Laser Scanning Laser Scanning and its Applications in Concrete Building Construction

PRODUCT FOCUS Laser Scanning

Laser Scanning and its Applications in Concrete Building Construction

➲Reality capture and laser scanning have been a hot topic in the last couple years in the AEC industry. Some are familiar with this technology while some are still hesitant with this new and complex solution. In this article, I hope to shed some light on what laser scanning technology is and share some applications that are relevant to the structural discipline through an example project that I recently worked on. My hope is after reading this article, you are inspired to find ways to apply this tool to your daily work.

WHAT IS REALITY CAPTURE & LASER SCANNING?

Reality capture itself refers to technologies which can be used to record an object, building, or site and produce 3D data (Swenson 2017). Up until the incorporation of reality capture technologies for the documentation of built structures, recording techniques have generally involved the use of hand tools, such as tapes and levels, with machinery such as theodolites (total station) to record distances, areas, and angles of structures. These methods are time consuming and introduce human error in calculations or measurements (Swenson 2017).

As a result, the outcome of these documentations would often be inaccurate and difficult to cross-check with original blueprints. This became an increasing problem as more and more structures became more complex.

Reality capture technologies were developed as an answer to this problem with expanded applications since their introduction. Reality capture technologies are significantly more accurate and rapid than traditional methods and the resulting datasets can be easily incorporated into a wide range of projects for various purposes. There are multiple solutions that fall into the reality capture technology, but the most common ones are unmanned aerial vehicles (aka UAV or drones) and laser scanning (mobile, airborne LiDAR, and terrestrial). In this article, we will focus on terrestrial laser scanning since it was the technology that was used on the example project. Once you understand how this technology works and its application, you can apply the knowledge to other reality capture technology. (Hvidberg, 2020)

Laser scanners bounce rapid pulses of low-power and safe laser light on surrounding surfaces to generate three-dimensional “digital twins” of real-world objects and environments. The result of a single scan is a collection of millions of data points consisting of relative physical object locations, shapes, and sizes. A series of scans are then stitched together to create a “point cloud”, an accurate digital replica of the building or site conditions. An easy analogy for this concept is putting a puzzle together. Each scan represents a puzzle piece while a point cloud is the whole picture comprising of multiple puzzles.

USE CASES ON AN EXAMPLE CONCRETE BUILDING PROJECT

On a recent project that I was on, the client wanted us to hide all electrical conduits inside the concrete deck because they want a clean exposed concrete look. They were concerned that exposing cable and conduits would not allow them to achieve this aesthetic intent. In addition, the building utilizes power-over-ethernet technology, which essentially means anything that needs power will be connected with an ethernet cable, like the one connecting to your home Wi-Fi router. That also means a lot of cables and conduits required to each device. Below is an aerial image of the most congested deck in the building.

Figure 3 – Electrical conduits and rebars inside the concrete deck

Figure 1 – What a single scan looks like

Figure 4 –Some decks also include post-tension cables

Knowing the design of the interior was not 100% completed, and any unpredictable need to core the deck might happen, the team decided to laser scan the deck, right before we poured concrete. This included all the conduits, rebars, stud rails and post-tensioned cables, etc. Below is an image of laser scanning the deck, and an example of the point cloud.

PRODUCT FOCUS Laser Scanning

Figure 5 –Point cloud of an in-deck scan

WHAT DID WE USE THE POINT CLOUD FOR?

One highlight story was right after a pour. We were notified by the architect team that the building fire pump room needed to be relocated due to a city plan check comment. Unfortunately, the

Figure 6 – Aerial view of the new fire pump room area before pouring concrete best place to relocate the room was also where there were a lot of in-deck conduits. After carefully investigating the requirements, and determining the number of penetrations, their locations and sizes, we were able to review the proposal with the Structural Engineer using the pre-pour scan point cloud and got the approval to core 9 holes through the deck while still maintaining the structural integrity of the surrounding concrete area. Below is the image showing the core locations. It also shows the fire pump room boundary, rebar in cyan lines, and conduits are in orange & red lines. Fortunately, all these cores were done without cutting through any conduits and only slightly cutting through one reinforcement bar. It was like threading a needle.

After this use case, we continued to successfully utilize the prepour in-deck scanned point clouds for multiple unplanned coring or drilling locations, avoid cutting all PT cables and minimizing damages to reinforcement and conduits. When someone on a project team needed to find a place to core or drill, this person got with the laser scanning specialist to review the scanned point cloud and figure out whether the location would cut through any in-deck components.

Alternatively, without laser scanning, we could have used concrete imaging technology such as ground-penetrating radar (GPR), or x-ray to identify the conduits, rebars and PT cables inside the concrete. However, GPR is not as accurate as laser scanning and given the congestion of layers of conduits, it would be too difficult or nearly impossible to confidently trust the GPR results in this situation. Moreover, using x-ray requires the site to be evacuated due to safety concerns with radiation, and the cost to x-ray each area would have been collectively more than the cost of laser scanning for this project. That does not take into account the logistics of scheduling and coordinating this work into an already aggressive schedule.

