Performance of masonry enclosure walls: lessons learned from recent earthquakes

This paper discusses the issue of performance requirements and construction criteria for masonry enclosure and infill walls.Vertical building enclosures in European countries are very often constituted by non-load-bearing masonry walls, using horizontally perforated clay bricks.These walls are generally supported and confined by a reinforced concrete frame structure of columns and beams/slabs.Since these walls are commonly considered to be nonstructural elements and their influence on the structural response is ignored,their consideration in the design of structures as well as their connection to the adjacent structural elements is frequently negligent or insufficiently detailed.As a consequence,nonstructural elements,as for wall enclosures,are relatively sensitive to drift and acceleration demands when buildings are subjected to seismic actions. Many international standards and technical documents stress the need for design acceptability criteria for nonstructural elements,however they do not specifically indicate how to prevent collapse and severe cracking,and how to enhance the overall stability in the case of moderate to high seismic loading.Furthermore,a review of appropriate measures to improve enclosure wall performance and both in-plane and out-of-plane integrity under seismic actions is addressed.     

Fishers' perceptions as indicators of the performance of Marine Protected Areas (MPAs)

How users perceive the performance of Marine Protected Areas (MPAs) is fundamental for the social acceptance of these zones. Moreover, their perceptions may be relevant for monitoring the effects of MPAs on extractive activities. This study analyzes artisanal fishers' perceptions of the performance of a north-western Mediterranean coastal MPA, which encompasses two no-take zones (NTZs). Three viewpoints have been considered: the effect on the personal activity of fishers, the effect on the local fishery and the effect on the ecosystem. In order to test the hypothesis that biomass export (spillover) - which had previously been evidenced from the two NTZs - may influence fishers' perceptions of NTZ effects, fishers' perceptions were compared with both declared and observed fishing activity over an one-year period.The results show that negative perceptions of NTZs are either nil or are negligible. Most fishers are aware of the beneficial effects of NTZs on ecosystems and fisheries. However, they remain to be convinced of the beneficial effects of the NTZs on their own activity. For instance, the proximity of a NTZ appears never to be involved in the choice of a fishing spot. This partial lack of correspondence between scientific expectation and fishers' perceptions is discussed in the light of fishing habits in the zone adjacent to NTZs, and takes into account fishing grounds, targeted species and seniority (defined as the number of years the fisher has been fishing within the MPA). All three factors appear to influence fishers' perceptions. For example, having a positive perception about a NTZ and spending more time fishing in the adjacent zone are habits that can be associated with fishers with less seniority. Fishers' perceptions obviously indicate the social acceptance of the MPA and are an essential monitoring tool for MPA managers. However, perceptions cannot be seen as a substitute for scientific monitoring, as both approaches are clearly complementary.     

Research on compound plugging removal technology and its application in Xinmu oilfield of Jilin

Most fault-block reservoirs in Xinmu oilfield belong to heterogeneous sandstone in characters which has low permeability, and reservoir pollution is a common phenomenon in this area. Acidizing deplugging in oil wells has become one of the major measures to improve production efficiency in the field. A compound deplugging technology in high efficiency low corrosion is developed for this kind of low permeability sandstone reservoir. On the basis of profoundly understanding of the reservoir’s physical properties and sensitivity, along with comprehensive analysis of the cause for jams in oil wells, a series of experiments are carried out in order to investigate the dissolution reaction among samples and deplugging inhibitor, sample dissolving speed, formation fluid compatibility, reduction of secondary pollution, etc. Considered reservoir condition in nearby wells the optimized compositional deplugging liquid formula is selected for this reservoir. It is featured by reducing the deplugging reaction speed, extending solution for processing radius, preventing secondary damage in dissolution processing, and removing plug pollution effectively. To implement this high efficiency low corrosion deplugging measure based on reservoir condition in the borehole and nearby wells, a relatively better result of deplugging and production increasing is achieved, which enriches the measures to increase production in Xinmu oilfield, and this method can be applied to other similar oilfields for the purpose of maintaining the crude oil production and providing assistant for increasing the production significantly.     

区域旅游产业集聚与绩效的关系研究——基于中国31个省区的实证

利用Gini系数、E-G指数、行业地区集中度等产业集聚指标以及产业利润率、就业系数、劳动生产率等产业绩效衡量指标,基于2010年的截面数据,探究中国旅游产业集聚化发展及其与产业绩效之间的关系。结果表明:整体旅游产业的集聚程度较低,但产业内部各行业的区域集聚特征明显;旅游产业集聚程度的区域差异与区位条件差异具有较高的一致性;旅游产业集聚总体上对产业绩效的提高具有积极影响,其中,旅游产业集聚对产业利润率和劳动生产率的提高有显著的正向影响,但是对于就业机会的增加影响甚微。基于上述结论,提出相关政策建议。     

