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

Abstract

ENGLISH ABSTRACT: South Africa, when compared to the rest of the world has been relatively slow in implementing BIM technologies. This study aims to nd a new way in which BIM may address problems in construction associated with project change. By analysing Variation Orders (V.O.s) and the associated delay and disruption events, it was found that there exists an unforeseen impact of change on labour productivity. Although some contractors are aware of the reduced productivity associated with changes in construction, it is di cult to prove and, furthermore, di cult to quantify. This study analyses existing literature that suggests methods for quantifying the impact of change on labour productivity. However, the current methods are awed. Most of the methods are used upon completion of a project to resolve the nancial di erences caused by multiple change 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 well as the data analyses technique used (Sanders and Nagata 2003). A study by others suggests a method of using both a discrete and cumulative analyses to predict the impact of change. This method, by others was used as the basis for a proposed BIM plug-in which directs contractors to existing studies and quanti cation methods for factors in uencing productivity. However, it is 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 the impact of change on labour productivity for their relevant project. The BIM process developed is implemented in a case study where the change impact is quanti ed and compared to original contractor 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 labour costs 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 industry professionals 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 was presented (Revit). It was recommended that the plug-in be developed as a quantity surveying tool to be used through Navisworks. Nevertheless, the participants identi ed the plug-in as a useful 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 labour productivity. BIM can be used to manage the unforeseen impacts of multiple variation orders and quantify the time and cost impacts of variation orders on productivity.

AFRIKAANSE OPSOMMING: Suid-Afrika het Bou Inligtingsmodelle (BIM) relatief stadig ge-implementeer in vergelyking met die res van die w^ereld. Die oogmerk van hierdie studie was 'n nuwe wyse waarop BIM die probleme met veranderinge in konstruksie kan oplos. Deur die ontleding van wysigingsopdragte (V.O.s) en die gepaardgaande vertragings en ontwrigtings is gevind dat daar 'n onbeplande impak van verandering op arbeidsproduktiwiteit is. Alhoewel sommige kontrakteurs bewus is van die verband tussen veranderinge in konstruksieen en die verminderde produktiwiteit, is dit moeilik om te bewys en nog moeiliker om te kwanti seer. Hierdie studie analiseer bestaande literatuur wat metodes vir die kwanti sering van die impak van verandering op arbeidsproduktiwiteit voorstel. Die huidige metodes is egter gebrekkig. Die meeste metodes word gebruik by die voltooiing van 'n projek om die nansi ele verskille veroorsaak deur verandering op te los. Die betroubaarheid van elke model word bepaal deur die betroubaarheid van die bron data gebruik. Verder sal hierdie inligting afhang van die omvang van die werk, tipes werk waargeneem (ambagte) asook die data ontleed tegniek gebruik (Sanders and Nagata 2003). 'n Studie deur ander navorsers dui op 'n metode deur die gebruik van diskrete en kumulatiewe ontledings om die impak van verandering te voorspel. Hul metode is gebruik as die basis vir 'n voorgestelde BIM toepasting vir kontrakteurs om bestaande studies en kwanti serings metodes te gebruik om produktiwiteitsfaktore aan te pas. Dit is egter onredelik om te verwag dat 'n kontrakteur bekend sou wees van, of toegang sal h^e, tot hierdie studies. Die BIM benadering word in hierdie studie gebruik om die bestaande metodes in 'n aanvullende BIM program, of toepassing, te intergreer. Dit kan 'n kontrakteur toelaat om maklik toegang tot die nodige inligting te verkry om die impak van verandering op arbeidsproduktiwiteit vir 'n projek te voorspel. Die ontwikkelde BIM proses word toegepas in 'n gevallestudie waar die impak van veranding gekwanti seer word en vergelyk word met die oorspronklike beplanning. Dit is gevind dat daar 'n onbeplande impak op koste en tyde is vir drie veranderinge wat tydens die gevallestudie plaasgevind het. Die voorgestelde metode bereken dat arbeidskoste met 6% styg en dat daar 'n vier dae vertraging is as gevolg van die kummulatiewe impak van veranderinge. Daarna is persone in die konstruksie bedryf genader vir kritiek en vir aanbevelings ten opsigte van hoe die BIM toepassing ontwikkel kan word. Die deelnemers van die veri kasie proses het bevestig dat dit 'n instrument is wat hulle sou gebruik wanneer die veranderinge aangebring is. Die model is gekritiseer vir die platform waarop dit aangebied is (Revit). Daar is aanbeveel dat die toepassing ontwikkel word as 'n bourekenkunde hulpmiddel deur die gebruik van Navisworks. Nogtans het die deelnemers die toepassing as 'n bestuurshulpmiddel bevestig. Daar is ook erkenning gegee dat dit gebruik kan word om die arbeidsproduktiwiteit te kwantifiseer. BIM kan dus gebruik word om die onbeplande gevolg van projekveranderinge te bestuur en te kwantifiseer deur die tyd en koste impak op produktiwiteit te kwantifiseer.