Stochastic Construction Time-Cost Trade-Off Analysis

Abstract

Traditional time-cost trade-off analysis assumes that the time and cost of an option within an activity are deterministic. However, in reality the time and cost are uncertain. Therefore, in analyzing the timecost trade-off problem, uncertainties should be considered when minimizing project duration or cost. Simulation techniques are useful for analyzing stochastic effects, but a general strategy/algorithm is needed to guide the analysis to obtain optimal solutions. This paper presents a hybrid approach that combines simulation techniques and genetic algorithms to solve the time-cost trade-off problem under uncertainty. The results show that genetic algorithms can be integrated with simulation techniques to provide an efficient and practical means of obtaining optimal project schedules while assessing the associated risks in terms of time and cost of a construction project. This new approach provides construction engineers with a new way of analyzing construction time/cost decisions in a more realistic manner. Historical time/cost data and available options to complete a project can be modeled, so that construction engineers can identify the best strategies to take to complete the project at minimum time and cost. Also, what-if scenarios can be explored to decide the desired/optimal time and/or cost in planning and executing project activities. FIG. 1. Typical Discrete Relationship between Time and Cost of Activity

A mathematical model for crashing projects by considering time, cost, quality and risk

“…The main problem was that the time and cost uncertainties were not considered in the study. In an effort to solve this problem, Feng et al (2000) studied time and cost in an atmosphere of trade off uncertainty. Sakellaropoulos and Chassiakos (2004), in order to present a solution using realistic project features such as the interrelationship of the activities and external constraints, introduced a time-cost integer linear programming model, in a bid to minimize cost.…”

Minimization of direct costs in the construction of torrent control structures

“…Heuristic methods with less computing effort solve the problem, but they do not guarantee the optimal solution as opposed to the method of mathematical programming such as linear programming non-linear programming, mixed-integer linear programming integer or dynamic programming [23].…”

Time, Cost, and Environmental Impact Analysis for Sustainable Design at Multiple Building Levels

“…Many research studies were conducted to solve and examine the relationship between them (e.g., Hegazy, 1999;Feng et al, 2000;Leu et al, 2001;Chan, 2001;Choudhury & Rajan, 2003;Eshtehardin et al, 2009;Sonmez & Bettemir, 2012). In general, the trade-off relationship between time and cost is well understood and there is ample research on the subject.…”

“…Several studies acknowledged the effect of uncertainties in multi-objective models (e.g., Ghanmi et al, 2007;Feng et al, 2000). Bruni et al (2011) Marseguerra et al, 2002), modeling knowledge management performance measurement (Kuah et al, 2012), and managing spare part inventories (Marseguerra et al, 2005).…”

“…However, current optimization procedures do not consider data uncertainties in productivity, environmental impact, and unit costs of labor, building materials, and equipment; therefore, it is not known how data uncertainties may impact the determination of optimal solutions. Research carefully acknowledged the effect of uncertainties in multi-objective models (e.g., Ghanmi et al 2007;Feng et al 2000). Bruni et al (2011) addressed the importance of uncertainty and the availability of resources as a constraint to the project's schedule.…”