基于风险评价的重大火灾隐患判定方法

定义了广义和狭义的重大火灾隐患,分析了火灾隐患与火灾风险的关系。根据我国火灾统计数据,结合FN曲线和回归分析方法,确定了我国火灾社会可容忍风险及建筑重大火灾隐患判定标准。将所建立的方法应用于建筑重大火灾隐患工程评估中。运用事件树建立了具有代表性的火灾场景。运用FDS5.0火灾模拟软件和BuildingEXOUDS4.06疏散软件计算得到了各类火灾场景导致人员伤亡的量化结果。对某大厦判定结果显示,该单位存在重大火灾隐患。     

高层建筑边坡地质灾害危险性评估与防治

以湖南省长沙市通用国际社区南块地边坡项目建设场地为项目背景,综合项目建设场地的地质条件,采用定性—半定量的方法,对该边坡地质灾害的危险性进行了现状评估和预测,提出了相应的防治措施和施工建议。     

Methodologies for hazard analysis and risk assessment in the petroleum refining and storage industry — Part II

The report briefly describes the consecutive steps in the identification, assessment and comparison of hazards and associated risk. These techniques can be helpful in setting the priorities for the decision on measures to reduce risk. When quantifying risk for the comparison of alternative cases, the use of a consistent data base is stressed. It is pointed out that the risk assessment techniques described in the report, although potentially valuable tools for improving overall safety performance, have short-comings particularly in dealing with human factors. A glossary is appended to define terms as they are used in this report and a list of recommended further reading is included. Part I appeared inFire Technology, August 1984. Prepared by the Ad-Hoc Risk Assessment Group of the Oil Companies' International Study Group for Conservation of Clean Air and Water in Europe (CONCAWE) Reference: CONCAWE's Ad-Hoc Risk Assessment Group; “Methodologies for Hazard Analysis and Risk Assessment in the Petroleum Refining and Storage Industry, Part II,” Fire Technology, Vol. 20, No. 4, November 1984, p. 43     

Methodologies for hazard analysis and risk assessment in the petroleum refining and storage industry — Part I

The report briefly describes the consecutive steps in the identification, assessment and comparison of hazards and associated risk. These techniques can be helpful in setting the priorities for the decision on measures to reduce risk. When quantifying risk for the comparison of alternative cases, the use of a consistent data base is stressed. It is pointed out that the risk assessment techniques described in the report, although potentially valuable tools for improving overall safety performance, have shortcomings particularly in dealing with human factors. A glossary is appended to define terms as they are used in this report and a list of recommended further reading is included. Part II will appear inFire Technology, November 1984. Reference: CONCAWE's Ad-Hoc Risk Assessment Group; “Methodologies for Hazard Analysis and Risk Assessment in the Petroleum Refining and Storage Industry”, Fire Technology, Vol. 20, No. 3, August 1984, p. 23.     

项目风险评价方法及进展研究

参考了一般风险评估理论,对风险评估各种方法的特点和发展状况进行了详细的介绍和分析,对当前风险评估方法还存在的问题和未来发展方向提出了自己的见解,从而为项目管理者提供决策支持。     

A risk estimation method of railway embankment collapse due to heavy rainfall

Slope collapses of embankments and cut slopes along railways are often triggered by heavy rainfall of a typhoon, etc., and have much influence on the running safety of trains. It is of vital importance to find out the risky sites along the railway to control railway operations. For this purpose, it is desiable to develop a practical damage estimation method which can accurately predict the risks of slope collapse and can be simply applied by many railway workers. This paper deals with a method of estimating the railway embankment collapse in times of heavy rainfall based on a multivariate analysis. The critical rainfall is proposed to be defined as a product of the amount of accumulated rainfall and the maximum hourly rainfall. This value is also determined by a function whose variables include information on the embankment such as soil and structural properties, the surface ground geotechnical characteristics, the catchment and seepage, and the empirical rainfall. Therefore, the risk evaluation for embankments can be performed with the critical rainfall value.     

数值模拟联合算法及其在润扬大桥可靠度评估中的应用

为了定量研究大跨桥梁在外界随机因素作用下的结构安全性,实现在线状态的可靠度评估,利用可靠度的随机有限元法对润扬大桥悬索桥在正常运营和损伤等多种工况下的结构可靠度进行了数值模拟和可靠度评估。分析中采用蒙特卡罗重要抽样法和中心复合响应面法的联合算法作为数值模拟的基本工具,介绍了联合算法的具体实现途径、随机变量的参数定义并对大跨桥梁基于可靠度指标的评估准则进行了讨论。得到了多个随机变量的概率灵敏度、主要失效模式所对应的可靠度指标及其相应的状态等级。算例分析结果表明,基于随机有限元的可靠度分析方法可以较好地描述大跨桥梁的非线性特征,联合算法的应用提高了可靠度分析的效率和精度,其结果为润扬大桥悬索桥的状态评估和健康监测提供了参考。     

Reliability-based design optimization using convex linearization and sequential optimization and reliability assessment method

In this study, an effective method for reliability-based design optimization (RBDO) is proposed enhancing sequential optimization and reliability assessment (SORA) method by convex linearization. In SORA, reliability estimation and deterministic optimization are performed sequentially. And the sensitivity and function value of probabilistic constraint at the most probable point (MPP) are obtained in the process of finding reliability information. In this study, the convex linearization is constructed by utilizing the sensitivity and function value of the probabilistic constraint at the MPP. So no additional evaluation of the probabilistic constraint is required in the deterministic optimization in SORA. The proposed RBDO method is applied to numerical examples and compared to various RBDO methods. It is shown that the proposed method is very efficient with similar accuracy.     

Temporal moisture content variability beneath and external to a building and the potential effects on vapor intrusion risk assessment

Migration of vapors from organic chemicals residing in the subsurface into overlying buildings is known as vapor intrusion. Because of the difficulty in evaluating vapor intrusion by indoor air sampling, models are often employed to determine if a potential indoor inhalation exposure pathway exists and, if such a pathway is complete, whether long-term exposure increases the occupants' risk for cancer or other toxic effects to an unacceptable level. For site-specific vapor intrusion assessments, moisture content is, at times, determined from soil cores taken in open spaces between buildings. However, there is little published information on how moisture content measured outside a building structure compares with the moisture content directly beneath the building - where the values are most critical for vapor intrusion assessments. This research begins to address these issues by investigating the movement of soil moisture next to and beneath a building at a contaminated field site and determining the effect on vapor intrusion risk assessment. A two-dimensional, variably-saturated water flow model, HYDRUS-2D, is used with 2 years of hourly, local rainfall data to simulate subsurface moisture content in the vicinity of a hypothetical 10 x 10-m building slab at a contaminated field site. These moisture content values are used in vapor intrusion risk assessment simulations using the Johnson and Ettinger model with instantaneous and averaged moisture contents. Results show that vapor intrusion risk assessments based on moisture content determined from soil cores taken external to a building structure may moderately-to-severely underestimate the vapor intrusion risk from beneath the structure. Soil under the edges of a slab may be influenced by rainfall events and may show reduced vapor intrusion risk as a consequence. Data from a building instrumented with subslab moisture probes showed results similar to the modeling, but with a smaller difference between the subslab and outside average moisture contents. These results indicate that, depending upon the point of vapor ingress into the structure and soil type, risk-based cleanup concentrations based on outside-of-slab or default moisture content values may not be predictive of exposure to organic vapors from below a building.