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The frequency of urban fires has grown in recent years everywhere, especially in historic districts, including in Portugal, due to the existence of sensitive igniting materials, the proximity of buildings, the complex urban layout, and the presence of many people. The current study proposes a technique, applied in the Baixa Pombalina (downtown) area in Lisbon, to undertake an appropriate evaluation of the post-earthquake fire cascading effect, which may cause major damage. The earthquake vulnerability and damage scenario were carried out using the Risk-UE method. An empirical fire ignition model was then applied to determine the quantity and location of fire ignitions for different return periods. Furthermore, the simple fire spread Hamada's model was applied to both the equally spaced grid buildings, as in the original Hamada procedure, and the current study area layout for different time thresholds. Finally, the risk assessment for both models was carried out, allowing for the estimation of earthquake and fire losses, respectively. The results demonstrated that the models are comparable, showing that the Hamada model might be a useful tool for large-scale evaluations aimed at disaster-risk reduction and management since it gives useful information for managing and reducing natural and anthropogenic hazards. [ABSTRACT FROM AUTHOR]

The Roman town of Ostia offers a unique opportunity to study a wide range of structural damage affecting different types of ancient buildings. In the Piccolo Mercato, potential seismic effects are visible in the masonry walls and in some of the masonry pillars that in ancient times supported an arcade. This paper, with the aim of providing insight into the causes of the observed damage on one of these pillars, reports and discusses some results of an interdisciplinary study. The damaged pillar under consideration, in particular, is today broken with the upper part rotated about 12 degrees counterclockwise from the lower part. Numerical simulations of this pillar have been performed using finite element models, and incremental nonlinear time-history analyses were carried out for quite a large number of seismic input ground motions. From the obtained results, it appears that a rotation, similar to that exhibited by the upper part of the pillar, can be attributed to seismic action with Peak Ground Acceleration (PGA) values ranging from medium to high. [ABSTRACT FROM AUTHOR]

The 2022 M6.9 Menyuan earthquake caused severe damage to a high-speed railway bridge, which was designed for high-speed trains running at speeds of above 250 km/h and is located right next to the fault. Bridges of this type have been widely used for rapidly constructing the high-speed railway network, but few bridges have been tested by near-fault devastating earthquakes. The potential severe impact of the earthquake on the high-speed railway is not only the safety of the infrastructure, trains and passengers, but also economic loss due to interrupted railway use. Therefore, a field survey was carried out immediately after the earthquake to collect time-sensitive data. The damage to the bridge was carefully investigated, and quantitative analyses were conducted to better understand the mechanism of the bridge failure. It was found that seismic action perpendicular to the bridge's longitudinal direction caused severe damage to the girders and rails, while none of the piers showed obvious deformation or cracking. The maximum values of transverse displacement, out-of-plane rotation and twisting angle of girders reached 212.6 cm, 3.1 degrees and 19.9 degrees, respectively, causing severe damage to the bearing supports and anti-seismic retaining blocks. These observations provide a basis for improving the seismic design of high-speed railway bridges located in near-fault areas. [ABSTRACT FROM AUTHOR]

Experimental tests performed on scaled masonry buildings provide key information to improve the knowledge under seismic actions. Masonry buildings behavior is strongly influenced by their physical and mechanical parameters under dynamic actions. In fact, the actual structural behavior is very complex to predict due to the significant variability of the input parameters and the strong heterogeneity of masonry. Furthermore, the behavior of masonry buildings is often influenced by the interaction with adjacent building units. In this context, the SERA AIMS project aims to improve knowledge on the interaction between adjacent buildings. In order to assess the seismic capacity of masonry structures and their damage evolution, nonlinear models often require a numerical calibration of nonlinear parameters. Simplified Finite Element (FE) models, with some very simple assumptions, can be more suitable for complex problems like as the interaction between adjacent building aggregates. The low initial knowledge level in the SERA AIMS blind competition favored simple assumptions. The availability of simple models allowed to perform consecutive time histories including the cumulative effects of previous signals. In fact, the tested prototype was subjected to many replicas. The masonry structure and the crucial interfaces between the units have been modelled by means of nonlinear elements according to the reduced knowledge level at the blind prediction stage. The main goal was to estimate the key information of a masonry building under seismic action like as: triggering and the type of damage at the most stressed areas and therefore the load threshold at which evident damage is expected. Global FE model provides information on the global behaviour (in plane behaviour), while, according to the failure models typically found in masonry buildings, kinematic analyses have been performed to assess the out of plane (local) behaviour, too. The numerical results obtained by the preliminary analysis have been compared with the experimentally detected damages. The simplified approach, based on limited information without calibration, discussed in this paper, represents a useful support tool to design dynamic tests on full-scale or scaled masonry buildings, but also to assess the vulnerability of real masonry structures. [ABSTRACT FROM AUTHOR]

The Roman town of Ostia offers a unique opportunity to study a wide range of structural damage affecting different types of ancient buildings. In the Piccolo Mercato, potential seismic effects are visible in the masonry walls and in some of the masonry pillars that in ancient times supported an arcade. This paper, with the aim of providing insight into the causes of the observed damage on one of these pillars, reports and discusses some results of an interdisciplinary study. The damaged pillar under consideration, in particular, is today broken with the upper part rotated about 12 degrees counterclockwise from the lower part. Numerical simulations of this pillar have been performed using finite element models, and incremental nonlinear time-history analyses were carried out for quite a large number of seismic input ground motions. From the obtained results, it appears that a rotation, similar to that exhibited by the upper part of the pillar, can be attributed to seismic action with Peak Ground Acceleration (PGA) values ranging from medium to high.

