5D-based estimation of indirect construction costs

Development of an adaptive automation tool for improved efficiency of the ABK estimation process

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One of the fundamental goals for the success of a construction project is found to be completion within the budget. To reach this goal, cost estimation is a key process which can be divided into the estimation of direct and indirect costs. Unlike direct costs, indirect costs are not directly connected with the performance of any particular element of a project which makes proper allocation of these costs a challenging issue. Although the classification in the ABK model (2018) provides clarity regarding the content of the indirect cost items, estimation of these costs (ABK) and especially the tasks for quantity take-off (QTO) were identified as time-consuming and lacking standardised guidelines and procedures.
At the same time, Building Information Models (BIM), which are increasingly used, offer an effective platform for linking data regarding construction costs. The fifth dimension of BIM in particular adds cost information to the 3D construction model. Full interoperability between the various information models is still a goal that has not been reached yet within the construction sector. Recent studies have examined inefficiencies caused by inadequate interoperability, like manual re-entry of data and duplication of tasks.
This research aims to positively contribute to the efficiency of the indirect cost estimation process by developing a 5D computer-based tool. The development of the tool was based on literature review and interviews with practitioners. Features of BIM applications were used and linked to the outcome of the indirect cost estimate. The tool was able to reduce manual interventions and reduce task durations, which resulted in a positive contribution to the efficiency of the indirect cost estimation process. Main benefits of the tool were hereby the structured guidelines for quantity take-offs, a reduction in manual intervention and time for QTO tasks and implementation of project changes within the outcome of the ABK estimate.