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The purpose of this study is to introduce the top-level design ideas and the overall architecture of earthquake early-warning system for high speed railways in China, which is based on P-wave earthquake early-warning and multiple ways of rapid treatment.

The paper describes the key technologies that are involved in the development of the system, such as P-wave identification and earthquake early-warning, multi-source seismic information fusion and earthquake emergency treatment technologies. The paper also presents the test results of the system, which show that it has complete functions and its major performance indicators meet the design requirements.

The study demonstrates that the high speed railways earthquake early-warning system serves as an important technical tool for high speed railways to cope with the threat of earthquake to the operation safety. The key technical indicators of the system have excellent performance: The first report time of the P-wave is less than three seconds. From the first arrival of P-wave to the beginning of train braking, the total delay of onboard emergency treatment is 3.63 seconds under 95% probability. The average total delay for power failures triggered by substations is 3.3 seconds.

The paper provides a valuable reference for the research and development of earthquake early-warning system for high speed railways in other countries and regions. It also contributes to the earthquake prevention and disaster reduction efforts.

The purpose of this paper is to present an integrative review of the literature to understand the underlying risks of tectonic plate movements, earthquakes and possible earth tremors on Bangladesh as a country filled with waterways.

This study presents a review of seismic activities to present an overview of the active tectonic architecture of the region and its seismic potential with past consequence in Bangladesh region and its immediate surroundings. For the purpose of this review, peer-reviewed journals and electronic databases are the main sources for identifying studies, along with conference proceedings from the similar events and networks.

Review reveals that Bangladesh sits on three tectonic plates atop the world’s largest river delta and has blind faults, shallow faults and high amplified liquefiable zones. It has experienced few devastating earthquakes but most of the records are not documented and also a lack of proper seismic equipment could not record all the events. Also Bangladesh is ill prepared to tackle the aftermath of any strong earthquake and if an earthquake with 7 Mw or greater magnitude occurred, it would leave Bangladesh blighted by a catastrophic disaster with significant destruction of infrastructure, fire outbreaks resulting from breakdown of gas piping systems, fire from collapsed electrical lines and disruption of water connections both in urban and rural centres with greater impact on industrial cities that may not have adhered to standard building codes.

This paper outlined the necessity of an earthquake hazard catalogue, also preparation in sense of seismic risk mitigation and influence of decision-makers, policy institutes and professionals in ensuring infrastructure development and the building code provides for a safe environment and resilient buildings that can reduce or eliminate the risks.

Nonlinear dynamic analyses are employed for seismic collapse risk evaluation of existing steel moment frame buildings. The standards, such as ASCE 41-17, often define collapse thresholds based on plastic deformations; however, the collapse process involves several factors, and plastic deformation is only one of them. An energy-based approach employs deformation and resistance responses simultaneously, so it can consider various factors such as excessive deformation, stiffness and resistance degradation, and low-cycle fatigue as cumulative damage for seismic assessment. In this paper, an efficient energy-based methodology is proposed to estimate the collapse threshold responses of steel moment frame buildings.

This methodology uses a new criterion based on the energy balance concept and computes the structural responses for different seismic hazard levels. Meanwhile, a pre-processing phase is introduced to find the records that lead to the collapse of buildings. Furthermore, the proposed methodology can detect failure-prone hinges with a straightforward probability-based definition.

The findings show that the proposed methodology can estimate reasonably accurate responses against the results of the past experiment on the collapse threshold. Based on past studies, ASCE 41-17 results differ from experimental results and are even overly conservative in some cases. The authors believe that the proposed methodology can improve it. In addition, the failure-prone hinges detected by the proposed methodology are similar to the predicted collapse mechanism of three mid-rise steel moment frame buildings.

In the proposed methodology, new definitions based on energy and probability are employed to find out the structural collapse threshold and failure-prone hinges. Also, comparing the proposed methodology results against the experimental outcomes shows that this methodology efficiently predicts the collapse threshold responses.

This paper places a college at the centreof a multi-hazard assessment (earthquake, flood and landslide). The college is within a less studied, rural area of Ladakh, North India. Research focusses on a case study (Students Educational and Cultural Movement of Ladakh (SECMOL) College), close to Leh, Ladakh, and extends to incorporate/apply thinking from/to the wider Ladakh region. The approach adopted, centring on the hazard assessment of a single entity/local area, allows a rapid uptake of hazard recommendations within a college environment planning to continue its existence for decades ahead. A sister paper (Petterson et al., 2019) documents the active involvement of college staff and students in the principles of geohazard assessment and the development of student-centric hazard assessments of the college and their home village. SECMOL is a self-sufficient, alternative, college, organised along strong environmentally sustainable principles. The paper aims to discuss these issues.