锚杆挡土墙可靠度分析与计算方法

提出了锚杆挡墙中肋柱锚杆体系的串-并联模型。将肋柱视为连续梁,锚杆视为弹性支座,引入锚杆与锚固段周围岩土体的复合刚度系数,用位移法导出了各根锚杆所受荷载的统一计算公式。考虑各功能函数之间的相关性,运用系统可靠性理论,提出了单根锚杆3种破坏模式的串联系统与多根锚杆并联系统的体系可靠度计算方法,并编制了计算程序。对一工程实例进行计算,并对计算结果进行了分析,发现单根锚杆的3种失效模式并非相互独立,每种失效模式对锚杆可靠度的影响也不一样,而3根锚杆并联系统的失效概率近似等于在其他锚杆均未破坏的条件下每根锚杆单独失效概率之和。     

昆明大板桥岩溶地下水系统污染边界及其防污性能研究

大板桥岩溶地下水系统是滇东断陷盆地区较典型的裸露—覆盖型岩溶地下水系统,文章中定义了岩溶地下水系统污染边界,进行了大板桥岩溶地下水系统分级,即大板桥裸露—覆盖型岩溶水一级系统及横山—龙泉寺裸露型子系统和大板桥—阿地村覆盖型子系统两个二级子系统,确定了大板桥岩溶地下水系统侧向边界、裸露区顶界、裸露型子系统与覆盖型子系统的边界及覆盖区顶界四种裸露—覆盖型岩溶地下水系统污染边界,并对边界防污性能进行了研究,认为裸露区顶界防污性能弱、裸露型子系统与覆盖型子系统的侧向边界防污性能较弱,覆盖区顶界防污性能强。      

GPU用于高光谱数据高性能计算的应用实践与分析

高光谱遥感数据具有波段多、数据量大、处理复杂等特点, 基于GPU的高性能计算在遥感领域得到了快速发展, 为高光谱数据的快速处理提供了硬件和技术条件。采用GPU对高光谱遥感数据常用的SAM、PPI等处理算法进行应用实验, 验证基于GPU的高光谱遥感数据快速处理技术。实验采用新疆东天山地区的一景星载Hyperion数据, 利用支持IDL开发语言的GPULib、CUDA运行时API库进行算法效率的验证, 结果表明, 基于GPU的高光谱数据处理效率比常规的多核CPU主机处理效率有较大提升, 具有一定的应用推广价值。      

Assessment of various CPT based liquefaction severity index frameworks relative to the Ishihara (1985) H1–H2 boundary curves

The objective of the study presented herein is to develop an understanding of the predictive trends of four different liquefaction severity index frameworks, with emphasis on the utility of the frameworks for assessing liquefaction vulnerability in Christchurch, New Zealand. Liquefaction induced land damage was widespread following the four major earthquakes in Christchurch (M_w 5.9–7.1) between 4 September 2010 and 23 December 2011. As part of the rebuilding effort, a major focus, to date, has been on assessing/developing approaches for evaluating vulnerability to liquefaction induced damage in future events. The four liquefaction severity index frameworks that are evaluated herein are: the one-dimensional volumetric reconsolidation settlement (S_V1D), the Liquefaction Potential Index (LPI), and two new liquefaction severity indices developed following the major earthquakes in Christchurch, namely the Ishihara inspired LPI (LPI_ISH) and the Liquefaction Severity Number (LSN). To assess the predictive trends of the four severity index frameworks, the H₁–H₂ boundary curves developed by Ishihara (1985) are used as a reference of comparison. In large part, the severity index frameworks serve the same purpose as the Ishihara boundary curves, but they alleviate some of the difficulties in implementing the Ishihara boundary curves for assessing the highly stratified soil profiles that underlie much of Christchurch. A parametric study was performed wherein relatively simple soil profiles are evaluated using all the procedures and contour plots of calculated S_V1D, LPI, LPI_ISH, and LSN values were superimposed onto the Ishihara boundary curves. The results indicate that the LPI_ISH and LSN indices yield similar trends as the Ishihara boundary curves, whereas the S_V1D and LPI indices do not. Furthermore, little field data is available to assess the severity indices for the scenarios where the trends in the LPI_ISH and LSN indices differ.     

高烈度区重力式挡墙基于性能的抗震设计方法研究

介绍基于性能抗震设计的核心理念,以支挡结构震害调查分析为背景,阐述开展高烈度区重力式挡墙基于性能抗震设计研究的必要性;构建重力式挡墙基于性能的抗震设计框架,归类分析现行规范与基于性能抗震设计的关键技术问题;依据支挡结构震害调查及大型振动台模型试验,提出位移指数可作为衡量挡墙抗震性能的量化指标,确定重力式挡墙基于性能抗震设计的性能准则及流程;经对比计算基于性能与规范抗震设计的挡墙算例,显示基于性能抗震设计的优越性,为高烈度区重力式挡墙基于性能抗震设计的工程应用提出建议。