The frenetic pace of construction in Qatar needs all the assistance it can get to help meet the oft compressed delivery timelines. Technology is fast becoming a necessity in this endeavor and new to the scene, is laser scanning.
Ramzi Abu Qamar, managing director of Bimtec, is effusive about how this new technology is taking the construction scene by storm.
“No-one has one of these scanners in the Middle East yet – and we have two,” he says with barely contained pride and adds, “This makes us the only company – not the only BIM company, but surveying company – in Doha that has this number of scanners.”
So what makes this technology so ground-breaking for construction?
Abu Qamar explains: “Normally you would see two surveyors on the roads, one with the station and the other with a pole.
“Well, what they do is, they take one measured point at a time; that is normal surveying. The other way of doing this is with a GPS machine where you ‘click’ and mark a point,” he adds, with a hint of dismissiveness.
“Our machine, on the other hand, shoots one million points per second, with a range of 270m, 360˚ – on both vertical and horizontal axis,” he pauses, waiting for the info to sink in.
And difficult it is to absorb that information, unless you can see it in motion and CWQ was fortunate to be privy to this in the confines of our Doha office.
The device is hefty, weighing a few kilos and comes in a wheeled container that is brought into the office like a boxed R2D2 (Star Wars reference to those who need clarification).
Fixed to the top of an articulated tripod, the scanner is a little intimidating up close. It stares impassively ahead, at eye level, cyclops eye waiting for coordinates to be input, settings entered and then it’s all systems go, as the scanner lens whirls into action.
The office is filled with a resonant humming as the laser moves through its coordinates, taking points throughout the programmed arc.
“It can take around one billion, high density points in a minute,” say Abu Qamar. “It is also able to take 360˚ photos at the same time. The end result is a photo-like scan of points of the environment, whereas, today’s surveyors take individual points,” he reiterates.
“The scanner scans whatever it sees, whatever the human eye can see, it doesn’t see ‘through’ surfaces. It is so accurate that it cannot be debated,” he says with absolute conviction.
Abu Qamar goes on to explain further: “For example, take a sand stockpile. This sand is sold, and cost and profit are measured on the volume of sand. If there is a miscalculation in the volume, this impacts and affects outcome of revenue, cost and loss. What normally happens is a surveyor takes a GPS with a total station, walks up onto a mountain and clicks a point and comes back down.
“He may manage 300 points per day with this method –possibly taking a full day to achieve this – for one stockpile. He then goes back to the computer and calculates the volume. With our scanner, you click a button and it shoots the lasers, takes the points and you get a 3D representation of your stockpile. You do the calculation and get the result,” he beams.
He continues, “In one project, they do the surveying roughly every month. With our method, we found that within one month, the discrepancy was 45,000m³. Multiply that by QAR6 per cubic meter and you get an idea of the impact that type of inaccuracy.
“That’s around QAR300,000 loss, without even realizing it. Then multiply that over two years…” he drifts off.
The other use for the system is as-builts. This was the initial reason for Bimtec procuring the scanner: “We wanted accuracy in the as-builts. Most of the big projects, Qatar Foundation, QP, ASTAD etc all request laser scanning. Europe uses this method widely and we realized that there was a gap in the market here in the Middle East for this technology.”
He explains that this laser scanning is more accurate than the drone technology, one of the more recent methods of capturing structural information. “The error tolerance with scanning is 0.8mm, whereas the drone’s accuracy is 1cm. Depending on requirements, some clients are satisfied with 12mm tolerance; if it’s a stockpile 12mm suffices and the 360˚ photos are 70 Mega pixels,” he elaborates.
He says that the most accurate requirement and highest definition is about 3mm within the industry, but the consideration here is managing billions of points requires data storage.
He describes why the system is well suited to FM.
“With large corporations FM is normally outsourced, and the companies get to understand exactly what assets the clients have – from the number of lights in a room to desks.
“The scanner technique also has an interface wherein tagging of elements is possible. All this info can be input onto the scan and exported into a facilities management software, where the system can notify the FM company when the bulb needs replacing,” Abu Qamar elaborates.
He continues: “We can do scan-BIM as-builts, and we can do scan-FM, which is what the client would want. A regular surveyor would take points, not details. If you want anything outside of that point, the surveyor would have to return to the site. The beauty of the system is that you capture reality. You never need multiple site-visits, it’s done in one visit and all information is collated in one application.”
As the scanner records what it sees, everything is detailed, from a glass on a table to a light fixture; “This system does away with debates or contesting issues – everything is recorded, in situ, as is.”
The scanner understands its location geographically, it records its coordinates and is thus able to connect all the scans.
He points out that the time saving on the scanning process is around 40% of regular surveying, depending on the project. “A building may take a little longer, depending on the structure, whereas an open site visit is faster.
“You then have an asset,” he says, “which you are able to refer to at any stage; an accurate capture of reality” he emphasizes.
The scan is then cleaned up and converted and the client may choose to have a model overlaid if necessary, “modelled off reality and not 2D drawings” he reiterates.
The company is presently under discussion to scan existing buildings to help companies understand exactly what assets they have, as often items are overlooked in inventory.
“As a contractor you don’t take note of the small details such as the light bulbs in an environment, it’s not normally captured information. But when you have a laser scan, locality of light bulbs etc are captured, and you can work around this information if for example you’d have to change accessibility within the structure.”
The biggest obstacle is planning the scans. Each stage must be planned and scanned accordingly. “While it’s not perfect in the sense of workflow, it is perfect in the end result, when planned with the contractor.”
Abu Qamar stresses, “This does not replace BIM, it enhances BIM” and indeed it does; taking BIM’s diversity one step further, creating a photographic rendition of the structure, with such a high degree of accuracy that it is absolutely beyond debate.