Machine‐learning models play a crucial role in structural seismic risk assessment and facilitate decision‐making by analyzing complex data patterns. However, the dynamic nature of real‐world data introduces challenges, particularly data drift, which can significantly affect model performance. This adversely affects machine‐learning models intended to aid emergency responders and disaster recovery teams. This study primarily focused on assessing the impact of column corrosion‐induced data drift on the performance of machine‐learning models for seismic risk assessment of bridges. The machine‐learning model performance was evaluated with and without considering the impact of corrosion. The results revealed a significant decrease in prediction accuracy when the data drift effect was not considered. To address this challenge, this study proposes integrating principal component analysis‐based anomaly detection to enhance the model performance. The optimized model considering drift demonstrates significant improvements in accuracy across corroded bridges aged 25, 50, and 75 years, with accuracy rates increasing from 90%, 85%, and 81% to 98%, 97%, and 96%, respectively. [ABSTRACT FROM AUTHOR]

This study aims to develop simple equations for assessing the damage of reinforced concrete (RC) columns subjected to seismic loading. A fiber element model in OpenSees, validated against experimental data, was used to generate a large dataset of 56 548 data values for various RC columns. The Monte Carlo Hierarchical Adaptive Random Partitioning strategy was then applied to evaluate the sufficiency of the dataset and propose reliable equations for estimating the residual displacement ratio, damage index, and residual curvature of RC columns under given displacement demands. A relationship between these parameters and the structural performance levels was also established. Residual displacement is a practical measure that can be observed in the field after an earthquake. The proposed equations facilitate the determination of the performance level of the structure after an earthquake event. The findings of this paper can also be used in designing new structures within a performance-based seismic design context. [ABSTRACT FROM AUTHOR]

In this study, a novel equivalent damping ratio model that is suitable for reinforced concrete (RC) structures considering cyclic degradation behavior is developed, and a new equivalent linearization analysis method for implementing the proposed equivalent damping ratio model for use in seismic damage evaluation is presented. To this end, Ibarra's peak-oriented model, which incorporates an energy-based degradation rule, is selected for representing hysteretic behavior of RC structure, and the optimized equivalent damping for predicting the maximum displacement response is presented by using the empirical method, in which the effect of cyclic degradation is considered. Moreover, the relationship between the hysteretic energy dissipation of the inelastic system and the elastic strain energy of the equivalent linear system is established so that the proposed equivalent linear system can be directly integrated with the Park-Ang seismic model to implement seismic damage evaluation. Due to the simplicity of the equivalent linearization method, the proposed method provides an efficient and reliable way of obtaining comprehensive insight into the seismic performance of RC structures. The verification demonstrates the validity of the proposed method. [ABSTRACT FROM AUTHOR]

Improving building efficiency is essential for reducing energy consumption, greenhouse gas emissions, and operational costs. In OECD Countries the average share of the Residential and Commercial Sector for space conditioning accounts for 30–37% of the cumulative final energy use. The current situation is somewhat typical of post-industrialized Countries: while the technology for reducing the external thermal losses and for installing more energy-conscious devices and procedures (including real-time monitoring and better design of the enclosures) is readily available, the cost of such measures is often perceived as excessive for the private user. For this reason, some governments have resolved to launch incentivization campaigns to encourage both private and public actors to invest in building efficiency. This strategy has been successful and its large-scale application -even if enacted on a preliminary basis- led to substantial reductions of the energy load per square meter −50 to 100 kWh/(m2 yr)- so that subsidies and incentives are likely to assume a major role in shaping the energy conversion market. Technologies that are deemed “more environmental benign” or “of strategic interest” will receive institutional funding to promote their implementation, the funds being allocated both to design techniques, new materials and less energivorous devices. Since the funding is usually provided in the form of tax rebates, this approach is not devoid of problems: in fact, previous campaigns at regional and national level in the primary Energy Conversion and in the Transportation Sector have resulted in monumental failures. While it is clearly in the interest of a community to enact a reduction of their final energy uses, it is also true that such incentivization plans, if not properly and carefully implemented, may constitute an economic and ecological “doping” of the market (detail price increases, material and components shortages, etc.). This paper is a follow-up of a previous study conducted in 2021–22 that proposed a rational and thermodynamic-based approach to the issue: in that paper we presented an innovative cost/benefit procedure that considers the primary exergy savings of an “energy saving” intervention and the installation/ operation costs and combines them with the statistically foreseeable savings in the improvement of the building seismic class. The method is intended to serve as a possible model for future policy decisions, and it makes use of the fundamental principles of Exergy Analysis augmented by a conventional cost/ benefit analysis and by basic resilience considerations. The case study analyzed in the previous paper is re-examined here in the light of some recent normative developments the Eco-Sisma-Bonus (“Superbonus”), the incentivization plan launched between 2014 and 2020 by the Italian Government. [ABSTRACT FROM AUTHOR]

In this study, experimental and numerical investigations were conducted to examine the time-dependent creep and earthquake performance of the historical Plaka stone bridge, which was constructed in 1866 in Arta, Greece. During the original construction of the bridge in 1866, Khorasan mortar with an egg white additive was used between the stone elements. Furthermore, when the bridge underwent restoration in 2015, Khorasan mortar with an eggshell additive was employed between the stone elements. Consequently, two distinct 3D finite-difference models were developed for this study. In the first bridge model, egg white was used in the Khorasan mortar, replacing water at various proportions of 0%, 25%, 50%, 75%, and 100%. In contrast, for the second model, eggshell was incorporated into the Khorasan mixture at percentages of 25%, 50%, 75%, and 100%, relative to the lime amount. Subsequently, the mortars were subjected to curing periods of 1 day, 7 days, and 28 days, and their mechanical properties were determined through unconfined compression strength experiments. Taking into account the determined strengths of the mortars, the kn and ks stiffness values of the interface elements between the stone elements and Khorasan mortar were calculated. In the 3D model, each stone element was individually represented, resulting in a total of 1,849,274 stone elements being utilized. Non-reflecting boundary conditions were applied to the edge boundaries of the bridge model, and the Burger creep and Mohr–Coulomb material models was employed for time-dependent creep and seismic analyses, respectively. Subsequently, time-dependent creep analyses were conducted on the bridge, and seismic events that occurred in the region where the bridge was located were simulated to assess their impact. Based on the results of the time-dependent creep and seismic analyses, we observed that the use of 50% eggshell-mixed Khorasan mortar between the stone elements had a positive influence on the earthquake and creep behaviors of both restored and yet-to-be-restored historical bridges. [ABSTRACT FROM AUTHOR]

