin glued sandwich panels. The tests have shed light on the basic mechanical properties of both foams and sandwich panels. [ABSTRACT FROM AUTHOR]

This paper provides an updated understanding of the reservoir stratigraphy, sedimentology, palaeogeography and diagenesis of the Upper Permian Hauptdolomit Formation of the Zechstein Supergroup ("Hauptdolomit") in a study area on the southern margin of the Mid North Sea High. The paper is based on the examination and description of core and cuttings data from 25 wells which were integrated with observations based on existing and new 3D seismic. Based on thin‐section petrography of cuttings and core from the wells studied, it is evident that Hauptdolomit microfacies are distributed in a relatively predictable way, and well‐defined platform interior, platform margin, slope and basin settings can be distinguished. Platform margins are typically characterised by the development of ooid shoals and, to a lesser‐extent, by microbial build‐ups. High‐energy back‐shoal settings are characterised by a more complex combination of peloid grainstones, thrombolitic and microbial build‐ups, and fine crystalline dolomites. Lower energy lagoons which developed further behind the platform margin are characterised by a variety of microfacies types; fine crystalline dolomites are common in this setting as well as peloidal facies and local microbial build‐ups. Intertidal and supratidal settings are typified by increased proportions of anhydrite and the development of laminated microbial bindstones (stromatolites). Platform margins are in general relatively steep and pass into slope and basinal settings. Only a few wells have penetrated Hauptdolomit successions deposited in a slope setting, and these successions are characterised by a range of resedimented shallow‐water facies together with low‐energy laminated dolomicrites and fine crystalline dolomites. Slope zones in the study area are interpreted from seismic data to be typically 1‐1.5 km in width. Basinal Hauptdolomit deposits have been strongly affected by post‐depositional diagenesis and are dedolomitised to variable degrees. The original depositional facies are rarely preserved. Diagenetic studies show that dolomitisation has affected almost the entire Hauptdolomit Formation throughout the study area in both basinal and platform settings. The dolomite is considered to result from seepage‐reflux processes and is an early diagenetic phase. Mouldic porosity is present in many facies types as a result of dissolution, especially in ooid grainstones, thrombolitic build‐ups and peloidal facies. The dissolution cannot be associated with any one diagenetic phase but was most likely a result of the dolomitisation process itself. Stable isotope analyses indicate that all dolomites were precipitated from Permian marine‐derived pore fluids. Fluid inclusion analyses of dolomite cements indicate that cementation continued into the burial realm. Anhydrite cementation occurs in two phases: early anhydrite precipitation was associated with dolomitisation, and can be distinguished from a later, pore‐filling cement which is highly detrimental to reservoir quality. The Hauptdolomit succession in basinal wells (and in some slope wells) in the study area has undergone significant dedolomitisation. Dedolomitisation was a shallow burial process which affected precursor dolomites, whereby excess calcium from the transition of gypsum to anhydrite during burial combined with CO2 and organic acids derived from basinal sediments. The process was triggered by excess calcium reacting with excess carbonate ions from dissolution. 3D seismic volumes supplemented by numerous 2D lines were available in the study area and allowed an interpretation to be made of Hauptdolomit gross depositional settings; platform margins and base‐of‐slope polygons were mapped, with the greatest confidence in areas of 3D seismic. The basin, slope and platform settings were distinguished using seismic data integrated with the results of micro‐facies analysis and incorporating seismic‐to‐well ties. The data shows that large parts of the study area are characterised by the presence of polyhalites within the overlying (Z2) Stassfurt Halite Formation, which may create particular seismic geometries at the Hauptdolomit slope. These are interpreted to be intra‐Stassfurt Halite features, providing an alternative model to the thickened, prograded Hauptdolomit which has been suggested in previous publications. Because few wells drilled in the study area had the Hauptdolomit as the primary target, cores were limited but significant data was obtained from cuttings analyses. More than 400 thin sections were evaluated, allowing depositional models based on microfacies observations to be developed, verifying the seismic‐scale observations. [ABSTRACT FROM AUTHOR]

