A combined risk analysis approach for complex dam–levee systems

In many areas of the world, dams and levees are built to reduce the likelihood of flooding. However, if they fail, the result can be catastrophic flooding beyond what would happen if they did not exist. Therefore, understanding the risk reduced by the dam or levee, as well as any risk imposed by these flood defences is of high importance when determining the appropriate risk reduction investment strategy. This paper describes an approach for quantifying and analysing risk for complex dam–levee systems, and its application to a real case study. The basis behind such approach rely on the potential of event tree modelling to analyse risk from multiple combinations of ‘load-system response-consequence’ events, tested by the authors for a real case study. The combined approach shows how the contribution to system risk of each sub-system can be assessed. It also describes how decisions on risk mitigation measures, at the individual asset scale, can and should be informed in terms of how they impact the overall system risk.     

A flood risk assessment to municipal infrastructure due to changing climate part II: case study

Flooding often has devastating consequences. It is important to understand the evolution of these risks as climate changes. Municipal infrastructure is designed using historical data that no longer accurately represents current climate conditions, indicating infrastructure may underperform. The purpose of this study is to apply a new methodology for the assessment of climate change caused flood risk by Bowering et al. (2013) to the City of London, Ontario, Canada. Floodplain maps derived from climate, hydrologic and hydraulic analyses provide direct input into risk assessment procedure. Inundated infrastructure and high risk areas are identified in tables and maps for two climate and two hydraulic scenarios. Results indicate the most critical flood scenario is the 100 year climate change upper bound and high risk is driven by expensive infrastructure located in the floodplains. Results of the study are used as the support for climate change adaptation policy development and emergency management.     

New developments in TBM tunnelling for changing grounds

Mechanized tunnelling has seen substantial growth in the recent years in the construction industry for small to large scale infrastructure works. This development is due to a growing number of large-scale projects that were successfully realized with certainty and reliability in construction, compliance with construction schedules and thus supported the economic success of the projects. Tunnel projects are planned and implemented today in changing grounds that could not be realized without the newest technological progress and innovations in mechanized tunnelling. Today’s demand in tunnelling is to construct tunnels with high safety standards especially in urban areas with sensitive geological and hydrogeological conditions. In the context of this publication, new developments in TBM tunnelling related to changing ground conditions are highlighted. References of major infrastructure projects will be addressed that illustrate also the effect and importance of mechanized tunnelling technology used today to complete infrastructure projects on time and with high quality and technical standards.     

The current state of the use of large wood in river restoration and management

Trees fall naturally into rivers generating flow heterogeneity, inducing geomorphological features, and creating habitats for biota. Wood is increasingly used in restoration projects and the potential of wood acting as leaky barriers to deliver natural flood management by ‘slowing the flow’ is recognised. However, wood in rivers can pose a risk to infrastructure and locally increase flood hazards. The aim of this paper is to provide an up‐to‐date summary of the benefits and risks associated with using wood to promote geomorphological processes to restore and manage rivers. This summary was developed through a workshop that brought together academics, river managers, restoration practitioners and consultants in the UK to share science and best practice on wood in rivers. A consensus was developed on four key issues: (i) hydrogeomorphological effects, (ii) current use in restoration and management, (iii) uncertainties and risks and (iv) tools and guidance required to inform process‐based restoration and management.     

An empirical investigation on how portfolio risk management influences project portfolio success

Project risk management is recognized as essential in order to cope with the challenges arising from the environment. Literature suggests a portfolio-wide perspective for managing risks in project portfolios. However, research on risk management and its success in a project portfolio context is scarce. This study examines how portfolio risk management influences project portfolio success. Using a sample of 176 firms, this study provides evidence that portfolio risk identification, the formalization of the portfolio risk management process, and risk management culture directly influence risk transparency, whereas risk prevention, risk monitoring, and the integration of risk management into project portfolio management are directly connected to risk coping capacity. The findings also suggest that both risk transparency and risk coping capacity have a direct impact on project portfolio success. However, the results did not confirm the hypothesis that risk transparency and risk coping capacity have a complementary effect on success. Implications for scholars and project portfolio managers are discussed.     

中国大坝安全与风险管理的现状及其战略思考

分析了中国大坝安全管理的三个发展阶段,认为中国大坝安全保障体系正在不断加强,大坝安全管理水平已经有了大幅度提高,风险理念已经在中国得到广泛接受,风险管理技术正在日益受到重视。认为在计划经济体制向市场经济体制逐步过渡中,中国的大坝安全管理还面临着巨大的挑战:如何向市场经济体制模式过渡,政府职能和大坝业主职能如何剥离,如何走上良性循环发展的道路;从管理体制、运行机制和法规建设方面提出了应对挑战的一些战略思考和建议。     

Hochwasserschutzdeiche – aktuelle Entwicklungen zur Verbesserung der Hochwassersicherheit

River dikes – actual developments for improvement in flood safety. For centuries dikes have been constructed along rivers as protection against flooding at high water levels and they still exist today over long stretches. In the course of time numerous changes have occurred concerning the materials to be used and the inner structure when building dikes, so that a dike constructed in several zones according to today's technical standards generally holds out under prolonged hydraulic stress. Many related questions arise with regard to the subject of flood safety. In this article specific examples of current developments are taken and illustrated with reference to the assessment, prognosis and improvement of the stability of flood protection dikes, in particular of old dikes.     

