Five Successful Cases of Construction Efficiency Improvement — Secrets of Site Reform Through Cost Reduction and DX

In recent years, the construction industry has faced many challenges, including labor shortages, long working hours, and inefficient paper-centered workflows. In addition, there is strong pressure around safety management, skill transfer, and cost reduction, and digital transformation (DX) has attracted attention as a means to address these issues. Real-world success cases of companies that achieved operational efficiency and cost reduction reveal the significant impact DX can have on site reform. This article presents five concrete cases of construction site efficiency improvements for executives at construction companies, DX promotion staff, site managers, and civil engineering technicians in local governments. We cover five cases ranging from major general contractors to small and medium-sized contractors, explaining each in the flow of “challenge → DX measures → results → future outlook.” We will look at what kinds of reforms were implemented in areas such as surveying, as-built management, progress management, cloud sharing, safety management, work-style reform, and paperless operations, and what changes DX brought to the field.

Case 1: Shimizu Corporation — Enhancing Construction Management with a BIM Platform and AR

Challenge

As a major general contractor, Shimizu Corporation faced challenges such as fragmented information across design, construction, and maintenance, and a heavy burden on site supervisors. Work often relied on paper drawings and on-site checks, causing rework and inefficient information sharing. For example, construction managers had to spend long hours touring sites for progress and quality checks, leading to workload and time losses.

DX Measures

To address these issues, Shimizu developed an internal BIM platform, “Shimz One BIM,” creating a foundation to centrally manage and share 3D models and information across design, construction, and maintenance phases. They also introduced the following advanced tools:

• Cloud-integrated BIM: By linking “Shimz One BIM” with cloud services, drawings and model data are shared in real time internally and externally. This allows staff to check construction information on tablets from anywhere, drastically reducing time spent on site rounds (site rounds that used to take about 4 hours were reduced to around 30 minutes).

• Intuitive construction checks with AR: They developed an AR application called “Shimz AR Eye.” By overlaying BIM 3D models on live site footage via iPad, complex piping and equipment interfaces can be checked intuitively on the spot, helping to prevent overlooked details and construction mistakes.

• AI-equipped rebar inspection system: They introduced a rebar inspection system with a three-lens camera called “写らく,” enabling automatic capture and analysis of rebar placement. This reduced the time required for complex rebar inspections by about 75% compared to conventional methods, improving efficiency while raising inspection accuracy.

Results

Through these DX measures, Shimizu dramatically improved construction management and information-sharing efficiency. By rolling out the BIM platform company-wide, data flows seamlessly across design, construction, and maintenance phases, allowing all stakeholders to share the latest information at all times. Site supervisors’ tour time was shortened from 4 hours to about 30 minutes, and rebar inspection time was reduced to a quarter of the previous duration. AR visualization made complex work visible, enabling even less-experienced staff to verify tasks without relying on veteran intuition. As a result, the company achieved both reduced rework and improved quality, contributing to cost reductions and shorter construction durations. Reduced site travel and improved work efficiency also produced benefits in work-style reform, allowing employees to focus on more productive tasks.

Future Outlook

Shimizu plans to continue promoting company-wide DX under the banner of a “digital general contractor,” leveraging BIM, AI, and IoT. They intend to further develop Shimz One BIM and expand it into post-completion building management services. By utilizing the vast amounts of data collected from sites, they aim to optimize construction processes and pursue predictive maintenance to foresee and prevent issues, advancing even more sophisticated site reforms. Shimizu’s example demonstrates that investing heavily in building a platform and addressing site-specific issues with dedicated tools can fundamentally transform construction site practices.

Case 2: Kajima Corporation — Dramatically Raising Productivity with Machine Automation and IoT

Challenge

Kajima Corporation, another major general contractor, faced low productivity on large-scale projects, worker shortages, and safety assurance challenges. Civil engineering works, in particular, require many heavy machines and operators, so improving efficiency amid labor shortages was essential. Heavy equipment operations are always risky, so safety improvements were also demanded. To address labor shortages and advanced construction needs, automation and labor-saving at the site became urgent.

