An immersive virtual reality serious game to enhance earthquake behavioral responses and post-earthquake evacuation preparedness in buildings

Enhancing the earthquake behavioral responses and post-earthquake evacuation preparedness of building occupants is beneficial to increasing their chances of survival and reducing casualties after the mainshock of an earthquake. Traditionally, training approaches such as seminars, posters, videos or drills are applied to enhance preparedness. However, they are not highly engaging and have limited sensory capabilities to mimic life-threatening scenarios for the purpose of training potential participants. Immersive Virtual Reality (IVR) and Serious Games (SG) as innovative digital technologies can be used to create training tools to overcome these limitations. In this study, we propose an IVR SG-based training system to improve earthquake behavioral responses and post-earthquake evacuation preparedness. Auckland City Hospital was chosen as a case study to test our IVR SG training system. A set of training objectives based on best evacuation practice has been identified and embedded into several training scenarios of the IVR SG. Hospital staff (healthcare and administrative professionals) and visitors were recruited as participants to be exposed to these training scenarios. Participants’ preparedness has been measured along two dimensions: 1) Knowledge about best evacuation practice; 2) Self-efficacy in dealing with earthquake emergencies. Assessment results showed that there was a significant knowledge and self-efficacy increase after the training. In addition, participants acknowledged that it was easy, helpful, and engaging to learn best evacuation practice knowledge through the IVR SG training system.     

高烈地震带内膏体排尾坝体稳定性分析

尾矿坝的稳定是矿山安全生产的重要保障。为了研究在高烈地震带内某上游式膏体排尾尾矿库的稳定性,用Slide软件计算正常及地震工况下湿排和膏体排尾尾矿库的稳定性并进行稳定性分析。结果表明,湿排尾矿库的坝体抗滑稳定最小安全系数随地震烈度的增加降低较快,膏体排尾尾矿库的坝体抗滑稳定最小安全系数随地震烈度的增加降低较慢;湿排和膏体排尾坝体抗滑稳定最小安全系数降低规律基本一致,降低曲线呈"S"型,降低过程可分为降低初始时期、加速时期以及减速时期;不同地震烈度下膏体排尾与湿排坝体抗滑稳定最小安全系数的比值K先增加后降低;湿排尾矿库的稳定性受地震影响较大,膏体排尾尾矿库的稳定性受地震影响较小。因此,在高烈地震带内,采用膏体排尾的尾矿库更稳定。     

Geosynthetic-sheet pile reinforced foundation for mitigation of earthquake and tsunami induced damage of breakwater

Earthquake and tsunami impose great threats on the stability of a breakwater. Foundation of the breakwater is weakened by these forces, and it may result in collapse of the breakwater. Lateral flow of seabed soils take place beneath the breakwater, and excess pore water pressure is generated in the foundation by an earthquake that precedes tsunami. These factors may lead to excessive settlement and horizontal displacement of the breakwater. Tsunami introduces additional instability to the deformed breakwater. Due to water level difference between seaside and harborside of the breakwater during a tsunami, seepage occurs through its foundation, and it may cause pipping of seabed soils. Tsunami induced scouring of mound is also a big problem for the stability of the breakwater foundation. Finally, these result in failure of the breakwater foundation. Due to failure of its foundation, the breakwater may collapse and cannot block the tsunami. It results in entering of the tsunami in coastal areas. In order to make a breakwater resilient against earthquake and tsunami induced damage, reinforcing countermeasures were developed for foundation of a breakwater. Geogrid, gabions and sheet piles were used for reinforcing a foundation model. The effectiveness of the model is evaluated through physical modeling for mitigating the earthquake and tsunami induced damage. Shaking table tests were performed to determine the effectiveness of the reinforced model under different earthquake loadings. Tsunami overflow test was conducted on the same deformed model in order to see the effects of tsunami on the model. Comparisons were made between the unreinforced and reinforced foundations, and it was observed during the tests that the reinforced foundation performed well in reducing the damage of the breakwater brought by the earthquake and tsunami. Overall, this study is useful for practice engineering, and the reinforced foundation model can be adopted for designing a breakwater foundation to reduce damage triggered by an earthquake and tsunami in the future.     

