The era of building information modeling (BIM) for the pre-cast concrete industry has taken a leap forward with a new integrated model from the Precast Concrete Institute's (PCI) BIM Committee, the Charles Pankow Foundation, a handful of software developers, and a dedicated professor.

Chuck Eastman, professor and director of the Georgia Tech Digital Building Laboratory, presented the potential of openBIM at the PCI Annual Convention and National Bridge Conference in Salt Lake City in October. OpenBIM and the Industry Foundation Classes file exchange will allow precast producers, architects, and engineers using preferred software applications from multiple vendors to leverage BIM to become more efficient, reduce errors, and ultimately deliver higher performing precast concrete structures.

Developing BIM for concrete producers is not new. In 1997, the Strategic Development Council (SDC) formed to help the concrete industry identify and implement new technologies. In 2001, the Precast Concrete Software Consortium was established to create a 3D modeling system.

The consortium of 23 precast producers in North America led to two specific products. Tekla (www.tekla.com), an operating software company based in Finland, came out with a pre-cast module. StructureWorks (www.structureworks.net), an Apopka, Fla.-based developer of 3D modeling software for the precast concrete industry, developed its package on top of a popular mechanical parametric modeling tool, Solidworks. More recently, SDC secured $75,000 in grants from the Charles Pankow Foundation and the RMC Research Education Foundation to implement a plan.

New developments

The current Precast National BIM Standard (NBIMS) has about 20 members, led by Jason Lien of Encon United from Denver. This group addresses interoperability or exchange of data, principally between the two major precast BIM applications, and other applications that are part of the precast workflow. These include structural analysis, rebar bending, quantity take-off, material tracking, and plant management.

The newly developed Precast NBIMS supports all of the major exchanges for precast design, engineering, production, and erection. The demo showed an example workflow from an architectural BIM tool, Nemetschek Vectorworks (www.vectorworks.net), that exchanged the precast structure to Scia Engineer (www.scia-online.com) for structural analysis, and received changes back. Vectorworks then passed the precast model to both Tekla and StructureWorks for precast detailing.

Each system partially detailed the structure in various ways, involving hollowcore and double-tees. Tekla passed its model onto the Nemetschek Part Manager for precast plant management, and StructureWorks passed its model to its own Part Tracker plant management application. “This demo is just an initial stepping stone to deal with all of the major exchanges facilitating precast workflow,” Eastman says. “We expect other companies aspiring to support precast work will be joining later.”

There are many advantages for pre-cast producers. The tools produce effective shop drawings and shop tickets accurately. In Autocad or other human-managed drafting systems, consistency issues show up from time to time as errors.

Precast producers will be able to generate bills of material for the shop floor on the day of a pour, and do a better job tracking the erection sequence. “These systems are set up to integrate all of those things together,” says Eastman. “Firms might be doing that okay today, but it makes it very easy to do with these systems and focus on other issues.”

There will also be major implications for rebar bending. Rebar bending manufacturers will receiving the bending patterns, allowing them to produce it faster while reducing costs.

Meeting requirements

Owners and general contractors are increasingly requiring BIM models from their subcontractors because of the overall quality and speed at which projects can be carried out. The U.S. General Services Administration, the U.S. Army Corps of Engineers, many universities, and some states require BIM. “Many contractors are requiring it when they put their teams together,” Eastman adds.

The precast BIM standard provides an ideal basis for future development of a cast-in-place reinforced concrete standard, Eastman says. This new effort, involving steel-reinforced concrete, is just getting underway.

E-mail Chuck Eastman at charles.eastman@coa.gatech.edu; visit the Georgia Tech Digital Building Laboratory at www.dbl.gatech.edu.