AR Guidance and As-built Data Realize Civil Engineering DX: Technology Transfer That Leads to Young Worker Development

Japan's civil engineering and construction industry is now facing a serious labor shortage and a crisis in technology transfer. The number of construction workers, which peaked at about 6.85 million in the late 1990s, had declined by roughly 30% to around 4.8 million by the 2020s. On worksites, veteran generations are retiring in succession, while there are not enough young personnel to inherit their skills. For example, workers aged 55 and over account for more than 30% of the workforce, whereas those 29 and under make up only about 10%. Long working hours, harsh working environments, and the negative image of the "3Ks (kitsui, kitanai, kiken: tough, dirty, dangerous)" continue to deter young people, and the decline in new hires and early turnover are accelerating the aging of on-site staff. This distorted age structure casts great uncertainty over future technology transfer.

Moreover, on-site work is so time-consuming that it is difficult to secure time for training, and know-how that relies on veterans' "intuition and experience" tends to become person-dependent. Young workers often do not know what to do or how to do it and become confused, sometimes losing confidence before they gain sufficient experience. On the other hand, veteran instructors are stretched thin due to labor shortages, and there are increasing cases in which valuable knowledge is lost without being passed on to the next generation. So how can we support generational change on worksites and create an environment in which young workers can grow?

The key expected here is civil engineering DX (digital transformation). Civil engineering DX, which uses ICT and digital technologies to improve productivity, has the potential not only to compensate for labor shortages and increase operational efficiency but also to transform on-site work itself and create an environment in which young workers can thrive. This article focuses especially on two topics: AR (augmented reality) guidance for on-site work and the utilization of as-built data, explaining how these contribute to improving construction accuracy and developing young workers. Let’s look together at how these new initiatives that connect technology and the field can support technology transfer to the next generation.

The Significance and Background of Civil Engineering DX: Advancing Digitalization and National Policies

"DX (digital transformation)" is not simply the introduction of IT devices, but an effort to transform business workflows themselves through digital technologies to achieve dramatic efficiency improvements and value creation. In civil engineering, DX is progressing across processes from surveying and design to construction and maintenance. Examples include 3D surveying with drones, automated control of construction machinery, the introduction of BIM/CIM (design methods using 3D models), inspection efficiency improvements through remote presence and AI image analysis, and the on-site use of AR/MR technologies—various digital reforms are beginning to change the face of worksites.

Backing these civil engineering DX efforts are national policies. In 2016, the Ministry of Land, Infrastructure, Transport and Tourism proposed a productivity revolution called *i-Construction* and began initiatives to improve construction site productivity through full-scale use of ICT. Specifically, public works have actively introduced ICT construction equipment, drone surveying, and tablet use on site, and since fiscal 2020 the use of new technologies has been mandated in principle for directly managed projects, promoting widespread adoption. Recently, under keywords such as "construction DX" and "infrastructure DX," movements to innovate entire business processes through data linkage and AI utilization—beyond mere operational efficiency—have been accelerating. The ministry has drafted guidelines for as-built management using 3D models and begun to position digital utilization as standard practice by moving toward electronic submission of reports. The application of overtime work regulations to the construction industry in 2024 (the so-called "2024 problem") is also imminent, making DX-driven labor-saving and sophistication imperative.

Against this backdrop, many construction companies are getting serious about promoting DX. DX not only helps offset labor shortages but also leads to quality improvement and strengthened safety management, and contributes to creating a smarter workplace environment attractive to younger generations. An active stance toward adopting cutting-edge technologies can also help dispel the image of the industry as "old-fashioned" among young people. In other words, civil engineering DX is an important key supporting the industry's future from three angles—productivity improvement, workstyle reform, and human resource development.

How AR Guidance Changes Construction Accuracy and Young Workers’ Autonomy: Worksites Where Young Workers Can Move Without Hesitation

Have you ever hesitated on site with plans in hand, wondering "Is this the right spot?" AR (augmented reality) guidance for on-site work can greatly alleviate such uncertainty. AR work navigation overlays lines and models based on design data onto the live camera view on a smartphone or tablet. For example, a 3D model of a structure according to the design can be projected onto the ground so you can check on the spot whether the position and elevation are off. Because you can imagine the finished form on screen and work without relying on veterans' intuition, anyone can intuitively grasp the precise work position.

