Search results

Refurbishment is inherently more sustainable than building new. However, planned and actual costs of refurbishment projects are bound to vary due to the complex nature of most such projects. This can affect the performance of refurbishment work. The purpose of this paper is to examine factors responsible for elemental cost variations between the actual and planned costs of refurbishment projects. The study also examines factors that contribute to differences in actual and planned cost between refurbishment and new build projects.

A quantitative approach was adopted for this study. A literature review identified factors responsible for elemental cost variations in refurbishment projects, as well as factors responsible for differences in actual and planned cost of new build and refurbishment projects. This was followed by a questionnaire survey of refurbishment projects across Malaysia. A total of 55 respondents provided input through a questionnaire survey to identify these factors.

This study demonstrates that procurement strategy (PS), inappropriate contractors (IC), poor project management (PPM), availability of funding, materials and equipment, and force majeure (FM) significantly affect refurbishment cost performance. Electrical installations, firefighting equipment, and painting were the building elements most affected by cost variations. A regression model for refurbishment cost prediction indicates that PS, IC, PPM, availability of funding, materials and equipment, and FM were significant predictors of building refurbishment cost performance.

This paper provides insight into the major factors affecting elemental cost variation of refurbishment works, as well as building elements most affected by cost variations and provides a model for predicting refurbishment cost performance.

There has been a lack of research, particularly within the New Zealand (NZ) context, focusing on the identification and assessment of risk factors for construction projects, leading to a wide variation between design-phase elemental cost plans (ECPs) and the outturn tender sums (OTS). Still to be investigated is how risks interact to produce such variability. This study aims to determine the risk-influencing factors, identified through risk measurement, during design development.

This study adopted literature review and online questionnaire survey. The literature review was used to identify the factors affecting project budgetary performance, which was used to design the questionnaire survey culminating in data analysis. The questionnaire was administered to 64 practising project managers (PMs) in NZ. Their responses were analysed using descriptive statistics, mean ranking analysis, degree-of-risk measure and correlational analysis, to find the top-five risk factors impacting the variability observed, through ranking the mean and degree of risk values that produce such variability.

Significant risk factors were identified from the questionnaire survey analysis, such as changes in project owner/stakeholder requirements, experience of project team, site condition information, competency of consultants and information flow and quality. These provided some insights in explaining the variability between the design-phase ECPs and OTS based on risk impacts from PMs’ viewpoints.

Findings revealed a drift of 23.86% in budgeted costs (inflated risks), which seems significant. Prioritising top risk factors may provide handy information for researchers on the variables that could be relied upon for the development of a forecasting model for application in NZ.

The study findings have implications for PMs seeking to provide information on mitigation strategies by using risk management approach, considering the influence of development risks on building project delivery and, consequently the project owner’s financial position. To guard against wide variation between design-phase ECPs and OTS, the main contribution of this study is to raise consultants’ awareness of the important risk factors for their planning at the outset, thus assisting PMs in pro-actively managing their clients' budgets.

This study creates value by synthesising literature on construction project budgeting and highlighting areas for further research. By giving adequate attention to key risks associated with budget overruns in commercial projects, variability between ECPs and OTS, a common phenomenon in NZ, can be controlled to achieve cost savings. Based on this, further study suggests the development of a model that could assist the stakeholders in NZ to more reliably predict OTS from the design-phase ECP and pro-actively avoid unfortunate budget/cost overruns, disputes and even project abandonment.

The study aims to find out an appropriate volume of power to be procured through long-term power purchase agreements (PPAs), the volume to be sourced from the power exchange through day-ahead and term-ahead options and also a suitable volume to be sold at different points of time within a day, which would finally lead to the optimum cost of power procurement.

The study has considered a Delhi-based power distribution utility and has collected all relevant data from its archival sources. A stochastic optimization model has been developed to capture the problem of power procurement faced by the distribution utility, which is modelled as a mixed integer linear programming problem. Sensitivity analyses were carried out on the important parameters including hourly demand of power, unit variable cost of power available through PPAs, maximum back-down percentage allowed under PPAs, etc., to investigate their impact on daily cost of power under PPAs, daily cost of power under day-ahead and term-ahead options, daily sales revenue and also the net total daily cost of power procurement.

