Drastic Reduction in Construction Errors! Quality Assurance and Rework Reduction Enabled by AR Civil Engineering

Table of Contents

• Errors and rework challenges at construction sites

• What is AR civil engineering?

• Innovations in quality assurance brought by AR civil engineering

• Dramatic reduction in construction errors: effects AR brings to the field

• Rework reduction: why AR reduces redo work

• AR civil engineering initiatives advancing in Japan

• High-precision positioning is key: technologies that support AR use

• Simple surveying with LRTK

• Summary

• FAQ

Errors and rework challenges at construction sites

On civil engineering sites, small construction errors often develop into major problems. Misreading drawings, surveying mistakes, and communication lapses—minor discrepancies—can cause quality defects and schedule disruptions, ultimately leading to rework (redo work). Once rework occurs, delays and cost increases are inevitable. Site supervisors and craftsmen take great care every day to prevent such mistakes, but there are limits to traditional methods that rely solely on human visual checks and experience.

Rework caused by construction errors not only lowers construction quality but also directly impacts corporate credibility and safety risks. For example, domestic surveys report that a considerable proportion of new construction projects have some kind of defect pointed out. In fact, global research suggests that about 5–10% of total construction project costs are spent on rework. This is a figure that greatly impairs site productivity, and more than half of the causes are attributed to insufficient information transfer or communication errors. In other words, mistakes are caused when drawings or instructions are not shared correctly or when misunderstandings arise on site.

In current quality assurance processes, it is common to discover and correct errors through inspections during construction or checks after completion. However, the later a problem is found, the greater the cost and time required to correct it. Regrets of “If only we had noticed earlier…” are all too common on sites. So how can we achieve early detection and prevention of these construction errors and strengthen quality assurance?

What is AR civil engineering?

Attention is turning to the use of AR (civil engineering). AR stands for Augmented Reality, a technology that overlays digital information onto the real-world view. AR civil engineering refers to initiatives that apply this AR technology at civil engineering and construction sites. Specifically, it becomes possible to project design drawings and 3D models onto construction sites in real time through tablet or smartphone cameras, or dedicated AR glasses.

For example, you can display a 3D model of a planned bridge or road on an empty lot where the structure has not yet been built, or visualize the positions of underground utilities (pipes, cables, etc.) on excavated ground. Workers can proceed with tasks while checking the “finished state” or “hidden structures” via the screen, gaining a sense as if reality and drawings have merged and thereby grasping the site more intuitively.

AR civil engineering thus creates an environment where physical reality and digital design information can be confirmed simultaneously on site. As a result, information that was difficult to convey with paper drawings or 2D diagrams becomes intuitive, and on-site recognition gaps are closed. AR civil engineering is expected to be a technology that brings digital transformation (DX) to traditional construction management and quality assurance.

Innovations in quality assurance brought by AR civil engineering

Introducing AR technology significantly innovates quality assurance processes in civil engineering. One of the biggest advantages is that as-built (dekigata) inspections and quality checks can be performed in real time. Traditionally, as-built inspections were done after a stage of work was completed using surveying equipment or visual checks by staff; with AR, you can overlay the digital design model onto the actual progress and check it on the spot during construction.

For example, in earthworks such as embankment or excavation finishing, AR can project a color-coded heat map of finished heights on site. This makes it instantly clear “which parts are higher or lower than the design.” Tasks that were previously confirmed by batter boards (reference stakes) or level surveys can be automatically visualized by AR, thereby greatly reducing human measurement errors and missed checks. Site personnel can understand excesses or deficiencies in quality simply by viewing the color-coded information on a tablet screen and correct the work immediately.

Furthermore, AR also enables greater efficiency in quality inspections. Until now, quality inspections often required multiple people to attend and time-consuming measurement tasks. But overlaying data with AR allows even one person to check extensive areas in a short time in many cases. For instance, for rebar placement inspections, comparing the designed rebar locations on the model with the actual rebar via AR makes it easy to detect misalignments that might be missed by visual inspection. For quality assurance personnel, AR becomes “another eye for the site supervisor,” allowing them to determine construction quality with high precision and speed.

Dramatic reduction in construction errors: effects AR brings to the field

The effects of AR civil engineering are not limited to quality checks. As a tool that prevents construction errors themselves, AR is extremely powerful. Because workers can operate while viewing images overlaid with digital information, the risk of workers proceeding based on incorrect interpretations is greatly reduced.

Traditionally, workers would hold paper drawings and confirm instructions such as “dig a hole here” or “build up to this height.” Less experienced workers often struggle to translate dimensions and positional relationships from drawings to the field, leading to measurement mistakes and misplacement. However, with AR, on-site visual guides such as “excavate to this point” or “place the structure here” appear through the camera, reducing reliance on intuition. As a result, AR creates an environment in which construction errors are less likely to occur.

