A mixed integer model for optimization of discrete time cost tradeoff problem

2016-06-25
Tatar, Ali Can
Bilir, Mert
Sönmez, Rifat
Atan, Sabri Tankut
In construction projects, activity durations can be expedited by allocating additional resources. Decreasing activity durations by means of crashing, usually leads to increase in the direct expenses. This trade-off between time and cost is called as the time-cost trade-off problem. Since in practice many resources are available in discrete units, numerous research has focussed on the discrete version of this problem called the discrete time-cost trade-off problem (DTCTP). Achieving the project schedule that satisfies the project requirements at an optimum cost is crucial for effective scheduling and management of construction projects. Despite the importance of DTCTP, very few research focused on generating and solving of large scale instances. The objective of this proceeding is to generate large scale instances that reflect the size of real-life construction projects and to solve these instances using mixed integer programming method (MIP) to enable a benchmark set with optimal solutions. Within this context, large scale instances that reflect the size of real-life-size construction projects are generated. A MIP model is developed and the majority of the instances is solved to optimal using GUROBI optimizer.
Creative Construction Conference (2016)

Suggestions

A Mixed integer programming method for pareto front optimization of discrete time cost trade-off problem
Bilir, Mert; Sönmez, Rifat; Atan, S. Tankut; Department of Civil Engineering (2015)
There is a reverse relationship between the activity durations and costs in construction projects. In scheduling of construction projects, the project duration can be compressed (crashed) by expediting some of its activities in several ways including; increasing crew size, working overtime, or using alternative construction methods. As a result, when duration of a critical activity is decreased, its cost increases and project duration decreases. In construction projects, resources are usually available in d...
A genetic algorithm for resource leveling of construction projects
Iranagh, Mahdi Abbasi; Sönmez, Rifat (2012-01-01)
Critical path method (CPM) is commonly used in scheduling of construction projects. However, CPM only considers the precedence relations between the activities and does not consider resource optimization during scheduling of projects. Optimal allocation of resources can be achieved by resource levelling. Resource levelling is crucial for effective use of construction resources particularly to minimize the project costs. However, commercial scheduling software has very limited capabilities for solving the re...
A genetic algorithm for the resource constrained project scheduling problem
Özleyen, Erdem; Sönmez, Rifat; Department of Civil Engineering (2011)
The resource-constrained project scheduling problem (RCPSP) aims to find a schedule of minimum makespan by starting each activity such that resource constraints and precedence constraints are respected. However, as the problem is NP-hard (Non-Deterministic Polynomial-Time Hard) in the strong sense, the performance of exact procedures is limited and can only solve small-sized project networks. In this study a genetic algorithm is proposed for the RCPSP. The proposed genetic algorithm (GA) aims to find near-o...
Branch and bound based solution algorithms for the budget constrained discrete time/cost trade-off problem
Degirmenci, G.; Azizoğlu, Meral (2013-10-01)
The time/cost trade-off models in project management aim to reduce the project completion time by putting extra resources on activity durations. The budget problem in discrete time/cost trade-off scheduling selects a time/cost mode for each activity so as to minimize the project completion time without exceeding the available budget. There may be alternative modes that solve the budget problem optimally and each solution may have a different total cost value. In this study we consider the budget problem and...
A Mixed integer programming method for integrated discrete time-cost trade-off and manpower resource leveling problem
Tatar, Ali Can; Sönmez, Rifat; Atan, S. Tankut; Department of Civil Engineering (2016)
Construction projects have to meet all of the objectives of scope, quality, schedule, budget simultaneously. These objectives, however, cannot be considered as independent of each other. For example, an increase in direct resources will usually lead to shorter activity durations. A shorter project duration results in lower indirect costs, whereas the additional resources cause an increase the project’s direct costs, in general. This phenomenon is defined as time-cost trade-off problem (TCTP). Nevertheless, ...
Citation Formats
A. C. Tatar, M. Bilir, R. Sönmez, and S. T. Atan, “A mixed integer model for optimization of discrete time cost tradeoff problem,” Budapest, Hungary, 2016, vol. 1, p. 478, Accessed: 00, 2021. [Online]. Available: http://2016.creative-construction-conference.com/wp-content/uploads/2016/06/CCC2016_Proceedings.pdf.