城市地下基础设施项目中的安全文化培育

城市地下基础设施建设项目安全风险源复杂,工程安全风险控制要求高,但是我国实际工程的安全控制水平与世界发达国家还存在一定的差距。基于城市地下基础设施建设项目中培育安全文化有利于避免重大安全事故,在分析城市地下基础设施项目管理中安全文化建设的必要性及其主要特征的基础上,探讨了工程项目管理中安全文化的培育及其评价指标。服务于项目风险控制的安全文化的培育,应在充分考虑工程项目属性和环境因素的基础上,针对工程核心目标,从组织单元（架构）、社会内在核心价值观和主观心理状态等方面综合发展。     

3. Risk Management of Major Aqueducts

T he paper D escribes the methodology applied to determine the security of ageing aqueducts by the application of risk analysis techniques. Targets for safety and reliability are suggested within a strategy for risk management.
A case study of a security study of a major aqueduct is briefly described.     

Bridge life-cycle performance and cost: analysis,prediction, optimisation and decision-making

The development of a generalised framework for assessing bridge life-cycle performance and cost, with emphasis on analysis, prediction, optimisation and decision-making under uncertainty, is briefly addressed. The central issue underlying the importance of the life-cycle approach to bridge engineering is the need for a rational basis for making informed decisions regarding design, construction, inspection, monitoring, maintenance, repair, rehabilitation, replacement and management of bridges under uncertainty which is carried out by using multi-objective optimisation procedures that balance conflicting criteria such as performance and cost. A number of significant developments are summarised, including time-variant reliability, risk, resilience, and sustainability of bridges, bridge transportation networks and interdependent infrastructure systems. Furthermore, the effects of climate change on the probabilistic life-cycle performance assessment of highway bridges are addressed. Moreover, integration of SHM and updating in bridge management and probabilistic life-cycle optimisation considering multi-attribute utility and risk attitudes are presented.     

Network level bridges maintenance planning using Multi-Attribute Utility Theory

Bridge infrastructure managers are facing multiple challenges to improve the availability and serviceability of ageing infrastructure, while the maintenance planning is constrained by budget restrictions. Many research efforts are ongoing, for the last few decades, ranging from development of bridge management system, decision support tools, optimisation models, life cycle cost analysis, etc. Since transport infrastructures are deeply embedded in society, they are not only subject to technical requirements, but are required to meet the requirements of societal and economic developments. Therefore, bridge maintenance planning should accommodate multiple performance goals which need to be quantified by various performance indicators. In this paper, an application of Multi-Attribute Utility Theory (MAUT) for bridge maintenance planning is illustrated with a case study of bridges from the Netherlands road network. MAUT seeks to optimise multiple objectives by suggesting a trade-off among them and finally assigns a ranking to the considered bridges. Moreover, utility functions of MAUT appropriately account for the involved uncertainty and risk attitude of infrastructure managers. The main contribution of this study is in presenting a proof-of-concept on how MAUT provides a systematic approach to improve the decision-making of maintenance planning by making use of available data, accommodating multiple performance goals, their uncertainty, and preferences of infrastructure managers.     

Risk analysis of combined rainwater detention and pumping systems

Storm sewer systems (SSSs) are complex, with many hydraulic, mechanical and electrical components which may fail during natural extreme events, changing environmental conditions (including urban development), or simply due to poor maintenance. System complexity and management are important and still debated concepts within the framework of SSS risk analysis. A new probabilistic model for a conceptualized urban SSS, including a storage unit (SU) and a pumping station (PS), shows how single-component risk analysis can be extended to complex SSSs and demonstrates the combined effect of key design parameters (SU volume, detention time, prescribed outflow discharge) and management strategy on the overall SSS risk of failure. The risk of failure evaluated in a typical case study, demonstrates that economic restrictions leading to the loss of reliability of PS elements and the lack of redundant mechanical elements represent a major threat to SSSs and suggests a new risk-based definition of ’extended’ SU.     

Uncertainty in risk of highway bridges assessed for integrated seismic and flood hazards

Probabilistic risk assessment for bridges under natural hazards is of great interest to engineers for the development of risk mitigation strategies and implementation plans. The present study evaluates risk of an existing highway bridge in California, USA, under the integrated impact of regional seismic and flood hazards. A sensitivity study combining tornado diagram and first-order second moment reliability analyses is conducted to screen significant uncertain parameters to which bridge response is mostly sensitive. A rigorous uncertainty analysis, employing random sampling and Monte Carlo simulation techniques, is performed to obtain variations in fragility and risk curves of the bridge. Observed variations in risk curves at various risk levels are quantified through 90% confidence intervals and coefficients of variation (COV) of risk. It is observed that uncertainty in the estimated risk increases due to the presence of flood hazard at the bridge site, although mean risk does not vary with flood hazard level. Research outcome signifies that the variation in risk due to parameter uncertainty and varied flood hazard level should not be ignored to ensure bridge safety under the stated multi-hazard condition.     

