One Alberta builder is using BIM and automation to cut material and delays
Proponents of Building Information Modelling (BIM) see reduction of waste as being among the key benefits from using BIM systems. Waste reduction, they say, can occur throughout the life cycle of a building-from initial design conception to de-commissioning and demolition.
BIM can cut waste significantly in the design and construction phases and thus lower the biggest single hurdle for many construction projects: capital cost. Design typically accounts for around 10 per cent and construction for around 90 per cent of the capital cost of a project.
"So even a two to three per cent improvement in productivity on the construction side is very significant in real dollars," points out Klaas Rodenberg, chief executive officer of the new Alberta Centre of Excellence for Building Information Modelling (ACE-BIM).
"Some buildings are costing $200 [million] to $300 million."
The shared knowledge base that BIM systems support is one of the ways that BIM can help in eliminating many errors. Traditionally, Rodenberg says, "Most construction is done by small outfits who mostly do a thing once and don't often have an opportunity to learn from the experience. There's no transparency through shared knowledge as builders don't share what costs are or how well things work."
Underlining that BIM is focused on information, he says the use of BIM addresses such issues, potentially providing useful data for how best to do comparable projects in the future. "One of the values of BIM is that it enables the sharing of information to boost productivity," he says. "BIM allows you to do things on the basis of a factory routine, not one pipe, one part at a time. Instead, it brings information out of the silos, with all players working off a single model of a building and being able to make the decisions before a single sod of soil is turned."
The use of BIM software like Autodesk Revit Architecture, sometimes referred to as a 3-D version of AutoCAD but often known simply as Revit, enables building components to be treated as fully 3-D objects at the design and drafting stage. It therefore provides superior clash detection-for where two things fit together on paper but not at the site-thus eliminating one of the most common sources of logjams in the design-construction continuum.
This and other technologies and software that support BIM can tell a design team-and everyone else on the project-everything from, say, whether a type of pipe is the best choice and how it behaves under certain stresses, to the precise siting of a proposed building, along with utilities and other infrastructure, based on 3-D and global positioning system information, Rodenberg says.
BIM is used in Alberta to prefabricate components and, indeed, whole complex sections of structures, via off-site manufacturing.
For example, the washroom facilities for The Bow in Calgary were largely prefabricated before being installed with the help of a crane, says John Leurdyke, director of building products at the Alberta government's Advanced Industries Development Unit.
BIM systems are being used to streamline processes and eliminate waste on all kinds of building, from industrial and institutional structures to high-rises and single-family homes, according to Leurdyke. As an example, Landmark Group of Builders last summer launched a manufacturing facility to build homes under climate-controlled conditions with the use of BIM, CNC machines (machines that uses programs to automatically execute a series of machining operations) and other automated equipment.
Under these conditions, the levels of accuracy achieved are within less than one-sixteenth of an inch, Leurdyke notes.
"To optimize the benefits of BIM, the design must be done more comprehensively," he says. "But with BIM, digital technologies, automation and CNC, these can do for the building sector what repeatability did for the auto sector."
In many residential construction projects, almost all the work is done by trades and sub-trades. But, with the Landmark manufacturing process, much of this work is done at the new Edmonton plant. (A Calgary plant is expected soon.)
A BIM BELIEVER
Reza Nasseri, founder and chief executive officer of Landmark, points to some of the ways that BIM-based manufacturing can help reduce waste: "OSB [oriented strand board] is precut. Because of BIM, the machine is able to cut the OSB for three or four homes. Suppose there is a small piece [of OSB] remaining. The software guiding the CNC machine will locate a section from another home that the piece could fit. Each machine has a bucket for waste, but the amount of waste is almost nothing. BIM identifies all the pieces and components from the frame to the insulation, drywall, flooring. It can calculate how much insulation is to be used."
Materials waste at the plant is sharply down from industry norms. "On average, in conventional construction, you see about 20 per cent waste in framing materials," Nasseri says. "We're down to under five per cent."
BIM, he says, enables the company to use lean methods, which he describes as an "established methodology" in the manufacturing sector. As well as reducing materials waste, BIM is also helping Landmark reduce time wasted as a result of delays. A half-built home where work has stopped to wait for materials can cost a builder from $150-$400 a day.
"In manufacturing, BIM saves time and materials, but it also helps create an even, continuous work flow," Nasseri says. "With BIM, it's possible to calculate all the materials ahead, so you get the exact amount of materials that are needed. Without BIM, you have to add extra materials [to have on hand to avoid delays]."
On-site time is sharply reduced with this method of home building. Once the basement is dug and footings installed, everything from the basement, which comes in concrete panels, to the roof can be installed within about five days or even less, with the help of laser levellers and a crane.