American Society of Civil Engineers


Algorithm for Time-Cost Tradeoff Analysis in Construction Projects by Aggregating Activity-Level Singularity Functions


by Shannon B. Terry, (Department of Civil Engineering, Catholic University of America, 620 Michigan Avenue NE, Washington, DC 20064 E-mail: 15terry@cardinalmail.cua.edu) and Gunnar Lucko, (Department of Civil Engineering, Catholic University of America, 620 Michigan Avenue NE, Washington, DC 20064 E-mail: lucko@cua.edu)
Section: Construction Planning, Control, and Risk Management, pp. 226-235, (doi:  http://dx.doi.org/10.1061/9780784412329.024)

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Document type: Conference Proceeding Paper
Part of: Construction Research Congress 2012: Construction Challenges in a Flat World
Abstract: Construction projects often encounter challenges during their execution that require careful mitigation - construction managers must optimally accelerate selected critical activities to still meet the deadline, but at an increased cost. The objective of a time-cost tradeoff is to identify options that balance these two counteracting factors. The dependency structure of schedules combined with often non-linear timecost relationships of their activities make tradeoff a complex problem. It eludes direct solution, but can be addressed algorithmically. Previous approaches could only model discrete relationships of activities and costs for network schedules. Linear schedules facilitate short project durations, but lack such methodology. This paper thus explores how versatile singularity functions, which capture changes in output for given ranges of input, can be used to enable tradeoff in linear schedules. It examines if it is feasible to establish the tradeoff curve for the overall project from the individual cost slopes at the activity level and illustrates its newly developed algorithm in a worked example.


ASCE Subject Headings:
Construction management
Project management
Algorithms
Time factors
Construction costs