BIM in Retrofit
In recent years , an increasing number of studies indicate the importance of retrofitting the existing housing stock in order to improve sustainability . Retrofit has received greater attention within the current research agenda given that it has a crucial role to meet sustainable targets ( Kemmer ; Koskela 2012 ). Given that a large share of the buildings that influence climate currently and in the future have already been built , efficient actions regarding retrofitting and renovation are demanded . Gholami et al . ( 2013 ) state that one of the challenging issues during the retrofit process is to find an approach that improves collaboration and integration during works .
Building Information Modelling ( BIM ) is an approach for managing construction project information , which includes functions needed to model the lifecycle of a building . BIM provides the basis for new designs and construction capabilities , and changes roles and relationships in the project team ( Eastman et al . 2011 ). BIM tools enable stakeholders to manage project information across its several stages in a virtual environment and can be used for many purposes in new construction or in retrofits ( Sheth et al . 2010 ). Thus , there is a potential to use BIM tools to assist the process of retrofitting , such as 4D BIM .
According to Kymmell ( 2008 ), 4D BIM simulates the construction process in a virtual environment . The main benefit of having the project in its virtual form is the possibility of experimenting construction activities and making appropriate adjustments before execution . Graphical simulations can reveal potential problems in their origins , and opportunities for their improvement in terms of construction works , equipment involved , spatial conflicts ( logistics ), security issues , among others ( Eastman et al . 2011 ). Thus , simulation supports decision-making from the very early construction stages and facilitates the development of solutions ( Capeluto ; Ochoa 2014 ).
The simulation of construction ’ s sequence is based on a preliminary programme , schedule of works and a BIM model . What-if scenarios can be visualized in 4D sequences to help communicate the advantages and disadvantages of various scheduling options ( Kymmell 2008 ). Early 4D BIM simulation can provide to stakeholders a better understanding of the related processes and constraints that can affect construction operations .
Ultimately , 4D BIM simulation enables the understanding of potential disruption to occupants , which supports a better decision-process and mitigates the impact of construction activities on home environment . The 4D BIM simulations can be used as a visual management tool , given that images representing the different stages of the construction process can be displayed on site to workers . Dave et al . ( 2013 ) argue that collaborative planning can be enhanced with the support of 4D BIM , where the team visually gains deeper understanding of the project when compared to traditional approaches ( i . e . meetings discussing the schedule of works ).
In the context of project delivery in the retrofit of existing housing , an optimal solution is the one with the capacity to cope with compressed lead-times and to cause minimum disruption to occupiers . Site layout , temporary accommodations , site facilities and storage , logistics and the construction programme and time-scales might affect not only the residing family but also the neighbourhood . The effects on occupiers depend on the family profile and on the need for temporary relocation of the family for the duration of the works . In order to determine appropriate scenarios that are effective for saving cost and time , early stage simulation methods are likely to be helpful to overcome uncertainty , to evaluate the performance of different design strategies ,
Using 4D bim in the retrofit process of social housing 281