Can Ground Penetrating Radar Reliably Verify Earthquake-Damaged Foundations? Insights from a Real Industrial Case Study

Earthquakes frequently cause visible structural damage, yet some of the most critical failures remain hidden beneath the ground. Foundation defects such as cracks, fractures, or excessive settlement may not be immediately apparent after a seismic event, making post-earthquake safety assessment both technically challenging and economically important. Conventional inspection methods often require destructive testing or provide limited information regarding subsurface structural conditions. Consequently, engineers increasingly seek reliable non-destructive evaluation (NDE) techniques capable of rapidly assessing foundation integrity without interrupting construction or building operations.

The study reviewed in this article investigates how Ground Penetrating Radar (GPR) can be applied to evaluate the condition of a deep pile foundation following the 2022 West Pasaman earthquake in Indonesia. Rather than relying solely on a single inspection technique, the researchers demonstrate how GPR can complement conventional foundation integrity testing to provide greater confidence in engineering decision-making. Their findings offer valuable insights for civil engineers, structural consultants, infrastructure managers, disaster mitigation specialists, and researchers interested in resilient infrastructure and post-earthquake structural assessment.

Bibliographic Information

Item	Information
Article Title	Application of Ground Penetrating Radar for Evaluating Foundation Structure Condition After Earthquake
Authors	Risma Apdeni, Zel Citra, Fitra Rifwan, Prima Yane Putri, Nevy Sandra, Yosie Malinda, Paksi Dwiyanto Wibowo, Reza Ferial Ashadi, and Annisa Prita Melinda
Journal	Teknomekanik
Volume & Issue	Volume 7, Issue 1
Publication Year	2024
Pages	85–100
DOI	https://doi.org/10.24036/teknomekanik.v7i1.26772
Publisher	Universitas Negeri Padang
License	Creative Commons Attribution 4.0 International (CC BY 4.0)

1. Research Background

Indonesia is one of the world's most seismically active regions. Located at the convergence of the Eurasian, Indo-Australian, Pacific, and Philippine tectonic plates, Indonesia experiences frequent earthquakes that pose significant risks to buildings, infrastructure, and public safety. West Sumatra is particularly vulnerable because it lies close to the Sunda subduction zone and the Great Sumatra Fault.
Foundation failure is a major contributor to structural collapse during earthquakes. Although visible damage often attracts immediate attention after seismic events, hidden damage within foundation systems can compromise the long-term safety and stability of buildings. Even minor undetected defects may develop into serious structural problems during future loading conditions.
The 2022 West Pasaman earthquake created an urgent need for structural evaluation. A magnitude 6.1 earthquake struck West Pasaman, Indonesia, while a ten-story feed mill tower was under construction. Because strong ground motion was experienced at the project site, engineers needed to verify whether the deep foundation system remained structurally sound before continuing construction.
Conventional non-destructive testing methods have practical limitations. Techniques such as Ultrasonic Pulse Velocity (UPV) testing and the Pile Integrity Test (PIT) are widely used to assess concrete quality and pile integrity. However, each method has inherent constraints related to interpretation, accessible inspection depth, material characteristics, and uncertainty when evaluating connection joints or subsurface anomalies.
Ground Penetrating Radar (GPR) has emerged as a promising complementary inspection technology. By transmitting high-frequency electromagnetic waves into the ground, GPR enables engineers to visualize subsurface features without excavation. Previous studies have demonstrated its capability for identifying buried structures, estimating pile depth, and detecting discontinuities within concrete and foundation systems.
Previous GPR investigations were generally conducted as stand-alone evaluations. Earlier research primarily interpreted foundation conditions using only GPR observations, without comparing the findings against results obtained from other non-destructive testing methods. Consequently, evidence regarding GPR's role in resolving uncertainties generated by complementary inspection techniques remained limited.
The study addresses an important engineering gap. Following inconclusive Pile Integrity Test (PIT) results indicating possible impedance reduction within the foundation, the researchers employed Ground Penetrating Radar as an additional verification tool. This integrated assessment strategy provides a practical example of how multiple non-destructive techniques can be combined to improve confidence in post-earthquake structural evaluation.
The research emphasizes engineering reliability rather than technological novelty alone. Instead of introducing a new sensing device or signal-processing algorithm, the study demonstrates how an existing geophysical technology can be strategically incorporated into structural health assessment workflows to support more reliable engineering decision-making after seismic events.

