One major reason why contractors go out of business is unforeseen errors and conflicts among different trades during the erection and installation of new buildings. These conflicts generate delays, waste time and material, and can lead to years of litigation that can bring down a whole business.
When work on site has started and hundreds of workers are out there, the flow of work can be greatly affected if the plans used for construction are not detailed enough and uncoordinated.
Pat Henderson, president of Hardstone Construction, and a veteran of the construction industry knows that very well. He has managed hundreds of public works buildings and has had the satisfaction of bringing in many of them on budget. But he has also experienced the frustration of watching deadlines pass as unexpected conflicts lead to cost overruns.
A Unique Vision for the Future
When Hardstone was named general contractor of Tivoli Village, there were already multiple challenges to overcome. The project consisted of a two-million-square-foot area of retail, office, and parking space, including 16 buildings set atop a tri-level, underground parking garage.
Henderson believed that creating an accurate 3D model of a virtual Tivoli Village before returning to build the real one would help overcome many of the project’s obstacles and lower his risk exposure. His objective was to give his team the possibility to recognize and eliminate any conflicts between the different trades before construction started.
This is when he called in our team. Our three member team, collaborating with support staff from Hardstone, had to make sure that those different drawings going out for construction accounted for all design elements. They are optimized and perfectly coordinated so that every subcontractor would be able to do his work in the most efficient way possible.
To assume that responsibility, we took an integrated approach to the coordination process by developing an interlinked and parametric 3D model. The architectural, structural, and mechanical/electrical/plumbing (MEP) scopes of work were all modeled in-house using one platform. With a single platform approach, all information about the project was available to all stakeholders. This allowed the team to develop a more efficient coordination process and produce accurate shop drawings and quantity take offs.
The Challenge for the Concrete Structure
One area where the benefit of 3D modeling was seen immediately was in building the $80 million structural concrete parking garage. The 1 million-square-foot parking structure carries three-floor buildings on top of it. The challenge was to coordinate the positioning of MEP sleeves within 60-foot-long by 4-foot-deep post-tensioned concrete beams. All electrical conduits and plumbing are designed to run through these sleeves. To do so, the post-tensioning cable reservation needed to be modeled within each beam so that when locating the sleeves, they were not interfering with the cables.
Since the position of post-tensioning cables changes in each beam and since there were about a thousand of them in the parking garage, it didn’t make sense to model every single one. By using a Product Lifecycle Management (PLM) solution as the single-design platform, automation capabilities inherent in the technology were able to link the information available in the post-tensioning-cable fabricator’s Excel database to the 3D virtual model that Hardstone built of the garage. This showed Hardstone the perfect position for each cable within each beam and consequently allowed them to perfectly locate the sleeves.
From there, a drawing was generated showing the location and the size of the holes needed, so workers were able to account for them before pouring. This process was used again to model beam rebar for conflict checks and quantity take offs. The tool that was developed automated the modeling of the rebar and extracted information for each beam from an associated excel spreadsheet to determine rebar size and layout. It then accounted for the post-tensioning cables and the sleeves that were located within that beam. By linking the model to the Excel spreadsheet, it became easy to update the model whenever the design values changed. This gave everybody powerful visual support to validate the design and helped keep track of the exact quantities installed in every phase of the pouring process.
