公路沥青路面预防性养护初探

阐述道路预防性养护的基本概念,介绍了沥青路面预防性养护的必要性、养护方案的制定过程及几种常用预防性养护措施,从而推广预防性养护的应用,保持或改善路面的使用性能,提高道路的经济效益。     

Water services performance: do operational environment and quality factors count?

Decision makers must keep in mind that water services have an invaluable ‘price’ for the public budget and society’s welfare. However, due to the specific features of the service, water utilities are prone to inefficiency. Thus, performance evaluation becomes indispensable to face this constraint. Besides the application of the traditional technique of Data Envelopment Analysis to evaluate the performance of Portuguese water utilities, this study also implements the robust technique of order-m to assess the influence of operational environment on water utilities’ performance. In spite of several reforms, the Portuguese water sector still reveals significant levels of inefficiency, partially caused by an inappropriate operating scale. Concerning the operational environment, it was possible to observe a positive influence of private sector participation, economies of scope, and groundwater sources on efficiency. The influence of the ‘quality of service provided’ was also studied in this performance analysis.     

关于城市道路交通设计若干问题的探讨

本文从交通设计的视角分析研究道路设计的若干问题 ,包括 :道路横断面形式、车道宽度、设计车速、公交停靠站以及交叉口的标线与渠化问题。其研究成果对于提高道路的利用效率和服务水平 ,修编城市道路设计规范皆具有重要的实用意义和参考价值。     

A risk management approach to safety assessment of trenchless technologies for culvert rehabilitation

Proper functioning of culverts is not only critical to protecting the transportation system from flooding but also critical to maintaining the expected service life of the overall transportation system. During the service life of culverts, they deteriorate due to many reasons such as corrosion caused by road salt, blockage by debris and sediment, poor construction techniques, etc. Trenchless technologies have been used by several State Departments of Transportation (DOTs) to rehabilitate deteriorated drainage structures without disrupting the traffic and within a relatively short span of time. These technologies provide many benefits in terms of cost, time, quality, and expected service life. However, the safety aspects of these techniques have not been discussed and documented in detail probably due to the complexity and the lack of safety standards and specifications directly associated with the techniques. This paper discusses the application of a risk assessment framework to assess potential safety issues of currently available trenchless technologies for culvert rehabilitation. The findings of the study will provide additional information to improve the decision making process in selecting and planning culvert rehabilitation projects.     

BMA天然沥青的性能及应用研究

为评价天然沥青BMA对沥青路面的贡献,对BMA改性沥青及沥青混合料进行了室内性能试验,并铺筑了天然沥青试验路。室内试验结果表明,BMA天然沥青能显著提高沥青混合料的高低温性能、抗水损害能力,试验路也证明采用BMA天然沥青的沥青路面具有良好的抗车辙能力和耐久性,能提高道路的服务水平。BMA天然沥青能延长路面正常使用寿命,降低路面维修费用,适用于重载道路、钢桥面铺装、机场道面等场合。     

公路养护机械设备管理不足点及改进策略

随着人类社会的不断发展与进步,公路发挥的重要作用不断突出。人类自身发展和经济发展需求的满足都离不开公路这一连接性纽带。所以公路的养护工作显得尤为重要。做为公路养护的基础,公路养护机械设备的配置以及使用管理极其重要。这项工作是否能够做好做到位直接关系到公路的质量以及使用寿命。但是目前看来,我们国家在公路养护机械设备的配置以及使用管理中仍然存在一些不足,使得公路养护设备配置不当,使用管理欠缺科学的方式和方法,严重影响公路养护工作的效果,对公路使用寿命造成不良影响。为了提高公路养护机械设备的配置水平以及管理维护水平,使其发挥应有的效果,本文首先分析了目前公路养护机械设备的配置以及使用管理现状,根据实际情况,针对目前存在的不足,进一步探讨加强公路养护机械设备的良好配置以及日常使用管理的建议。     

A Markov‐Based Road Maintenance Optimization Model Considering User Costs

User costs of different maintenance actions need to be assessed in road maintenance as well as the maintenance costs. The vehicle operating cost (VOC) and the travel delay cost are two major components of the user costs associated with road maintenance actions. This article simplifies the general calculation models of these two user cost components and develops a multiobjective Markov‐based model to minimize both maintenance cost and user cost subject to a number of constraints including the average annual budget limit and the performance requirement. The road deterioration process is modeled as a discrete‐time Markov process, the states of road performance are defined in terms of the road roughness, and the state transition probabilities are estimated considering the effects of deterioration and maintenance actions. An example is provided to illustrate the use of the proposed road maintenance optimization model. The results show that the optimal road maintenance plan obtained from the model is practical to implement and is cost‐effective compared with the periodical road maintenance plan. The results also indicate that the maintenance cost and the user cost are competitive. When maintenance works are carried out more frequently, the life‐cycle maintenance costs will increase while the life‐cycle user costs will decrease. This is because the VOC contributes the most amount of the user cost and its change has a contrary trend to the change of the maintenance cost over time.     