Coupling beams are used in double-column high-pier bridges to improve the integrity of the two piers. The stiffness of coupling beams has a significant effect on the seismic performance of double-column piers. The seismic behavior of a double-column pier with triple-coupled beams was investigated by cyclic loading test. The failure mode and cyclic response, as well as the shear deformation of a double-column bridge pier, were analyzed to investigate its seismic behavior. The test results, especially after a drift ratio of 1/83, indicated the presence of non-uniform damage characteristics between the coupling beams. Finite element models were developed and parametric analysis was carried out after validation. The focus was on the effects of the variable stiffness of the coupling beam along its height. By analyzing the bearing capacity, ductility, and damage of the double-column piers, the upper flexible and lower rigid coupling beam is a more reasonable arrangement principle. The research results can provide a reference for the innovation design ideas of similar bridge piers. [ABSTRACT FROM AUTHOR]

Historical and recent earthquakes have struck the city of L'Aquila, located in the axial zone of the Central Apennines, Italy, causing severe damage to the historic centre. Recent studies have shown that higher intensity of damage to buildings in L’Aquila downtown, both in the case of the 2009 earthquake (Mw: 6.29) and the 1703 earthquake (Mw: 6.7), is associated with higher post-seismic subsidence rates, detected through A-DInSAR maps, in the time range 2010–2021. This finding suggests the existence of geological factors that drive deformation (and building damage). The availability of long time series of InSAR data acquired from the Cosmo-SkyMed and Sentinel-1 missions, has enabled us to analyze the relationships between ground deformations and geological, hydrogeological, and geomorphological factors that may affect them. The correlation analysis between predisposing factors and SAR deformation has highlighted an increase in subsidence strongly conditioned by the outcropping lithology, showing how compositional variations within lithology can significantly influence ground deformations. Furthermore, hydrogeology has been recognized as playing an important role in determining deformation processes: the water table depth locally influences long-term subsidence, while seasonal fluctuations in the water table may be responsible for secondary areal variations in ground deformations.

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Over the last two decades, the UAE's construction sector has grown significantly with the development of tall buildings, but the region faces seismic risks. Similar concerns in China led to earthquake simulation research on a city scale. The objectives include developing programming for parallel computing and creating simplified models for estimating losses. The challenges include computational complexity and uncertainties in various modules. In 1995, the structural engineering community adopted performance-based engineering principles, shifting to a probabilistic design process. The Computational Modeling and Simulation Center (SimCenter) implemented this into a generic software platform, with the 2010 release of Regional Resilience Determination (R2D) automating the methodology. A research plan aims to advance realistic seismic simulation in the UAE, integrating studies and custom developments. The goal is to create an end-to-end seismic risk assessment framework aligned with digital trends, such as BIM and GIS. The investigation focuses on a virtual dataset for tall buildings, considering variations in location, material properties, height, and seismic activity. For the studied archetypes, the average expected losses include a 3.6% collapse probability, a 14% repair cost, 22 days repair time per asset, and almost 1.5% total population injuries, ranging from 1% for the lowest severity to 0.15% for the highest. [ABSTRACT FROM AUTHOR]

Different from a single tunnel, the cross tunnel with ultra-small spacing is characterized by high crossing risk, significant coupling of multiple effects, and difficulty in controlling stability. A shaking table model test was carried out to study the failure process and dynamic response of the cross tunnel with ultra-small spacing under seismic motions with various types and peak accelerations. The results show that the seismic damage of the cross tunnel model has significant failure stages. The deformation of the upper-span tunnel lining is cumulative progressive damage from the left wall to the invert, while the under-crossing tunnel lining is cumulative progressive damage from the left wall to the crown. The acceleration response of the model when inputting Wenchuan seismic motions is greater than that of El-Centro seismic motions, and the Wenchuan seismic motions may cause a peak lag in the acceleration response of the model. Compared with inputting El-Centro seismic motions, the 1st predominant frequency of the model increases while the 2nd predominant frequency decreases when inputting Wenchuan seismic motions. Additionally, the 2nd predominant frequency components are significantly amplified in the propagation of seismic motions from bottom to top through the lining structure. Although the energy ratio of the wavelet packet frequency components gradually tends from low-frequency bands to relatively high-frequency bands, the low-frequency bands still play a dominant role in the failure of the model. [ABSTRACT FROM AUTHOR]

This study presents an updated view of the effects of the 1940 Vrancea earthquake. Recently compiled studies in the literature from the time of the event, as well as other studies, present the opportunity to gain additional and relevant information regarding this large-magnitude event. The effects of this earthquake on various locations in Romania are compared to those observed after the subsequent large Vrancea earthquake of 1977. An assessment of the economic losses caused by the seismic event is also attempted. The seismic vulnerability of some building typologies commonly used before 1940 is assessed by employing the earthquake damage data and the well-known macroseismic method. The impact of this event on the design and construction practices in Romania is evaluated using the collected information as well. Finally, the policy of repair and strengthening of buildings applied after the event is also discussed, and case studies are presented. [ABSTRACT FROM AUTHOR]

