E. Jones and F.G.R. Cook
FROM the conventional wartime under‐carriage consisting of a straight through axle suspended on bracing struts by shock absorber cord has developed the complex modern…
Abstract
FROM the conventional wartime under‐carriage consisting of a straight through axle suspended on bracing struts by shock absorber cord has developed the complex modern undercarriage which is required to absorb the energy of descent, provide smooth taxying and the braking effort, and disappear when not in use. These requirements have brought in their trail a collection of hydraulic, pneumatic and electrical auxiliaries and a comprehensive treatment of the subject would assume some magnitude. This paper therefore summarises existing practice to some extent, and presents some notes on various design aspects which, it is hoped, will prove informative.
Some of the physical and intellectual requirements for management have been outlined, and in table ii, para 3.20, some generally agreed qualities are listed. Items 1 to 3 are…
Abstract
Some of the physical and intellectual requirements for management have been outlined, and in table ii, para 3.20, some generally agreed qualities are listed. Items 1 to 3 are individual and are not easily altered, certainly not at later stages in a career.
RICHARD FELLOWS and ANITA M.M. LIU
This paper supplements and extends consideration of quantitative models with application to building (costs and) prices by examining human elements inherent in modelling. In…
Abstract
This paper supplements and extends consideration of quantitative models with application to building (costs and) prices by examining human elements inherent in modelling. In considering the concepts of modelling, attention is focused on the recently developed sociology of science, which questions the traditional perspective of total separation of a reality from the observer—the ‘objective’ basis of scientific positivism. It is argued that human activities are fundamental in, and inseparable from, reality and so, they are integral in modelling. The aim of modelling should be to enhance understanding and knowledge rather than to secure inert objectivity. Application to modelling of prices of building projects investigates how prices are formulated, which prices are commonly modelled and the impact of the decision‐makers involved. It is concluded that new models are required, perhaps developed through methodological pluralism, which identify people‐oriented variables and assumptions explicitly. Further, the models should be stochastic and with sound bases in theories of economics and human behaviour to ensure that users are aware of the major variabilities in the processes modelled and so, by realistically informing, promote better decision making.
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Mega construction projects (MCPs), characterized by their vast scale, numerous stakeholders and complex management, often face significant uncertainties and challenges. While…
Abstract
Purpose
Mega construction projects (MCPs), characterized by their vast scale, numerous stakeholders and complex management, often face significant uncertainties and challenges. While existing research has explored the complexity of MCPs, it predominantly focuses on qualitative analysis and lacks systematic quantitative measurement methods. Therefore, this study aims to construct a complexity measurement model for MCPs using fuzzy comprehensive evaluation and grey relational analysis.
Design/methodology/approach
This study first constructs a complexity measurement framework through a systematic literature review, covering six dimensions of technical complexity, organizational complexity, goal complexity, environmental complexity, cultural complexity and information complexity and comprising 30 influencing factors. Secondly, a fuzzy evaluation matrix for complexity is constructed using a generalized bell-shaped membership function to effectively handle the fuzziness and uncertainty in the assessment. Subsequently, grey relational analysis is used to calculate the relational degree of each complexity factor, identifying their weights in the overall complexity. Finally, the weighted comprehensive evaluation results of project complexity are derived by combining the fuzzy evaluation results with the grey relational degrees.
Findings
To validate the model’s effectiveness, the 2020 Xi’an Silk Road International Conference Center construction project is used as a case study. The results indicate that the overall complexity level of the project is moderate, with goal complexity being the highest, followed by organizational complexity, environmental complexity, technical complexity, cultural complexity and informational complexity. The empirical analysis demonstrates that the model can accurately reflect the variations across different dimensions of MCP complexity and can be effectively applied in real-world projects.
Originality/value
This study systematically integrates research on MCPs complexity, establishing a multidimensional complexity measurement framework that addresses the limitations of previous studies focusing on partial dimensions. Moreover, the proposed quantitative measurement model combines fuzzy comprehensive evaluation and grey relational analysis, enhancing the accuracy and objectivity of complexity measurement while minimizing subjective bias. Lastly, the model has broad applicability and can be used in MCPs across different countries and regions, providing a scientific and effective basis for identifying and managing MCP complexity.
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It is widely believed that the construction industry is more volatile than other sectors of the economy. Accurate predictions of the level of aggregate demand for construction are…
Abstract
It is widely believed that the construction industry is more volatile than other sectors of the economy. Accurate predictions of the level of aggregate demand for construction are of vital importance to all sectors of this industry (e.g. developers, builders and consultants). Empirical studies have shown that accuracy performance varies according to the type of forecasting technique and the variable to be forecast. Hence, there is a need to gain useful insights into how different techniques perform, in terms of accuracy, in the prediction of demand for construction. In Singapore, the residential sector has often been regarded as one of the most important owing to its large percentage share in the total value of construction contracts awarded per year. In view of this, there is an increasing need to objectively identify a forecasting technique which can produce accurate demand forecasts for this vital sector of the economy. The three techniques examined in the present study are the univariate Box‐Jenkins approach, the multiple loglinear regression and artificial neural networks. A comparison of the accuracy of the demand models developed shows that the artificial neural network model performs best overall. The univariate Box‐Jenkins model is the next best, while the multiple loglinear regression model is the least accurate. Relative measures of forecasting accuracy dealing with percentage errors are used to compare the forecasting accuracy of the three different techniques.
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Bee Lan Oo, Florence Yean Yng Ling and Alexander Soo
Contractors rely on effective pricing methods in order to translate potential business into reality for long-term survival of their firms. This involves effective utilization of…
Abstract
Purpose
Contractors rely on effective pricing methods in order to translate potential business into reality for long-term survival of their firms. This involves effective utilization of bidding feedback information toward winning jobs with high profit potential. The purpose of this paper is to experimentally investigate student (inexperienced) bidders’ competitiveness under full and partial information feedback conditions when the number of competing bidders is large (n=12).