Economics and the selection and development of energy standards for buildings

Energy-conservation standards for new buildings will play a major rôle in federal and state conservation policies in the coming decade. This article discusses economic-efficiency considerations that can be incorporated into the selection and development of such standards. Three types of energy budgets — ‘fixed energy budgets’, ‘partially variable energy budgets’, and ‘economically efficient energy budgets’ (EEEB) — are examined for use as standards. Economic-efficiency criteria are presented for use in selecting an appropriate energy budget. An illustrative example shows the potential dollar losses in life-cycle terms from failing to apply an EEEB. Research and operational requirements for developing and implementing an energy budget are described. Three energy-budget standards are evaluated in terms of economic efficiency, administrative feasibility, equity, and consistency in design requirements. An EEEB appears optimal in that it ranks highest overall with respect to the four criteria. Failure to begin research for, and development of, EEEBs now would impose unnecessary social costs in the form of extra expenses to achieve any chosen target levels of energy conservation in buildings.     

Performance Measurement Innovation in English Planning Authorities

Much scholarly and practical policy work has been carried out in recent years on evidence-based policy making and measurement-based performance management. Yet research on performance measurement in spatial planning is still rare. The ‘Best Value’ performance management framework imposed by the UK central government has precipitated a flurry of initiatives amongst English local planning authorities. This article reports on innovations in performance measurement amongst some of these local authorities, reviewing the objectives and mechanisms of measurement, as well as the drivers and inhibitors of measurement behaviour. The research reflects a nationally fragmented picture of measurement and uneven innovation within and amongst authorities, but highlights a number of initiatives that show promise as the basis upon which to develop a more holistic framework for measurement in the future, both in the UK and elsewhere.     

Multi-strategy budget allocation decision support system for seismic rehabilitation of road infrastructure

Economic efficiency is an important factor in seismic rehabilitation of road infrastructures. An inventory of structures is screened to identify seismically deficient parts and prioritise them in the order of need for rehabilitation purposes. In most cases, the financial resources for road infrastructure rehabilitation projects are limited. Therefore, there is a need to efficiently allocate resources to various projects. This article presents a multi-strategy decision support system (DSS) for seismic rehabilitation budget allocation across existing road infrastructures. This DSS employs a multi-criteria assessment module that takes into account different criteria to estimate the financial needs for rehabilitation and to establish an allocation methodology based on the available budget in a fiscal year. To select the optimal package of projects, a genetic algorithm (GA) optimisation module is developed. Multi-objective decision-making is conducted under a specific decision strategy (DS) by solving a (0–1) Knapsack problem. To demonstrate the applicability of the GA-based approach, a hypothetical decision-making problem is presented. The results reveal that the optimal package is more sensitive to the available budget and DS than to the weights of criteria and project scores. Using this system, managers can compare their decisions for different strategies and significantly improve management efficiency.     

Integrated performance assessment model for water distribution networks

The American infrastructure report card in 2013 rated the US water system infrastructure with grade of ‘D’. The Canadian infrastructure report card in 2012 stated that around 15.4% of Canada’s water infrastructure has a condition of fair to very poor. Thus, there is a critical need to develop efficient inspection, maintenance and rehabilitation plans for water distribution networks. However, such plans require an assessment tool to evaluate the performance and condition of water distribution networks. Therefore, the main purpose of this paper is to develop an integrated performance assessment model for water distribution networks. Two modules were developed to assess the performance of water pipelines and accessories, respectively. A third module was developed to assess the performance of water segments that includes pipelines and accessories. Moreover, a fourth module was built to assess the performance of each sub-network and the entire network based on the segments’ connection type using a reliability-based approach. To assess the performance of the water distribution network, the critical factors affecting its pipelines and accessories were identified and studied. The fuzzy analytic network process technique was used to obtain the importance weights of the identified factors.     

Rural water asset management practices in Ghana: the gaps and needs

This study evaluates primary and secondary data from two districts to assess the status of asset management practices, and to examine requirements for improved asset management. Asset inventory data shows that asset management practices in the districts are currently poor, leading to high rates of nonfunctionality and low service levels. The existing ‘fix on failure’ approach to water systems’ repair has become a common practice. However, many repairs which relied on ‘fix on failure’ were found to have delayed, often due to the length of time it takes to mobilise financial resources from ‘post‐paid’ water users. This paper contends that without an improved asset maintenance, system it is likely that rural water systems in Ghana will continue to provide unsustainable services. The Findings demonstrate that improving the current asset management practices is dependent on human and financial resources, access to timely water service monitoring data at district levels, and planning and budgeting regime to reflect life cycle costs of water systems.     

Private financing of roads and optimal pricing: Is it possible to get both?

