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