This study presents the design and structural analysis of a bridge to protect two natural gas pipelines against static and dynamic loads resulting from a new railway line to be constructed above them. Structural analyses were conducted considering earthquake effects, particularly using the load combinations and coefficients recommended by AASHTO LRFD [2017]. The railway bridge is not designed to span any crossings. However, since the existing railroad is situated directly on the ground, a train load is transferred to the pipelines through the ground. To reduce this load transfer, a 25-30cm gap is maintained between the deck and the ground in this protective bridge design proposal. The maximum anticipated displacement of the bridge was considered in the analysis. Site-Specific Earthquake Hazard Analysis was first performed for the proposed bridge due to the critical implications of the pipelines. In the second stage, the structure underwent nonlinear dynamic displacement loading and bridge-pile-soil interaction was analyzed using both linear and nonlinear methods. The performance targets - Uninterrupted Use for DD2a class ground motion and Controlled Damage for DD1 earthquake) - stipulated by the Turkish Bridge Design Standards [TBDS, 2020] were evaluated using strength-based linear and strain-based nonlinear analyses. The results confirmed that the proposed bridge satisfied all target safety levels. In conclusion, this study aims to guide both designers and practitioners, as it is among the first to address the newly enacted TBDS-2020 regulation in Turkiye and serves as an exemplary engineering solution for similar protective bridge designs.

Due to their distinct geotechnical and structural features, soft rock tunnels pose serious issues because of their seismic sensitivity. These tunnels, often constructed in formations with lower shear strength and higher deformability, are particularly susceptible to damage during earthquakes. Fragility curves, which graphically represent the probability that a structure may sustain damage up to or beyond a particular threshold as a function of seismic intensity, are essential tools for evaluating the seismic resilience of these infrastructures. This research looks closely at the use of fragility curves to assess the seismic vulnerability of soft rock tunnels. Exploring the fundamental concepts and methodologies involved in constructing fragility curves, including seismic hazard analysis, structural modeling, damage state definition, data collection and statistical analysis is looked at first. The review highlighted the integration of soft rock characteristics such as strength and deformation properties into the fragility assessment process. Key developments in the topic are covered such as how machine learning and Bayesian inference might improve the precision and usefulness of fragility curves. The paper identified key findings such as the high sensitivity of fragility curves to geotechnical properties and seismic intensity levels and emphasized the importance of accurate data collection and model calibration. Important gaps in seismic risk evaluations are filled by integrating cutting-edge methodologies, such as Bayesian inference and real-time machine learning models that clarify the seismic behaviour of soft rock tunnels in the real world. For the purpose of strengthening earthquake-resistant infrastructure in earthquake-prone areas, engineers, scholars and policymakers are given practical insights.

PurposeThe primary goal of this research is to evaluate the seismic performance of Asla Hocine Primary School, a heritage school building in Annaba, Algeria, to prevent additional damage during future earthquakes in the region. The study aims to guide decision-makers in strengthening weak parts or elements in the building, implementing preventive measures and ultimately reducing earthquake disaster risk by mitigating vulnerability.Design/methodology/approachThe research employs the 3Muri software to model the seismic behavior and structural failures of the school's elements. An integrated multimodal pushover analysis is used to generate the non-linear capacity curve of the school to assess its seismic performance. The seismic demand is determined based on Algerian seismic regulations, with peak ground acceleration derived from a probabilistic seismic hazard analysis of Annaba city for return periods of 100, 200 and 500 years. The study develops three seismic scenarios to evaluate performance levels and expected damage probabilities.FindingsThe study reveals that the Asla Hocine Primary School faces a high risk of damage and potential collapse under the expected seismic hazard of the region. The analysis indicates variable resilience across different seismic return periods (100, 200 and 500 years), with the performance level degrading from life safety to collapse prevention and total collapse under increasing seismic intensity. This underscores the need for targeted structural analysis and potential retrofitting to enhance the building's seismic robustness.Research limitations/implicationsThe paper encouraged to account for soil-structure interaction in similar studies, as it can significantly affect the overall seismic performance of buildings. Furthermore, conducting out-of-plane analysis when necessary can offer valuable insights into the structural behavior of specific components.Practical implicationsThe insights provided by this study contribute vital data toward conservation efforts and risk mitigation strategies for heritage structures in seismic zones. The findings are intended to guide decision-makers in implementing preventive measures and strengthening weak parts or elements in the studied school building, ultimately reducing earthquake disaster risk by mitigating vulnerability.Originality/valueThis research offers a comprehensive framework for assessing the seismic vulnerability of heritage schools using detailed modeling and analysis. It highlights the importance of considering return periods of seismic events in assessing a building's seismic performance and provides a deeper understanding of the structural response to seismic stresses at both macrostructural and individual element levels. The study emphasizes the critical need for seismic risk assessment and targeted retrofitting to preserve cultural heritage assets and ensure their continued use.