This work has adopted different strategies for different hazards. Fieldwork involved the collection of quantitative and qualitative data (e.g. shape and size of valleys/river channels/valley sides, estimation of vegetation density, measurement of sediment clasts, angle of slopes, assessment of sediment character, stratigraphy of floodplains and identification of vulnerable elements). These data were combined with satellite image analysis to: define river catchment character and flood vulnerability (e.g. using the methodology of Collier and Fox, 2003), examine catchment connectivity, and examine landslip scars and generic terrain analysis. Literature studies and seismic database interrogation allowed the calculation of potential catchment floodwater volumes, and the collation of epicentre, magnitude, depth and date of seismic events, together with recent thinking on the return period of large Himalayan earthquakes. These data were used to develop geological-seismic and river catchment maps, the identification of vulnerable elements, and disaster scenario analyses.

This research concludes that SECMOL, and much of the Ladakh region, is exposed to significant seismic, flood and landslide hazard risk. High magnitude earthquakes have return periods of 100s to c. 1,000 years in the Himalayas and can produce intense levels of damage. It is prudent to maximise earthquake engineering wherever possible. The 2010 Leh floods demonstrated high levels of devastation: these floods could severely damage the SECMOL campus if storms were centred close by. This study reveals the connectivity of catchments at varying altitudes and the potential interactions of adjacent catchments. Evacuation plans need to be developed for the college. Northern ridges at SECMOL could bury parts of the campus if mobilised by earthquakes/rainfall. Slope angles can be lowered and large boulders moved to reduce risk. This work reinforces recommendations that relate to building quality and urban/rural planning, e.g. using spatial planning to keep people away from high-risk zones.

The frequency of hazards is low, but potential impacts high to very high. Hazard mitigation actions include engineering options for hazardous slopes, buildings to be earthquake-proofed, and evacuation management for large floods.

Methodologies undertaken in this research are well-tested. Linkages between disciplines are ambitious and somewhat original. The application of this work to a specific college centre site with the capacity to rapidly take up recommendations is novel. The identification of catchment inter-connectivity in this part of Ladakh is novel. This work complements a sister paper (Petterson et al., 2019) for community aspects of this study, adding to the novelty value.

Investigates the effects of earthquakes in the Victoria region of Australia. Looks at how they can be predicted by the use of seismology, and how this information can be used to protect buildings from major damage. Examines a system developed by the Seismology Research Centre, Bundoora, Australia, to provide alarm, damage scenario and response information after moderate or large earthquakes.

The study investigates the performance of a three-story unprotected steel moment-resisting frame (SMRF) designed for high seismic demand in the fire-only (FO) and post-earthquake uniform and traveling fires (PEF). The primary objective is to investigate the effects of seismic residual deformation on the structure's performance in horizontally traveling fires. The traveling fire methodology, unlike conventional fire models, considers a spatially varying temperature environment.

Multi-step finite element simulations were carried out on undamaged and damaged frames to provide insight into the effects of the earthquake-initiated fires on the local and global behavior of SMRF. The earthquake simulations were conducted using nonlinear time history analysis, whereas the structure in the fire was investigated by sequential thermal-structural analysis procedure in ABAQUS. The frame was subjected to a suite of seven ground motions. In total, four horizontal traveling fire sizes were considered along with the Eurocode (EC) parametric fire for a comparison. The deformation history, axial force and moment variation in the critical beams and columns of affected compartments in the fire heating and cooling regimes were examined. The global structural performance in terms of inter-story drifts in FO and PEF scenarios was investigated.

It was observed that the larger traveling fires (25 and 48%) are more detrimental to the case study frame than the uniform EC parametric fire. Besides, no appreciable difference was observed in time and modes of failure of the structure in FO and PEF scenarios within the study's parameters.

The present study considers improved traveling fire methodology as an alternate design fire for the first time for the PEF performance of SMRF. The analysis results add to the much needed database on structures' performance in a wide range of fire scenarios.

An analytical investigation is performed on zipper-braced frames. Zipper-braced frames are an innovative bracing system for steel structures. Conventional inverted-V-braced frames exhibit a design problem arising from the unbalanced vertical force generated by the lower story braces when one of them buckles. This adverse effect can be mitigated by adding zipper columns or vertical members connecting the intersection points of the braces above the first floor.

This paper critically evaluates over strength, ductility and response modification factors of these structures. To achieve the purpose of this research, several buildings of different stories are considered. Static pushover analysis, linear dynamic analysis and nonlinear incremental dynamic analysis are performed by OpenSees software concerning ten records of past earthquakes.

