Light Detection And Ranging, or LiDAR, is a technology for measuring distances by using a laser to reflect off of objects. LiDAR is increasingly finding application in civil engineering projects, as the technology is far more accurate and faster in determining distances between objects than human surveying teams walking across a project site.
How does LiDAR work?
Though not exactly new, as it made it to the surveying and engineering worlds in the mid to late 1990’s, you may not be entirely familiar with this versatile mapping technology which can be utilized while moving or from a stationary position. It uses drones or unmanned aerial vehicles, or remote sensing instruments mounted on ground-based platforms, to perform photogrammetry – collecting millions of elevation points in minutes. The data collected from the reflections of lasers compiles into several 3D environments such as images and point clouds, thus providing an accurate representation of objects in the area of concern and, if visible, areas within range of the detection device.
Civil engineers find numerous advantages from the use of LiDAR. The gathering of precise orthophotos and 3D representations by drones and remote sensing instruments mounted on the ground makes it possible for the critical spatial data for engineering projects to be ready in a matter of hours and not weeks! The gathering of stationary and terrestrial data is done by individual positions. These are tied together to get 100% of the area of concern to achieve an accuracy and precision of 1/16th to 1/8Th of an inch.
Here are some additional ways in which LiDAR is improving efficiency and accuracy in civil engineering projects:
Delivers accurate surveys
As a civil engineer with a focus on project effectiveness, you know that it is crucial to take a thorough and precise survey at the beginning of every construction project. LiDAR inspections can help you survey the terrain and any existing manmade features that will remain or be removed as you set up the project and determine if the land will need any leveling or alteration. The accuracy of plans for the project depends on the accuracy of this inspection.
LiDAR provides more precise representations of the terrain than traditional photogrammetric technology. That technology works by taking scans of multiple photographs and/or laser reflections, which it then stitches together using various algorithms that suit the accuracy and precision needed. This output, unlike traditional methods of data collection, will ensure all data is collected since LiDAR picks up everything. This eliminates the need for return trips to gain additional data or forgotten data.
When this technology is used in projects during the construction process, money can be saved. Cost savings are accomplished when the amount of rework is reduced as installations of floors, beams, HVAC and MEP can be tracked. Shown below are actual savings on past projects illustrated by data captured during construction.
Enhances safety at civil engineering projects
The safety of everyone working at the project site is paramount. You do not want any problems to arise during the project that could potentially harm people on or near the construction site. LiDAR can help you to spot potential safety issues such as ingress/egress, aerial lines, etc. When combined with drone technology, LiDAR can provide various types of 3D options along with precise measurements of all areas within or visibly surrounding the site in a short time so that you can analyze, detect, and most importantly eliminate potential hazards at the site.
The project site may be too big for humans to walk around, checking for faults, or the place may be too dangerous. According to the American Society of Civil Engineers, more than 4,095 dams across the U.S. are of questionable safety and structural integrity, requiring the use of LiDAR technology to inspect them.
Helps in project simulation and analysis
Collecting LiDAR data enables you to create a realistic 3D projection of the terrain surrounding your construction project. The 3D representation is so accurate and real that you can use it to make a precise simulation of the construction project, fully integrated into the existing territory.
You can then test the project for such factors as how the sunlight will be shining down on it so you can determine window sizes, shape, and position. Consequently, LiDAR reduces the chances of rework in the project, which always is quite expensive. We have helped clients go from the traditional 8-10% rework costs of a project reduced to 1-2%!
Faster than human surveyors
LiDAR is faster than human surveyors. Having humans move from one end of the project to another can be quite time-consuming, especially if on massive engineering project such as dams, bridges, airports, or huge buildings for housing factories or large offices.
In just a few hours, the lasers would have done their part, presenting representations of the terrain
and the project in 3D. Humans would likely have taken weeks and sometimes months to complete a thorough inspection of the site. It also means that you can complete the project within the given timeline since the onsite survey time is reduced significantly when using LiDAR.
Helps in maintenance and repair of equipment on the project
LiDAR technology has also helped improve civil engineering projects' accuracy and efficiency by enhancing maintenance and repair activities at the construction site. LiDAR scans can come in handy when it is important to locate potential areas or systems that require repair. This includes high-risk areas, such as under a bridge or on high rooftops, where drones can safely capture footage for analysis.
You can also use LiDAR scans to gauge the progress of the project. Use the 3D images and simulations of the project's current state to compare them with the projected job progress to see if the project is still on track. They can also help you to identify any potential issues that may arise as the project progresses.
Since LiDAR is so much faster than other technologies, it is possible to employ this technology regularly or at every stage of the project. LiDAR technology helps civil engineers and other personnel at project and construction sites enhance the efficiency and accuracy of civil engineering projects. It is faster, more accurate, and helps improve safety, since you can send a laser beam where a man used to go!
If you need more information about LiDAR or would like to explore how it might apply to your project, please contact us.