The findings include the appropriate volume of power procured from different suppliers through PPAs and from the power exchange under day-ahead and term-ahead options and also the surplus volume of power sold under the day-ahead arrangement. It has also computed the total cost of power purchased under PPAs, the cost of power purchased from the power exchange under day-ahead and term-ahead options and also the revenue generated out of the sale of surplus power under the day-ahead arrangement. In addition, it has also presented the results of sensitivity analyses, which provide rich managerial insights.

The paper makes two significant contributions to the existing body of power procurement literature. First, the stochastic mixed-integer linear programming model helps decision makers in determining the right volume of power to be purchased from different sources. Second, based on the findings of the procurement model, a power procurement framework is developed considering the dimensions of uncertainty in power supply and the cost of power procurement. This power procurement framework would aid managers in making procurement decisions under different scenarios.

Using Nigeria, as a point of reference, this study aims to explore the applicability of climatic variables as analytically valid factors for conceptual cost estimation. This is in view of the vastness and topographical alignment of Nigeria's landmass, which makes it a country of extreme climatic variability from north to south. As construction costs in Nigeria, similarly, tend to show a north-south alignment, the study's objective is to establish cost-estimating relationships (CERs) between the variability of climatic elements and the variance in construction cost, to arouse interest in the concept.

Deploying correlation analysis and multiple regression analysis, significant associations/relationships between meteorological variables and building cost for selected locations, following a North-South transect of the major climatic zones, are sought, to explain climate-induced construction cost variance. Validation of the regression model was carried out using variance analysis and the Mean Absolute Percentage Error of a different dataset.

Climatic indices of atmospheric moisture exhibited strong direct and partial correlations with construction costs, while sunshine hours and temperature were inversely correlated. The study further establishes statistically significant CERs between climatic variables and building cost in Nigeria, which accounted for 47.9% of the variance in construction cost across the climatic zones.

The study outcome provides a statistically valid platform for the development of more elaborate analytical costing models, for prototype buildings to be cited in disparate climatic settings.

This study establishes the statistical validity of climatic variables in constituting CERs for predicting construction costs in disparate climatic settings.

The aim of this study is to investigate the reasons for disparity between design stage elemental cost plan and final tender sum (contract sum) in building procurement. A number of risk factors responsible for such variation were identified through case study projects from which data were extracted.

Literature review determined the risk factors inherent in the preparation of design stage elemental cost plan. Interviews and thematic analysis identified the risk factors responsible for the disparity between design stage elemental cost plans and final tender sums. Analysis of documents obtained from the archives of study participants (consultant quantity surveyors) complemented responses from the interviews.

The review revealed a number of inherent risks in the design stage elemental cost plan development. The interviews further indicated that risks have an impact on and are responsible for the deviations experienced. The assessment of these risk elements could assist in determining the final tender sum from cost plans.

Findings revealed disparity between elemental cost plans and final tender sums in the region of −14 and +16 per cent. The risk factors identified were responsible for the deviations observed. With this information, Quantity Surveyors are more able to accurately forecast final tender sums of building projects from cost plans through proper risk identification and analysis, thus increasing the accuracy of design stage elemental costing.

To the best of the knowledge of the researchers, there is no recent documentary evidence of an investigation into the reasons for disparity between design stage elemental cost plan and final tender sum in traditional building procurement in New Zealand construction.

This paper reports on the development of a framework for a standardized programme of works for construction projects. A sample of 50 buildings, encompassing a total of 11 different project functions, were surveyed and analysed. The sample was then investigated further to assess the existence of similarities and repeated operations in each individual construction project. A minimum of 20 standardized elemental options were identified. From analysis of the data and the application of practitioners’ expertise, a logical sequence of activities, including their respective dependencies, was produced. A set of six new test projects was used to see if the initial methodology was sound. It could be concluded that despite each project being unique, most buildings retain cognate, elemental options that provide the basis for any structure, and these can be standardized and used as a basis for a universal programme of construction works. The standardization of activities would enable the automation of project planning processes and hence would result in reduced administration and management costs. This will encourage contractors and other project team members to undertake planning at earlier stages of the project, hence providing the basis for more accurate cash flow, duration and cost forecasts.

The impact of ‘context of use’ to the whole life costs (WLC) of building elements has not yet been studied in previous researches. Lack of hard and detailed historical data constrained the use of traditional methods for this purpose. A fuzzy rule‐based system (FRBS) for any type of carpet cleaning cost estimate is one of a series of fuzzy models developed to estimate the WLC of building elements with the consideration of context of use to the elements. The fuzzy reasoning method, as the representation of human reasoning, is applied to WLC for the first time for carpet cleaning cost. The data used are the linguistic judgments from some experienced experts based on interview surveys. The implementation of the model is demonstrated in a case study. The result is assessed by the experts as an acceptable estimate.The paper concludes that Fuzzy Rule Based System is an appropriate method to model running costs of building elements. The model allows user to predict the cost variation of cleaning cost of carpet flooring according to its designed context of use.

