BIM as a tool to quantify the impact of change on labour productivity

[摘要] ENGLISH ABSTRACT: South Africa, when compared to the rest of the world has been relatively slow in implementingBIM technologies. This study aims tond a new way in which BIM may address problems inconstruction associated with project change. By analysing Variation Orders (V.O.s) and theassociated delay and disruption events, it was found that there exists an unforeseen impact ofchange on labour productivity. Although some contractors are aware of the reduced productivityassociated with changes in construction, it is di cult to prove and, furthermore, di cult toquantify.This study analyses existing literature that suggests methods for quantifying the impact ofchange on labour productivity. However, the current methods are awed. Most of the methodsare used upon completion of a project to resolve thenancial di erences caused by multiplechange orders. The reliability of each model is determined by the reliability of source data used.Furthermore, this data will depend on the scope of work, types of work observed (trades) as wellas the data analyses technique used (Sanders and Nagata 2003). A study by others suggests amethod of using both a discrete and cumulative analyses to predict the impact of change. Thismethod, by others was used as the basis for a proposed BIM plug-in which directs contractorsto existing studies and quanti cation methods for factors inuencing productivity. However, itis unreasonable to expect that a contractor would have heard of, or have access to these studies.The BIM solution is used to integrate the current methods into a supplementary BIM program,or plug-in, that may allow a contractor to easily access the necessary information to predict theimpact of change on labour productivity for their relevant project. The BIM process developedis implemented in a case study where the change impact is quanti ed and compared to originalcontractor estimates. It was found that for three changes that occurred during the case study,there was an unforeseen impact on cost and time. The proposed method calculated that labourcosts increased by 6% and there was a four day delay due to the cumulative impact of change.Subsequently, the case study and developed model was validated by consultation with industryprofessionals for criticism and recommendations as to how the BIM plug-in should be developed.The participants in the validation process agreed that it is a tool that they would use once the challenges have been corrected. The model was criticised for the platform in which it waspresented (Revit). It was recommended that the plug-in be developed as a quantity surveyingtool to be used through Navisworks. Nevertheless, the participants identi ed the plug-in as auseful management tool to visually communicate changes and its e ect amongst project parties.It was also recognised as an objective means to quantifying the impact of change on labourproductivity.BIM can be used to manage the unforeseen impacts of multiple variation orders and quantifythe time and cost impacts of variation orders on productivity.

[发布机构] Stellenbosch University