To ensure the seismic safety of important buildings and infrastructure facilities in seismically active areas, it is necessary that, in addition to the various ground motion parameters, the seismic hazard is also characterized in terms of many other destructive natural effects of earthquakes like soil liquefaction and permanent fault displacement for example. The probabilistic seismic hazard analysis methodology can in principle be applied to quantify any of the destructive effects of the earthquakes in a region, provided a formulation has been developed to compute the probability with which a specified level of that effect can be exceeded at a site of interest due to given earthquake magnitude and location. Several investigators have developed necessary relationships and methodologies to estimate this probability for the permanent fault displacement, which may be a potential and primary cause of damage to long structures like bridges, tunnels, pipelines, dams and buried structures, if an active fault happens to cross or pass by such a structure. Based on a comprehensive literature survey and critical analysis of the results obtained for various possible alternatives, we have finalized a methodology for probabilistic fault displacement hazard analysis suitable for a 257 km long strand of the main boundary thrust (MBT) in the Garhwal-Kumaon Himalaya. Formulations are proposed for estimation of both the on-fault principal displacement and the off-fault distributed displacement, which can also be applied to any other thrust fault in any other segment of the Himalaya. The application of the proposed methodology to obtain the on-fault displacement estimates for a site at the midpoint of the selected strand of the MBT is found to provide physically realistic displacement values for very long return periods of upto 100,000 years. The off-fault displacements are found to decrease very fast with distance from the site on MBT and become practically insignificant at a distance of only two km.

The emphasis of seismic design regulations on applying nonlinear dynamic analyses (NDAs) promotes using accelerograms that characterize site-specific ground motions. Commonly, amplitude levels of such accelerograms are defined by a target spectrum that could be based on a uniform hazard spectrum (UHS), which is determined by a probabilistic seismic hazard analysis (PSHA) and represents a response spectrum with ordinates having an equal probability of being exceeded within a given return period, Tr\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${T}_{r}$$\end{document}. Conversely, the definition of ground-motion duration levels is not yet properly defined in current regulations to select accelerograms. Thus, adhering to data handling as that for amplitude ground-motion parameters, this study motivates executing PSHAs to define hazard-consistent levels for the ground-motion duration. That is, accelerograms can be selected to match both amplitude and duration ground-motion levels associated with Tr\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${T}_{r}$$\end{document}. Further, fragility functions conditional on Tr\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${T}_{r}$$\end{document} that cover typical performance objectives can be developed using sets of hazard-consistent accelerograms to implement, e.g., multiple stripe analyses (MSAs). To demonstrate the importance of choosing fully hazard-consistent accelerograms to perform NDAs, this study includes the displacement- and energy-based seismic-response evaluation of a steel frame building located at different soil-profile sites in Mexico City. Sets of fully hazard-consistent accelerograms and solely amplitude-based hazard-consistent accelerograms were artificially generated per site for values of Tr\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${T}_{r}$$\end{document} up to 5000 years. Results indicate that the probability of failure can be underestimated if the ground-motion duration is unvaried in MSAs, e.g., structural damage caused by 50-year return-period or higher events can be more noticeable when fully hazard-consistent accelerograms take place.

