Concrete and BIM

Building Information Modeling (BIM) is a phrase currently being thrown around the construction industry a lot. You might have heard it, but you might not know what it means. Simply put, BIM is a software program that offers a 3D version of a project - a virtual picture of what a building will look like before an excavator digs its first bucket of dirt. Taking a step beyond that simple definition, you'll find BIM is so much more.

The grand idea behind BIM is to achieve one construction document that everyone can work from, including the architects and engineers, the owner, the general contractor, and the various concrete, HVAC, electrical and other subcontractors working on the project. This one document can replace the several sets of building plans a concrete contractor often has to deal with on a job.

There are currently a number of BIM software programs on the market, including Revit Structures, VICO Constructor, Bentley Structures and Tekla Structures. Most of the programs can work in conjunction with each other. For example, a contractor using Tekla Structures can import information from an architect's Revit files and work off that plan.

Find problems before you start building

Aaron Stegmeier is president of A.R. Stegmeier Enterprises, Inc. in Lakewood, Wash. His company primarily works as the structural concrete subcontractor on a variety of commercial projects. Stegmeier started using AutoCAD, which creates 2D building plans, more than 10 years ago. Last year he started seeing things in 3D when he began using Tekla Structures. Stegmeier has used Tekla on five projects since then.

He says the biggest benefit he's seen with BIM is its ability to catch discrepancies when the architect's model and structural engineer's plans don't match up. "If I get on the jobsite and start rolling along with 2D prints and hit conflicts on the job, I have to go through the RFI (request for information) process, and that is a waiting game that costs a lot of frustration and money," Stegmeier says. "With BIM modeling I can draw a model of the concrete ahead of time and put all the architectural and structural information in, and I can see the clash points two or three months ahead of time and deal with them then."

One instance of a clash Stegmeier found preconstruction on a project recently concerned the way his concrete work interacted with the structural steel. "Our embeds for the steel contractor were drawn outside our concrete wall, and no one knew it from the 2D plans," Stegmeier explains. "So when I showed it to the designer in 3D he was able to tell me I needed to change the concrete."

Andy Lock is chief estimator with F.A. Wilhelm Construction Co., Inc. out of Indianapolis, Ind. The company performs work as a concrete trade contractor and also self-performs concrete on projects where they act as the general contractor. Lock says Wilhelm has expertise in large and complex concrete projects. Two years ago, Lock's office began its transition from 2D systems into the 3D BIM world. Lock sees many benefits of the BIM programs over the 2D systems, one of which is having the opportunity to walk through multiple scenarios about how you might build a project, how long it might take or how much equipment you'll need.

"You can see how your resources might flow from location to location. Many projects require multiple crews starting in different areas, resulting in a wide range of outcomes," Lock explains. "With BIM you can reduce the time and effort required to analyze multiple scenarios. Finding the best scenario is a critical component of improving work flows and productivity."

A database of information

BIM's ability to create a 3D model of a project before it's built is only one beneficial element of the programs. BIM modeling can take the project into 4D with the addition of time and scheduling and 5D with the addition of cost. It becomes a central location for all information about a project.