DX Measures

Kajima actively introduced ICT construction and IoT to drive site automation and visualization. They developed several proprietary systems and platforms, including:

• Heavy equipment autonomous operation system “A4CSEL (Quad Accel)”: This groundbreaking system links multiple construction machines via GPS and various sensors, enabling a single operator to remotely operate multiple machines simultaneously. For example, on a dam project, automatically operated bulldozers and dump trucks were controlled such that 15 machines were managed by 4 people, roughly doubling productivity and reducing fuel consumption by about 50%. Automation enabled large-volume construction with few personnel in a short time.

• Integrated site information platform “Field Browser”: An IoT platform that aggregates and manages all site information—people, materials, machines, and environmental data—in real time. It monitors machine operation status, worker positions, safety sensor data, and weather data in a unified manner. This allows off-site offices to accurately grasp site conditions and provide immediate instructions and decisions, reducing the need to visit sites and speeding up decision-making.

Results

Kajima’s DX efforts significantly improved site productivity and safety. Automation of heavy equipment with A4CSEL increased the amount of work that could be handled within the same construction period, reduced the required number of machine operators (lowering labor costs), and cut fuel costs. Automating hazardous tasks also contributed to reduced occupational accident risks. Using Field Browser for visualization enabled site managers to control many operations remotely, improving overall progress and schedule management. For example, analyzing equipment operation data eliminated unnecessary idle time, and using environmental sensor data allowed precise decisions on work stoppages—enabling optimal, data-driven site operations. These achievements allowed Kajima to realize cost reductions, shorter schedules, and improved safety on large-scale projects.

Future Outlook

Kajima plans to further leverage advanced technologies including robotics and AI, continuing efforts toward full site automation. Although results have been achieved in earthworks and dam construction, they aim to deploy autonomous construction systems in the building sector in the future—challenging concepts like 24-hour operation and unmanned construction to push productivity to the limit. They also intend to use the vast construction data collected by Field Browser to start AI-based anomaly detection and advanced quality control. Kajima’s case is expected to remain a leading example of “smart construction” that will drive industry-wide DX.

Case 3: Kumagai Gumi — Making Dangerous Tunnel Work Unmanned via Remote Operation

Challenge

Midsize general contractor Kumagai Gumi faced major challenges in mountain tunnel work: ensuring worker safety and improving work efficiency. The tunnel face, known as the “heading,” is a high-risk environment vulnerable to collapse. Traditionally, blast charging (loading dynamite) and shotcrete spraying at the heading were done manually, putting even skilled workers at risk of accidents. The careful nature of work in hazardous areas also slowed processes, hindering productivity improvements.

DX Measures

Kumagai Gumi introduced remote operation technologies to make dangerous work near the tunnel heading as unmanned as possible. Specifically, they developed and implemented the following systems:

• Remote blast charging system: Equipment was introduced that allows explosives to be set by remote control from a safe distance, so workers no longer need to enter the heading directly.

• Remote-controlled shotcrete application: A system was built where high-definition cameras capture images of the heading and operators in a remote control room manipulate a robot arm nozzle to spray concrete. Operators can work from a shielded, safe environment while achieving injection accuracy equal to or better than conventional methods.

Results

These DX measures enabled Kumagai Gumi to successfully unmanned the most dangerous processes in tunnel construction. Eliminating personnel entry into the heading significantly reduced the risk of collapse and explosion accidents, representing a major step toward zero occupational accidents. Productivity also improved: for example, the remote charging system cut explosive loading time by about 45%, speeding up work cycles. Shotcrete work performed by remote robots could be carried out continuously with fewer interruptions, raising work efficiency. Overall, they achieved both improved safety and efficiency. Site workers reported that not having to go to the most dangerous front lines provided great peace of mind, increasing mental comfort and productivity. This also positively influenced worker motivation and the recruitment of young talent.

Future Outlook

Kumagai Gumi plans to expand the tunnel know-how to other civil engineering fields and further develop “unmanned construction.” They will not only pursue remote operation but also focus on robot technologies that combine AI to perform tasks autonomously. Additionally, they plan to enhance safety management with sensors and image analysis to monitor heading conditions in real time and have AI assess risk levels and issue warnings. These initiatives aim to realize a new site model where aging skilled workers are protected by machines handling dangerous tasks while humans act as supervisors. Kumagai Gumi’s success is a DX example that advances safety and efficiency in tandem and is likely to be applied to other infrastructure works.