The benefits brought by this AR guidance are immense. Key points include:

• Reduction in construction errors and quality improvement: It can significantly reduce rework caused by overlooking drawings or measurement mistakes. Because workers can always work while viewing lines and elevations as per the design, finishing accuracy improves and the fine-tuning work that relied on veterans' intuition becomes unnecessary.

• Real-time confirmation and immediate correction: It prevents traditional failures such as discovering defects after concrete has been poured and set. AR allows immediate detection of deviations on site and instant correction, enabling early rectification of problems and avoiding waste such as rearranging machinery or personnel later.

• Autonomy and growth of young workers: Even inexperienced young workers can proceed without hesitation with AR acting as a navigator. They can act on their own judgment without repeatedly asking seniors "Is this correct?", which builds confidence. Opportunities for contributing to the site as a "fully fledged" worker increase, accelerating skill acquisition through practical experience.

• Smooth information sharing and consensus building: If stakeholders share the completed image displayed in AR, misalignments in perception are reduced and communication improves. Young and veteran workers can look at the screen together and discuss in real time—"Let's lower that spot a bit"—and explanations to clients become intuitive just by showing the images.

AR guidance is like a "car navigation" for worksites. It offers reassuring directions for newcomers and reduces the burden of detailed instruction for veterans. As a result, the whole team moves more smoothly and quality improves, creating a virtuous cycle. AR is playing a major role in creating worksites where young workers can perform without hesitation.

The Educational Value of Visualizing As-built Data: Making Skills Visible Through Review and Comparison

On site, as-built data are measured after construction to verify whether the work was carried out according to the drawings. Traditionally, as-built management has been an indispensable process for quality assurance, but measurement results have often been submitted only as reports and not fully utilized for on-site learning. Valuable numerical data have tended to fail to resonate with workers and be treated as "as long as it passes inspection, it's fine."

However, recently the development of 3D scanners and photogrammetry technologies has made it possible to visually check as-built data on site. With tablets equipped with high-performance LiDAR sensors and small surveying devices attachable to smartphones, anyone can obtain point cloud data (three-dimensional as-built measurement information) on site in a short time. If the obtained 3D data are overlaid on the design data and displayed as a color-coded heatmap showing deviations, it becomes immediately clear where there are excesses or shortages. (For example, areas higher than the design are shown in red, and areas lower are shown in blue.) Checking this on-site lets you immediately see where embankments are too high or too low compared to the design and issue corrective instructions the same day. Digital technology is enabling real-time confirmation and visualization of as-built checks.

The visualization of as-built data not only aids quality control but also has a significant effect on developing young engineers. Specific educational benefits include:

• Immediate feedback for review: By reviewing their work immediately after construction with data, teams can quickly share what went well and what should be improved. Instead of holding a review the next day and trying to recall what was wrong, data-driven on-site discussion about improvement measures greatly speeds up the PDCA cycle.

• Objective self-evaluation: Deviations shown on a color map allow even young workers to objectively evaluate the accuracy of their work. Because feedback is based on visual facts rather than numbers or sensations, it is convincing and clarifies what to pay attention to next. Workers can grasp their growth in data terms, which boosts motivation.

• Making skills visible: Tacit knowledge that used to rely on veterans' experience becomes visible through data, making it easier to share skills. For example, subjective advice like "You should compact this a bit more" becomes easier for young workers to understand if supported by measured data. By verbalizing and visualizing veterans' know-how through data, technology transfer proceeds more smoothly.

• Knowledge accumulation and material creation: Accumulated as-built data become valuable company knowledge assets. By referring to past project data, newcomers can grasp "the level of accuracy required to pass," and failure and success cases with 3D models can be shared as training materials. This provides systematic learning opportunities that on-the-job training alone cannot cover.

Thus, by not merely making as-built data into reports but visualizing and utilizing them, on-site quality and productivity improve and the learning effect for young workers increases dramatically. If a culture of data-driven review takes root, continuous improvement and technical capability enhancement across the site can be expected. Furthermore, accumulated data can be maintained as a digital twin useful for maintenance and planning future work, so one construction becomes a resource for the future.