Also, ductility factor, over strength factor and response modification factor, has been calculated for zipper-braced frames system. The values of 3.5 and 5 are suggested for response modification factor in ultimate limit state and allowable stress methods, respectively.

The fragility curves were plotted for the first time for such kind of braces. It should be mentioned that these curves play significant roles in evaluating seismic damage of buildings.

In this study, the application of a novel combined steel curved damper (SCD) and steel plate shear wall (SPSW) system in the 5-, 10- and 15-storey steel moment-resisting frames (SMR) subjected to earthquake excitation has been investigated. The proposed system is called here as the SMR-WD (steel moment resisting–wall damper).

At the beginning of this research, an SMR-W and an SMR-D are separately modeled in ABAQUS software and verified against the available experimental data. After that, three different heights SMR-WD systems (5-, 10- and 15-storey) are designed and simulated. Then, their performances are examined and compared to the corresponding SMR-W under the effects of six actual earthquake records.

The obtained results show that the proposed system increases the mean values of the base shear for 5-, 10- and 15-storey SMR-WD equal to 27, 20.15 and 16.51%, respectively compared to the corresponding SMR-W. Moreover, this system reduces the drift of the floors so that the reduction in the average values of maximum drift for 5-, 10- and 15-storey SMR-WD is equal to 10, 7 and 29%, respectively with respect to the corresponding SMR-W. The results also reveal that the considered system dissipates more energy than SMR-W so that the increase in the mean values of the energy absorption for 5-, 10- and 15-storey SMR-WD is 30.8, 25.6 and 41.3%, respectively when compared to the SMR-W. Furthermore, it is observed that SMR-WD has a positive effect on the seismic performance of the link beams and panel zones of the frames. By increasing the height of the structure in the SMR-WD, the energy dissipation and base shear force increases and the drift of floors decreases. Hereupon, the proposed SMR-WD system is more useful for tall buildings than SMR-W frames.

For the first time, the application of a novel combined steel curved damper (SCD) and steel plate shear wall (SPSW) system in the 5-, 10- and 15-storey steel moment-resisting frames (SMR) subjected to earthquake excitation has been investigated.

The purpose of this paper is to offer two Web-based platforms for systematic analysis of seismic processes. Both platforms are designed to analyze and forecast the state of the environment and, in particular, the level of seismic hazard. The first platform analyzes the fields representing the properties of the seismic process; the second platform forecasts strong earthquakes. Earthquake forecasting is based on a new one-class classification method.

The paper suggests an approach to systematic forecasting of earthquakes and examines the results of tests. This approach is based on a new method of machine learning, called the method of the minimum area of alarm. The method allows to construct a forecast rule that optimizes the probability of detecting target earthquakes in a learning sample set, provided that the area of the alarm zone does not exceed a predetermined one.

The paper presents two platforms alongside the method of analysis. It was shown that these platforms can be used for systematic analysis of seismic process. By testing of the earthquake forecasting method in several regions, it was shown that the method of the minimum area of alarm has satisfactory forecast quality.

The described technology has two advantages: simplicity of configuration for a new problem area and a combination of interactive easy analysis supported by intuitive operations and a simplified user interface with a detailed, comprehensive analysis of spatio-temporal processes intended for specialists. The method of the minimum area of alarm solves the problem of one-class classification. The method is original. It uses in training the precedents of anomalous objects and statistically takes into account normal objects.

The purpose of this paper is to present a new modification of the multimodal pushover method, named the target acceleration method. The target acceleration is the minimum acceleration of the base that leads to the ultimate limit state of the structure, i.e., the lowest seismic resistance.

A nonlinear numerical model is used to determine the target acceleration, which is achieved using the iterative procedure according to the envelope principle. Validation of the target acceleration method was conducted on the basis of the results obtained by incremental dynamic analysis.

The influence of higher modes is highly significant. The general failure vector corresponding to the target acceleration differs from the first load vector and the form of the load with uniform acceleration according to the height of structure, as contained in the European Standard EN 1998-1. Comparison between the target acceleration, including the equivalent structural damping, and the failure peak ground acceleration obtained from the dynamic response of the structure exhibits notably good agreement. This result implies that the equivalent structural damping as calculated according to the formulation presented in this paper should be greater than that suggested in the literature.

The originally developed procedure named multimodal pushover target acceleration method can reasonably estimate the minimum acceleration of the base that leads to the ultimate limit state of the structure, and consequently provides a reliable tool for the assessment of the lowest seismic resistance.