China is located in the intersection area of two seismic zones. Due to this special geographical location, earthquake disasters occur frequently in China. Earthquake emergency rescue work is one of the key construction works of disaster prevention and mitigation in China. This paper mainly studies the earthquake disaster rescue model based on the complex adaptive system theory and establishes the earthquake disaster rescue model by analyzing the complex adaptive system theory and combining the earthquake rescue process. In this paper, through the task allocation mechanism task, the disaster rescue task is divided into simple task and complex task, and the executive task subject is divided into single task subject and multitask subject. On the basis of considering the shortest emergency rescue time goal and the goal of maximizing the deployment utility of rescue team, the reasonable deployment of a rescue team is realized through a complex adaptive system, that is, the deployment utility of the rescue team is maximized. In this paper, the simulation experiment and comparison of the earthquake disaster rescue model based on the complex adaptive system theory are carried out. The experimental results show that the model used in this paper is better than the other two models in terms of algorithm convergence, rescue number, and overall score; in different scenarios, the relative survival probability of the model in this paper is 58.92%, 67.85%, and 77.46%, and the proportion of the wounded rescued is 66.31%, 76.45%, and 83.06%, which were higher than those of the other two models. The earthquake disaster rescue model based on the complex adaptive system theory proposed in this paper provides an effective theoretical basis and method system for postdisaster emergency rescue decision making and enhances and improves the emergency response ability to deal with large-scale geological disaster events. [ABSTRACT FROM AUTHOR]

The Andes, located along South America's western side, is among the world's longest mountain ranges and is one of the most intense seismic activity areas caused by the Pacific Oceanic plate sliding under the South American continent, mainly when the range passes through Peru and Chile, covering an area of 3.37 million km2. The Himalayas mountain range is among the most seismically active regions in the world, mainly when the range passes through Nepal, China, India and Pakistan, due to the collision between the Indian and the Eurasian continental plates, covering an area of 1.09 million km2. Eastern Anatolia mountain range of Turkey covering an area of 0.15 million km2 is also one of the most seismically and tectonically active regions due to the frequent occurrence of earthquakes. These three areas and other few in the vicinity of high seismicity were considered for this paper based on in situ working experience for several dam spillways and large dams with heights up to 335 m. Of these 50% under operation, 25% under construction and 25% under final design stages. The earthquake safety of dams is an important topic in dam engineering and dam safety, and the seismic behavior of dams subjected to severe earthquakes and mainly their consequences downstream must be very well defined providing the adequate seismic factors not only from the engineering point of view but also thinking on damage risks, for a proper application. This paper evaluates the main concept of seismic hazard analysis and the PGA value defined for these dams in the Andean, Himalayas and Eastern Anatolia mountain ranges for the MDE, SEE and OBE earthquakes and their implications for the dynamic and static analysis. [ABSTRACT FROM AUTHOR]

This paper reports a study on the Intermediate Isolation System (IIS) applied to existing buildings. This kind of application is particularly suitable when a vertical addition is planned for buildings in seismic zones; in such a case, an isolation system can be placed at the base of the extension to prevent the increase, or, better, to reduce the seismic demand on the existing structure. In previous works, parametric response spectrum analyses have been carried out on lumped mass models by varying the period of the isolation system. As a result, a sort of IIS design spectrum has been derived and used for selecting design solutions for the vertical extension that minimize the overall seismic response. In this paper, the above design indications are assessed in the light of nonlinear time history analyses, accounting for the hysteretic response of the existing structure and the nonlinear behaviour of the isolation system. The IIS configurations are analysed and the results are discussed and compared in terms of peak response. In light of the obtained analysis results, the effectiveness and robustness of IIS applications for vertical extensions are discussed, and design implications are suggested. [ABSTRACT FROM AUTHOR]

This paper analyses cultural and aesthetic phenomena and their inherent meanings within the Japanese city. In the introduction, I first briefly define the key concepts used in the analysis: cultural archetype, collective memory, and cultural identity. I will approach the theme from a comparative point of view by examining Japanese urban features and archetypal principles in contrast to the European city. Early Japanese urbanisation centred around imperial palaces, with the first cities founded by successive emperors from the 7th century onwards in the Nara region, near present-day Kyoto. The orthogonal plan for the imperial capital was copied from the contemporaneous Chinese dynasties. Spatial organisation was hierarchical, imperial quarters were located at the northern end of the central south-north axis of the city, and the most prestigious plots were around the Emperor's palace. Kyoto, the historical Heian-Kyô, was founded as the imperial capital in 794. Tokyo, the historical Edo, became a "castle city" in 1457 when a military castle was built, and subsequently the capital when the shôgun moved government from Kyoto to Edo in 1603. The shôgun's castle, the centre of power, intertwined with the hierarchical urban order spiralling around it. Edo gradually became a modern capital, Tokyo, while Kyoto remained the traditional centre of high culture and the seat of the powerless Emperor until 1868. The Japanese city is a cultural metaphor. Psychological uncertainty, due to the country's location in a precarious earthquake and volcanic zone, and an awareness of the perishability of life based on Buddhist philosophy, have all deeply influenced both Japanese culture and the Japanese mind. Emptiness, the Taoist ideal linked to Buddhist thinking, is also reflected in the urban space. For instance, a Japanese city has no designated urban centre whereas in the European city this is a culturally and economically accentuated place. In this paper, I also analyse the Japanese spatial concepts ma and oku, along with their archetypal manifestations in urban tissue and street scape. While ma means experiencing space in time, oku refers to the hidden dimension of the urban experience, or the psychological state of processing a path whereby the urban core remains hidden and only partially discovered. Regardless of Japan's recent historical and economic development, the cultural characteristics of urban spaces have not changed a great deal. Tokyo is still a mosaic city of small village-type communities with an inherent feeling of togetherness. Hidenoby Jinnai has called this phenomenon an "ethnic continuity" whereby the new and the old are mixed in an ethnic order. [ABSTRACT FROM AUTHOR]

