Modelling the running costs of buildings

The Building Maintenance Cost Information Service (BMCIS) offers a comprehensive and rigorous framework for collecting data about the running costs of buildings. Nevertheless, it is pitched at such a level of detail that the amount of data collected and analysed may be constrained. This paper describes the deveopment and testing of a novel technique which reduces the amount of data to be collected without any unacceptable reduction in utility. It draws on the principle of cost-significance to create a simple model of maintenance and operating costs (together called running costs) from a rare and consistent set of data for 20 buildings at York University. The model contains only 11 elements, yet can predict the total running costs of each of four categories of building to an accuracy of about 21 2%. It can also predict annual costs to about 7%, despite variations in the periodicity of costs such as painting and insurance. The model was tested using the jacknife method and on virgin data. It proved to be extremely robust, predicting the running costs of 12 new buildings to within 5%. The model offers a simple framework for collecting and analysing reliable and consistent data on running costs.     

论业主如何有效降低建设项目的投资成本

本文首先解释了建设项目投资成本的概念,紧接着,对业主目前在建设项目投资成本控制方面存在的问题及其成因进行简要分析,在此基础上,重点详细论述了如何通过事前、事中、事后控制来有效降低建设项目的投资成本。     

Quantifying the causes and costs of rework in construction

Very few construction companies and consulting firms in Australia measure their costs of quality. Consequently, it is difficult for them to prove that systems for preventing quality failures are cost-effective. Although the direct costs of a quality system can be quantified with some accuracy (salaries, costs of documentation, audits, etc.), the corresponding benefits are far more difficult to assess. Indeed quality failures have become an endemic feature of the procurement process in construction and invariably lead to time and cost overruns in projects. Thus, in order to improve the performance of projects it is necessary to identify the causes and costs rework. The research presented in this paper quantifies the causes, magnitude and costs of rework experienced in two construction projects that were procured using different contractual arrangements. The causes and costs of rework projects are analysed and discussed. The findings reveal that the cost of rework for the case study projects was 3.15% and 2.40% of their project contract value. Changes initiated by the client and end-user together with errors and omissions in contract documentation were found to be the primary causes of rework. It is recommended that construction companies and consultant firms (particularly design consultants) implement quality management practices as well as place emphasis on coordinating project documentation during the design development process so that the amount of rework in projects can be reduced or even eliminated.     

A cost-benefit analysis of increased investment in Melbourne's public transport system

Abstract

The paper considers economic effects of increased investment in public transport in Melbourne, based on investment plans of VicRail and the M.M.T.B. over a 5 year period, 1981–5. If the investment were to encourage a shift in patronage from private to public transport, this would change the magnitude of costs associated with passenger transport in Melbourne. Calculations are made of these possible cost savings, given particular levels of shift in patronage. The paper concludes by reviewing the feasibility of achieving given patronage changes.     

谈引进进口设备的造价控制

本文将就如何才能科学地、合理地控制好引进进口设备的造价分几方面进行论述。     

Costs of urban utility water connections: Excessive burden to the poor

A global research programme was undertaken to investigate the actual costs and charges of obtaining a water connection in urban areas. Drawing from the Uganda case study, this paper will contribute to the understanding of the enormity of the barriers of the connection process and costs levelled against the urban poor, and the importance of programmes and pricing structures for enabling access to the water supply systems. The researchers found a mean cost of new water connection of US$500 (median of $197). This is unaffordable for $2 per-day-households, which are therefore unable to access the benefits from piped water services.     

Subcontracting in commercial and residential construction: an empirical investigation

Some twenty years ago Robert Eccles argued for the theoretical existence of the quasifirm, a semi-integrated form of production in the construction industry, following a field study of home building firms in the USA. The study was aimed at substantiating some aspects of Williamson's transaction cost theory. The present work has similar intents, and illustrates the results of two recent field studies of homebuilders and commercial contractors, and the specific features of their subcontracting practice. Given the difficulty of an effective measurement of transaction costs in construction, Williamson's concept of atmosphere is suggested to explain the different approaches observed in subcontracting.     

弱电施工企业的项目成本管理探讨

弱电施工企业项目前期成本管理包含了立项、投标、合同签订三个阶段,每个阶段都有其相应的成本管理要点,弱电施工企业可以根据这些要点对弱电工程项目进行合理有序的成本控制。     

Predicting completed project cost using bidding data

Neural network and regression models have been developed to predict the completed cost of competitively bid highway projects constructed by the New Jersey Department of Transportation. Bid information was studied for inclusion as inputs to the models. Data studied included the low bid, median bid, standard devi9 ation of the bids, expected project duration and the number of bids. A natural log transformation of the data was found to improve the linear relationship between the low bid and completed cost. The stepwise regression procedure was applied, and yielded the best performing predictive model. This regression model used only the natural log of the low bid as independent variable to predict the natural log of the completed cost. Radial basis neural networks were also constructed to predict the final cost. The best performing regres4 sion model produced superior predictions to the best performing neural network model. Hybrid models that used a regression model prediction as an input to a neural network were also studied and were found to also produce reasonable predictions. The calculated models produced good predictions of the completed project cost, but were found to be deficient in predicting very large cost increases. Simple models using the natural log of the low bid as input produced the best results. From the analysis it may be concluded that additional information about the variability of the bids submitted does not provide useful information for predicting the final project outcome.     