Case 4: Kato Construction — A Midsize Firm’s Paperless and Drone Survey Reform

Challenge

Kato Construction (pseudonym) is a midsize construction firm with several dozen employees. The company faced inefficiencies in internal procedures and site surveying. In the back office, stacks of paper application forms required processing—around 100 types of forms such as approval requests and various notices were handled by handwritten forms and fax, causing approval delays and operational stagnation. On-site, measurement and as-built verification of existing structures during bridge reinforcement and tunnel planning were performed manually, requiring many personnel and days. As a small firm, staff shortages made it urgent to reduce both administrative and surveying workloads.

DX Measures

As DX measures feasible within limited resources, Kato Construction digitized office operations and introduced ICT to field surveying. Specific initiatives included:

• Paperless workflow system: They introduced a cloud-based electronic approval and application system (e.g., “X-point Cloud”), converting about 100 internal forms into electronic forms. This eliminated paper circulation, allowing application-to-approval workflows to be completed online and reducing application processing time by about 50%, significantly lowering administrative burden for both staff and managers. It also removed the need for physical storage and made information retrieval easier.

• Use of drone surveying: For site measurements, they adopted photogrammetry using drones. Numerous aerial images are processed with dedicated software to automatically generate high-precision 3D point-cloud models of existing structures and terrain. This enabled tasks that previously required multiple people and several days—such as measuring bridge dimensions and terrain— to be completed quickly by a small team. For example, reinforcement design for bridge piers now uses millimeter-scale 3D models from drone data, making on-site measurement almost unnecessary. In tunnel work, they implemented a system that uses laser scanners to measure excavated soil volumes on conveyors in real time, assisting in surface subsidence risk monitoring and automating as-built management.

Results

Through this two-pronged DX approach, Kato Construction achieved notable efficiency gains in both office and field work. Paperless workflows halved the time required for internal approval flows, speeding up decision-making. Staff were freed from printing, stamping, and mailing tasks and could spend time on more productive work. Drone surveying greatly reduced the number of personnel and days required for surveys; for instance, a task that had needed five people and two days could be completed with one drone and one operator in about half a day. This led to reductions in labor and subcontracting costs, improved measurement accuracy, and shorter lead times for planning, reducing total project costs. By advancing DX in both back office and field, employee mindset shifted toward reviewing workflows using digital technology, fostering a corporate culture of continual improvement.

Future Outlook

Building on this success, Kato Construction plans to continue promoting work-style reform through company-wide DX. They will refine the electronic workflow and expand digitalization to other departments such as sales and accounting. On site, they consider introducing terrestrial 3D laser scanners and ICT-equipped construction machinery to further enhance construction management and safety. Although large-scale investments are challenging for small firms, Kato intends to continue a “start small where you can” approach using cloud services and low-cost equipment. Their achievements are a useful reference for other small and medium enterprises, and Kato hopes to share their know-how within the industry to promote regional construction DX.

Case 5: Hazemoto Construction — DX for Small Sites Using Smartphones and the Cloud

Challenge

Hazemoto Construction, a local small contractor in Kitakyushu, Fukuoka Prefecture, handles many residential and office renovations as a community-based builder. They sought ways to improve site productivity without large investments. Traditionally, site measurements were done manually with tape measures and sketches, and creating floor plans could take multiple people a whole day, so surveys and measurements required significant time and manpower. Photos and drawings taken on site were brought back to the office and sent via fax or email, creating time lags in information sharing. The company needed DX measures that could be implemented with limited budgets and personnel.

DX Measures

Hazemoto focused on small-scale DX using smartphones and easy cloud tools—combining familiar devices and services rather than expensive specialized equipment. Their initiatives included:

• Efficiency in as-built surveys via smartphone apps: They adopted as-built survey apps that integrate with iPhone/iPad LiDAR scanners, allowing automatic generation of dimensioned 3D models and floor plans simply by photographing the interior with a smartphone. This enabled surveys that used to take multiple people a day to be completed quickly by one person, and digitalization of walls, floors, and ceilings improved the accuracy of estimates and design.

• Faster information sharing using the cloud: For communication between site and office, they used a cloud-based construction management system. Photos taken during construction and drawing revision requests were uploaded to the cloud from the field via smartphone and shared with stakeholders in real time. This eliminated the need for site supervisors to return to the office to prepare reports, and questions and approvals could be exchanged online instantly.