2. Research Objectives

Evaluate the structural condition of a deep pile foundation after the 2022 West Pasaman earthquake using Ground Penetrating Radar (GPR) as a non-destructive testing technique.
Determine whether cracks, fractures, or discontinuities exist within the slab, pile cap, or spun pile foundation following strong seismic loading.
Measure the actual depth of the foundation piles and compare the observed dimensions with the original engineering design specifications.
Assess the thickness of the slab and pile cap to verify whether the constructed foundation complies with design documentation.
Investigate the uncertainty identified during previous Pile Integrity Test (PIT) inspections by providing an independent verification using GPR measurements.
Demonstrate the practical applicability of Ground Penetrating Radar as a complementary inspection method for post-earthquake structural assessment of deep foundations.
Provide engineers with more reliable information for determining whether construction activities can safely continue following a significant seismic event.

3. Why This Research Matters

Improves post-earthquake structural safety. Rapid and reliable assessment of foundation integrity enables engineers to determine whether buildings remain safe for construction, occupancy, or continued operation after seismic events.
Supports evidence-based engineering decisions. Rather than relying solely on visual inspection or a single testing technique, integrating multiple non-destructive evaluation methods reduces uncertainty when assessing critical infrastructure.
Advances non-destructive testing (NDT) practices. The research demonstrates how Ground Penetrating Radar can complement conventional inspection methods, expanding the practical toolkit available to structural and geotechnical engineers.
Reduces unnecessary excavation and repair. Accurate subsurface imaging helps engineers identify whether foundation damage is genuinely present, avoiding costly demolition, intrusive investigations, or unnecessary reconstruction.
Enhances infrastructure resilience. Reliable post-earthquake assessment contributes to safer buildings and more resilient industrial facilities by ensuring that structural decisions are based on verified engineering evidence.
Supports disaster risk reduction. Faster evaluation of foundation conditions can accelerate post-disaster recovery while helping authorities prioritize inspections, allocate resources, and reduce safety risks associated with hidden structural damage.
Contributes to sustainable engineering practice. Non-destructive inspection minimizes material waste, preserves existing structures whenever possible, and supports more resource-efficient maintenance strategies throughout the infrastructure lifecycle.
Provides a valuable industrial case study. Because the investigation was conducted on an actual high-rise industrial construction project affected by a major earthquake, the findings offer practical lessons that extend beyond laboratory-scale demonstrations.

4. Research Methodology

Research Type
This study employed an applied engineering case study using a non-destructive testing (NDT) approach to evaluate the structural condition of a deep foundation after a significant earthquake. Rather than developing a new sensing technology, the researchers investigated the practical application of Ground Penetrating Radar (GPR) for verifying foundation integrity in an actual industrial construction project affected by seismic loading.
Research Object
The investigation focused on a ten-story feed mill tower under construction in the Padang Industrial Park, West Sumatra, Indonesia. The steel-framed structure utilized a spun pile foundation system with a pile diameter of 600 mm. According to the original engineering design, the foundation depth ranged between 16 and 19 meters, the pile cap thickness was 1 meter, and the floor slab thickness was 20 cm.
Engineering Background
The project experienced strong ground shaking during the magnitude 6.1 West Pasaman earthquake in February 2022. Preliminary inspections and previous non-destructive tests, including Ultrasonic Pulse Velocity (UPV) and Pile Integrity Testing (PIT), produced results that required further verification. In particular, PIT measurements indicated impedance reductions at approximately three meters below the pile head, creating uncertainty regarding the actual condition of the foundation system.
Ground Penetrating Radar Equipment
The researchers employed an IDS RIS-ONE Ground Penetrating Radar system equipped with a TR 40 MHz antenna manufactured by IDS GeoRadar. The relatively low-frequency antenna was selected because it provides greater penetration depth, making it suitable for investigating deep pile foundations beneath reinforced concrete slabs.
Working Principle
Ground Penetrating Radar operates by transmitting high-frequency electromagnetic waves into subsurface materials. Whenever these waves encounter interfaces between materials possessing different dielectric properties, part of the signal is reflected back to the receiving antenna. The recorded reflections enable engineers to estimate the position, geometry, and depth of buried structural components while identifying potential discontinuities such as cracks or fractures.
Field Investigation Procedure
The investigation followed a systematic workflow beginning with the review of construction drawings and foundation layouts. Survey lines were then established to intersect the foundation system strategically. Field measurements were conducted using predetermined scanning paths before the collected radar data were processed and interpreted to determine slab thickness, pile cap thickness, and foundation depth.
Measurement Layout
To obtain representative coverage of the foundation system, ten measurement tracks were established across the building foundation. Each track followed the structural grid layout of the building to ensure that the major pile caps and foundation elements were included within the inspection area.
Data Processing Software
Raw radar signals collected during field measurements were processed using Reflex-W software. Signal processing aimed to enhance diffraction patterns, suppress measurement noise, and improve the interpretation of subsurface reflections. The processed radargrams were subsequently analyzed to estimate the location and dimensions of the structural components beneath the slab.
Evaluation Criteria
The interpreted GPR results were compared directly with the original structural design. Particular attention was given to three engineering indicators: the detected depth of the spun piles, the measured thickness of the slab, and the thickness of the pile cap. In addition, the radar images were carefully examined for reflection interruptions that could indicate cracks, fractures, or structural discontinuities within the foundation system.
Validation Strategy
Rather than evaluating GPR independently, the researchers compared the radar observations with previous inspection results obtained from PIT and visual examination. This complementary verification strategy enabled the researchers to determine whether the impedance reduction detected by PIT represented actual structural damage or merely reflected the connection between pile segments.