THERE WAS MORE THAN THAT!

It would be a lie to say that we missed everything, but in every crisis, there is an opportunity. We had a few locations where conduits were damaged from rebar dowels and blocked by the

Figure 8 – Area of concrete removed to fix the damaged conduit

epoxy. One incident involved a conduit for power to the main elevator, which would have required a fire rated enclosure if not installed within the concrete deck. This conduit blockage could have also delayed the elevator start date as well as project schedule overall. Fortunately, with the help of our electrician, we were able to run a wire through one end of damaged conduit to find out the how far from the end was the blockage. With this information, we were able to use the point cloud and closely locate the spot to chip out concrete to find the broken conduit and remove the epoxy blockage. It also minimized the impacted area on the structural integrity of the deck. Without the point cloud, it would have required a larger area of concrete to be removed and negatively affected the structural integrity of the deck.

IT’S NOT JUST A FANCY TOY!

It has been proven to me and my team at DPR Construction through many successful projects, that laser scanning is not just a fancy and expensive toy. At first, we all think it’s a really advanced tape measure or total station, but we didn’t realize that by digitizing real world into a “digital twin” in a really rapid process, it enables us to do a lot more with data that we couldn’t do with the traditional tools. Or, it would be really difficult and costly. There are other use cases of laser scanning related structure, such as verifying existing structures matching the record as-built drawings, monitoring beam camber and slab deflection, QA/QC of embeds pre-pour to avoid incorrect placement, analyze elevator shaft walls deviation, etc.

We are fortunate to have a scanner and a specialist on staff to utilize this technology more frequently, but if you can’t afford to acquire one, your general contractor team may already have one, or the project team can hire a local scanning service to perform the capturing and/or analysis work. We often find that the cost of laser scanning is less than the cost of not scanning and making risky assumptions and decisions based on inaccurate data.

My goal from this article is to inspire you to think of laser scanning when encountering challenging problems that traditional tools cannot solve or would be very difficult to use. The sky is the limit with what we can do with laser scanning.

Ocean Van is a VDC and Reality Capture (RC) Manager for DPR Construction. He has been with DPR for 6 years and is responsible for VDC and Reality Capture implementation in the Southern California business unit. Ocean also co-leads DPR Innovation Group in the region, where he explores new construction technology and pilots it DPR’s operation. Moreover, he is a subject matter expert in Virtual Reality, Augmented Reality and Wearables, in which he researched tremendously through previous internal initiatives.

Swenson, Kylee 2017 What is Reality Capture? Electronic document, https://www.autodesk. com/redshift/what-is-reality-capture/, accessed January 7, 2019.

Hvidberg, Madisen 2020 The Use of Reality Capture Technologies to Mediate Relocation Impacts: A Case Study at the Perrenoud Homestead Provincial Historic Resource, Alberta, Graduate Program thesis, accessed September 1, 2020.

COLUMN Tech Manager I Get By…

With a Little Help…

➲Autodesk products can be customized. Most of us have done some customization along the road. It may have been high end customization that no one else is doing, or it might be tinkering with the entry level tools to make your products do the dance that you want. Even defining a file structure or template is considered customizing. Programming, script writing, GUI enhancements, and so much more can be done. From easy to hard, it is all there to make things easier and working the way you may want. Not everyone is comfortable with all levels of customization, so from time to time you may need to reach out to others for help.

Now that the song is stuck in your head… let’s get some help…

FROM MYSELF

The song does not mention getting help from yourself, but that is the first place I will turn. You may enjoy customizing (I certainly do). I have tweaked everything I could get my hands on. If it did not work like I wanted, I changed it. I added on, replaced, expanded, and enhanced the tech tools I have used from day one. If you enjoy this and have a knack, then turn to yourself, first. Learn more, apply more, extend more. It is not hard to get started, just dive in, and try it. Start with the easiest way to customize, which is using the tools in the product. Only move to advanced tools when the lower end tools do not do what is needed.

But… No one can do it all. You may not have the time to learn a new trick or method or programming language. Or, you may not have the time to use the skills that you already have. We are all swamped. We are all trying to do more with less. There is nothing wrong with expanding your resources beyond your own brain and hands.

FROM MY FRIENDS

The song does mention this, and I will also. Having connections is the best, first place to look for help. Be it customizing or anything else. The folks around you can get you started. Generally, there will be someone you can tap into for help. It might be someone at your firm or at another. CAD/BIM users usually love to share knowledge. Just ask around. You can get some great ideas from those who have been down this road before. Be willing to share your knowledge also. It should be a two-way street.

I generally ask how others do something or what tools they use to get something done. That starts a conversation that might end up with some custom setups or scripts. It is okay to use something that another person gives you after you test it in your environment. It is polite to ask if you can use it. I seldom have someone tell me no. When interacting with others, the creative juices flow. Ideas

will generate more ideas. You may just need a hint at the answer or a suggestion of where to look. You may need troubleshooting help. When I am programming, a new set of eyes looking at my code sometimes uncovers something that I am missing (or a typo). Make sure you give credit to those that help and thank them for their assistance.

