Topcon: Construction Verification

November 11, 2019 David Campbell

What exactly is construction verification? I find that the word verification often has several varied definitions. It could be a comparison of what was designed versus the as built conditions, utilizing scans of the existing structure and comparing it against what was designed. Or it could be a comparison of what was designed versus what was installed on site, allowing us to know whether we are on schedule and what has been installed out of specified tolerances. Typically, when I think of verification on a construction site, I think of someone walking the jobsite, noting any issues and placing either sticky notes, or making markups on PDFs using software. Essentially making sure things were built or designed to tolerance.

But all in all, it is really utilizing the technology that is available to us to better our processes and workflows. Now I know technology can sometimes instill a rage that forces one to fantasize about hitting it with a baseball bat like that scene from Office Space where they demolish the copier. Technology, more specifically construction related technology, has gotten us to a place where we can share large files such as point clouds, use instruments and scans to establish and ensure QA/QC processes, as well as allowing us to compare the point clouds against the model. These improvements allow us to make corrections whether they need to be fixed in the model or corrected in field.

topcon-bodyBeing an Autodesk Partner and involved with the various construction trades we get exposed to a lot of ‘fire drills’ that could make or break a project. Many times, we hear about technology not working as it should. This leads to 1 of 3 issues: a missing update or patch, user error, or the technology is not complete/buggy. Regarding user error, I am not picking on a user but rather any human caused issue such as poor training, mindset (for the curmudgeon saying they’ll never adopt this piece of junk and their way is faster, better, or more accurate), or simply oversight or lack of information that compounded through construction.

I’d like to take this time to illustrate a few examples of where projects were not only saved but were made by technology. Disclaimer: names have been redacted for the safety and protection of those involved.


Construction Verification in the Field

In the past few years I’ve had the pleasure to meet and develop a professional relationship with a BIM Coordinator who shared his story with me on an interesting project for a large technology firm. His company was tasked with a traditional tenant improvement where they did the core with one architect and the shell was completed by another team of GC and architect. The architect developed a model which was used by all. This model which was designed to illustrate design intent was used for the remodel by the GC as it had structural components in the model. These components dictated where the subcontractors would place utilities, piping, ductwork, and would define how the spaces were laid out. That is well and good, but something was amiss; the structure was modeled for design intent and was not accurately portraying the existing structure. It wasn’t until the GC and the owner came together to scan the project floor by floor that they realized everything was off and it gave them a point cloud to use to fix their model. They used this model to reroute and coordinate with the trades. The simple relatively short exercise in scanning the existing conditions paved the way for a successful remodel in what is truly a remarkable building. 

Another great story I would like to share involves a restoration project on a large steel and concrete structure. There were 583 steel items that were analyzed over the course of 16 hours. That was with scanning, analysis, and verification. The findings were that more than 50% of the steel was installed incorrectly and some of the steel members were found to be more than 3” out of tolerance. It also found that the structure on the face of the building was out of tolerance by 2”, we found that the steel in the model was shown to be angled but the steel installed in the field was flat. 36 elements on this project were found to be out of tolerance enough to warrant a field inspection. They were able to identify several substantial installation errors early and save themselves from extensive rework costs. Also, the fabrication of glazing based on the as-built steel model allowed them to avoid schedule delays.  

It is great stories like these that let us know that technology is improving the quality of work, the speed at which work is completed, and enable better more effective communication between all parties. 


Why Construction Verification Matters

The technical construction verification workflow is one I currently believe to be underutilized. Partially, because who wants to be the person to specify that verification with technology needs to be done? Mostly, because who is going to be the person paying for the scope of adopting that technology? I find that most of the time these are the biggest hurdles that contractors must jump from project to project. When I can sit back and look at some of the mistakes being made on these job sites, and how long these issues take to become recognized and changed or at least adopted, it is mind boggling. Errors made on projects can often prove to be extremely costly, sometimes spending years correcting mistakes that weren’t picked up. As efficiency and accuracy become increasingly important in the industry, I find that we cannot afford to waste any more time deciding who or why. The desire to build directly from the model is driving the construction process to perform construction verification with scanning and layout in a fraction of the time. Construction verification can provide users with a live, as-built model, and the same resection setup for layout. It will allow project engineers to have near real-time adaptations on site to identify and rectify any discrepancies quickly and reduce the financial impact of clashes with a touch of a button. Therefore, saving everyone involved time and money.



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