Digital Twins in Construction
What if we could have instant access to all the data within a construction site, down to smallest details about every person, tool, & part? What if measurements & locations were completely accurate ? What if we could always track the supply of materials, rate of use & ensure optimum deliveries so labour never needs to remain idle?
All this is possible with the use of a digital twin — A concept first used in the fields of astronautics & aerospace by NASA in 2002, the concept of having a real-time digital representation of a physical object.
Usually, digital data is formed by sensors that continuously monitor changes in the environment & report the updated state in the form of measurements & images.
A digital twin is essentially a link between a real world object & its digital representation that is continuously transferring & collating data from the sensors; this data is used to establish the representation of a virtual object, which then may be later used for visualization, comparison, modeling, analysis, simulation or further planning.
Useful Application Of Digital Twins In Construction
Digital twins allow for access to as-built & as-designed models, which are constantly synced in real-time. This allows companies to continuously monitor progress against the schedule laid out in a 4D BIM model.The predictive control approach can also be employed in order to make decisions based on extrapolation, beginning with the current state of the project.. Different possibilities can be simultaneously planned to estimate their probabilities & corresponding cost functions in order to optimise decision making.
Some possible real-time digital twins applications on construction site include;
▼Automated Progress Monitoring verifies that the completed work is consistent with plans & specifications.
A physical site observation is needed in order to verify the reported percentage of work done & determine the stage of the project. By reconstructing an as-built state of a building or structure we can compare it with an as-planned model in BIM and analyze the two to find any deviations. This is usually done by reconstructing the geometry of a building & mapping it to the model coordinate system, which is later compared to an as-planned model on a shape at object level. Therefore, having automated means of data collection & comparison means that the resulting model to as-designed BIM models is less liable to human error.
▼As-Built Vs As-Designed Models With a real-time digital twin, it is possible to track changes in an as-built model — daily & hourly.
Early detection of any discrepancies can lead to a detailed analysis of historical modeling data, which adds an additional layer of information for any further decision making processes. The project manager can then reconstruct the steps that led to the error & make changes in the future work schedule in order to prevent any similar mistakes from occurring. They can also detect underperformers & try to fix the cause of the problem earlier in the project, or plan the necessary changes to the budget & timescale of the whole project.
▼Resource Planning And Logistics
Digital twin technology provides automated resource allocation monitoring & waste tracking, allowing for a proactive approach to resource management. The monitoring enables the dynamic predictions of resource requirements on construction sites, thus avoiding the need to move resources over long distances, over-allocation & in turn improving time management.
According to the Construction Industry Institute, about 25% of productive time is wasted on unnecessary movement and handling of materials.
Image-processing algorithms make it possible to check the condition of concrete through a video or photographic image. It is also possible to check for cracks on columns or any material displacement at a construction site. This would trigger additional inspections & thus help to preemptively detect potential problems.
▼Optimization Of Equipment Usage
Efficiency in equipment utilization is a key metric for construction firms always. Unused machines should be released earlier to the pool so others can use them on other sites where they are needed. With advanced imaging & automatic tracking, it is possible to know how many times each piece of machinery has been used, at what part of the construction site, & on what type of the job.
▼Monitoring And Tracking Of Work
This includes having a digital record of all personnel & their location within the site, so that this information could be used to track efficiency as well as by rescue teams in case of emergency. Monitoring is another digital twins application. Still, it is better to integrate digital twin-based monitoring with an automatic entry & exit registration system, to have multi-modal data fused into a single analytics system.
Virtual representations of construction sites can be obtained by using multi-modal sensor data & algorithms based on computer vision techniques & deep neural networks. Various types of sensors are often used to infer the 3D structures including;
Conventional Digital Cameras
Autonomous UAV And Robots
Video Surveillance Cameras
Head-Mounted Cameras & Body Cameras
Data Processing Algorithms
A high rate of generated data demands an even higher rate of data processing & fully-automated pipelines, from data capturing and analysis to knowledge & decisions. Recent advancements in computing power, the processing shift from CPUs to GPUs & deep learning algorithms crunching through massive amounts of data, have opened the door to automatic data processing. The rise of self-driving cars, which generate 1-2 GB/sec of data, is pushing companies to find solutions for extracting knowledge & making decisions fast and in real-time, without sending all data to the cloud.
A construction site, in comparison, is a contained & controlled environment that generates data at the same rate as self-driving cars, & where we can use the technologies of these cars to better navigate the project according to schedule, using fewer resources & with higher safety standards. With digital twins companies in the industry are at the forefront of the technological revolution.