5. Key Findings

Ground Penetrating Radar Confirmed the Structural Integrity of the Foundation

The principal finding of this investigation is that Ground Penetrating Radar detected no evidence of structural cracks or fractures within the inspected slab, pile caps, or spun pile foundations. Throughout all measurement tracks, electromagnetic wave propagation remained continuous from the surface to the detected pile tips, indicating that no significant discontinuities interrupted the signal.

This result provides strong evidence that the deep foundation system maintained its structural integrity despite experiencing intense seismic loading during the West Pasaman earthquake. The study demonstrates that GPR can effectively distinguish between intact and potentially damaged foundation elements without requiring destructive excavation or structural dismantling.

Measured Foundation Depths Closely Matched the Original Design

Across the ten investigation tracks, the detected foundation depths ranged from approximately 17.10 to 17.82 meters. These measurements fall well within the planned design depth of the spun pile foundation, confirming that the constructed foundation remained consistent with the original engineering specifications.

Agreement between measured and designed foundation dimensions is particularly important after an earthquake because abnormal settlement or structural displacement may alter the apparent position of foundation components. The close correspondence observed in this study indicates that no measurable foundation displacement occurred during the seismic event.

Concrete Slab and Pile Cap Dimensions Remained Consistent

In addition to evaluating pile depth, the Ground Penetrating Radar measurements consistently identified a slab thickness of approximately 20 cm and a pile cap thickness of approximately 1 meter across the investigated foundation system. These values correspond closely with the original structural drawings used during construction.

Maintaining the expected geometric dimensions is an important indicator that neither the slab nor the pile caps experienced significant deterioration or material loss following the earthquake. The findings therefore strengthen confidence in the structural reliability of the entire substructure rather than only the foundation piles themselves.

Ground Penetrating Radar Clarified the Uncertainty Identified by PIT

One of the most valuable outcomes of the research lies in its ability to resolve uncertainty generated during previous Pile Integrity Testing. Earlier PIT measurements suggested a reduction in impedance at approximately three meters below the sensor location, raising concerns regarding possible damage within the pile foundation.

However, the subsequent Ground Penetrating Radar investigation detected no corresponding structural discontinuities at the same locations. This finding supports the interpretation that the impedance reduction observed by PIT most likely reflected the connection joint between pile segments rather than actual structural deterioration. Consequently, the combined use of multiple non-destructive testing methods significantly improved the reliability of engineering assessment.

The Study Demonstrates the Value of Integrated Non-Destructive Evaluation

Rather than treating Ground Penetrating Radar as a replacement for conventional inspection techniques, the research highlights its effectiveness as a complementary verification tool. By integrating visual inspection, Ultrasonic Pulse Velocity testing, Pile Integrity Testing, and Ground Penetrating Radar, engineers obtained a far more comprehensive understanding of the foundation condition than any individual method could provide independently.

This integrated inspection strategy reduces diagnostic uncertainty and supports more informed engineering decisions regarding structural safety, construction continuation, and post-earthquake infrastructure management. The approach demonstrated in this study may therefore serve as a practical model for future post-disaster structural evaluations.

The Industrial Case Demonstrates the Practical Readiness of Ground Penetrating Radar

Unlike many previous investigations conducted under controlled experimental conditions, this study evaluated Ground Penetrating Radar within an active industrial construction project immediately following a significant earthquake. The successful application of the technology under realistic field conditions demonstrates that GPR is sufficiently mature for routine engineering practice rather than being limited to academic research.

The findings suggest that Ground Penetrating Radar can provide rapid, reliable, and non-invasive support for post-earthquake structural assessment, particularly for deep foundation systems where direct visual inspection is impossible. This practical validation strengthens confidence in adopting GPR as part of standard engineering inspection protocols for critical infrastructure.

