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This issue This issue promotes the need for research studies with a systemic view of the construction industry, following recent high-profile construction failures. The Grenfell disaster inquiry is currently uncovering failures in the construction industry in the UK, such as how construction products are marketed, tested, and regulated. As the industry embarks on the new challenges associated with larger buildings, innovative designs and new construction products, and as we orientate towards a low carbon built environment future, it is perhaps more important than ever to learn from previous failings that will help equip the industry for the journey ahead. Guest Editors: David Oswald (Senior Lecturer, RMIT University, Australia) Léon olde Scholtenhuis (Assistant Professor, University of Twente, Netherlands) Trivess Moore (Senior Lecturer, RMIT University, Australia) Simon Smith (Reader, University of Edinburgh, UK) More than 4 years after the UK Grenfell Tower tragedy in 2017, the ramifications of the failures continue to reverberate across the building industry and policy makers globally. [Extracted from the article]

Archaeological remains around the world are testament that large-scale construction projects have been successfully carried out for millennia. This success is particularly evident through the great infrastructural works of the Roman Empire. Yet, it was when the capital was moved from Rome to Constantinople that the largest of these projects was undertaken. This megaproject of the fourth- and fifth-century water supply was made of hundreds of kilometres aqueduct channels and bridges that brought fresh water to the city’s complex system of reservoirs and cisterns. Unlike projects of the previous centuries, we are left with no written record of how this titanic project was undertaken and existing archaeological and historical commentaries on structures of this period do not provide details of organization of construction. We explore the nature of building Constantinople’s water supply through diverse sources of knowledge and the application of agent-based modelling - a method for simulating the actions, interactions and behaviours of autonomous agents and the resulting emergent properties of the system in which they are a part. This paper demonstrates the ability of ABM to develop and test richer hypotheses about historical construction organization and management than physical and historical evidence on their own. [ABSTRACT FROM AUTHOR]

Large construction projects frequently operate with multi-national workforces, utilizing migrant workers to provide both skilled and unskilled labour. Multi-national workforces are also brought together through joint ventures, as companies from different countries collaborate and share their expertise to construct large and complex construction projects. A multi-national joint venture in the UK provides the case study for an examination of the safety management challenges found on such projects. Whilst language and communication issues amongst workers are typically primary concerns, here they have not been prioritized. Instead, findings are presented that illuminate more nuanced and unquantifiable problems that faced the safety management team. An ethnographically informed approach was mobilized, with the lead researcher spending three years on the site with the safety team gathering data. Analysis revealed several challenges: problems with non-UK company compliance with UK legislation and standards; differences in working practices amongst both non-UK workers and their managers; differences associated with national cultures; and problems of poor worker welfare. It is suggested that awareness of these challenges should inform both the way in which such projects are initially contracted, as well as the development of more sophisticated safety management systems that better support multi-national construction projects in practice. [ABSTRACT FROM AUTHOR]

An introduction is presented in which the editors discuss various articles within the issue selected from the 30th Annual Association of Researchers in Construction Management Conference on topics including business models, carbon mitigation in buildings and Australian construction sector.

Hazard identification is fundamental to construction safety management; unidentified hazards present the most unmanageable risks. This paper presents an investigation indicating the current levels of hazard identification on three U.K. construction projects. A maximum of only 6.7% of the method statements analyzed on these projects managed to identify all of the hazards that should have been identified, based upon current knowledge. Maximum hazard identification levels were found to be 0.899 (89.9%) for a construction project within the nuclear industry, 0.728 (72.8%) for a project within the railway industry, and 0.665 (66.5%) for a project within both the railway and general construction industry sector. The results indicate that hazard identification levels are far from ideal. A discussion on the reasons for low hazard identification levels indicates key barriers. This leads to the presentation of an Information Technology (IT) tool for construction project safety management (Total-Safety) and, in particular, a module within Total-Safety designed to help construction personnel develop method statements with improved levels of hazard identification. [ABSTRACT FROM AUTHOR]

The process of concrete supply and delivery exhibits traits of random nature, which render control arduous. This random nature allows concrete placement operations to be considered as a stochastic system and therefore cannot be analyzed by deterministic techniques. In modeling the process realistically, it may be necessary to recreate the variability through fitting a sufficiently flexible theoretical probability distribution to observed data. There is a significant body of work relating to the probability distributions which represent general construction activities. However, there is a lack of literature aimed at determining the optimum representative of the concrete placement process. Therefore, the aim of this paper is to identify a sufficiently flexible representative of this process. To this end, construction data were collected from a number of concrete pours in Scotland, U.K. To identify a suitable distribution in this context, a computer package, PDFit, is presented. It is founded upon the production of probability density functions of select theoretical probability distributions plotted against the histogram of the input data. The principal method of assessment is a visual comparison of the shape of the probability density function and the input data histogram. This paper presents the lognormal distribution as a sufficiently flexible theoretical probability distribution to represent the concrete placing process. [ABSTRACT FROM AUTHOR]

Discrete-event simulation has been used extensively in the past to analyse construction operations and has been shown to be an effective tool for improving construction process planning. Unfortunately, the widespread application of simulation has been prevented, in part, by the requirement for the developer and user to understand the stochastic features of the process. Further, if the stochastic inputs are not representative of the real system, the simulation output will be misleading. This article proposes that case-based reasoning (CBR) could be used to: improve the input and output data of a simulation model and remove the requirement for a user to have specialist statistical knowledge of the process. Case-based reasoning works by solving new cases from knowledge stored in a case base. Two models are presented in this article: a discrete-event simulation model, MatSim, and a hybrid CBR-simulation model, CBRSim. Both models were developed using real construction data. The models were compared to measure any improvements in simulation output, by using a CBR suggested input. Data from an independent construction project were used to test both models, and the results indicate that CBRSim can achieve estimates of observed values that are more accurate and reliable than those from MatSim. [ABSTRACT FROM AUTHOR]

The estimation of productivity rates in cyclic construction processes is a difficult, but essential task in the planning of construction projects. The conventional method—a calculation by intuition—for devising such estimates is often laborious and inaccurate. To overcome these difficulties this paper proposes that Case-Based Reasoning could be employed to provide estimates from historical cases of construction. To this end a model, Case-Based Estimator (CBE) is presented. CBE is a small model, consisting of five input features, one output and a small case base, and it is suggested that the findings within this paper could be applied to any small model of similar characteristics—not only within the construction field. The development and implementation of the model is discussed and an experiment was performed to assess the ability of two retrieval mechanisms (one a simple mathematical formula, the other an adaptation of the ID3 decision tree generating algorithm) to measure similarity. The simple formula was found to be more preferable, both in terms of consistency and development effort.CBE was validated, not only against the performance of past operations (which were not used in the model development), but also against estimates provided by a professional construction planner. The model was found to provide more precise and consistent estimates than the planner, with 90% of the estimates being within a 10% relative error of the observed value. However, CBE did not perform as accurately when estimating operations which were thought to occur only rarely (outliers). [Copyright &y& Elsevier]

With an increasingly competitive global market, the UK construction industry finally realised that in order to survive, a marked increase in efficiency and effectiveness have to be achieved in all areas. This paper will describe the UK's approach to planning and designing the concrete operations that form a major part of many civil engineering construction projects. A productivity study has been carried out on three different construction projects and over 200 concrete pours have been observed. The data and knowledge collected on site have been subjected to lean construction philosophies, producing a "lean" measure of productivity" and it has been shown that major productivity increases could be achieved by implementing several relatively simple principles. [ABSTRACT FROM AUTHOR]

Concrete operations include various processes such as batching, transport and placement all of which are subject to unplanned disruptions and irregularities. The problem of accurately estimating the productivity of concrete operations is not a new one and unless a definitive model is developed it is unlikely that the efficiency and effectiveness of these operations is improved. The problem is exacerbated by the poor understanding of some of the key characteristics involved in concrete operations, which is one of the most common operations in today's construction industry. This paper presents a multiple linear regression analysis based on data collected on a major civil engineering project in the North-East of Scotland involving three smaller projects. From the three sites, a total of 202 separate concrete operations were observed for the entirety of the process, thus supplying a generous set of data recording multiple cycles. The results show a strong linear relationship between the chosen operating conditions and productivity. The derived model is then validated using data collected on a different site with some interesting and favourable findings. [ABSTRACT FROM AUTHOR]

Earthworks and earthmoving operations are a major part of many civil engineering construction projects. Because of their labour and plant intensity, the planning and estimating of such operations is crucial to both the cost and duration of the project; earthworks are considered by many practitioners to be indicators to the success or failure of the project as a whole. Traditionally, a mixture of manufacturers' data (through published charts or computer databases) and historical company data are used in the estimating of earthworks. This process has two main drawbacks. First, plant haul velocity is dependent on the rolling resistance at the soil-wheel interface, which is notoriously difficult to determine; second, the stochastic interface between types of plant provides a non-deterministic system, resulting in estimates of output which may be unrealistically high. An alternative system of earthworks estimating is presented based on a combination of work undertaken in both the soil/vehicle and stochastic estimating fields. This system is demonstrated via a case study based on an actual highway project. The main conclusion to be drawn is that the traditional estimating approach results in a scheme costed well below realistic values. [ABSTRACT FROM AUTHOR]