This paper presents the design and commissioning of a novel pseudo‐static test apparatus for underground structures that accounts for soil‐structure interaction by simulating the soil with suitably designed springs. The developed apparatus was employed to conduct 1:10 large scale tests on a two‐story three‐span prefabricated subway station structure. Two comparative cyclic load tests were conducted: one involved the developed springs‐structure system; and one involved the structure alone (no springs). The test results demonstrated important differences in the damage location, damage degree, bearing capacity, and deformation capacity of the prefabricated subway station structure under the two loading conditions (i.e., with and without springs). The presence of springs (i.e., soil‐structure interaction) enhanced the lateral collapse resistance of the underground structure and affected the inter‐story displacement ratio (IDR) between the upper and lower layers of the two‐story prefabricated subway station structure. However, it did not affect the deformation coordination of the walls and columns of each layer. A finite element model of the prototype station was also established to conduct dynamic time history analysis simulating the soil‐structure interaction. The results from the dynamic analysis validated the effectiveness of the pseudo‐static test method employing the spring‐structure system. The excellent agreement between the calculated dynamic responses and the responses obtained from the pseudo static tests confirmed the ability of the developed apparatus to conduct seismic tests on complex large‐scale underground structures such as prefabricated subway stations. Thus, this test methodology might be utilized to attain valuable insights into the seismic performance of prefabricated subway stations at a relatively low cost and effort. [ABSTRACT FROM AUTHOR]

Improving building efficiency is essential for reducing energy consumption, greenhouse gas emissions, and operational costs. In OECD Countries the average share of the Residential and Commercial Sector for space conditioning accounts for 30–37% of the cumulative final energy use. The current situation is somewhat typical of post-industrialized Countries: while the technology for reducing the external thermal losses and for installing more energy-conscious devices and procedures (including real-time monitoring and better design of the enclosures) is readily available, the cost of such measures is often perceived as excessive for the private user. For this reason, some governments have resolved to launch incentivization campaigns to encourage both private and public actors to invest in building efficiency. This strategy has been successful and its large-scale application -even if enacted on a preliminary basis- led to substantial reductions of the energy load per square meter −50 to 100 kWh/(m2yr)- so that subsidies and incentives are likely to assume a major role in shaping the energy conversion market. Technologies that are deemed “more environmental benign” or “of strategic interest” will receive institutional funding to promote their implementation, the funds being allocated both to design techniques, new materials and less energivorous devices. Since the funding is usually provided in the form of tax rebates, this approach is not devoid of problems: in fact, previous campaigns at regional and national level in the primary Energy Conversion and in the Transportation Sector have resulted in monumental failures. While it is clearly in the interest of a community to enact a reduction of their final energy uses, it is also true that such incentivization plans, if not properly and carefully implemented, may constitute an economic and ecological “doping” of the market (detail price increases, material and components shortages, etc.). This paper is a follow-up of a previous study conducted in 2021–22 that proposed a rational and thermodynamic-based approach to the issue: in that paper we presented an innovative cost/benefit procedure that considers the primary exergy savings of an “energy saving” intervention and the installation/operation costs and combines them with the statistically foreseeable savings in the improvement of the building seismic class. The method is intended to serve as a possible model for future policy decisions, and it makes use of the fundamental principles of Exergy Analysis augmented by a conventional cost/benefit analysis and by basic resilience considerations. The case study analyzed in the previous paper is re-examined here in the light of some recent normative developments the Eco-Sisma-Bonus (“Superbonus”), the incentivization plan launched between 2014 and 2020 by the Italian Government.

Abstract On February 6, a successive rupture of major faults in the Eastern Anatolian Fault Zone and Cardak-Surgu fault triggered a strong mainshock (Mw 7.7) and a major aftershock (Mw 7.6) in Kahramanmaras. The successive earthquake sequence hit southern provinces in Türkiye and northern regions in Syria, causing severe fatality and economic loss. After the earthquakes, the International Consortium on Geo-disaster Reduction (ICGdR) organized an investigation team, involving specialists from China, Japan and Türkiye, to conduct a primary field reconnaissance on seismic damage of infrastructure and ground failures. The 10-day reconnaissance, including a mini-symposium at the Istanbul Technical University (ITU), was conducted from 25 March to 3 April and specifically focused on fault ruptures, liquefaction, landslide, rockfall and lateral spreading along the major ruptured faults from Antakya in Hatay to Goksun in Kahramanmaras, passing through provinces of Gaziantep, Adıyaman and Malatya. By this reconnaissance, a large amount of original seismic data was collected and a primary understanding was established for further steps on mitigation and reduction of seismic damages and its secondary geohazards.

On February 6, a successive rupture of major faults in the Eastern Anatolian Fault Zone and Cardak-Surgu fault triggered a strong mainshock (Mw 7.7) and a major aftershock (Mw 7.6) in Kahramanmaras. The successive earthquake sequence hit southern provinces in Türkiye and northern regions in Syria, causing severe fatality and economic loss. After the earthquakes, the International Consortium on Geo-disaster Reduction (ICGdR) organized an investigation team, involving specialists from China, Japan and Türkiye, to conduct a primary field reconnaissance on seismic damage of infrastructure and ground failures. The 10-day reconnaissance, including a mini-symposium at the Istanbul Technical University (ITU), was conducted from 25 March to 3 April and specifically focused on fault ruptures, liquefaction, landslide, rockfall and lateral spreading along the major ruptured faults from Antakya in Hatay to Goksun in Kahramanmaras, passing through provinces of Gaziantep, Adıyaman and Malatya. By this reconnaissance, a large amount of original seismic data was collected and a primary understanding was established for further steps on mitigation and reduction of seismic damages and its secondary geohazards. [ABSTRACT FROM AUTHOR]