6. Scientific Contribution

Demonstrates the practical application of Ground Penetrating Radar (GPR) for post-earthquake foundation assessment. Rather than focusing on laboratory validation, the study evaluates GPR under real engineering conditions, providing valuable evidence of its applicability for inspecting deep foundations after seismic events.
Introduces a complementary non-destructive evaluation strategy. The research illustrates how Ground Penetrating Radar can be integrated with visual inspection, Ultrasonic Pulse Velocity (UPV), and Pile Integrity Testing (PIT) to improve confidence in structural diagnosis and reduce uncertainty associated with individual inspection methods.
Provides engineering evidence for interpreting ambiguous PIT results. By comparing GPR observations with previous PIT measurements, the study demonstrates that impedance reductions detected by PIT do not necessarily indicate structural damage, thereby contributing to more accurate engineering interpretation.
Expands knowledge on non-destructive assessment of deep pile foundations. The findings confirm that GPR can accurately estimate pile depth, slab thickness, and pile cap thickness while simultaneously evaluating the structural continuity of buried foundation components.
Supports resilient infrastructure engineering. The study contributes to the growing body of research on structural health monitoring and post-disaster engineering by presenting a practical workflow for rapid foundation evaluation following earthquakes.
Provides a transferable inspection framework. Although conducted on an industrial feed mill tower, the proposed inspection approach may also be adapted to bridges, industrial plants, commercial buildings, transportation infrastructure, and other deep foundation systems exposed to seismic hazards.

7. Industrial Implications

Supports safer post-earthquake construction decisions. Contractors and project owners can use Ground Penetrating Radar to verify foundation integrity before resuming construction activities, reducing the risk of continuing work on damaged structures.
Reduces unnecessary excavation. Because GPR provides subsurface information without destructive investigation, engineers can avoid costly excavation unless structural damage is actually detected.
Improves structural inspection efficiency. Rapid field deployment and immediate visualization of subsurface conditions enable engineers to evaluate multiple foundation locations within a relatively short period.
Enhances quality assurance during construction. Beyond post-earthquake assessment, GPR may also be incorporated into routine quality control procedures to verify foundation dimensions and construction compliance before project completion.
Supports infrastructure maintenance planning. Reliable information regarding foundation condition enables asset managers to prioritize maintenance resources toward structures that genuinely require repair or rehabilitation.
Strengthens disaster recovery operations. Rapid confirmation that critical foundations remain structurally sound can accelerate post-disaster recovery while minimizing unnecessary project delays.
Contributes to digital engineering practices. Integrating geophysical sensing technologies with engineering design data supports more data-driven decision-making and aligns with the increasing adoption of digital inspection methods within the construction industry.
Encourages wider adoption of non-destructive evaluation technologies. The successful application presented in this study demonstrates that advanced geophysical inspection tools are practical for routine engineering projects, not solely for research purposes.

8. Research Limitations

The investigation was conducted on a single industrial building, and the findings therefore represent one specific foundation configuration rather than all types of structural systems.
Only one Ground Penetrating Radar configuration using a 40 MHz antenna was evaluated. Different antenna frequencies may provide alternative balances between penetration depth and imaging resolution.
The research focused on verifying the condition of an existing foundation after a single earthquake event rather than monitoring structural changes over an extended period.
The evaluation concentrated on identifying structural continuity, foundation depth, slab thickness, and pile cap dimensions. Other aspects of structural performance, such as long-term settlement or material deterioration, were beyond the scope of the investigation.
Interpretation of radar signals still depends on appropriate signal processing and engineering expertise, highlighting the importance of experienced personnel during data analysis.
Although GPR effectively complemented previous inspection methods, the study did not compare its performance with additional advanced non-destructive technologies such as seismic tomography or electrical resistivity imaging.

9. Future Research Opportunities

Investigate the performance of Ground Penetrating Radar across different foundation types, including bored piles, raft foundations, and caisson foundations.
Compare multiple antenna frequencies to determine the optimal balance between penetration depth and imaging resolution for various engineering applications.
Integrate GPR with complementary geophysical methods to develop multi-sensor structural health assessment frameworks.
Develop artificial intelligence and machine learning algorithms to automate radargram interpretation and crack detection.
Conduct long-term monitoring studies to investigate structural changes before and after multiple seismic events.
Evaluate the effectiveness of GPR under different geological conditions, groundwater levels, and soil types.
Expand investigations to critical infrastructure such as bridges, ports, tunnels, airports, and offshore facilities located in earthquake-prone regions.
Assess the economic benefits of incorporating GPR into routine infrastructure inspection and maintenance programs.
Develop digital twin models that integrate GPR data with Building Information Modeling (BIM) for continuous structural asset management.
Establish standardized engineering guidelines for the application of Ground Penetrating Radar in post-earthquake structural inspections.