Risk management is fundamental to the success of a major project. However, the variations in using risk management practices are considerable and are dependent on numerous factors such as the industry sector, the size of the project, and the stage in the project life cycle. One of the major constituents of successful risk control is the use of risk response. This paper concentrates on the choice and use of the most successful risk response techniques within the oil and gas industry and compares them with the use of those chosen by the construction industry. Results were ascertained through a survey of over one hundred companies within these two sectors by use of an extensive questionnaire. The main conclusions are that risk reduction as a response to assessed risks is most commonly used by both sectors; and that the construction industry concentrates almost exclusively on reduction of financial risk. It is proposed that the construction industry can benefit greatly from the more experienced oil and gas industry in managing technical risk which, with the advent of private finding, is likely to become a more predominant part of construction procurement. [ABSTRACT FROM AUTHOR]

Many large construction organisations use safety observation reporting (SOR) as part of their safety management system on sites, although research around their effectiveness in practice is limited. During an ethnographically-informed research project, the lead author spent three years working with the health and safety team on a large (+£500 m) construction project in the United Kingdom with such a system in place. The SOR system encouraged everyone on site to report unsafe acts or conditions, either via computer or handwritten cards, for subsequent action by the health and safety team. Despite good intentions, problems with the SOR system emerged. These included: significantly increased administration to deliver predictable data; poor data quality; an unwelcome focus on the number rather than content of the reports; their use as a tool to ascribe individual or organisational blame; and the perception that the SOR forms were being censored before they reached the health and safety team, which ultimately eroded trust between the workforce and management. Overall, the system as implemented on this site had the potential to cause more harm than good, and both disengage the workforce and frustrate the health and safety team. Although presented as a case study, it is suggested that the research methods used here have been able to expose and illuminate issues that would otherwise go unreported. It is recommended that these issues be considered within the design and implementation of such SOR systems in the future. [ABSTRACT FROM AUTHOR]

Abstract: The ready mixed concrete delivery system is a common construction process in a very wide range of construction projects. The ability of the planners and estimators of such projects to accurately determine the level of resources needed, and to estimate the output of an efficient and effective operation is highly important and thus modeling of the process can be useful. This paper presents a Neural Network methodology to the modeling problem and outlines the two main architectures employed: a feed-forward network and an Elman network. Many combinations of layers, training algorithms, number of neurons, activation functions and format of data were considered and the results were validated using an independent validation data set with five goodness-of-fit tests. The results indicate that two- and three-layer feed-forward networks provide the best estimates of concrete placing productivity and that the Elman network, not previously considered in this type of study, was less successful. [Copyright &y& Elsevier]

• The paper explores the consequences of sub-optimal cost-safety trade-offs. • An ethnographic approach is used to complement prior quantitative cost-safety studies. • We demonstrate how low-winning tender bids can elevate safety risks. • The construction industry is currently structured for unsafety. • There is a critical need to rethink the industry's competitive bidding practices. Construction accidents can have major social, financial, reputational and legal implications. Hence, it is to be expected that safety is often presented as a key priority for construction organisations. However, existing evidence suggests that within the construction industry, safety often loses the battle when a trade-off is required with project cost. Improved understanding of the manifestations of the cost and safety interaction are needed. A three-year longitudinal study afforded the opportunity to investigate the safety implications of sub-economic bids on a large infrastructure project in the UK. While low-bidding to win tenders is not new, this paper presents empirical evidence of the consequential safety risk implications of such bidding at the project delivery stage. Faced with a perverse form of the tender 'Winner's Curse' where the successful bid is frequently the lowest, cost-saving strategies are often implemented to recoup lost pricing margins. Our investigation revealed several instances of consequentially elevated safety risks, through cheaper and poor-quality equipment, machinery and temporary structures. In addition, lower-paid migrant workers – who already experience a statistically greater safety risk than local workers – were employed on the project without appropriate investment in a safety management approach suitable for a multinational workforce. The study both contributes to the call to critically rethink the construction industry's competitive bidding practices, and highlights an industry structure that creates the conditions for high safety risks and accidents. [ABSTRACT FROM AUTHOR]