The tall building construction sector has recently exhibited an increasing development, especially in Europe. This activity is aligned with European policies regarding soil conservation and social housing. Due to their slenderness, such structures are particularly sensitive to wind and earthquake loads. Nevertheless, current building codes, standards, and most scientific literature neglect the interaction of these events as simultaneity has always been considered a rare design case due to the limited effect on the structural elements. The present work carries out a careful statistical investigation on the occurrence of strong earthquakes accompanied by a wind load event, characterized by non-negligible daily mean-wind velocities in Italy, where more than onethird of its area is occupied by high mountains, limiting the urban development to confined zones. Subsequently, the effect of the simultaneous occurrence of earthquake and wind loads has been studied, both from the numerical and experimental points of view (i.e., shaking table and wind tunnel tests) to evaluate the consequences on structural and non-structural elements (e.g., fa & ccedil;ades) of a building case study. Results show that the cumulative effect of typical and noncatastrophic daily mean wind velocity (i.e., in the range of 5-10 m/s at 10 m from the ground) and a typical and non-catastrophic seismic daily shock (i.e., with magnitude in the range of 3-5), can trigger large inter-story drift ratio values and fatigue, causing damage to non-structural elements - like fa & ccedil;ades - and consequently a risk for occupants and high economic losses.

Following the 2016 Chauk earthquake in Bagan (Myanmar), numerous old pagodas and temples suffered severe damage. This research presents a study on the seismic hazard analysis of the Bagan city in Myanmar, based on a probabilistic framework focussing on analysing 43 temples with their associated local soil information. To this end, two seismic source models are developed based on the tectonic setting of the region and information available. Instrumental and historical records are compiled from both literature and international earthquake catalogues while conducting catalogue completeness. This study uses state-of-the-art ground motion models to perform probabilistic seismic hazard analysis and develop seismic hazard maps for different return periods in the region. Results are also expressed for selected temples in the region in terms of site-specific uniform hazard spectra. The findings indicate significant seismic activity, with peak ground acceleration in the region ranging from 0.25 to 0.36 g for a return period of 2475 years, 0.22-0.32 g for a return period of 975 years, and 0.18-0.24 g for a return period of 475 years. The updated hazard levels indicate that the literature slightly underestimates hazard in the region under study.

In this study, the earthquake risk assessment of single -story RC precast buildings in Turkey was carried out using loss curves. In this regard, Kocaeli, a seismically active city in the Marmara region, and this building class, which is preferred intensively, were considered. Quality and period parameters were defined based on structural and geometric properties. Depending on these parameters, nine main sub -classes were defined to represent the building stock in the region. First, considering the mean fragility curves and four different central damage ratio models, vulnerability curves for each sub -class were computed as a function of spectral acceleration. Then, probabilistic seismic hazard analyses were performed for stiff and soft soil conditions for different earthquake probabilities of exceedance in 50 years. In the last step, 90 loss curves were derived based on vulnerability and hazard results. Within the scope of the study, the comparative parametric evaluations for three different earthquake intensity levels showed that the structural damage ratio values for nine sub -classes changed significantly. In addition, the quality parameter was found to be more effective on a structure's damage state than the period parameter. It is evident that since loss curves allow direct loss ratio calculation for any hazard level without needing seismic hazard and damage analysis, they are considered essential tools in rapid earthquake risk estimation and mitigation initiatives.

Maharashtra stands out as a crucial state in India, demonstrating significant progress in infrastructural development and industrialization. Several prominent cities, including Mumbai, Pune, Nagpur, etc., are significantly contributing to the Indian economy. Considering the importance of the state, a deterministic seismic hazard analysis is executed to reduce the damages to critical and important structures and fatalities caused due to earthquakes. Past earthquakes data are collected within and around the state to prepare a homogenised earthquake catalogue. Seven seismic zones are prepared using K- mean cluster analysis. Independent earthquake events i.e., mainshocks are identified using four renowned declustering methods. Additionally, with the help of mainshocks from each zone, the maximum observed earthquake magnitude ( m(max)) and positive correction factor (Delta) are estimated. By superimposing all the m (max) mainshocks (after adding A) onto the fault map, the maximum observed possible earthquake magnitude of all faults (M-max) are assigned to each fault. M-max value is used to estimate surface rupture length (RLD) and consecutively, the maximum magnitude (M-Max) from fault sources are estimated. Three region-specific ground motion prediction equations (GMPEs) are adopted in the logic trees assigning a proper weightage to each GMPE. A seismic hazard contour maps are prepared at bedrock level, C, and D-type soil sites for Maharashtra. In the western part of the study area, the maximum PGA value is found to be 0.58 g, 0.70 g, and 0.33 g at bedrock level, C, and D-type sites, respectively.