A new earthworks estimating methodology

Abstract

Earthworks and earthmoving operations are a major part of many civil engineering construction projects. Because of their labour and plant intensity, the planning and estimating of such operations is crucial to both the cost and duration of the project; earthworks are considered by many practitioners to be indicators to the success or failure of the project as a whole. Traditionally, a mixture of manufacturers' data (through published charts or computer databases) and historical company data are used in the estimating of earthworks. This process has two main drawbacks. First, plant haul velocity is dependent on the rolling resistance at the soil-wheel interface, which is notoriously difficult to determine; second, the stochastic interface between types of plant provides a non-deterministic system, resulting in estimates of output which may be unrealistically high. An alternative system of earthworks estimating is presented based on a combination of work undertaken in both the soil/vehicle and stochastic estimating fields. This system is demonstrated via a case study based on an actual highway project. The main conclusion to be drawn is that the traditional estimating approach results in a scheme costed well below realistic values.

Keywords:

• Earthworks
• Hauling
• Rolling Resistance
• Earthmoving Plant
• Plant Cycle Times