On February 6th, 2023, an earthquake sequence with moment magnitudes (Mw) of 7.8 and 7.5 rocked southern and eastern Turkiye, affecting 15 million-residents and a significant portion of Turkiye's industrial community. In the days following the earthquake sequence, a reconnaissance team was organized to visit the industrial districts in the five provinces of the earthquake region. While performance and functionality of 131 industrial facilities were inspected using the proposed data-collection protocols, 18 interviews with industrial representatives were conducted. The inspection and interview results show that the earthquake sequence had a significant impact on industrial facilities, resulting in enormous economic losses and business disruptions lasting three months to two years. While the sequence imposed severe demands on the facilities, their poor performance is mostly due to discrepancies between seismic design code requirements and building practice. The most affected facilities were found to be those built before 2000, as well as precast reinforced concrete structures with pin-supported roofs. As a result, these types of facilities in earthquake-prone areas are strongly advised to be re-evaluated. Furthermore, various nonstructural building components, such as claddings and equipment/machinery, were substantially damaged at the majority of the assessed sites, causing lengthy interruptions. To reduce future seismic losses and disruptions to industry, the proposed protocols and findings of this field study can be utilized to support further resilience studies on the development of business continuity plans and risk management approaches for industrial facilities. [ABSTRACT FROM AUTHOR]

Earthquakes are sudden and unpredictable disasters that pose significant threats to human lives, property, and societal stability. Utilizing remote sensing techniques enables the rapid acquisition of disaster information from affected areas, aiding in the localization, identification, and serving as a reference for emergency response to damaged buildings. This study proposed a UAV image-based approach for seismic damage assessment in mountainous regions, combining recursive feature elimination (RFE) and object-oriented coupling with the random forest classifier. The ESP2 tool is employed to determine optimal segmentation scales, reducing the manual labor of segmenting images at various scales and improving the efficiency of selecting the best segmentation scale. Taking the June 18, 2019 post-earthquake UAV imagery of Shuanghe Town, Changning County, Sichuan Province as the study area, an object-oriented multi-level classification system is established using the ESP2 algorithm. Subsequently, features selected through recursive feature elimination (RFE) are utilized in conjunction with an optimized random forest classifier for building seismic damage identification. Results show that optimal segmentation scales for vegetation, rivers, and buildings are 196, 156, and 130, respectively, with RFE elimination process reducing the initial 57 features to 24. Following RFE optimization, the overall accuracy of building seismic damage identification reaches 95.3%, with a Kappa coefficient of 0.807. This approach, utilizing a reduced number of features for enhanced accuracy, effectively contributes to seismic damage identification for buildings. [ABSTRACT FROM AUTHOR]

Cimandiri Fault in West Java is one of the active faults in West Java, Indonesia. The activity of the fault could potentially result in damage to the surrounding areas. This paper presents a study of ground response analysis and the potential seismic damage to structures in sites surrounding the Cimandiri Fault. The site investigation data are collected. Furthermore, ground motion prediction is conducted. To estimate the potential damage, the potential seismic damage is performed. The spectral matching method determines artificial ground motion represented by the investigated sites. The seismic ground response analysis is conducted to observe ground motion parameters and soil response. The results show that the prediction of damage intensity level in the study area is about Scale VIII at maximum. The site amplification during seismic response is observed to vary from 1.4 to 2.7. The results also show that spectral acceleration design is still reliable in covering the effect of spectral acceleration amplification. However, the results also indicate that the trend of spectral acceleration shows that the amplification generally occurs at a medium-long period. It implies that the resonance effect may occur in medium-high-rise buildings. [ABSTRACT FROM AUTHOR]

Abstract Diyarbakır City Walls, one of the longest defensive structures in the world, following the Great Wall of China, the walls of Antakya, and the walls of Istanbul, is a UNESCO World Heritage site since 2015. With a history of approximately 5000 years, the Diyarbakır City Walls have been affected by consecutive earthquakes centered in Kahramanmaraş in 2023, resulting in damages to various sections. Urgent restoration and repair interventions are needed for these sections of the Diyarbakır City Walls due to earthquake-induced damages. Although there are limited studies presenting stone analysis of the Diyarbakır City Walls in the literature, no studies focusing on mortar analysis have been found. The objectives of this study are as follows: (I) to identify the mechanisms and factors of earthquake damages in the Diyarbakır City Walls, (II) to conduct necessary analyses for the selection of mortar materials for post-earthquake repairs, and (III) to provide restoration and strengthening recommendations to ensure the sustainability of the original structure. Observational, petrographic, chemical, and SEM analysis techniques were used, and the findings were interpreted comparatively. The results demonstrate that the most severe damages after the earthquake in the Diyarbakır City Walls were caused by the inadequate adhesion of missing mortar joints and different types of materials used between double-walled structures. Additionally, the presence of clay minerals identified in the mineralogy of the mortar through experimental analysis was defined as an internal issue causing the loss of mortar due to osmotic pressure created by water absorption. Another factor causing the loss of mortar is the presence of chloride-type salts, which were found to be present in a significant amount in all samples and were attributed to the use of Portland cement in previous faulty repairs. It was also determined that recent faulty repointing works contributed to the loss of mortar. Finally, this article presents original restoration and strengthening recommendations to repair the earthquake-induced damages and prevent their reoccurrence in the future.