城市地震灾害经济损失预测方法综述

本文结合城市地震灾害损失大、牵连性强的特点,对现有地震灾害损失的预测方法进行了讨论和评述,认为在地震灾害损失预测时应把受灾城市看作一个灾场,充分考虑城市各系统之间的相互影响和作用,最后指出了进一步研究的方向和内容。     

Method for detecting moment connection fracture using high-frequency transients in recorded accelerations

The 1994 Northridge earthquake caused brittle fractures in steel moment frame building connections, despite causing little visible building damage in most cases. Future strong earthquakes are likely to cause similar damage to the many un-retrofitted pre-Northridge buildings in the western US and elsewhere. Without obvious permanent building deformation, costly intrusive inspections are currently the only way to determine if major fracture damage that compromises building safety has occurred. Building instrumentation has the potential to provide engineers and owners with timely information on fracture occurrence. Structural dynamics theory predicts and scale model experiments have demonstrated that sudden, large changes in structure properties caused by moment connection fractures will cause transient dynamic response. A method is proposed for detecting the building-wide level of connection fracture damage, based on observing high-frequency, fracture-induced transient dynamic responses in strong motion accelerograms. High-frequency transients are short (<1 s), sudden-onset waveforms with frequency content above 25 Hz that are visually apparent in recorded accelerations. Strong motion data and damage information from intrusive inspections collected from 24 sparsely instrumented buildings following the 1994 Northridge earthquake are used to evaluate the proposed method. The method’s overall success rate for this data set is 67%, but this rate varies significantly with damage level. The method performs reasonably well in detecting significant fracture damage and in identifying cases with no damage, but fails in cases with few fractures. Combining the method with other damage indicators and removing records with excessive noise improves the ability to detect the level of damage.     

Effect of damping model on pre-yielding earthquake response of structures

The present paper examines differences between responses of single-degree-of-freedom (SDOF) systems with viscous and hysteretic damping to earthquake ground motions. Only responses within yield limits are considered. The structural behavior of SDOF systems with hysteretic damping is modeled by a generalized elasto-slip model of the Masing type. The model leads to a force–displacement relationship similar to that proposed by Ramberg and Osgood. The responses of the two systems are compared for a number of earthquake records. To achieve consistent comparison, parameters of the linear system with viscous damping are determined by the secant stiffness method. In many cases significant differences in the peak displacement responses and energy values have been observed between the systems. This indicates that the prediction of the response of structures to earthquake ground motions before yielding based on linear models with viscous damping may not be as accurate as used to be believed. Tentative estimates of error associated with such predictions are presented.     

Probabilistic loss assessment of light-frame wood construction subjected to combined seismic and snow loads

In some areas, e.g., mountainous areas in the western United States, both seismic and snow loads are significant. Limited research has been conducted to investigate the seismic risk of light-frame wood construction in those areas considering the combined loads, particularly the snow accumulation. An object-oriented framework of the risk assessment for light-frame wood construction subjected to combined seismic and snow hazards is proposed in this paper. A typical one-story light-frame wood residential building is selected to demonstrate the proposed framework. Economic losses of the building due to the combined hazards are evaluated using the proposed framework. It is found that in areas with significant snow accumulation, the snow load has significant effects on the seismic risk assessment for light-frame wood construction.     

消能减震技术

本文介绍了地震的危害及减少震害的措施，通过对传统的抗震设计方法的分析和研究，提出了一种新的抗震设计方法消能减震技术，并简单介绍了它的原理，并重点介绍了消能减震结构设计的设计方法，以及这种新技术提出的原因和特点。此外，还对消能减震产品的种类，工程应用等作了介绍。     

地震作用下多层砖混结构TMD控制及其应用研究

在结构地震反应时程分析基础上,对地震作用下多层砖混结构TMD控制优化设计方法进行了初步探讨;给出了地震作用下多层砖混结构TMD控制优化设计步骤。并用算例验证了该设计方法用于地震反应控制的可行性。     

工程地震动模型化研究综述及展望（Ⅱ）：平稳模型及均匀调制过程

综述了几十年来地震工程模型化研究的发展模型地分析了目前常用的平稳模型及均匀调制过程。