The paper presents the results of research on a nearly full-scale, 1-story reinforced-concrete (RC) spatial frame structure with masonry infill walls tested on a shake table. The experiment was conducted in four phases to investigate the in-plane and out-of-plane responses of the infill walls of the specimen. The use of a digital image correlation (DIC) technique with noncommercial analysis system allowed the computation of principal strains for the infill. Two methods of infill-RC frame protection using polyurethane resin (PU) flexible joints (PUFJ) at the RC frame-infill connection and an external innovative fiber-reinforced PU (FRPU) repair system were considered in the research. The test results indicated that the in-plane and out-of-plane infill performance was enhanced under seismic excitations. The PUFJs at the interface of the frame and infill walls helped the infills to withstand dynamic excitation of high intensity with repairable damage. Furthermore, the externally applied glass FRPU repair system efficiently protected the damaged masonry infills against collapse under out-of-plane excitation while restoring a significant portion of their in-plane stiffness. The variable contributions of the RC frame and of the brick infills when protected with innovative joints are evaluated through three-dimensional finite-element models. Externally bonded fiber-reinforced PU composite is prefabricated or constructed on-site repair and strengthening solution, consisting of strengthening fibers and flexible polyurethane matrix. It is capable of carrying high loads and high deformations simultaneously and allows for reducing of stress concentrations and redistributing them over large bonding area, what results in higher load capacity of the composite strengthening systems. This innovative composite solution is dedicated to structures made of brittle materials (concrete, masonry) located in seismic areas. Flexible polyurethane matrix allows working with even low-strength fibers and low-strength brittle substrates, introducing greater strength, ductility, and load-bearing capacity, making it safer in exploitation. This composite strengthening system was examined as emergency strengthening of infill walls damaged by vibrations on a shake table. Repeated seismic excitations of high intensity were unable to cause collapse of the infill walls protected by this innovative composite system, neither in in-plane nor in out-of-plane modes. The tested building specimen of natural scale, protected by the flexible composite system, survived many seismic excitations remaining in good structural shape. This paper presents results of dynamic tests, proving practical efficiency of the composite system examined in more dangerous conditions than are present during strong earthquakes. [ABSTRACT FROM AUTHOR]

Irregular configuration and multi-storey buildings are becoming necessary to accomplish one of the basic requirements of growing population. Nevertheless, the irregular configuration of the buildings poses design challenges when subjected to earthquake. Study of former seismic actions has disclosed that plan irregular buildings exposes to critical damage due to immoderate torsion and stress accumulation. This paper presents a performance study on high-rise RC building with reentrant corner, which is a form of plan irregularity, in high seismic zone by varying the plan aspect ratio. Four buildings of Lshape, Plus-shape, I-shape and T-shape with 30 stories are analyzed by carrying out pushover analysis using ETABS17 software. Parameters such as ductility ratio, displacement, storey drift, base shear and stiffness are considered for the performance evaluation. In this paper a detailed study of the ductility ratio has been made and it can be concluded that the I-shape building is more ductile compared to all the other shape buildings. [ABSTRACT FROM AUTHOR]

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When evaluating an area's seismic risk or resilience, it is necessary to use the spatial correlation to analyze the ground motion parameters of multiple sites together in an earthquake. These two large earthquakes in Türkiye provided the possibility for spatial correlation analysis of ground motion intensity measurements in this area. Based on the strong motion records provided by The Disaster and Emergency Management Authority of Türkiye (AFAD), this study uses the local ground motion prediction equation in Türkiye to give spatial correlation analysis of Intensity Measurements. This study gives an exponential model based on a semivariogram and compares it with the correlation model obtained from previous studies. [ABSTRACT FROM AUTHOR]