Design/methodology/approach
This paper adopted an experimental research design. The design used between-subjects variation and involved information feedback as the treatment variable with 120 students who enrolled in a cost-estimating course participated in the experiment.
Findings
The result shows that the variations in bids over time for both levels of information feedback are statistically significant. It is found that bidders with full bidding feedback information are more competitive than those with partial bidding feedback information. The bid-spread analysis and the identified effect of these two information feedback conditions on awarded contract sum, provide some further evidence that full information feedback condition would lead to lower average bids in construction bidding.
Practical implications
The implication of the findings for construction clients is that they should provide as much bidding feedback information as possible so that the bid prices will be competitive.
Originality/value
Given the ambiguity inherent in field data, this paper provides strong justification of using experimental research design in advancing the understanding of construction pricing under different information feedback conditions. In addition, it demonstrated the suitability of using student subjects in similar experiments in the context of construction bidding.
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IT has been stated above that the rate of heat transfer is closely proportional to the temperature difference between the plate and the free air stream, and over the laminar…
Abstract
IT has been stated above that the rate of heat transfer is closely proportional to the temperature difference between the plate and the free air stream, and over the laminar portion it will also be proportional to the conductivity of the air. It remains to consider to what extent the actual temperature of the air in the boundary layer will influence the rate of heat transfer. The conductivity of air increases with temperature by reason of the increased molecular velocities, and we might expect, therefore, that the hotter the surface the greater will be the rate of heat transfer per unit of temperature difference above that of the air. This is, in fact, found to be the case.
Abdullahi Babatunde Saka and Daniel W.M. Chan
Building information modelling (BIM) research studies are highly contextual as the contexts provide lenses for interpreting the results. However, there has been a growing…
Abstract
Purpose
Building information modelling (BIM) research studies are highly contextual as the contexts provide lenses for interpreting the results. However, there has been a growing decontextualization in extant studies especially between the small and medium-sized enterprises (SMEs) and large firms; and between developed and developing countries. Albeit these contexts are all in the same construction industry, they often react differently to the same conditions. Thus, this study aims to evaluate the perceptions of firms in varying contexts of size and location on the perceived barriers to the implementation of BIM in the architecture, engineering and construction (AEC) industry.
Design/methodology/approach
The perceptions of 228 firms gleaned from 26 countries across the 6 continents were collated via an international empirical questionnaire survey. The data was analysed using the mean score, rank agreement analysis, Mann-Whitney U test and factor analysis.
Findings
The findings revealed the major factors impending BIM implementation in each of the contexts and a comparative analysis emphasized the difference in their perceptions. The findings underscore that there is a general digital divide as regard BIM implementation between the SMEs and large firms, and a deepening divide between the developed and developing countries.
Originality/value
The study has provided empirical evidence for the BIM divide in the AEC industry, which would influence the promulgation of BIM policy and transferability of best practices across varying contexts of both firm size and country level.
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Olivier Vassart, C. Bailey, M. Hawes, A. Nadjai, W. Simms, B. Zhao, T. Gernay and J.-M. Franssen
This paper describes a full scale fire test performed the 27th of February 2010 on a composite floor for analysing the possibility of tensile membrane action to develop when the…
Abstract
This paper describes a full scale fire test performed the 27th of February 2010 on a composite floor for analysing the possibility of tensile membrane action to develop when the unprotected steel beams in the central part of the floor are made of cellular beams. The natural fire was created by a wood crib fire load of 700 MJ/m2 and the 9 × 15 m floor survived the fire that peaked at 1000°C and lasted for 90 minutes. Blind predictions of the air temperature development by the software OZone and of the structural behaviour by the software SAFIR which proved quite satisfactory are also described.
Alireza Ahmadian Fard Fini, Mojtaba Maghrebi, Perry John Forsythe and Travis Steven Waller
Measuring onsite productivity has been a substance of debate in the construction industry, mainly due to concerns about accuracy, repeatability and unbiasedness. Such…
Abstract
Purpose
Measuring onsite productivity has been a substance of debate in the construction industry, mainly due to concerns about accuracy, repeatability and unbiasedness. Such characteristics are central to demonstrate construction speed that can be achieved through adopting new prefabricated systems. Existing productivity measurement methods, however, cannot cost-effectively provide solid and replicable evidence of prefabrication benefits. This research proposes a low-cost automated method for measuring onsite installation productivity of prefabricated systems.
Design/methodology/approach
Firstly, the captured ultra-wide footages are undistorted by extracting the curvature contours and performing a developed meta-heuristic algorithm to straighten these contours. Then a preprocessing algorithm is developed that could automatically detect and remove the noises caused by vibrations and movements. Because this study aims to accurately measure the productivity the noise free images are double checked in a specific time window to make sure that even a tiny error, which have not been detected in the previous steps, will not been amplified through the process. In the next step, the existing side view provided by the camera is converted to a top view by using a spatial transformation method. Finally, the processed images are compared with the site drawings in order to detect the construction process over time and report the measured productivity.
Findings
The developed algorithms perform nearly real-time productivity computations through exact matching of actual installation process and digital design layout. The accuracy and noninterpretive use of the proposed method is demonstrated in construction of a multistorey cross-laminated timber building.
Originality/value
This study uses footages of an already installed surveillance camera where the camera's features are unknown and then image processing algorithms are deployed to retrieve accurate installation quantities and cycle times. The algorithms are almost generalized and versatile to be adjusted to measure installation productivity of other prefabricated building systems.