Road pricing has been defended by economists as a useful instrument to internalize the costs that road users impose upon other users and the rest of society, with the aim of allocating scarce space and to reduce congestion to an efficient level. More recently, private participation in the construction, maintenance and operation of road infrastructure has been growing all over the world to face the challenge of tight budget constraints and increasing demand for additional road capacity. Fixed term concessions have been the standard contract between the public sector and private operators. Demand uncertainty and fixed term contracts have made impossible to fulfill the concession agreement in many cases, and contract renegotiation has been used to restore financial equilibrium. This has some undesirable economic consequences: selecting the most efficient concessionaire is not longer guaranteed and prices lose their role as signals for allocative efficiency. This paper addresses the problem of giving that role back to pricing, analyzing the possibility of achieving efficient pricing and cost recovery without contract renegotiation.We gratefully acknowledge the financial support of Fundación Fondo para la Investigación Económica y Social (FIES, Madrid) and Secretaría de Estado de Educación y Universidades. We are also in debt with Alejandro Lago, Gustavo Nombela and the referees for useful comments.Received: January 2003 / Accepted: July 2003     

Assessing urban lifeline systems immediately after seismic disaster based on emergency resilience

Resilience is an emerging concept for analyzing the dynamic performance of critical infrastructures during the post-disaster recovery process. Although a number of studies examined how to assess long-term resilience (1 year +), very few have investigated short-term resilience (few days to several weeks following a disaster). This study presents the new concept of ‘emergency resilience’ and the framework for assessing this short-term resilience for urban lifeline systems in the emergency recovery stage. This framework can quantify differences in system performance (pre-disaster vs. post-recovery) using the new ‘recovery degree’ feature. It also integrates a new performance response function which is based on network equilibrium theory to assess emergency resilience in both the technical and organisational dimensions. In the case study of the water pipeline network in Lianyungang, China, the results showed that the levels of the recovery budget b and recovery resource r had different effects on emergency resilience R in seismic disaster. Furthermore, it is demonstrated how the concept and its assessment framework can provide a quick reference tool for optimal decision-making under various scenarios. This study also examined the effects of two anti-seismic reconstruction measures, namely meshed expansion and ductile retrofitting, on the expected emergency resilience of the water pipeline network.     

城市道路刚改柔工程设计探讨

就目前国内外水泥混凝土路面使用状况而言,尤其是一些早期修建的水泥混凝土路面不同程度地出现了结构性破坏和功能性缺陷,严重影响了道路的服务水平及车辆的行驶安全,考虑城市道路特点,此文对城市道路改建存在问题研究其解决方法,得出了一些有价值的结论。     

公路养护作业的安全管理分析

高质、高效而又安全的公路养护工作是确保公路安全通行和延长公路寿命的有效手段之一，具有重要意义。在公路的养护作业中存在着各种问题，最受到重视的问题就是养护作业中的安全问题，各方面的高度重视。     

Real Estate Property Maintenance Optimization Based on Multiobjective Multidimensional Knapsack Problem

The real estate property maintenance problem (REPMP) deals with the problem of the maintenance of real estate property buildings’ components using a limited budget in a limited period to achieve multiple and often conflicting objectives. Maintenance of the components requires a multiannual maintenance action plan optimized simultaneously on different criteria relative to buildings’ maintenance objectives (the quality of service, client satisfaction, regulatory compliance, etc.) while respecting a predetermined budget. This article presents an innovative modeling of REPMP into a multiobjective multidimensional knapsack problem and its optimization using a generalization of the discrete multiobjective particle swarm optimization algorithm and the Pareto optimality. An application of this methodology using data from a real estate property of 22 buildings of a major French company is presented and discussed.     

南京江东路道路改造设计理念的综合应用

结合南京市江东路道路改造实例,通过横断面设计、交叉口渠化、交通岛设置、公交专用道、人行横道、主线绿波交通、绿化景观等设计理念的综合应用,极大地提高了城市道路的服务水平。道路预计通行能力由2103pcu/h提高到3450pcu/h;公交运营速度增加;大大提高了交通安全性;良好的景观效果得到了一致好评。     

An evaluation of the rationale of tenant satisfaction surveys

Over recent years the housing press in Britain has covered with increasing regularity details of surveys of tenant satisfaction in housing associations and local authorities. In the summer of 1989 the first article appeared in the specialist press of the UK market research industry related to a survey of tenant satisfaction (Roe and Martin, 1989). The article adds to the body of housing literature that assumes tenant satisfaction measures as the means of bridging the gap between the housing manager and the ‘silent majority’. Often incorporating explicit or implicit details of ‘how to do it’, such work has received little criticism. However, when setting out to measure any phenomena, we need to examine ‘What is the purpose of the measurement?’ and further: ‘What is the nature of the phenomena being measured?'; and ‘What utility do our measures possess?’. This paper examines these questions, related to tenant satisfaction. The concept of consumer satisfaction, the bedrock of the discipline of marketing, is examined in a business context to enable parallels to be drawn with the non‐profit‐making rented housing sector. This questions the rationale for conducting satisfaction surveys.     

Medium-Scale Anatolian Cities: Conceptual and Physical Routes of Urban Transformation

Banu Tomruk investigates the post-1980s transformation of the built environment of medium-scale Anatolian cities. She examines the subject through a conceptual and physical framework that places as much emphasis on populist rhetoric – ‘identity crisis’, ‘historicisation’, ‘the making of a tourist city’ – as on the built structures themselves and their realisation as standardised apartment blocks and gated communities. Copyright © 2010 John Wiley & Sons, Ltd.