Scouring of pile group foundations is a common phenomenon for cross-river bridges and can produce significant damage in earthquake-prone regions. This study experimentally investigated the seismic failure mechanism and postearthquake vertical load-carrying capacity of scoured pile group foundations. Three identical 2 × 3 reinforced concrete (RC) pile group specimens were embedded in homogeneous medium density sand with an overall scour depth equal to five times the diameter of a single pile, and then were subjected to lateral cyclic loads applied to the pile cap in order to produce a predetermined damage state in the piles. Pushover in the vertical-downward direction (pushdown) was finally applied on these damaged specimens exhibiting a permanent lateral displacement to evaluate their residual load-carrying capacities. Experimental results show that the leading pile was more prone to seismic damage, as both the first aboveground and first belowground plastic hinges originally occurred on it. The embedded depth of potential plastic hinges in leading, middle, and trailing piles gradually increased. In addition, the extension of pile damage had a significant influence on the residual vertical load-carrying capacity and the corresponding vertical failure mode of the pile group. Reductions of 10.4%, 47.5%, and 73.8% in the vertical load-carrying capacity of these scoured pile group specimens were recorded when they previously suffered a displacement ductility of 1.75, 3.5, and 5.0, respectively. Based on the experimental results, a linear degradation formula on the normalized postearthquake vertical load-carrying capacity of pile groups with respect to the displacement ductility was developed. The experimental results presented in this paper could be used to validate the ductility capacity and residual vertical load-carrying capacity of pile groups numerically evaluated by using three-dimensional nonlinear finite-element models. This research represents also a first step toward the development of a rapid postearthquake assessment approach for bridges with pile group foundations.

Terrestrial Laser Scanning (TLS), as an emerging technology, is gradually being applied to various fields such as surveying, and it is the main way to obtain LiDAR high-precision data for ground-based targets. TLS can detect more detailed information about the building, mainly including deformation and damage of the building structure (including shear cracking of the building walls, wall shedding and damage of load-bearing elements), and it can obtain more measurement data such as wall tilt, spatial distribution of cracks, volume and position change calculation, etc. The acquisition of TLS high-precision data provides technical assistance for extracting damage features that are less deformed and cannot be identified by the naked eye. This study reviews and summarizes the research of TLS in building deformation monitoring, 3D modeling, data analysis methods and building ballast loss analysis. After the literature review and in-depth discussion, future research directions of TLS in seismic analysis of buildings are proposed.

Uneven settlement of foundation (USF) has a significant effect on the seismic response of rigid foundation structures. However, the main reason for USF is that the balance between superstructure and site soil is failure. For investigating seismic response characteristics of the USF structure considering soil-structure interaction (SSI), USF closer to reality is achieved by nonlinear direct integration method and Stage-Construction method. And the model reliability is verified by Sway-Rocking model and Lagrange energy method. Five different models, three seismic intensities, and different values of USF are performed. The natural period, inter-story drift ratios, the plastic hinges rate, and torsional angles are extracted to investigate structural seismic response. The results show that the effect of SSI on the magnitude of increase in structural inter-story drift ratio is not monotonous with the increase of USF in the presence of earthquakes. The USF structure considering SSI may significantly affect its seismic response, and will suffer more structural damage compared to the rigid foundation and the even settlement foundation. The rigid foundation structure with large value of USF leads to severe stretching on the settlement area and increases damage to the structure. Finally, the USF structures have relatively large torsional angles at the top story, and will exhibit significant torsional behavior. Hence, it is necessary and reasonable to consider SSI in the seismic design of USF structures. The research results can provide some references for seismic design.

A shallow earthquake (MW=5.8 ; depth=10 km) hit the Mirpur City of Pakistan at 16:01 local time on September 24, 2019. The earthquake severely damaged RC structures, low-rise brick masonry structures, and various other civil infrastructure facilities. The close location of seismic stations to the damaged area provided the opportunity to assess the seismic response of the buildings subjected to real ground motions. This study aims to provide insight into the failure modes during a field reconnaissance trip following the 2019 Mirpur, Pakistan, earthquake. Damage procedures and causes were determined by analyzing the specific responses of the site to the ground motions and comparing them to the spectral intensity of the ground motions recorded in the vicinity. Insights gained from the damages were then used to identify specific design requirements or general design principles. The findings suggest strong relevance of the vertical component of the Mirpur, Pakistan, earthquake with excessive axial force demands in masonry piers in addition to various inherent structural properties such as soft-story mechanisms. Poor construction practices and nonseismic detailing combined with deficient structural materials induced major seismic damages in brick masonry and reinforced concrete structures. It is concluded that damage from short-period ground motion originating at shallow depths can be exceptionally serious for unreinforced brick masonry (URBM) structures, even with low-magnitude ground accelerations. Dominant failure modes observed in this investigation suggest excessive axial compression or shear-axial compression, shear-flexure cracking, slab rotations, foundation settlement, and soft-story mechanisms. The damage survey highlighting the observed failure modes serves as a useful tool for researchers and practitioners in formulating seismic-resistant design guidelines. [ABSTRACT FROM AUTHOR]

This paper discusses the nonlinear dynamic seismic response of a 14‐story reinforced concrete core wall building designed with the prescriptive requirements of the 2019 California Building Code for a near‐fault site in Los Angeles, California, simulated with a detailed nonlinear analysis of the complete structure and subjected to an ensemble of three‐component ground motion input. The study follows up on a recently published work by the authors, which examined the response of the specific building to static lateral loads. The nonlinear model of the building was developed in the software FE‐Multiphys using a shell‐element implementation of the beam–truss model (BTM). The BTM has been extensively validated through prior studies for planar, flanged, and coupled walls under static and dynamic loading. The building model was subjected to an ensemble of ground motions scaled at the design and risk‐targeted maximum considered earthquake levels. The vertical ground motion component and the out‐of‐plane shear degradation of wall piers were included in the simulations. The analyses elucidate the profound effect of nonlinear flexure–shear interaction and of the multidirectional behavior of the flanged coupled core wall on the evolution and localization of damage and on residual deformations. The coupling behavior between the core wall, the slabs, and the columns is also analyzed, and the importance of modeling the nonlinear behavior of all slabs for the residual damage evaluation is demonstrated. The aim of this study is to improve the understanding of issues arising from prescriptive design requirements as well as of issues associated with limitations of standard nonlinear seismic analysis. [ABSTRACT FROM AUTHOR]