Results

Hazemoto’s small-scale DX produced surprisingly large efficiency gains even on small sites. For as-built surveys, work time was reduced to one-tenth or less compared to analogue methods, and storing survey results as 3D data prevented rework and virtually eliminated measurement errors. Cloud sharing drastically reduced waiting times for site reports and instructions, eliminating communication losses. Problems occurring on site could be reported with photos immediately, and head office technicians could promptly instruct countermeasures—greatly accelerating decision-making. As a result, project durations shortened and overtime decreased, yielding cost savings and work-style reform benefits. Importantly, because these DX measures were centered on smartphones and inexpensive apps, the cost performance was high, giving employees confidence that small companies can achieve significant DX benefits.

Future Outlook

Based on this success with familiar technologies, Hazemoto plans to continue pursuing low-cost, practical DX. Specific plans include introducing small surveying devices that can be attached to smartphones for more precise measurements, expanding cloud-based drawing sharing and client presentation materials, and sharing their DX know-how with regional partner firms to lift the construction industry in their area. Hazemoto’s case is a prime example that DX can succeed with a small start, and they will continue incremental digitalization tailored to site challenges.

Above, we have reviewed five success stories that achieved operational efficiency and cost reduction in the construction industry. Despite differences in scale from major firms to small businesses, they all share the approach of accurately identifying site issues and applying appropriate digital technologies to solve them. Each company began with careful problem analysis before introducing solutions and embedded DX by accumulating small wins. DX has delivered not only productivity improvements but also added value such as enhanced safety and better work styles.

So, what should companies that want to start DX do first? The key point is to “start small.” It is not always necessary to adopt a large-scale system from the outset. Starting with low-cost, ready-to-use solutions such as cloud services and smartphone-based tools is a good approach.

For the First Step in Site Improvement, Consider Simple Surveying with LRTK

A particularly recommended small-start DX measure is digitizing simple surveying. Are you familiar with a cutting-edge tool called “LRTK,” developed by a startup originating from Tokyo Institute of Technology? LRTK is a pocket-sized, all-purpose surveying device that attaches to a smartphone, enabling anyone to easily achieve high-precision field measurements. By attaching a small device weighing only about 165 g and about 1 cm thick to an iPhone or iPad, precision positioning and 3D scanning—tasks that once required specialized surveying instruments—become possible. With LRTK, you can perform the following all-in-one functions:

• Centimeter-class positioning: It supports RTK-GNSS (real-time kinematic) technology, allowing the smartphone to function as a positioning antenna and obtain coordinates with centimeter-level accuracy. The high precision is suitable for as-built management, and it can accurately measure elevation and distances.

• Point-cloud measurement with a smartphone: By cooperating with an iPhone’s camera and LiDAR sensor, you can walk around and scan surrounding structures and terrain into 3D point-cloud data. Because LRTK constantly provides high-precision position corrections, it is possible to obtain point-cloud models with less distortion than is achievable with a smartphone alone—for example, quickly digitally measuring mounds of excavated soil or as-built terrain.

• AR composited display: Measured point clouds and design data can be overlaid on the real-world view on the smartphone screen for AR display. This supports layout tasks and visualizes assumed positions of buried objects on the spot, enabling intuitive construction management.

• Instant cloud sharing: Survey data and point-cloud models acquired with LRTK can be uploaded to the cloud with a single button and shared within the team. Collaborators or clients without dedicated software can view 3D models in a browser, smoothing data linkage between site and office and allowing all stakeholders to work with the same real-time information.

By using LRTK, a single person can easily perform high-precision surveying and record-keeping, allowing tasks once dependent on specialized surveyors to be handled in-house. This can significantly reduce labor and time costs for surveying and immediately lead to site efficiency improvements and cost reduction. The device is simple to use and designed for intuitive operation by site staff, reducing resistance when introducing DX tools. It is also compatible with the Ministry of Land, Infrastructure, Transport and Tourism’s i-Construction initiative and has the potential to become a future standard.

As a first step in site reform, consider introducing such simple surveying DX tools. Small initiatives, when accumulated, produce substantial effects. As the cases presented here show, the success experience gained from the first step can accelerate DX promotion within the company. Identify solutions that match your challenges and start DX where you can. Site efficiency and reform begin with a decisive first step. Let your site be the next success story!