Eccentrically braced frames are renowned for their capacity to absorb seismic forces while offering greater adaptability. These frames incorporate bracings that are joined to the beams with an intentional offset, forming a connection within the beams. Nevertheless, there are drawbacks associated with implementing these beam connections when renovating frames. This paper seeks to enhance the design approach by introducing an eccentric link within the column of a composite structure. Eccentric braced frames (EBFs) are hybrid systems that offer both ductility in moment resisting frames (MRFs) and lateral stiffening in the concentrically braced system. The study examines composite frames with 5, 10, and 15 stories using eccentric X- and V-type bracings with an eccentricity of 0.5 m and 1 m. Three different earthquake zones are considered, based on Indian seismic code provisions: zone 3, zone 4, and zone 5. The structures are analyzed computationally by nonlinear time history analyses. The lateral load-resisting behavior of the structure with the same eccentricity in beam links and column links is compared. Then, the structure is subjected to a pushover analysis to study the performance characteristics such as capacity curve, lateral displacement, inter-storey drift, and plastification of the structure. As anticipated, compared to conventional moment resisting frames (MRFs) and concentrically braced frames (CBFs), eccentrically braced frames have better energy dissipation. Furthermore, the behavior of X-braced column links is found to be similar to the performance of beam links, but V-braced frames showed better performance in column link frames than in beam link frames. Also, the increase of the link length played a major role in the ductility of the frames. [ABSTRACT FROM AUTHOR]

Assessment of the seismic damage of coal mine overburden (OB) dump slopes gets compromised due to negligence of the consideration of heterogeneity in the shape and size of its particles. In this paper, in situ material parameters for an OB dump slope were evaluated through multichannel analysis of surface waves (MASW) investigations performed at the Jambad opencast coal mine of India. To realistically simulate the heterogeneity of the OB dump materials, Voronoi tessellation scheme coupled with extended finite-element method (XFEM) (using RS2 software) was employed. Behavior of a double-benched OB dump slope under earthquake excitations with a wide range of strong motion parameters (such as peak ground acceleration, predominant frequency, bracketed duration, and Arias intensity) was investigated through XFEM. The influence of strong motion parameters on the seismic behavior of a double-benched OB dump slope was reported in terms of transient (during the earthquake motion) and permanent deformation (after the earthquake motion) at various key points of the slope. Finally, the levels of damage experienced by the OB dump slope under earthquake ground motions were assessed qualitatively. The study would be advantageous for the mining industry in framing the safety guidelines for OB dump slopes in coal mine areas susceptible to earthquakes. The performance of a double-benched coal mine overburden (OB) dump slope under earthquake excitations with a wide range of strong ground motion parameters (such as peak ground acceleration, predominant frequency, bracketed duration, and Arias intensity) was investigated by employing Voronoi tessellation scheme coupled with extended finite-element method (XFEM). The influence of strong ground motion parameters on the seismic behavior of the double-benched OB dump slope was reported in terms of transient (during the earthquake motion) and permanent or residual deformation of the slope at various critical points. Further, the levels of damage experienced by the OB dump slope under earthquake ground motions were assessed qualitatively. This research work may provide guidance to practicing engineers for considering the heterogeneity of the OB dump slope while assessing its seismic performance. The study is going to be useful for the design of OB dump slopes for coal mines located in a seismically active region. If the site-specific earthquake parameters are available, the study may provide important aspects of seismic design of the OB dump slope. [ABSTRACT FROM AUTHOR]

This paper investigates the mechanical properties of a traditional welded rigid joint with a weakened panel zone under seismic load. The created finite element model is calibrated by the high-strength steel joint test, carried out by the team in the early stage, and the effectiveness of the finite element method was verified. The finite element software ABAQUS is used to investigate the influence of different joint web thicknesses on the mechanical properties of middle column joints under a low-cyclic-loading test. Supported by a validated numerical model, the ductility, energy dissipation, and other properties of different thicknesses of panel zone column webs are carefully analyzed. The results indicate that the thickness of the web plate in the panel zone significantly affects the location of the joint plastic hinge. The ultimate loading capacity of the joints increased significantly with an increase in the thickness of the webs in the panel zones. Compared with the joint with a weakened panel zone, the hysteresis curve of the strengthened joint is fuller; meanwhile, it cannot alleviate the stress concentration at the weld holes of the web. When the thickness of the joint domain web is too weak, excessive deformation in the joint domain will lead to a decrease in the bearing capacity of the joint, causing damage. The stiffness degradation coefficient of the web-thickened specimen was found to be dominated and controlled by the stiffness of the beam; however, with an increase in the thickness of the web, the stiffness degradation coefficient remained basically unchanged. Finally, a recommendation for weakened beam–column interior joints based on the steel frame panel zone is made, which will lay a foundation for the simulation and analysis of the seismic performance of this structure. [ABSTRACT FROM AUTHOR]