VIRTUAL CONSTRUCTION

By Kerry Duff

BIM, or Building Information Modeling, is revolutionizing the construction and design industries by increasing productivity and saving time and money in the field. BIM is a virtual 3D model of an entire building

Modeling provides the building owner and construction team the opportunity to see every aspect of the building prior to construction — shape, size, color, walls, finish, heating and air conditioning, plumbing, electrical, etc. Each trade creates their own 3D model at the start of a project. Each model is then imported into a software program called Navisworks that analyzes the drawings to detect collisions in the project.

“Modeling detects 99 percent of the problems prior to construction resulting in reduced downtime in the field,” says Don Humke, operations manager for Midstate Mechnical of Phoenix, a full-service mechanical contracting firm specializing in commercial and industrial projects. “With the old method, the general contractor got the job then all the subs show up to decide where things went. Eventually one trade ran into another resulting in downtime, rework, re-fabricating of materials and throwing out materials that could no longer be used.”

Midstate Mechanical and The Weitz Company worked together recently on The Summit at Copper Square, a 23-story residential development in downtown Phoenix. The Weitz Company, general contractor on the project, created a 3D model for the post tension floor slabs. The model guided the construction team on where to leave holes in the floor before pouring concrete. This was an important step because the concrete had tension cables sandwiched inside that were pulled tight with a hydraulic machine after the concrete was dry to support the floor slabs. Thus the construction team could not go back later and core a hole in the floor without hitting a cable that would snap like a rubber band and fly 200 yards out the side of the building.

“BIM is a proactive approach that eliminates conflicts before they hit the field,” said Trent Mostaert, construction manager for The Weitz Company. “We jumped in with both feet to learn BIM and it has drastically changed our business. Modeling saves time and money and is safer for workers.”
Midstate Mechanical drew a 3D model of each condominium at The Summit and coordinated the electrical, plumbing, and mechanical, fire protection systems for the project. BIM allowed the construction team to go floor-to-floor looking for conflicts and then resolve them on the model before construction. It also provided the information to prefabricate all the plumbing, mechanical, fire and electrical systems for the project. For example, as the virtual model was created it downloaded information to a computer-aided pattern cutter that manufactures the duct work. For piping and plumbing, a spool drawing was produced and the parts were fabricated in the shop.

“The Summit was a tight site and we didn’t have enough room for everyone to bring their stuff down there and store it, so when an electrician or someone needed materials for a particular floor, his shop would send down all the specific parts for that floor,” said Mostaert. “Since many of the parts were prefabricated installation went quickly.”

Jon Haug, vice president of Midstate Mechanical, says the construction industry’s transition to BIM has been slow, especially in Arizona. “This is great technology and it’s going to help our industry immensley,” he says.