AR also revolutionizes on-site communication. For example, instead of a foreman or supervisor verbally explaining “build this thing at this position,” projecting the completed image at the location with AR prevents misunderstandings or differences in interpretation. Because veterans and newcomers, designers and constructors, and other members with different perspectives can work with a shared image, communication gaps that lead to confirmation errors and rework are reduced.

In fact, sites that have introduced AR report that human errors such as “misreading the drawing and redoing rebar placement” have almost disappeared. Workers can always perform tasks while seeing the correct finished image, which boosts their confidence and tends to improve construction speed as well. With fewer mistakes, rework due to quality defects is drastically reduced, creating a virtuous cycle that increases overall site productivity and morale.

Rework reduction: why AR reduces redo work

Reducing rework is a crucial topic for improving productivity in construction projects. There are two major reasons AR civil engineering reduces rework. One is the aforementioned reduction of errors themselves, and the other is the early detection of errors and rapid correction.

First, if errors are fewer, there is naturally less chance for rework to occur. If AR enables accurate construction from the start, there is no need for unnecessary demolition and redo work later. This also saves materials and reduces waste, offering environmental benefits.

Second, even if problems arise, AR helps detect them early. Because you can overlay the digital model and the actual state during construction, you can, for example, find formwork misalignments before concrete placement or notice pipe position errors before burying them. Mistakes that used to be found only in post-completion inspections can now be handled on site by real-time verification. If a problem can be corrected the same day, it will not escalate into major rework. As a result, the number of rework cases across the project is drastically reduced.

Moreover, AR is powerful for building consensus among clients and designers. Sharing the completed image in AR in advance makes it less likely that “this is not what I expected” design changes will occur later. Because clients can better visualize the finished product, zero rework due to misunderstandings is not a pipe dream. In one infrastructure project, for example, AR was used to explain the post-construction landscape to local residents, which smoothed understanding and agreement for the plan and resulted in no subsequent modification negotiations.

Thus, AR civil engineering usage leads to an environment of “not having to redo things.” The three elements of error prevention, early detection, and alignment of understanding among stakeholders together dramatically reduce the frequency of rework and promote a culture of getting construction right the first time.

AR civil engineering initiatives advancing in Japan

In Japan, initiatives for AR civil engineering are becoming increasingly active year by year. AR is being used across a wide range of sites, from major construction firms to small and medium-sized job sites, and even by government agencies and educational fields. This trend is driven by productivity improvement measures promoted by the Ministry of Land, Infrastructure, Transport and Tourism such as *i-Construction* and infrastructure DX, and by the need for digital technologies to offset the shortage of skilled workers.

As a concrete example, a major general contractor developed a proprietary system that overlays BIM data (3D design data) with camera images on tablets and conducted trial operations at many construction sites. As a result, confirming piping and structures above ceilings became easier, and common oversights and rework during renovation work were greatly reduced. Another construction company introduced a smartphone-based AR surveying app and reported that measuring earthwork volumes (excavation and embankment) was completed in less than one-tenth of the time previously required. What used to take half a day for as-built measurement finished in about 30 minutes, and the acquired data could be saved and shared directly as a 3D model, reducing time spent creating quality records.

On the governmental side, the MLIT’s regional development bureaus have established Infrastructure DX Centers to demonstrate and promote advanced technologies. AR-based as-built inspections and streamlined construction management are among the topics covered, and these methods are expected to spread nationwide as standard practice. At the municipal level, advanced cases have appeared where AR and high-precision positioning technologies are used for rapid damage assessment and design-change consideration at disaster recovery sites.

AR civil engineering is thus not a niche topic for a few special sites but is shifting toward industry-wide adoption. With national efforts toward digitalization, AR will become routine at many more sites in the future.

High-precision positioning is key: technologies that support AR use

One important technical point is required to fully utilize AR civil engineering in the field: high-precision alignment (positioning technology). If you are going to overlay a digital 3D model onto real space, even slight errors in position or scale will prevent achieving the intended effect. For example, if a model appears floating several tens of centimeters (tens of inches) away from the actual structure, it will not only fail to assist quality checks but may even hinder work. Therefore, to reliably produce results with AR, it is necessary to determine positions on site with accuracy within a few centimeters (within a few inches), and in some cases millimeter-level precision (mm, e.g., 1 mm = 0.04 in).

Traditionally, achieving this precision required linkage with surveying equipment such as total stations. There are cases where AR glasses combined with total stations achieved overlay errors on the order of about 5 mm (0.20 in) across large-scale works. However, total stations require specialized knowledge for setup and operation, and their cost and size make them difficult to deploy at every site. Ordinary GPS has errors in the range of about 5–10 m (16.4-32.8 ft), so it cannot be used for precision work as is.

