DX for As-built Management in the ICT Construction Era: New Methods That Transform the Field

Introduction: The "Digital Transformation" of As-built Management Has Begun

In recent years, terms like "ICT construction" and "DX (digital transformation)" have become commonplace in the construction industry. Among these, as-built management—which balances construction quality with accurate understanding of as-built conditions—is a critical process that greatly affects site productivity.

Traditional as-built management has relied on manual surveying using total stations and rods. However, this approach has faced the following issues:

• Requires two or more workers, resulting in high labor costs

• Transporting, setting up, and calibrating equipment is time-consuming

• Measurement conditions are limited by weather and terrain

• Transcribing and organizing survey results consumes significant man-hours

With a worsening labor shortage, establishing a system that enables high-quality surveying with limited personnel has become urgent.

"As-built management DX" addresses these challenges and achieves greater site efficiency and improved data quality. This article explains new as-built management methods required in the ICT construction era, following the actual construction management workflow.

Chapter 1: What Is As-built Management?

As-built management is the process of verifying that the shape, dimensions, and position of constructed structures conform to the design drawings. Accuracy of as-built conditions is the foundation of quality assurance for all types of work, including roads, slopes, embankments, and tunnels.

Conventional as-built management mainly used "point" measurements. In contrast, ICT construction requires management by "surfaces" and "volumes" using 3D data. This enables visualization of the overall shape of constructed elements and quantitative understanding of deviations from the design. In other words, unlike the conventional method that evaluated a limited number of measurement points, managing as-built conditions across the entire structure makes it possible to detect even minor unevenness that would otherwise be missed.

Chapter 2: The Role of As-built Management in Construction Management

The goal of construction management is to optimize quality, schedule, cost, and safety, and to complete construction as planned. Within this, as-built management directly verifies "quality" and "appearance," and serves three roles:

• Confirmation of consistency with the design: compare design values and measured values to verify they are within tolerances

• Feedback to the construction process: immediately reflect progress and error trends on site to improve subsequent processes

• Reporting results to the client: submit inspection materials to demonstrate quality

With the promotion of i-Construction (ICT-utilizing construction), the Ministry of Land, Infrastructure, Transport and Tourism formally recognizes as-built management using 3D measurement technology in its "As-built Management Manual." This is not merely automation of surveying; it aims for productivity improvement through centralized management and visualization of construction data.

1\. 3D conversion of design data

2\. Acquisition of construction data

3\. Coordinate unification and alignment Unify the site coordinate system (localization) with absolute coordinates (such as JGD2024 or WGS84) to align data to the correct positional reference.

4\. Comparison with the design Compare point clouds with design data to automatically calculate volume differences and shape errors.

5\. As-built reports and 3D visualization Automatically generate the inspection forms and cross-section drawings required for as-built inspection, and create 3D views that clients and supervisors can review.

\### 4-1. Reduction of surveying man-hours Conventional surveying used point-by-point measurements, but point-cloud scanning can acquire millions of coordinate points in 1 minute. This can shorten work time to one-tenth or less.

\### 4-2. Standardization of quality Human surveying inevitably introduces errors and variability. With DX, GNSS-RTK positioning with automatic corrections and AI recognition achieve the same level of accuracy regardless of who performs the measurement.

\### 4-3. Real-time sharing By sharing construction data on the cloud in real time, the office, site, and client can view the same data simultaneously. This dramatically shortens the time required for approvals and inspections.

\### 4-4. Prevention of re-surveying and rework With AR displays, the design model can be overlaid on the real scene on site. Because construction errors can be identified in real time, corrections can be made before rework occurs.

\### 4-5. Improved safety DX makes it easier to measure in hazardous or hard-to-access areas such as high slopes, under bridges, and narrow tunnels. Using drone aerial surveys or remotely operated 3D scanners, locations that were previously "unmeasurable" can be safely surveyed.

3D point cloud data dramatically improve the "reliability" and "efficiency" of as-built management.

• Visualization of overall shape: freely check cross-sections, longitudinal/transverse sections, and volumes

• Tracking changes over time: understand progress and deformation through time-series comparisons

• Automated report generation: automatically produce as-built inspection documents from 3D models

In the MLIT's "As-built Management Manual (earthwork edition)," as-built management using 3D data is clearly specified alongside the promotion of ICT construction (i-Construction).

• Formal approval of 3D laser scanners, UAVs, and GNSS surveying as measurement methods

• Standardization of design data in LandXML format

• Electronic delivery support for as-built reports

This trend is shifting site digitization from an "option" to the "standard." In other words, ICT utilization is becoming a commonplace prerequisite rather than a special option.

One local government introduced 3D point clouds for riverbank protection construction management. An as-built check that used to take 1 day was reduced to just 15 minutes with a single smartphone.

In another slope project, AR functionality was used to overlay the design model on the actual scene for confirmation. By visually understanding "how much to excavate to meet the design," they achieved zero rework.

What these cases have in common is ease of use that does not require specialized technicians. Even staff with limited field experience can perform high-quality construction checks, reducing reliance on individual expertise and raising overall organizational quality.

1\. Support for high-accuracy positioning (RTK method)

2\. Flexible handling of coordinate systems

3\. Integrated management of 3D point clouds, AR, and photos

4\. Cloud sharing capabilities

5\. MLIT-compliant report output

6\. Ease of use

LRTK is an ultra-compact RTK-GNSS receiver that can be attached to an iPhone or iPad. It weighs just 165 g and operates on battery power for 6 hours. No large tripods like traditional surveying equipment are required, and centimeter-level positioning (half-inch accuracy) is possible with a single smartphone.

• Point cloud scanning: acquire 3D data of embankments and slopes in 1 minute

• Volume and area calculations: automatically computed immediately after scanning

• AR display: overlay the 3D design model on site for construction verification

• Coordinate navigation: guide stake driving and control points with cm-level accuracy (half-inch accuracy)

It also automatically links with the cloud service "LRTK Cloud," allowing distance, volume, and cross-section measurements and comparisons in a 3D viewer.

Traditional surveying and as-built checks have been treated as specialist tasks. With LRTK, the workflow is completed through app operation and smartphone scanning alone.

• Site agents and foremen can record as-built data themselves

• Immediate sharing with designers and clients is possible

As-built management is not just an inspection step; it is the most important process that determines overall construction quality.

Achieving centimeter-level precision with a single smartphone, and seamless integration from site to cloud, LRTK is an innovative tool that removes the boundary between "as-built management" and "construction management."

If you feel the need to "reduce rework," "simplify surveying," or "make explanations to clients easier," experience simple surveying with LRTK.

Your smartphone can become the leading role of as-built management DX on your next site.