Soft systems methodology and integrated flood management: a study of the Adayar watershed,Chennai, India

This paper applies Soft Systems Methodology (SSM) within the context of action research and Integrated Flood Management (IFM). A case study from the Adayar watershed, Chennai, is provided as an example of how SSM can be used to understand complex situations and as a problem‐solving strategy for flood management. Flat topography, uncontrolled urban development, population growth, sand bar formation at the river mouth and low tidal action render complexity to flood management in Chennai. For effective flood management, a participatory and integrated approach, which includes stakeholders in the decision‐making process and an enabling institutional set‐up, is essential. As part of an integrated approach, the relationship between various organizations and the public is identified. SSM is an approach for addressing fuzzy problematic situations involving human activity. In this paper, SSM techniques like ‘Rich Picture Diagrams’ and ‘CATWOE analysis’ and participatory action research tools like ‘pairwise ranking’ and ‘force field analysis’ were investigated. Two workshops were conducted to define and explore the problematic situation, the role of various actors involved in the problem, to develop the conceptual model, to rank decision‐making criteria, and to analyse the forces for and against to solve the problem. The flood management approach provided in this paper can be used by government agencies and policy makers to manage floods.     

建设工程质量安全风险管理模式简介与试点应用

本文着重探讨了在建设工程质量安全领域引入保险,依靠经济手段合理分散风险。同时建议成立专门的风险管理机构,对工程建设过程中的质量安全风险实施全过程的控制,为工程质量安全构筑新型保障体系。     

The suitability of risk reduction indicators to inform dam safety management

Risk analysis can provide very suitable and useful information to manage the safety of critical civil infrastructures. Indeed, results of quantitative risk models can be used to inform prioritisation of safety investments on infrastructures’ assets and portfolios. In order to inform this prioritisation, a series of risk reduction indicators can be used. This paper reviews existing indicators for dam safety, tracks how equity and efficiency principles are captured, propose additional indicators and provides insights into how tolerability guidelines and benefit–cost analysis can also play a role in decision-making. All reviewed, analysed and/or combined indicators are later applied in a case study, a portfolio of 27 dams where 93 structural and non-structural investments are prioritised. The case study shows that prioritisation sequences based on risk model results provide suitable and useful information, acknowledging that other concerns may be conditioning decision-making processes. With the results of the case study, a full comparison between all studied risk reduction indicators is made, and three indexes are calculated for all of them to measure how close they are to a theoretical best.     

基于风险的城市燃气管道的安全管理

本文通过分析安全管理与风险管理的关系,提出了一种基于风险的城市燃气管道的安全管理方法。结合某市工程实例,运用风险矩阵图和模糊综合评价对潜在风险进行评估排序,确定风险性质并采取合理措施,以达到安全管理的目的。     

Why risk efficiency is a key aspect of best practice projects

This paper explains what ‘risk efficiency' means, why it is a key part of best practice project management, and why it may not be delivered by common practice as defined by some guidelines. This paper also explains how risk efficiency can be addressed operationally using comparative cumulative probability distributions (S-curves). Further, this paper explains why risk efficiency provides a foundation for a convincing business case for:

• formal project risk management processes designed for corporate needs,

• embracing the management of opportunities as well as threats,

• measuring threats and opportunities to assist decision making,

• developing a more effective risk taking culture,

• taking more risk for more reward.

The argument uses linked examples from four successful cases: the first use of a designed project risk management process by BP for offshore North Sea oil and gas projects, the first use of a designed process by National Power for combined cycle gas powered electricity generation, a culture change programme for IBM UK concerned with taking more risk to increase the rewards, and a due diligence assessment of project risk management for a railway infrastructure project. The concepts and tools described are relevant to any industry sector for projects of any size.     

基于风险排序的项目群风险管理研究

项目群在其生命周期内面临各种不同的风险,项目群管理组织该如何利用其拥有有限的资源去管理这些风险就成为每个项目群管理组织必须考虑的问题.利用在单个项目风险管理过程中对风险排序的方法,对项目群中的项目进行风险排序,得到每个项目风险的相对水平,从而使得项目群管理组织可以有的放矢地分配其有限的资源给不同风险等级的项目,最终达到合理控制项目群风险的目的.     

PLANNING FOR FLOOD RISK IN THE FENS

The fens of eastern England rely on flood defences for their existence, and planning for flood risk has always had a high priority. A new focus was given with the issue of Planning Policy Guidance 25, and this paper presents experience from a Strategic Flood Risk Assessment of South Holland District, in Lincolnshire. The assessment pioneered the examination of fenland flood risk in terms of risk zones related to flood hazard and standard of protection. Methods for evaluating the risk zones are described; they consider flooding from embanked rivers which are subject to tide locking, internal drainage systems, tide level and wave action. The methods would be appropriate for many lowland areas of the UK where conventional flood analysis cannot be used.