Specific Functions and Use Cases of LRTK: How It Lives in Training and Construction Sites

A solution that makes AR guidance and point cloud measurement like those described above easy to implement on site is LRTK. LRTK is an all-in-one surveying and AR system that combines a compact high-precision GNSS receiver with a smartphone or tablet. By launching a dedicated app and holding up the device, anyone can easily "see, measure, and record" on the spot. Main functions include:

• AR navigation: Design drawings and 3D models can be projected into real space to perform stakeout and as-built checks. Centimeter-level (half-inch-level) high-precision positioning using RTK-GNSS enables accurate AR display without troublesome calibration. Models do not drift while walking around the site and remain displayed in their designated locations, giving the sensation that the drawings are floating in space.

• 3D point cloud scanning: The surroundings can be scanned using a smartphone camera or LiDAR to acquire high-density 3D point cloud data. Survey work that once required specialized equipment can now be performed by taking a smartphone from your pocket—one person can perform surveying instantly with LRTK. Because the acquired point clouds have geographic coordinates, comparison with design data is easy, and creating as-built heatmaps or calculating volume and area can be done with a single tap.

• Geotagged photos and records: Photos taken with a smartphone are automatically tagged with position coordinates and orientation information and saved to the cloud. Site conditions that are difficult to convey with drawings can be intuitively shared using photos and map pins. For example, if a young staff member photographs a point of concern, a supervisor in the office can identify the location on a map while giving advice, making remote instruction simple.

• Cloud integration and data sharing: All data acquired with LRTK (survey point coordinates, point cloud models, photos, etc.) are synchronized to the cloud in real time (if outside radio coverage, data are stored on the device and uploaded once connectivity is available). Office PCs can immediately check on-site measurement results, and remote specialists can examine the data and provide advice—remote support becomes possible. The cloud also offers automatic processing functions (heatmap generation, report output), enabling seamless flow from measurement to report creation.

Using these functions can dramatically change workstyles on site. In training settings, LRTK can be used for "virtual stakeout experiences" and as-built measurement exercises during new employee training. Experiencing a site recreated in AR, rather than just classroom theory, greatly increases comprehension and interest. On construction sites, young employees are increasingly taking charge of stakeout positions and as-built checks with LRTK in hand. The barrier of "leave surveying to the surveyor" is breaking down, and even inexperienced people can actively participate in on-site measurements. In one site, a measurement task that used to take two people a half day was reported to be completed by one person in about one hour using LRTK. With this level of efficiency improvement, freed-up time can be used for the next work preparations or training young workers, raising both site productivity and training capability.

Moreover, LRTK's cloud features make remote support from veterans to young workers easy. A supervisor can check data measured by a young worker in real time and give immediate feedback—"dig a little more here"—without visiting the site. This represents a new form of skills transfer. Additionally, because LRTK is compact and operable through intuitive smartphone operations, even those unfamiliar with machinery or without physical strength can use it without trouble. Introducing the latest gadgets on site can also boost young workers' motivation and foster a sense of ownership—"our generation will drive DX"—which is another expected benefit.

Thus, LRTK provides a foundation enabling all on-site staff, including young workers, to actively use digital technologies. It can be considered a reliable partner for putting the article's themes—AR guidance and as-built data utilization—into practice on real worksites.

Conclusion: Pioneering the Future of Worksites with Digital Technology

As labor shortages and technology transfer issues come into sharper focus, the civil engineering industry is at a moment of transformation. Intuitive work support via AR guidance and immediate feedback through visualization of as-built data have created new styles of learning and work previously unseen on sites. Young engineers who proactively promote on-site DX and veterans whose experience is complemented by technology together strengthen the organization as a whole.

What is important is taking the first step to introduce these digital tools on site. Concerns such as "It looks difficult" or "Will it fit on site?" may arise. In practice, however, tools that anyone can master with only a smartphone and an app have appeared and are beginning to show results on many sites. Simple surveying and AR systems such as LRTK, introduced in this article, are representative examples designed for intuitive operation without specialized knowledge. Start by piloting them in a small department or project and observing the reactions of site staff.

With technology as an ally, tasks once considered possible only with experience can be handled by young workers. This not only increases efficiency but also gives young workers great confidence, pride in their site, and a sense of job fulfillment. As digital-generation young people demonstrate their abilities and fuse them with veterans' insights, future civil engineering sites will evolve into more resilient and attractive fields. Civil engineering DX is also a way to create people-friendly worksites. By leveraging the latest technologies and passing on skills and pride to the next generation, let us realize such a bright future with our own hands.