重庆市朝阳复建桥缆索吊装方案分析

由于现场设计环境发生重大变化,重庆市朝阳复建桥在建设过程中对大桥缆索吊装系统优化前后的3种方案进行比选和论证。结果表明：优化后的缆索吊装系统不仅有效地解决两岸地形限制和玻璃厂房拆迁的难题,而且更加安全、经济、合理。重点介绍大桥缆索吊装系统的主要比选方案,进一步论证缆、扣塔一体化吊装体系的优越性,旨在为今后同类型桥梁的建设提供工程借鉴和设计参考。     

A quantitative risk analysis by using interval type-2 fuzzy FMEA approach: the case of oil spill

ABSTRACT

Risk assessment in maritime domain is one of the most cited topics since maritime transportation poses potential hazard for human life, marine environment and property. To mitigate risk and enhance safety awareness in maritime transportation, safety researchers have been seeking proactive solutions. This article prompts a quantitative risk-based approach combining interval type-2 fuzzy sets (IT2FSs) with failure mode and effect analysis (FMEA) to perform a comprehensive risk analysis. Thus, potential failure modes and their effects are revealed by calculating risk prioritisation numbers (RPNs). Whilst the FMEA method provides a robust risk analysing tool with relevant control options, the IT2FSs deals with ambiguity and vagueness of linguistic assessment of decision-makers through the FMEA. Hence, expert’s linguistic assessment in risk assessment can be transformed into useful information in terms of enhancing safety and pollution prevention in maritime industry. To demonstrate the proposed approach, potential failures and effects of a real shipboard oil spill case are handled. The findings show that incomplete information exchanged with local maritime authorities, malfunction of oil skimmer and poor organization of shoreline clean-up team are the most important failures during case of oil spill. The proposed approach provides not only theoretical insight into the maritime transportation industry but also practical contributions to chemical/oil tanker safety and environmental protection by mitigating risk in terms of technical or operational aspects.     

天津港大沽沙航道施工期回淤研究

在淤泥质海岸开挖航道,其回淤的程度是能否建设成功的关键因素。为了研究天津港大沽沙航道施工期泥沙回淤特点和规律,在历年航道回淤监测资料的基础上,结合天津港主航道泥沙回淤研究成果,对大沽沙航道施工期回淤进行了系统的观测和研究,取得了大沽沙航道施工期各年的回淤量和回淤的平面分布、时间变化特点及航道回淤主要集中的部位。回淤情况基本与前期淤积预测结论一致,航道不会出现严重淤积情况的结论。     

Multi-period Research Designs for Identifying Causal Effects of Built Environment Characteristics on Travel Behaviour

Abstract

To date, most empirical studies have applied cross-sectional designs to investigate the relationship between the built environment (BE) and travel behaviour (TB). Since these studies cannot identify causal influence, the use of designs that provide data on multiple moments in time seems necessary. This article classifies these designs and describes how they can be applied to identify causality in this relationship. We recommend the use of natural experiments to assess the impact of changes in land use/infrastructure and prospective longitudinal designs to assess the impact of residential or job moves. In addition, the role of the BE can be explored by assessing the impact of (1) deliberate TB change experiments and (2) changes in household circumstances across different spatial contexts over time. The use of randomised experimental designs is recommended for the former and prospective longitudinal designs for the latter. The article concludes with an outlook on future research.     

Gender Issues within the Population-Environment Nexus in Philippine Coastal Areas

Sixty percent of the Philippine's population resides in the coastal zone. Women and men in coastal communities depend chiefly on the sea for subsistence. Over fifty percent of the dietary protein requirements of coastal communities are derived from municipal fisheries and shallow coastal habitats (reef fishes, marine plants, and mangroves). Coastal populations are young and expanding at rates that exceed regional and national averages. Expanding human pressures and man-made disturbances (over harvesting, destructive fishing, siltation, etc.) that offset natural processes are destroying habitats and creating protein food security crises and increasing malnutrition. At the same time conflicts among users of coastal resources are escalating. Access constraints, gender inequities, and cultural barriers stymie options for women and men to plan their families and create alternative livelihoods. National and local government agencies are addressing food security concerns through vertical policies and programs (e.g., fisheries management, integrated coastal management). The IPOPCORM project uses a cross-sectoral approach and quasi-experimental evaluation design to test the hypothesis that food security will be achieved more quickly when coastal resources management (CRM) and reproductive health (RH) management are implemented together. The purpose of this article is to review the project's experience and highlight the trends observed in program monitoring and evaluation during 2001–2004, which suggest better impact on RH, CRM, and gender indicators in the sites where the synergistic approach is being applied.     

Small-Scale Sicilian Fisheries: Opinions of Artisanal Fishers and Sociocultural Effects in Two MPA Case Studies

Marine resource management and related stakeholder conflicts have been clearly defined in recent decades as pressing issues worldwide. This article provides a comparative study of the management regimes of the Gulf of Castellammare Fishery Reserve and the Egadi Islands Marine Reserve in Sicily, Italy. What managers in these two reserves have neglected to include in management is a social science evaluation scheme to ensure the development of more effective overall management. This is a significant problem in both Italy and the rest of the Mediterranean, where few sociocultural and economic studies have been conducted. Using data collected with standard anthropological field methods, analysis was conducted on how artisanal fishers are impacted by reserves, the extent of their knowledge regarding regulations, their opinions on management, and demographics. The results indicate that while fishers in the two case studies are all aware of the marine reserves where they fish, most fishers are not well informed of the associated regulations. Fishers feel alienated from the management process, and would feel more comfortable with reserve managers and regulations if they were involved in management. The article concludes by showing how such data could help to develop more useful and practical management practices in both these and other MPAs with similar problems.     

局部结构简化对船体冲击响应的影响

为了研究水下远场非接触爆炸中,局部细小结构（开孔和肘板）的简化对舱段冲击响应的影响。选用某油船舱段作为模型,根据不同简化形式建立4个不同的有限元模型,进行对比分析。结果表明：在冲击响应的计算过程中．省略局部细小结构可以保证足够的精度。     

温度及荷载对沥青路面车辙的影响分析

构建有限元分析模型,分析路面内部温度场变化规律,以此为基础分析不同温度以及行车荷载对沥青路面车辙发展情况的影响.研究表明:高温条件下车辙发展速度远大于低温条件下的发展速度;车辙深度与荷载大小呈线性相关:对于同样的荷载增长幅度,较低温度下车辙的增长幅度更大,但高温条件下车辙深度增长绝对值则更大.     

成都市交通环境容量研究

在探讨影响交通环境容量的主要因素基础上,从成都市的现状出发,分析了成都市主要车型分类及城市交通网络,最终建立了成都市环境交通容量模型,从而为成都市环境质量保证及机动车数量的控制提供可靠的科学依据.     

现役桥梁混凝土钢筋在自然环境下的锈蚀特征及分级评价

运用多种电化学方法,对现役桥梁进行了无损量化检测,分析了自然环境下的钢筋锈蚀特征,总结了自然环境对钢筋锈蚀率的影响规律,通过与前期实验室结果对比,揭示了自然环境与加速模拟环境的区别与联系.并对实测情况做了分级讨论.实桥测量结果表明：潮湿处的钢筋失重率最高达到33%,最低为18%;而干燥处钢筋失重率则分布在8%--15%之间.实测结果还表明：涂刷了防水层的箱梁及护栏,有助于保护混凝土内部配筋,能有效降低内部配筋的腐蚀速率,其失重率仅为4%~8%.承载重的桥台钢筋高于承载轻的护栏钢筋的锈蚀率.