Wednesday 10 December 2014

Do It Right the First Time – Using BIM to Coordinate Systems During Design

Leveraging BIM for Design Fees
One of the problems encountered with implementing a BIM program in a design firm is the difficulty in leveraging the use of the BIM tools to generate more direct design fees. Of course, the use of BIM has plenty to offer in terms of greater efficiency and productivity, as I’ve mentioned in several previous posts (here and here). It would be great if a design firm could demand a higher fee by using sophisticated BIM tools – and it can be done. Depending on the market segment the firm is pursuing, it can be easier or harder to make the argument for higher fees for using BIM. Some design firms worry that, given the cutthroat business environment there’s been in the last six years or so, their clients (or potential clients) won’t give a hoot how the drawings are produced, as long as there is a legible stack of construction documents at the end of the design process. However, many more sophisticated clients understand the value that BIM brings not only to the design process, but also the construction and post-occupancy phases of the project. And they’re willing to pay extra to come away with a well-managed BIM model in addition to a stack of paper drawings.
Design firms can also make use of the BIM-based design by offering additional services based on the BIM model. These can be commissioning or post-occupancy studies, as well as space planning or maintenance scheduling. However, most of these “add-servs” aren’t possible until the construction – or at least the design – is complete. However, there is one highly marketable service available for the BIM-savvy designer during the design process: design coordination amongst the various disciplines.
Delivering a Well-Coordinated BIM Design
Of course, the designer always has a responsibility for performing coordination with the engineers and other technical design consultants. In the past, due diligence in this area has taken the form of overlaying plans and sections for various disciplines and checking for problems with architectural/structural/MEP system clashes. While this will pick up the more obvious clashes, it also allows smaller or well-hidden clashes to make it into the field, frequently resulting in costly RFIs and change orders. Now, BIM tools such as Navisworks takes systems coordination to a much more detailed level.
Navisworks is an “aggregator” program capable of importing a large variety of 3D file formats and overlaying them in their proper positions. Tests can then be performed to determine whether there are any clashes or intersections between different systems or objects in the models. These tests can be highly customized to make sure they are only turning up relevant clash issues. This information can be fed back to the design team, who can then quickly make adjustments to prevent these clashes from reaching the field.
Navisworks is capable of coordinating multiple complex systems
When working on a project that is entirely or mostly BIM-based, clash detection tools can be used to detect very obscure clashes and fix them during the design process. This is much less expensive than dealing with these clashes in the field, which frequently leads to large cost overruns. In the past, it has mostly been general contractors who have performed these clash tests, frequently having BIM models created from 2D design documentation in order to do so. Now, designers have the ability to perform this function during the design process, and earn more money by doing so. Additionally, they will be delivering a better design that will be less costly to construct – resulting a a happier client.
300% Return on Investment
Convincing the client to pay for additional coordination services during design can be challenging, but having strong numbers to back up your argument can help your pitch. Here’s a number that’s hard to argue with: a 300% return on investment for systems coordination during design. That’s right, for every dollar spent doing clash detection during late design, the owner will save $3 in the field in reduced rework costs. That’s a pretty impressive figure.
This number was validated with several projects. The first was a small mixed-use building. A Navisworks coordination effort was performed at the very end of the design process. The time spent doing clash detection was compared with the GC’s estimates of how much money had been saved by correcting these projects before they reached the field. It was determined that the project avoided $9,000 in field costs by incurring $2,945 of costs for Navisworks coordination, resulting in an ROI of 306%.
On a subsequent project, it was desired to perform a more in-depth study. This project was for a high-rise renovation project – a deep renovation which included taking the original building down to the structure. The Navisworks coordination was begun early during the CD production process. At weekly coordination meetings, the participants would review each clash, and make a determination over whether a particular clash would have made it into the field, or would have otherwise been caught during a traditional coordination/QC process. The vast majority of the clashes fell into this latter category.
For the clashes that would have made it into the field, a worksheet was generated. The designer, GC and relevant trade contractor were consulted, and an estimate of the time and cost of fixing each of the clashes in the field was generated. These included an administrative cost (usually $750 per rework item), and costs related to additional design work, additional GC involvement, additional trades work, and cost associated with schedule delays. These were totaled for the entire project and compared against the costs of performing the clash coordination.
 The costs included time spent running the clash tests, time spent by designers and contractors in meetings, and the cost of the Navisworks software. Total costs were $43,402.
The savings were based on an estimate of 21 RFIs that were averted, plus additional costs to electrical, mechanical and fire protections systems. Total estimated field savings was $127,850, for a total ROI of 295%.

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