FROM AUGI

Sometimes you need professional help. If you are taking on a large project of customization, it might serve you well to bring in an outsider to help. AUGI has a place where you can find help. Just a few clicks away may be the advanced help you need. It is online and is a repository of those that can help.

Resource Directory - https://www.augi.com/resource-directory

From the site: The AUGI Resources System is a one-stop shop for you, the user, to find products and services to aid in your usage of Autodesk applications. Developers, consultants, and resellers are welcome to contribute their “store front” to the ARS. Once added they can then be searched and contacted by users worldwide.

Each listing includes name, location, contact info, website link, products covered, and services offered. You just search for what you may need, find the providers, and contact them directly.

The search function helps…

FROM AUTODESK

Autodesk has a deep listing of resources that they have provided. It is online and covers a wide swath of tools.

Services Marketplace - https://servicesmarketplace.autodesk.com/

FROM THE WEBSITE: HIRE TRUSTED CONSULTANTS

From online training classes to software customization, find Autodesk consultants. Autodesk Services Marketplace is an integrated website where customers can easily connect with and hire vetted providers for the services they need to be successful with our software. As a customer, you can compare industry professionals who provide critical services such as customized training, software customization, workflow optimization, pipeline development, and more. You then can connect directly with and hire the service provider who meets your criteria. Providers listed on the Autodesk Services Marketplace must meet specific qualifications established by Autodesk. Ongoing analysis of response time, provider reporting, customer ratings, feedback, and other factors help ensure the continued quality of participating providers. Service providers are a mix of Autodesk Expert Elites, Autodesk partners, and other qualified third parties with a proven, successful track record providing services in our industries. Autodesk does not collect any proceeds from Autodesk Services Marketplace transactions at this time. We do not charge customers to use the site, and we do not charge providers a listing fee. Customers sometimes need assistance to unlock the power of our products, therefore, it’s in our interest to provide easy access to services that can provide short- and long-term help that can’t be achieved alone.

There are lots of providers on the site. 192 for AutoCAD and 188 for Revit, just to name a couple. You can search by Industry, Product, Service Type, Specialties, Location and more. Like AUGI, each individual listing includes name, location, contact info, website link, products covered, and services offered. They also include reviews by past clients.

No matter where you get help, get help. When you start customizing your design tools, you will need it. But watch out… once you start… you may not be able to stop. It is addictive.

Mark Kiker has more than 25 years of hands-on experience with technology. He is fully versed in every area of management from deployment planning, installation, and configuration to training and strategic planning. As an internationally known speaker and writer, he is a returning speaker at Autodesk University since 1996. Mark is currently serving as Director of IT for SIATech, a non-profit public charter high school focused on dropout recovery. He maintains two blog sites, www.caddmanager.com and www.bimmanager.com.

Welcome to AUGIWorld Inside Track! Check out the latest opportunities to advance your skills, processes, and workflows in your firm with the most current AEC-related software and hardware updates available.

NC Viewer

https://apps.autodesk.com/FUSION/en/Detail/In dex?id=2936176173947597837&appLang=en&os= Win64

Autodesk Fusion 360

This app takes the web page-based NC Viewer and embeds it into Autodesk® Fusion 360™ CAM workspace. Once installed, it allows a user to drag and drop NC code live into the NC Viewer palette and watch a simulation of the code within Autodesk Fusion 360. This app works hand in hand with the Haas Outpost add-in from the app store, because when the Haas outpost command is run, it will launch a Windows Explorer path where you saved the NC file that was just posted out. This allows easy drag and drop abilities from the Windows Explorer into the NC Viewer add-in.

Exploded View Generator

https://www.behance.net/bogdanbogdanovic

Autodesk 3ds Max: 2021, 2020, 2019, 2018

Overall functionality and advantages: This script creates Exploded View effect by scaling the generated The script works on a selection of multiple objects It is very easy to use Exploded View can also be animated

Master Controller (Box Helper)

FamilyReviser

https://diroots.com

Autodesk Revit: 2021, 2020, 2019, 2018

FamilyReviser is a free Autodesk® Revit® add-in/plugin to help you to manage Revit families in your projects.

How it will help you?

Export/save in an organized way, the Revit families from a project to a specific folder/subfolder. No more Revit families backup files in your system/project library. Add prefix and/or suffix to a family name or type name. Find and replace the family name or type name. Rename family name or type name in the easiest way. Workset Management - modify worksets by category and by rules.

AUGIWorld brings you recent developments in Autodesk and related software items

Conduit Audit

http://www.Interstates.com

Autodesk Revit: 2021, 2020, 2019, 2018

When a conduit route is modified, custom parameter values are not maintained through the entire conduit system. Conduit Audit will take the parameter values that exist in part of the conduit network and push them throughout the entire network to keep the parameter information and schedules up to date.

The list of parameters, and whether they apply to just a branch or the whole network is customizable. There is also an auto-number feature to automatically add a conduit number if the parameter is blank in the entire branch or network.

If you have some news to share with us for future issues, please let us know. Likewise, if you are a user of a featured product or news item and would like to write a review, we want to know. brian.andresen@augi.com