Diyarbakır City Walls, one of the longest defensive structures in the world, following the Great Wall of China, the walls of Antakya, and the walls of Istanbul, is a UNESCO World Heritage site since 2015. With a history of approximately 5000 years, the Diyarbakır City Walls have been affected by consecutive earthquakes centered in Kahramanmaraş in 2023, resulting in damages to various sections. Urgent restoration and repair interventions are needed for these sections of the Diyarbakır City Walls due to earthquake-induced damages. Although there are limited studies presenting stone analysis of the Diyarbakır City Walls in the literature, no studies focusing on mortar analysis have been found. The objectives of this study are as follows: (I) to identify the mechanisms and factors of earthquake damages in the Diyarbakır City Walls, (II) to conduct necessary analyses for the selection of mortar materials for post-earthquake repairs, and (III) to provide restoration and strengthening recommendations to ensure the sustainability of the original structure. Observational, petrographic, chemical, and SEM analysis techniques were used, and the findings were interpreted comparatively. The results demonstrate that the most severe damages after the earthquake in the Diyarbakır City Walls were caused by the inadequate adhesion of missing mortar joints and different types of materials used between double-walled structures. Additionally, the presence of clay minerals identified in the mineralogy of the mortar through experimental analysis was defined as an internal issue causing the loss of mortar due to osmotic pressure created by water absorption. Another factor causing the loss of mortar is the presence of chloride-type salts, which were found to be present in a significant amount in all samples and were attributed to the use of Portland cement in previous faulty repairs. It was also determined that recent faulty repointing works contributed to the loss of mortar. Finally, this article presents original restoration and strengthening recommendations to repair the earthquake-induced damages and prevent their reoccurrence in the future. [ABSTRACT FROM AUTHOR]

This paper presents the investigation results of a base-isolated RC frame-shear wall structure located in Luding County, Sichuan Province, China, which was damaged by a Ms 6.8 earthquake on September 5, 2022. This recently constructed school office building was about 9 km away from the epicenter. The isolation layer of this building consists of 54 rubber bearings and 12 viscous dampers. These viscous dampers or their connections failed during the earthquake, and the limit state included connection breaking or global buckling of the damper. Also, the superstructure suffered some minor damage. To investigate the cause of structural damages, a nonlinear time-history analysis is conducted using the ground motions recorded by four seismic stations close to the building. The onsite investigation and numerical simulation results revealed the possible reasons for the failure. [ABSTRACT FROM AUTHOR]

This paper presents an analysis of the identification of potential seismic damage in an area called Tanah Patah, Bengkulu City, Indonesia. This study is initiated by conducting site investigation and geophysical measurements. Ground motion prediction is conducted to estimate peak ground acceleration which is then used to estimate the damage intensity level during a large earthquake. A spectral matching method to generate ground motion at investigated sites is conducted. Seismic ground response analysis to observe ground response and soil behaviour is performed. The results show that peak ground acceleration in the study area is about 0.255–0.342 g during a large earthquake. IX is this area's Modified Mercalli Intensity (MMI) level scale. Since sandy soils dominate the study area, several sites could be more vulnerable to undergoing liquefaction. The thickness of potentially liquefiable soils is about 8.6–12.8 m. The results could help local governments develop spatial plans in the study area. [ABSTRACT FROM AUTHOR]

Two earthquakes struck the NW region of Albanian territory on 21 September 2019 (Mw = 5.6) and on 26 November 2019 (Mw = 6.4). The epicenters of the seismic activity were located offshore NW Durrës, one of Albania's most populated cities, located 30 km from the capital Tirana. Various aftershocks followed subsequently. While there were no reported injuries, a number of buildings sustained significant damage near the epicenter following the initial event. Subsequently, during the second event, there was loss of life and extensive damage to civilian structures, resulting in multiple collapses. This study focuses on the earthquake damages observed in residential and public buildings in the earthquake-affected region. The earthquakes predominantly affected low-rise masonry buildings, while the newly constructed RC structures built according to the latest seismic rules were almost unaffected. The commonly encountered building typologies in the region, together with photos showing the amount of destruction are presented here. As observed by the authors during the reconnaissance visit to the stricken area, examples of various damage patterns are presented, along with a technically substantiated description of the reasons for those damages. Although modern buildings during recent earthquakes in the region show acceptable performance, the detailed surveys from the Durrës Earthquakes showed that there is still an important level of deficiency in current masonry buildings built by conventional methods and materials. This problem may reoccur in future earthquakes that may hit other rural regions of Albania, which must be focused on systematically in the near future. [ABSTRACT FROM AUTHOR]

One of the major dangers for seismic damage of concrete dams is the propagation of cracks in dam concrete. The present study undertakes a numerical investigation of the seismic damage for Oued Fodda concrete gravity dam, located in the northwest of Algeria, considering the impacts of properties of joints along the dam-foundation rock interface and cross-stream earthquake excitation. Three-dimensional transient analyses for coupled dam-foundation rock system are carried out using Ansys software. The hydrodynamic effect of reservoir fluid is modelled using the added mass approach. The smeared crack approach is utilised to present the seismic damage of dam concrete using the Willam and Warnke failure criterion. The dam-foundation rock interface joints are presented with two ways, adhesive joints and frictional joints. The Drucker–Prager model is considered for dam concrete in nonlinear analyses. Consideration of the study results indicates that the frictional joints model can reduce the seismic response and damage hazard of the dam body to a better extent compared with the adhesive joints model. Furthermore, the application of cross-stream earthquake excitation reveals the significant effect on cracking response of the dam in the two models of joints. [ABSTRACT FROM AUTHOR]

Over the last two decades, the UAE’s construction sector has grown significantly with the development of tall buildings, but the region faces seismic risks. Similar concerns in China led to earthquake simulation research on a city scale. The objectives include developing programming for parallel computing and creating simplified models for estimating losses. The challenges include computational complexity and uncertainties in various modules. In 1995, the structural engineering community adopted performance-based engineering principles, shifting to a probabilistic design process. The Computational Modeling and Simulation Center (SimCenter) implemented this into a generic software platform, with the 2010 release of Regional Resilience Determination (R2D) automating the methodology. A research plan aims to advance realistic seismic simulation in the UAE, integrating studies and custom developments. The goal is to create an end-to-end seismic risk assessment framework aligned with digital trends, such as BIM and GIS. The investigation focuses on a virtual dataset for tall buildings, considering variations in location, material properties, height, and seismic activity. For the studied archetypes, the average expected losses include a 3.6% collapse probability, a 14% repair cost, 22 days repair time per asset, and almost 1.5% total population injuries, ranging from 1% for the lowest severity to 0.15% for the highest.