10. Potential for Public Policy Citation (Overton)

This article demonstrates moderate to high potential for citation within engineering policy documents, particularly those related to disaster risk reduction, infrastructure resilience, and post-earthquake structural assessment. Although the study focuses on a single industrial case rather than nationwide infrastructure policy, its practical findings directly support evidence-based inspection strategies for critical infrastructure in seismically active regions.

The research could be referenced in government technical guidelines covering post-earthquake building inspections, infrastructure resilience programs, construction quality assurance, and disaster recovery planning. Agencies responsible for public works, transportation, industrial infrastructure, and civil protection may also find the study valuable when developing standardized procedures for non-destructive evaluation of foundation systems following seismic events.

Potential policy relevance includes:

National earthquake damage assessment guidelines.
Infrastructure resilience and disaster recovery frameworks.
Construction quality assurance standards.
Building safety inspection protocols.
Engineering codes for non-destructive testing.
Public infrastructure maintenance strategies.
Industrial facility risk management guidelines.
Sustainable infrastructure development policies.

11. Who Should Read This Paper?

Civil engineers.
Structural engineers.
Geotechnical engineers.
Construction engineers.
Infrastructure asset managers.
Disaster risk reduction specialists.
Researchers in non-destructive testing.
Graduate students in civil and structural engineering.
Engineering consultants.
Government agencies responsible for public infrastructure.
Building inspectors.
Engineering educators.
Construction project managers.
Professionals working in infrastructure resilience and structural health monitoring.

12. Final Thoughts

This study provides a valuable example of how Ground Penetrating Radar can support engineering decision-making following major seismic events. Rather than positioning GPR as a replacement for established inspection methods, the researchers demonstrate its greatest strength as a complementary technology capable of resolving uncertainty that may remain after conventional non-destructive testing. The integration of GPR with visual inspection, Ultrasonic Pulse Velocity testing, and Pile Integrity Testing represents a balanced and practical engineering approach that improves confidence in structural assessment without requiring destructive investigation.

Another notable strength of the research is its reliance on an actual industrial construction project affected by a significant earthquake. This real-world context increases the practical relevance of the findings and demonstrates that Ground Penetrating Radar can be successfully deployed outside controlled laboratory environments. The study also highlights the importance of interpreting inspection results within the broader engineering context instead of depending on a single diagnostic technique.

Although the investigation focuses on one case study, its implications extend well beyond the specific project examined. As infrastructure resilience becomes an increasingly important priority worldwide, reliable, rapid, and non-destructive inspection methods will continue to play a central role in safeguarding critical facilities after natural disasters. This research therefore represents a meaningful contribution to structural health monitoring, post-earthquake engineering, and sustainable infrastructure management, while also providing a practical foundation for future studies aimed at integrating advanced sensing technologies into routine engineering practice.

Suggested Citation

Teknomekanik (UNP) Style

Apdeni R, Citra Z, Rifwan F, Putri PY, Sandra N, Malinda Y, Wibowo PD, Ashadi RF, Melinda AP. Application of ground penetrating radar for evaluating foundation structure condition after earthquake. Teknomekanik. 2024;7(1):85–100. https://doi.org/10.24036/teknomekanik.v7i1.26772

APA (7th Edition)

Apdeni, R., Citra, Z., Rifwan, F., Putri, P. Y., Sandra, N., Malinda, Y., Wibowo, P. D., Ashadi, R. F., & Melinda, A. P. (2024). Application of ground penetrating radar for evaluating foundation structure condition after earthquake. Teknomekanik, 7(1), 85–100. https://doi.org/10.24036/teknomekanik.v7i1.26772

IEEE Style

R. Apdeni et al., "Application of ground penetrating radar for evaluating foundation structure condition after earthquake," Teknomekanik, vol. 7, no. 1, pp. 85–100, 2024, doi:10.24036/teknomekanik.v7i1.26772.

Harvard Style

Apdeni, R., Citra, Z., Rifwan, F., Putri, P.Y., Sandra, N., Malinda, Y., Wibowo, P.D., Ashadi, R.F. & Melinda, A.P., 2024. Application of ground penetrating radar for evaluating foundation structure condition after earthquake. