Analytical Survey of Construction Change Systems: Gaps & Opportunities

AbstractThis paper surveys the studies on construction change systems and reveals some of the potential future works. It is tried to pick up the critical works to derive a true timeline of the systems. The findings show that leaping from best practice guides in late 1990s and generic process models in early 2000s to very advanced modelling environments in mid 2000s and early 2010s have made gaps along with opportunities for change researchers in order to develop some more easy and applicable models. Another finding is that there is a compelling similarity between the change and risk prediction models. So, integrating these two concepts, specifically from proactive management point of view, may lead to a synergy and help project teams avoid rework. Also, the findings show that exploitation of cause- effect relationship models, in order to facilitate the dispute resolutions, seems to be an interesting field for future works

A game theory approach for optimum strategy of the owner and contractor in delayed projects

Delay is one of the problems occurring between owners and contractors. Deviation from base plans can be found using project control methods, continuous assessment of the schedule, determining progress percentages and earned value parameters. In such circumstances, conflicts might arise between contractor and owner as restoring project’s original schedule needs added expenditures by the contractor. Moreover, continuation of the previous procedure and late completion of the project will cause the owner damage. In this research, a mathematical model using game theory has been presented. The model investigates the behaviour and strategies of the parties involved in a delayed project through bargaining. It helps owners and contractors gain deeper understanding of the given delay problem, get a fairly accurate analysis of their situation and consider possible strategies in facing with such circumstances without spending a long and inconclusive time. The points which both parties can agree rationally proposed with a numerical example. Results of the model indicate that parameters involved in the problem are effective in changing the range width of negotiation. In special cases, such as disproportionate delay penalty, these parameters even make it neutral in negotiation. Step by step analysis of the model showed which features can threaten negotiation

Cash flow forecasting with risk consideration using Bayesian Belief Networks (BBNS)

Cash-flow management is very important for contractors given that inadequate cash resources typically are the main causes for bankruptcy of construction companies. In comparison to most other industries, the construction industry is severely plagued by risk, and the success of construction projects usually depends on valuating all risks. However, conventional methods suggested by extant research on cash flow forecasting do not consider comprehensive identifica­tion of risk factors, interactions between the factors, and simultaneous occurrences of the factors. This study introduced a simple and appropriate probabilistic cash flow forecasting model using Bayesian Belief Networks (BBNs) to avoid bankruptcy of contractors by considering influence diagrams and risk factors that affect a project. Workability and reli­ability of the proposed approach was tested on an important building construction project in Iran as a real case study, and the results indicated that the model performed well

Time-cost optimization: using GA and fuzzy sets theory for uncertainties in cost

Uncertainties should be considered in any time-cost trade-off problems when minimizing project cost and duration, which leads to the so-called stochastic time-cost trade-off problem. A new approach to investigate stochastic time-cost trade-off problems employing fuzzy logic theory is presented. The proposed approach fully embeds the fuzzy structure of the uncertainties in total direct cost into the model. An appropriate GA is used to develop a solution to the multi-objective fuzzy time cost model. The accepted risk level of the project manager is defined through α cut approach for which a separate Pareto front with set of non-dominated solutions has been developed. To compare the alternative set of options for any assumed project duration, associated fuzzy costs for different values of α cut are ranked employing two appropriate approaches for fuzzy costs comparison. The proposed models are applied to solve two benchmark test problems. It is shown that the models facilitate the decision-making process by selecting specified risk levels and employing the associated Pareto front.Time-cost, optimization, uncertainties, fuzzy sets, Pareto front,