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ABSTRACT:
The effective selection/matching and operation of the best excavator-truck systems are paramount to the success of construction operations. In view of the uncertainty inherent in the excavator-truck system, huge front-end costs involved, varying operating and maintenance costs, project managers cannot leave the equipment matching process to chance. Computer simulation involves the use of complex mathematical modeling techniques to duplicate the processes to be optimized. This approach facilitates system analysis, decision support and serves as a cost-effective tool in sensitivity analysis (what-if scenarios) of construction excavation operations. The use of simulation together with best practices approach can lead to the identification of system drivers and aid in the optimization of the entire systems.
KEY WORDS: Computer modeling and simulation, Monte Carlo, and standard deviation
The decision-making process involved in the selection of excavator-truck systems used in construction operations is dynamic and probabilistic. In view of the complexity of the system, simple analytic tools are not fully equipped to handle the optimization of the system. The probabilistic component of the decision-making process does not lend itself to analytical decomposition. Computer modeling and simulation are therefore employed to optimize the excavator-truck system.
Methodology
The two schools of thought on the selection of equipment (e.g., truckexcavator systems) the technological feasibility and economic feasibility schools.
According to the technological feasibility school of thought, a project manager should select the best equipment based solely on the technological features and capabilities of the equipment without regard to the economics of the operation. This is applicable to cost-plus, specialized and government-sponsored projects. The discount rates employed by governments are generally lower than the market rate.
The economic feasibility school of thought involves application of project economics to select the best equipment for the project. Best in this case entails cost minimization or profit maximization. It is generally assumed that there is a pool of equally capable equipment but the equipment of choice is the one that can be operated at the minimum cost and/or will yield the maximum returns to the corporate entity.
Resources are limited and a company's investment or engagement in the most lucrative project is considered the best strategic plan. The discount rate employed is the market rate plus a risk factor. The economic feasibility paradigm is employed...