To help facilities managers understand the origins and aims of the National Health Service (NHS) asset valuation and capital charging system, of the depreciated replacement cost (DRC) approach to valuation, its strengths and weaknesses and how under devolution the Scottish Health Service is adapting DRC assumptions to meet multiple policy priorities.

This paper examines the history of the system since inception in 1989, as an accounting and FM tool, subsequent debates on problems arising from DRC valuation methodology and recent developments in the Scottish NHS.

The original aim of the capital charging system in 1989 was to adapt a primarily financial accounting system of asset registers to create a dynamic management system to inform facility managers of the opportunity cost of their assets, encourage them to sell obsolete assets and drive modernisation of the estate. In Scotland much modernisation has now occurred. Other issues have emerged to preoccupy managers such as sustainability, preservation in use of historic buildings and concern not to overburden health bodies with an inherited older estate with onerous charges.

The paper presents new historic material identifying trends in the health service and professional thinking. It continues the debate between FM and valuation professionals, central government clients and researchers. The debate has implications for other specialised public sector estates such as prisons, courts, roads and defence and specialised private sector estates valued on DRC.

The paper explains recent developments in the UK's NHS asset valuation methodology in Scotland, and the historic roots of the capital charging system.

A new method for the measurement of the complexity of a facility layout problem is described which can be viewed as the degree of ease (unease) with which a given number of facilities can be optimally arranged. The existing approaches, namely, coefficient of variation and problem complexity rating, do not always produce consistent results. In the proposed approach, a cost matrix is converted into a similarity coefficient matrix and the standard deviation of the elemental values of a similarity coefficient matrix is used to determine layout complexity. The application of the proposed approach is illustrated through examples and the results are shown to be consistent and reasonably acceptable.

In‐plane vibration of a balanced helicopter rotor is caused by variations with azimuth of the in‐plane forces acting on individual blades. These forces may be summarized under three headings: ‘Induced forces’ caused by the inclination of elemental lift vectors relative to the axis of rotation. ‘Profile drag forces’: variations are caused by changes with azimuth angle of the angle and airspeed of the individual blade elements. ‘Coriolis forces’, which are caused by blade flapping, which brings about a variation of blade moment of inertia about the axis of rotation. Equations are developed in this paper for the resultant hub force due to each of these forces, on the assumptions of small flapping hinge offset. It is assumed that blades are linearly twisted and tapered, an assumption which in practice can be applied to any normal rotor. It is shown that by suitably inclining the mechanical axis it is possible to balance out the worst induced and profile drag vibrations by the coriolis one, which can be made to have opposite sign. If the mechanical axis is fixed in the fuselage, this suppression is fully effective for one flight condition only. In multi‐rotor helicopters, vibration suppression can be extended over a much wider range by varying the fuselage attitude. The logical result of this analysis is, for single rotor helicopters, a floating mechanical axis which can be adjusted or trimmed by the pilot. This would be quite simple to do on a tip‐driven rotor, and has already been achieved with a mechanical drive on the Doman helicopter. The more important causes of vibration from an unbalanced rotor are next con‐sidered, attention here being confined principally to fully articulated rotors, which are the most difficult to balance because the drag hinges tend to magnify all in‐accuracies in finish and balance. From a brief discussion of the vertical vibration of an imperfect rotor it is shown that some contemporary methods of ‘tracking’ are fundamentally wrong. Finally the vibration due to tip‐mounted power units is described. In discussing the effect of a vibratory force on a helicopter a simple response chart is developed, and it is thought that its use could well be accepted as a simple standard for general assessment purposes. In the development of equations for vibration the following points of general technical interest are put forward: An equation for induced torque is developed which includes a number of hitherto neglected parameters. A new form of equation for mean lift coefficient of a blade is suggested. The simple Hafner criterion for flight envelopes is shown to give rise to considerable error, and the use of Eq. (28) is suggested in its place. The variation of profile torque with forward speed is given, and the increase due to ? varying round the disk is expressed as an explicit equation, thus allowing considerable improvement in the present methods of allowing for this effect.