Benchmarking of electricity networks: Practical problems with its use for regulation

Benchmarking is a technique derived for management purposes, intended to identify outliers in any population as possible problems for resolution. Several regulatory agencies have tried to use benchmarking to define the degree of inefficiency of regulated companies, by reference to some target or frontier. This paper identifies the main problem inherent in trying to adapt a management technique to a regulatory purpose – namely that it requires the exercise of subjective judgements. The resulting lack of predictability and objectivity is not conducive to the provision of efficient regulatory incentives.This paper explains where subjective judgement enters into regulatory applications of benchmarking, which is not always apparent. The choice of model and selection of data sets are two obvious areas, but the main problem arises over the assumption that any costs not explained by the model must be due to inefficiency. Such assumptions are simply unsupported by evidence and lead to cost targets (or cost reduction targets defined over several years) that are little better than subjective guesses. There are other, superior ways to set cost reduction targets, based on long-term trends in total factor productivity for the regulated sector, which are used in the US and in other countries. However, some regulators feel obliged to use benchmarking and the paper concludes with recommendations as to how benchmarking should support further and more objective investigations into the costs of regulated utilities.     

浅谈部分建筑安装工程投资估算的编制方法

为适应时代发展的需要和投资估算的编制及应用，合理确定投资估算。本文以施工招标工程预算造价资料依据为基础，研究和建立部分建筑安装工程费投资估算的编制方法，应用在前期阶段投资估算的编制。     

Periodic refurbishment and reductions in national costs to sustain dwelling services

This paper uses a simulation model to make exploratory estimates of current and potential reductions in national costs to sustain dwelling services due to refurbishment. Data and parameters are based on a typical New Zealand dwelling of lightweight timber framed construction. Dwelling service years provided by a dwelling over one year adjusted for depreciation serve as a proxy for benefits. The costs to construct one dwelling and fractions thereof serve as a proxy for the costs of maintenance, refurbishment, replacement, and new construction. Current levels of refurbishment reduce national average costs to sustain dwelling services by a magnitude of 15%. Potential reductions in national costs are modest (5%) should the housing stock be stationary, but are negligible when the expansion rate of the housing stock is as high as 2.0% per year. A decline in the expansion rate of a housing stock has a greater impact on reducing national costs than an increase in the number of cycles of refurbishment.     

Developing a methodology to recover the cost of wastewater reuse: A proposal based on the polluter pays principle

In this study, we propose a cost recovery model for a wastewater treatment and reuse process based on the polluter pays principle that, among other things, provides appropriate incentives for efficient waster use and guarantees its future availability. Finally, the proposed cost recovery model is then applied using date provided by the Wastewater Treatment Plant of Santa Cruz de Tenerife (Canary Island, Spain). Using the tariff system proposed in this article for wastewater reuse, citizens would become aware of the financial investments involved in this process with the consequent impact on saving water, which would then help maintain reserves.     

Governing the project process: a conceptual framework

There has been considerable development in a process approach in construction management research in recent years. However, such work begs the question of how those processes are governed. Processes, be they flows of information or materials, need to be channelled in the desired direction as they are handed from team to team. This paper aims to present a conceptual framework for understanding the governance of construction project processes, drawing on transaction cost economics. Earlier attempts to apply this theoretical framework in construction management research have been partial, in that they have focused on only one type of transaction, typically that between client and principal contractor. This paper aims to be comprehensive in covering all the different transactions throughout the project lifecycle within one conceptual framework, and thereby it is hoped that more incisive empirical research can be developed and executed.     

Health benefits and costs of filtration interventions that reduce indoor exposure to PM2.5 during wildfires

Increases in hospital admissions and deaths are associated with increases in outdoor air particles during wildfires. This analysis estimates the health benefits expected if interventions had improved particle filtration in homes in Southern California during a 10‐day period of wildfire smoke exposure. Economic benefits and intervention costs are also estimated. The six interventions implemented in all affected houses are projected to prevent 11% to 63% of the hospital admissions and 7% to 39% of the deaths attributable to wildfire particles. The fraction of the population with an admission attributable to wildfire smoke is small, thus, the costs of interventions in all homes far exceeds the economic benefits of reduced hospital admissions. However, the estimated economic value of the prevented deaths exceed or far exceed intervention costs for interventions that do not use portable air cleaners. For the interventions with portable air cleaner use, mortality‐related economic benefits exceed intervention costs as long as the cost of the air cleaners, which have a multi‐year life, are not attributed to the short wildfire period. Cost effectiveness is improved by intervening only in the homes of the elderly who experience most of the health effects of particles from wildfires.     