This study presents an updated view of the effects of the 1940 Vrancea earthquake. Recently compiled studies in the literature from the time of the event, as well as other studies, present the opportunity to gain additional and relevant information regarding this large-magnitude event. The effects of this earthquake on various locations in Romania are compared to those observed after the subsequent large Vrancea earthquake of 1977. An assessment of the economic losses caused by the seismic event is also attempted. The seismic vulnerability of some building typologies commonly used before 1940 is assessed by employing the earthquake damage data and the well-known macroseismic method. The impact of this event on the design and construction practices in Romania is evaluated using the collected information as well. Finally, the policy of repair and strengthening of buildings applied after the event is also discussed, and case studies are presented.

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Türkiye experienced great destruction during the Kahramanmaraş earthquake couple which occurred as Pazarcık (Mw = 7.7) and Elbistan (Mw = 7.6) on 6 February 2023. The weak structural characteristics and the magnitude of the earthquakes caused more than 50,000 casualties. Significant damage occurred in both urban and rural building stock in 11 different provinces that were primarily affected by the earthquakes. The dominant building stock is masonry structures in the rural areas of the earthquake region. Structural damages at various levels have occurred in adobe masonry structures built using local labours and resources without any engineering service. The main purpose of this study is to examine the failure and collapse mechanisms of adobe structures after Kahramanmaraş earthquakes in detail. First of all, information about both earthquakes was given. The earthquake intensity for all provinces was obtained by using the peak ground acceleration-intensity relation suggested for Türkiye, taking into account the measured PGAs in earthquakes. The observed structural damages were evaluated in terms of earthquake and civil engineering in adobe structures. Damage classification was conducted using European Macro-Seismic Scale (EMS-98) for a total of 100 adobe buildings. Of these structures, 25% were destroyed, 49% were heavily damaged, 15% were damaged moderately, and 11% were damaged slightly. In addition, the rules regarding adobe structures were compared considering the last two earthquake design codes used in Türkiye. In the study, suggestions were also presented to prevent structural damage in the adobe buildings in the earthquake region. Low strength of adobe material, usage of heavy earthen roofs, failure to comply with earthquake-resistant building design principles, and insufficient support of load-bearing walls are the main causes of damage. [ABSTRACT FROM AUTHOR]

The bridge network is an essential part of the transportation infrastructure for mobility. However, bridges are susceptible to seismic activity that produces damages and affects the entire transportation system. Their fragilities have been studied based mostly on analytical models but neglecting empirical data from reports. Few studies compared fragility curves from different development methods, analyzing their similarities, advantages, and limitations for a better risk assessment. This article aims to develop and compare fragility curves for bridges based on empirical and analytical methods. The empirical approach is based on damage reports from the 8.8Mw Maule earthquake, while the analytical approach is based on numerical simulations of the seismic response using ground motion components from stations that recorded the Maule earthquake. The curves are developed for bridges with steel and concrete beams, representative of 57% of Chilean bridges. The comparative Kolmogorov–Smirnov test revealed significant compatibility in moderate and severe damage curves when comparing these approaches, unlike the slight damage curves. The lognormal mean parameter varies between the methods by 36%, 1.5%, and 7.5% for the slight, moderate, and severe damage curves respectively for a particular bridge configuration, showing considerable differences in the slight damage curve between methods. [ABSTRACT FROM AUTHOR]

This paper discusses and compares two recently developed methodologies for the prediction of damage accumulation in structures subjected to multiple earthquakes within their lifetime, one based on a regression model and one based on a Markov-chain based approach. A stochastic earthquake hazard model is considered for generating sample sequences of ground motion records that are then used to estimate the probabilistic distribution of the damage accumulated during the time interval of interest using the various methodologies. A simulation-based approach provides a reference solution against which the other methodologies are compared. Besides assessing the effectiveness and accuracy of the two methodologies, some improvements of the regression model are proposed and evaluated. The comparison between the methodologies is carried out by examining a reinforced concrete (RC) bridge pier model and using the Park–Ang damage index to describe the damage accumulation. The study results demonstrate the importance of considering the possibility of occurrence of multiple shocks in estimating the life-cycle performance of structures and highlight strengths and drawbacks of the investigated methodologies. [ABSTRACT FROM AUTHOR]

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Copyright of Engineering Mechanics / Gongcheng Lixue is the property of Engineering Mechanics Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Archeologia dell'Architettura is the property of Edizioni all'Insegna del Giglio and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

On May 22, 2021, a 7.4 magnitude earthquake struck Maduo County (34.59° N, 98.34° E), Qinghai Province, China, with a focal depth of 17 km. The earthquake occurred near the northern boundary of the Bayan Har block. Two highway bridges, including the Yematan bridge, collapsed. Based on the analysis of the seismic damage characteristics of the Yematan bridge, a finite element model of a three-span simply supported girder bridge was established. Nonlinear analyses were performed using the bedrock wave at the bridge site during the earthquake and the seismic safety evaluation wave of the bridge as inputs to analyze the causes of seismic damage of the bridge. The results show that the large beam displacement owing to the velocity pulse and the low-frequency components of ground motion are the main causes of the bridge damage. [ABSTRACT FROM AUTHOR]