impact of 4d modeling on construction planning process - Chalmers ...

eorganize components is very critical for developing an accurate and flexible 4D
model (Eastman, Teicholz, Sacks, & Liston, 2011).
Temporary Components
The building model should also contain the temporary structures and activities to form
an effective 4D model that represents the realistic construction process. Excavation
details, scaffolding, tower cranes and other features that are a part <strong>of</strong> construction
process can be shown in 4D simulation. Integration <strong>of</strong> scaffolding and tower cranes in
4D model can help the planners to evaluate constructability and safety issues.
Scaffolding is also necessary because it influences the spatial constraints for
equipment and people (Eastman, Teicholz, Sacks, & Liston, 2011).
Decomposition and Aggregation
During the development <strong>of</strong> the 4D model, the objects shown as a single component
may need to be broken into a number <strong>of</strong> small portions to show how they will be
constructed. For example, a slab needs to be broken down into smaller portions to
represent the pouring sequence. This becomes an issue for the planners to breakup
specific components, such as slabs or walls, that the designer or architect modeled as
a single component. Most <strong>of</strong> the specialized tools do not provide this functionality,
and the planner must perform these split-ups <strong>of</strong> big components within the 3D tool
(Eastman, Teicholz, Sacks, & Liston, 2011).
Schedule Properties
4D models <strong>of</strong>ten use early start and early finish dates to simulate the construction
process. However, it may be desirable to explore other dates in some situations, such
as late start and late finish, to view the effect <strong>of</strong> alternate schedules on the simulation
process <strong>of</strong> the construction (Eastman, Teicholz, Sacks, & Liston, 2011).
3.3 Case studies
In order to produce more reliable results, a total <strong>of</strong> 9 case studies covering projects
with a variety <strong>of</strong> scope were selected from the literature. All the case studies involved
the implementation <strong>of</strong> 4D BIM in the construction practices. The case studies were
selected keeping in view the different diversity <strong>of</strong> projects. The projects also varied
from small to large scaled projects located in different parts <strong>of</strong> the world.
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