The Singapore buildable design appraisal system: a preliminary review of the relationship between buildability,site productivity and cost.

This paper presents preliminary findings of a study to examine the relationship between site productivity, construction costs and the ‘buildable score’ of a buildable design appraisal system recently developed by the Singapore Construction Industry Development Board. The buildable score for a building is a numerical figure computed by taking into account the level of standardization, simplicity and extent of integrated elements used in the design of a building. The stated objective of the appraisal system is ‘to promote more buildable designs in the industry through assessing the contribution of design to site efficiency and produc6 tivity’. Empirical results from 37 completed building projects provide support for the appraisal system's proposition that ‘a design with a higher buildable score will result in more efficient labour usage in construction and therefore higher site labour productivity’. However, the relationship between construction costs and buildable score is less distinct.     

A process approach in measuring quality costs of construction projects: model development

One of the most effective tools for evaluating the success of a quality management programme is the measurement of quality costs (prevention, appraisal and failure costs). The application of the concept of quality costs originated in the manufacturing industry in the early 1950s. As increasing attention has been given to improving the overall quality in the construction process since the early 1980s, the application of total quality management (TQM) practices in the construction industry has gained much popularity. A systematic approach is needed for measuring quality costs, especially in the construction industry, due to the great number and complexity of activities involved in a typical project. This paper describes how a simple methodology can be used to capture quality costs in construction projects. Pre-existing models for capturing construction quality costs, by Davis, by Abdul-Rahman, by Low and Yeo and by others, recognize quality cost components but do not address the causes or sources of unwanted deviations. This paper proposes an alternative approach, based on the process cost model and in conformance with BS6143 (1992), which is thought to better facilitate the fundamental goal of TQM, i.e. continual process improvement. A number of professionals involved in construction quality management were interviewed and responded favourably to the practicality of the proposed framework in the construction context.     

纳撒尼尔·利奇菲尔德及其社会影响规划评价理论

介绍利奇菲尔德的背景和他的规划评价的基本理念和方法论,并对其运用于我国城市规划成效评价的可能性和适宜性进行简要分析。以期为探讨和建立符合我国国情的、理性而科学的城市规划评价理论和实践方法提供赋有价值的参考和启示。     

Cost comparison of infrastructure on greenfield and infill sites

Planning policy in most Australian capital cities aims to divert development from the fringe into established inner urban areas. A fundamental logic underlying this policy of land recycling is that State and Local governments are challenged financially to provide appropriate standards of infrastructure and services in greenfield locations. This paper explores the range of infrastructure provision issues and seeks to identify the actual costs of provision in different locations. Three case studies in metropolitan Adelaide are used to explore the cost factors for developers and government. The study highlights the complexity of analysing the infrastructure cost of different developments which arises from variable record keeping and accounting practices. Nevertheless, the study is able to draw conclusions about the relative costs of infrastructure provision in different locations and reinforces previous studies that have demonstrated the higher costs of infrastructure on the fringe as opposed to infill. The estimated infrastructure costs for the infill development case study at Bowden are shown to be approximately one third that of both greenfield and renewal areas of the Playford Alive project on the urban fringe.     

A method for reliability-based economic design of building structures

In limit states design codes for building structures, the load and resistance factors are derived based on a ‘;target’ reliability index, which is determined based on a code calibration process. It is not clear whether the target reliability index selected through the code calibration is optimal with respect to the cost, because through calibration the structural safety is achieved quantitatively while the economic aspects are only considered qualitatively. The intention of the present paper is to formulate a basic approach to reliability-based economic design, based on structural reliability theory. The focus of the paper is to derive an analytical solution to optimized reliability index. A parametric study is conducted for sensitivity analysis of the optimal reliability index to different variables. Finally, the application of the solution to design codes, i.e. determining load and resistance factors in design formulae, is outlined.

Dans les codes de conception d'états limite se rapportant à la construction des structures de bâtiments, la charge et les facteurs de résistance reposent au départ sur un index de fiabilitié ‘cible’, qui est basé sur un processus de calibrage de code. Il n'est pas possible de savoir si l'index de fiabilitié cible choisi par le calibrage de code est optimal en ce qui concerne le coût parce que lors du calibrage, la sécurité structurelle est évaluée de façon quantitative. L'objectif de cet article est de formuler une appréciation de référence sur la conception reposant sur la fiabilité économique, basée sur la théorie de fiabilité structurelle; le point fort de ce texte est de trouver une solution analytique afin d'optimiser l'index de fiabilité. Une étude paramétrique est conduite pour analyser la sensibilité de la fiabilitié optimale de l'index par rapport aux diffeérentes variables. Au total, est proposée une solution consistant à concevoir des codes, c'est-à-dire la détermination de la charge et des facteurs de résistance sous l'aspect de formules.