### Nondominated Archiving Multicolony Ant Algorithm in Time-Cost Trade-Off Optimization

Abstract

Time-cost trade-off analysis is addressed as an important aspect of any construction
project planning and control. Nonexistence of a unique solution makes the time-cost
trade-off problems very difficult to tackle. As a combinatorial optimization problem
one may apply heuristics or mathematical programming techniques to solve time-cost
trade-off problems. In this paper, a new multicolony ant algorithm is developed and
used to solve the time-cost multiobjective optimization problem. Pareto archiving
together with innovative solution exchange strategy are introduced which are highly
efficient in developing the Pareto front and set of nondominated solutions in a time-cost
optimization problem. An 18-activity time-cost problem is used to evaluate the
performance of the proposed algorithm. Results show that the proposed algorithm
outperforms the well-known weighted method to develop the nondominated solutions
in a combinatorial optimization problem. The paper is more relevant to researchers who
are interested in developing new quantitative methods and/or algorithms for managing
construction projects.