The planning and design practice involves a lengthy sequence of decisions intended to produce a final outcome. All the improvements are made at every single decision-making point which is a significant improvement over non-model-based planning/design practices. From a contractor's perspective, if an AE is used only for the purpose of producing bids, the benefit is limited. However, if contractors are involved in planning/design processes, as in alliancing agreements, design-build contracts, etc., many estimating activities are required throughout the planning/design process. The benefits to contractors are considered significant compared to non-model-based practices which improve constructability at the planning/design stage. By studying existing documents and through interviews with design engineers, contractors and estimators, we have established that current civil engineering prctices (mainly roads/bridges) do not use model-based planning/design. Drawings are executed in 2D and only completed at the end of lengthy planning/design project management lifecycle stages.
↧