naire , the set of categories of disruption was revised and extended , and an assessment of their importance was made from the stakeholders ’ perspective . Based on those categories , disruptions for tenants can be highlighted and characterized in 4D simulations to assist the creation of scenarios and to facilitate the comparison between them . At this stage , new factors of disruption were added : disruption of external environment ( e . g ., when the tenant performs some improvement out in the backyard such as a wood deck and it needs to be removed ); and disruption in the parking spaces ( e . g ., when there is a reduction in parking facilities for residents by skips , vehicles of tradespeople and storage facilities for works ). In order to obtain a deeper understanding of disruption for tenants , a new questionnaire was developed , and this will be applied to tenants .
d . Method for creating what-if scenarios focused on disruption for tenants using 4D BIM
Considering the outcomes from the empirical study – Phase 1A and cycle 1 - a method for creating what-if scenarios with minimal disruption for tenants in social housing retrofit projects was developed . This method uses 4D BIM simulation to create what-if scenarios and seeks to understand how the disruption for occupiers can be minimized and avoided while the retrofit process is carried out . Also , this method enables the choice of an appropriate execution process to be used in further retrofits .
This method provides a wide support to the user when understanding , visualizing , and improving the production process in social housing retrofit projects , as well as in identifying and minimizing disruption for tenants . A schematic representation of the proposed method is shown in Figure 7 .
Figure 7 : Method for creating what-if scenarios focused on disruption for tenants using 4D BIM
The method is divided into two main stages : developing what-if scenarios and decision-making . The stages comprise the following steps :
1 . Development of a 3D BIM model of existing building : What-if scenarios are developed from 4D BIM models , therefore it is essential to have the 3D BIM model of the existing building . In most cases , the building that will be refurbished does not have an up to date documentation . Thus ,
286 ZEMCH 2015 | International Conference | Bari - Lecce , Italy