ICE - Institution of Civil Engineers - Virtual Library

A new stochastic water distribution network (WDN) modelling tool has been developed with the aim of providing a sound basis for cost-effective strategic planning of WDN monitoring schemes in terms of quantifiable leakage. Through an analysis of uncertainties in water demand and its propagation through a WDN, the developed computer tool recommends the most cost-effective solution in terms of the number and location of monitoring sites necessary to increase the probability of identifying the location of leaks (or other system anomalies). The methodology was tested on a medium-sized WDN in the UK and the results are presented in this paper.

The aim of this paper is to present an appreciation of the way a refurbishment problem was tackled in the firstinstance, subsequently the technical merits of the seismic qualification and finally the system employed to achieve the cost benefits and set targets. The set aim was to provide a cost effective solution to the problem of qualifying an existing pipebridge to an acceptable level of seismic loading. The technical solution to the problem involved the use of a dynamic isolation system, in particular the use of elastomeric bearings to limit the likely levels of dynamic interaction of a multi component system. The practical solution to the problem of refurbishment - the cleaning, strengthening and addition of the isolation system was achieved without the neccesity of providing substantial temporary works to expedite the required solution. A quality system was in use throughout to reinforce the effectiveness of the end result.

• Synopsis

• 1.0 Introduction

• 2.0 Background to Case Study

• 3.0 Initial Technical Assessment

• 4.0 Analysis in Detail

• 5.0 Validation and Test

• 6.0 Summary of Project Design & Analysis Methodology

• 7.0 Conclusion

Travel demand management or mobility management is growing in interest as political decision-makers realise that it is not financially and socially feasible to attempt to build enough roads to satisfy growing car use. In reaching this conclusion, political decision-makers confront a dilemma. Car users want quicker travel times for their car trips but they are not prepared to suffer the negative impacts of excessive car use. The solution lies in changing the travel behaviour of individuals but not through measures that are seen to constrain current car use. Therefore low-cost voluntary behaviour change programmes that deliver change are very appealing. The implementation of the Western Australian large scale TravelSmart programme proves that it is possible to motivate people to use their cars less without constraining access to their destinations. The outcome is a very cost-effective alternative to building expensive road infrastructure solutions and provides better use of public transport, cycling and walking infrastructure. The programme has been able to achieve a modal split which parallels that of the early 1980s and the planned programme will be implemented on a large scale reaching over 300 000 people. This programme provides a way forward in a field of transport that has been bereft of effective techniques acceptable to political decision-makers. The winning of resources for the programme has been undertaken within a ‘campaign’ framework comprising proof of public value, developing a capacity to deliver, and winning community support. TravelSmart has developed from an extensive knowledge of travel behaviour and applied within a leadership and community learning paradigm.

Despite the use of design procedures and construction practices that have been developed over many years, unexpectedly early deterioration of concrete structures has become a matter of considerable concern in many countries.

This paper contains a brief view of the need for inspections of structures to be accompanied by well-targeted testing, carried out by well qualified dedicated technical staff, with results being interpreted by experienced engineers in order that owners of structures receive cost-effective quality advice for the management of their structures.

Monitoring in the form of observations and testing over a period of time produces an indicator of the rate of deterioration of a structure. Case studies are presented that demonstrate the benefits of testing of structures.

• Introduction

• The Need for Testing, a Clients Perspective

• Causes of Deterioration

• Visual Inspection

• Testing

• Planning for Testing

• Types of Testing

• Bellevue Bridge Case Study

• Conclusions

• References

Despite the use of design procedures and construction practices that have been developed over many years, unexpectedly early deterioration of concrete structures has become a matter of considerable concern in many countries. One effect of premature deterioration is that significant expenditure has to be diverted from capital works to the management of those structures. This paper contains a review of the need for inspections of structures to be accompanied by well-targeted testing, carried out by well- qualified dedicated technical staff, with results being interpreted by experienced engineers. The condition of these structures can then be accurately assessed, the extent, severity and causes of any deterioration determined, and any appropriate management actions identified with confidence. The base-line data obtained can be used for subsequent conditioning monitoring of the structures.

• Introduction

• The Need for Testing, a Clients Perspective

• Causes of Deterioration

• Visual Inspection

• Testing

• Planning for Testing

• Types of Testing

• Conclusions

• References

A study on the use of recycled aggregate concrete for structural concrete was carried out under the concept of Life Cycle Assessment (LC A) for environmental management of construction utilizing recycled products. The use of these products are often discarded, especially where existing electric power stations are rebuilt or upgraded in order to meet increasing power demands. In pursuing the reuse of recycled materials, the basic policy was composed of three items. These include quality assurance, reduction of environmental impact and construction cost. The study was divided into three main parts, (i) feasibility study on the reuse of recycled aggregate concrete, (ii) experimental study on the quality of recycled aggregate and (iii) concrete made with this material. This paper presents the results of the feasibility study on the cost effectiveness and environmental impact (CO2 emission volume). The findings of the feasibility study is used as a replacement model for thermal power stations. Based on the investigation and the analysis of results, valuable data were obtained regarding the concept and practice to the reuse construction debris based on LCA. Keywords: Life cycle assessment, Feasibility study, Recycled aggregate, Recycled aggregate concrete, Cost effectiveness, Environmental impact, Simulation, Thermal power station.

• Abstract

• Introduction

• Outline of the Study

• Analytical Condition

• Analytical Model

• Factors and Levels Used in this Simulation

• Simulation System

• Simulation Results and Discussion

• Summary of Main Findings

• Acknowledgments

• References

This paper examines different clear-zone improvement alternatives in rock cuts, and compares the likely effect on safety and construction costs. Where a roadway passes through rock cuts, the construction cost of providing the clear zone is very high. This paper is based on research that demonstrates a method for selecting the appropriate clear zone in rural two-lane highways in Iran based on the site and traffic conditions expected at the site. A method is described for determining the rock-cut width that best balances the cost of construction with the improvements in safety that would result from a wider clear zone in the rock cut. The objective of this study is to quantify the societal cost of rock-face accidents, so that the costs and benefits associated with different clear-zone policies can be explicitly addressed during the preliminary design process. This study shows that the need for extra clear-zone width in steep and bendy routes (specially with external curves of less than 195 m radius) is more critical than that for straight and level ones. The existence of external horizontal curves simultaneously with severe longitudinal slopes increases the probability of vehicles' encroachment by as much as eight times in comparison with straight and level routes. An interesting point to note is that, by providing wider lanes, the need for extra clear-zone width is reduced dramatically.

Using geotextiles in secondary roads to stabilize and reinforce weak subgrades has been a well-accepted practice over the past 30 years. However, from an economics point of view, a complete life-cycle cost analysis, which includes not only costs to agencies but also costs to users of the road, is urgently needed to assess the benefits of using geotextiles in secondary road flexible pavements. This paper presents a cost analysis process that includes costs for the initial construction, each rehabilitation, work-zone queue delays, moving delays, accidents, and fuel consumption. Two of the most practical design methods, developed by Al-Qadi and Perkins, were adopted to quantify the cost–benefits provided by geotextiles when incorporated in secondary road flexible pavements. Although both methods showed significant traffic benefit ratio (TBR) at very low California Bearing Ratio (CBR), the benefits suggested by Perkins diminished as the CBR became greater than 2%. This study also shows that, when user costs are considered, a greater TBR value may not result in the most effective life-cycle cost. Hence, for an optimum secondary road flexible pavement design with geotextile incorporated in the system, a life-cycle cost analysis that includes user cost must be performed.