Job Book 9th Edition - Book - Page 38
ONLINE VERSION
26
Stage 0 > Strategic Definition
0.5.4.5
If appropriate, advise the client on the purpose, benefits and
implications of implementing BIM on the project.
Agree the extent to which BIM will be used, including 4D (time),
5D (cost) and 6D (facilities management), following software
assessment, and inform the design team.
4D (time) BIM
By adding ‘time’ to the information in the project model (by linking
attributes in the model to a construction programme) it is possible for
the contractor to review the construction of the building. For large,
complex projects or those on challenging sites, this can be a particularly
useful tool as it can be used to examine critical path activities, logistical
issues such as deliveries and craneage, and to generally discuss and
refine how the building is to be constructed. As interoperability improves
it will become more straightforward to consider different buildability
options, allowing a number of construction options to be prepared and
rapidly translated into a 3D representation of the construction process.
If the model is updated to reflect activity on site, it can also be a useful
tool for reviewing progress against the programme, highlighting where
progress is behind. The model and project schedule can also be used to
examine ways to make up time. Conversely, the contract administrator
will be able to use the programme for assessing delays and any
applications for an extension of time.
5D (cost) BIM
The ability of BIM models to contain cost information and quantity
schedules allows the cost estimates for a given design to be produced
faster. This allows option appraisals at the concept stage to be more
accurately assessed and, because designers have cost information at
their fingertips, the iterative design process will be accelerated, making it
more likely that designs are aligned with the client’s budget.
Consideration will need to be given to how cost consultants provide
and integrate cost information into the model. Common methods of
outputting area and quantity information – so that it can be converted
into a robust cost plan that takes due cognisance of project-specific cost
drivers and market trends – will have to be determined.
