The real cost of inefficient construction layout
Contractors at all phases of a construction project are continually faced with the same looming challenge: a thin profit margin and a host of potential ways that margin can be eaten away. As a result, everyone should be on the lookout for efficiencies that can allow them to complete their jobs faster with less overhead cost. At the same time, they need to maintain the highest quality since errors and resulting rework are just as costly as scheduling overruns and excess labour.
Let’s consider this universal issue by zooming in specifically on layout activities. For many contractors, layout can account for up to 25% of a project’s cost. So, like most construction professionals, you’re likely seeking efficiency and cost savings in this aspect of your company’s work. We’ll discuss where inefficiencies are often found in the layout process, how they translate to real costs to the contractor, and how improvements in tools and techniques can make the layout process dramatically more efficient and cost-effective.
Layout inefficiency: manual tools and methods
Traditional manual layout involves the use of numerous tools, including a tape measure, string, levels, a theolidite and measuring rod, and more. With every turn of a knob, mark of a pen, or off-the-cuff calculation, the possibility of human error is introduced. That means more time and money will be spent fielding RFI’s and remeasuring erroneous points. Worse yet, layout errors that aren’t caught quickly enough can cause even bigger problems down the road and cost you money.
Also, the more manual the process is, the more people are required to complete it, the longer it takes, and the more inconsistent documentation can become.
A more efficient option: automatic positioning equipment and linked layout software
The introduction of the first total stations in the early 70’s finally combined the distance and angle measuring requirements into one instrument. More recent advances in measuring and positioning equipment, such as robotic total stations and rapid positioning tools, have accelerated the layout process while enhancing accuracy and improving documentation. Through connection to powerful layout software, QA/QC and accountability have never been higher.
Today’s construction companies are seeing lower costs and fewer delays caused by human error because so much of the layout process is automated and self-correcting.
Layout inefficiency: teams of two or more
The common manual method of construction layout described above involves at least two individuals walking around the jobsite taking measurements. For larger projects, there may be more than one team working simultaneously, but it’s almost always in twos.
A more efficient option: one technician and an RTS
Using a robotic total station (RTS), one layout technician can handle the work that used to require at least two because the RTS can be controlled remotely via a connected controller or tablet. What’s more, one technician working with an RTS can lay out more points in the same amount of time. Compared to traditional manual layout, you can expect a 300 percent increase in points laid out per day and 87.5 percent decrease in cost per point. Even compared to the far more common traditional total station, running a RTS results in twice the points laid out per day at one quarter the cost.
And, due to the RTS’s precise accuracy, camera overlay, and connected field point software, human error that often creeps into manual layout operations is avoided, along with the costly rework that comes along with it.
Layout inefficiency: working from 2D drawings
While 2D drawings developed in CAD programs are still construction documentation standards, they’re not the fastest or easiest way to coordinate layout at any stage of the project. If you’re working with physical plans, the reams of prints required for a large commercial project are simply unwieldy and frustrating to deal with as part of the layout process.
And, even if you’re working from digital versions of the drawings, you’re forced to constantly translate what’s expressed on the screen into the 3D world around you. That’s not easy or natural and, once again, it leaves room for human error with every point you lay out.
A more efficient option: working from a 3D model
The use of 3D BIM models is becoming more common in many aspects of construction planning and design, so there’s a good possibility the 2D drawings you’re using have a 3D counterpart on someone’s computer. The real magic happens when that 3D model can be brought directly to the instrument via cloud-based BIM coordination software. Combined with the layout software you’re already using, layout tasks become far more straightforward, eliminating the need to rekey or recalculate.
Without a doubt, there are plenty of opportunities for making building construction projects more efficient and cost-effective by leveraging field technology – in particular by reaping the benefits of a modern layout process. To explore more tips regarding optimal layout, check out our free guide, “The Ultimate Guide to Optimizing Layout for Steel and Concrete.”
Author – Bryan Williams, Segment Manager, Field Technology Group, Trimble Buildings.
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