Monday at FIATECH I learned about Field BIM, using BIM to bring lean manufacturing techniques to the job site. The approach was illustrated using a case history of the ongoing construction of Giants Stadium.
The new Giants stadium was entirely designed in BIM, meaning that complete three dimensional objects for the entire stadium were known in advance. The major structural components are a steel frame and pre-cast concrete forms. In essence, the largest issue on site is the most efficient assembly of these pre-existing modules. Examples of complicating issues are that erecting the steel frame for the upper decks would block access of cranes to lift inner pre-cast units into place.
An additional challenge, one that turned out to be an opportunity, is that the new stadium is collocated with the existing Giants stadium. This meant that the site staging was severely limited, as job site and parking for the old stadium were in direct conflict.
The team set up direct data exchanges between the scheduling system, the BIM software, the job site management system, and augmented it all with RFID tags. RFID (Radio Frequency Identification) is the name for the tagging technology that is used for inventory control in modern stores and warehouses.
Using the 4D BIM (BIM over Time), the team created an optimum sequence for assembly. This work was shared iteratively with the project management system, until a plan that the construction team could commit to was finished. This schedule was transmitted to the fabrication companies creating the pre-cast concrete. This schedule was also synchronized with the job site management software.
The fabrication plants received all forms as templates in CAD, and the delivery dates expected for each component. Just as in lean manufacturing, the agreements allowed no product to be shipped to sit until they were needed. This, by itself, improved efficiency because all on-site inventory was easily visible.
One of the requirements for the job was that an RFID tag was cast into each pre-cast module. This tag was then scanned and associated with the matching module in the job site scheduling system, which was them marked as “Manufactured”. The tag was re-scanned at the key stages of the module life-cycle: QA Inspection, Shipped, Received, Inspected (again), Erected, and, occasionally inevitable, Damaged.
This approach enabled the construction managers to anticipate problems at every level and prevent changes to the schedule. When looking ahead, the manager relies on the assembly schedule prepared in the 4D BIM. Looking ahead, the expediter could see instantly which materials needed in the next week were on site or en route. With only the materials about to be installed on-site, inventory and hunting time were minimized. As each module is scanned during installation the current state of the construction gets updated automatically, and re-synchronized back into the BIM.