Finance-based Scheduling for Cash-flow Management of Maintenance Portfolios: Multi-objective Optimization Approach

Bridge agencies are often challenged to develop maintenance programs under
given budgets. Numerous studies developed budget-allocation models for
maintenance programs during defined planning horizons of multiple fiscal years
while totally ignoring the crucial aspect of cash flow. The payment schedules
(both timing and amount) for contractors might indicate agencies’ cash needs
that exceed the available budgets during certain fiscal years, which create cash
flow problems. While numerous finance-based scheduling (FBS) models were
developed to manage cash flow for contractors, this function was totally
overlooked for portfolio owners. Thus, this research reintroduces the FBS from
the perspective of portfolio owners. A FBS model is developed to schedule the
activities of the portfolio projects, utilize the schedules to define the payment
schedules of projects’ contractors, calculate the agencies’ cash needs during the
fiscal years, and utilize the multi-objective optimization algorithms of NSGA-II,
SPEA-II, and MOPSO to optimize the projects’ schedules to achieve a balance
between the cash needs during the fiscal years and the available budgets. The
anticipated extensions in projects’ completion represent the conflicting
objectives. Finally, the optimized schedules make the contractors’ payment
schedules affordable by the agencies’ budgets, which help to complete projects
successfully and achieve the programs’ strategic goals.