To solve this issue, a high-precision positioning technology called RTK (Real-Time Kinematic) has emerged. Using RTK-GNSS, special correction signals can reduce satellite positioning errors to below a few centimeters. Recently, devices that make RTK easy to use have been developed, and when combined with smartphones and tablets, they allow anyone to obtain highly accurate position information. With the availability of high-precision positioning, the barriers to AR civil engineering adoption have fallen dramatically, and practical use at many more sites is progressing.

Simple surveying with LRTK

When discussing the fusion of high-precision positioning and AR use, it is worth mentioning a solution called LRTK. LRTK is designed so that a single person can easily perform high-precision surveying without traditional surveying equipment. By attaching a compact high-precision GPS receiver (antenna) to a smartphone and linking a dedicated app with cloud services, you can quickly acquire accurate coordinate data and point-cloud data on site.

Using LRTK, for example, a single person can scan the ground surface across a wide construction area in minutes and immediately create a 3D model. Because the acquired point-cloud data has absolute coordinates attached, displaying it in AR makes the real and digital match exactly. In other words, you can significantly reduce the cumbersome surveying work while ensuring the accuracy needed for AR civil engineering. Tasks that previously required two people and half a day can be completed quickly by one person operating the device when using LRTK simple surveying.

LRTK simple surveying is designed so that even non-specialist survey personnel can handle it. The equipment is lightweight and easy to carry; by walking the site with a smartphone-sized device in a pouch, the necessary positioning and data collection are performed automatically. This “democratization of surveying” is enabling an era in which anyone on site can use high-precision position information.

As a result, the foundation for maximizing the effects of AR civil engineering is established. Combining the accurate measurement data acquired by LRTK with AR technology allows consistent visualization and utilization of differences between digital and real—from as-built management and quality inspections to design discussions. Simple surveying solutions like LRTK will be a reliable ally in AR adoption that realizes quality assurance and rework reduction.

Summary

AR utilization in civil engineering (AR civil engineering) is an innovative approach that achieves dramatic reductions in construction errors, leaps in quality assurance, and productivity gains via reduced rework. By visually sharing digital information on site, all workers can hold the same target image and proceed with accurate, efficient construction. Rework that used to be considered inevitable can be drastically reduced through the power of AR combined with high-precision positioning technologies.

Japan’s construction industry is now at a major turning point. Challenges such as labor shortages caused by population decline, responses to work-style reforms, and increasing maintenance demand for aging infrastructure are mounting. One key to overcoming these is the use of digital technologies, and AR in particular is a strong tool that raises intuitive understanding and work accuracy on site. From sites that have implemented it, voices like “We can never go back to working with drawings alone” are heard, showing the clear benefits.

Going forward, AR civil engineering will become more widespread and commonplace at many construction sites. New technologies like LRTK simple surveying will support this trend, and a future where everyone can achieve advanced construction management is near. If your site struggles with construction errors or rework, consider a solution that combines AR and the latest surveying technologies. It could very well be the first step that dramatically changes how your site works and what it produces.

FAQ

Q: What is AR civil engineering? A: AR civil engineering refers to the overall use of augmented reality (AR) technology in construction and civil engineering fields. Specifically, it is a technology that displays design drawings and 3D models over actual scenery on-site using smartphones, tablets, or AR glasses. This allows intuitive understanding of the finished appearance and the positions of buried utilities, helping to prevent construction errors and enabling quality verification.

Q: Will adopting AR really reduce construction errors? A: Yes, it is expected to. By introducing AR, workers can always confirm the correct finished image and design information while working. As a result, human errors such as misreading drawings or misjudging positions are greatly reduced. On sites that have used AR, there are reports that rebar mistakes have disappeared and surveying errors have drastically decreased, and the number of rework tasks has gone down.

Q: What is needed to use AR technology on site? A: At a minimum, you need an AR-capable device (tablet, smartphone, or AR glasses) and digital design data to display. In addition, to achieve accurate alignment, using systems with positioning capabilities such as GPS or RTK will enable higher-precision AR use. Dedicated AR apps and cloud services are also available nowadays, making the introduction to sites relatively easy.

Q: Can site staff who are not tech-savvy master AR? A: Yes. Modern AR solutions are designed to be user-friendly for field personnel. They feature intuitive interfaces and simple operation, and basic operations can be learned in a short training session. Once users experience the convenience, many say they cannot return to traditional methods. In particular, when combined with simple surveying systems like LRTK, even those without specialist knowledge can achieve high-precision AR display and surveying with button operations, so non-technical users can feel secure.

Q: What is LRTK simple surveying? A: LRTK is a high-precision positioning system leveraging RTK-GPS technology, developed to enable easy surveying and positioning by anyone. It is used by attaching a small positioning device to a smartphone and using a dedicated app to acquire and process position information and point-cloud data. It enables surveying tasks that previously required specialized equipment and skilled personnel to be done quickly by one person, and the acquired data can be used directly in AR for construction management and quality verification.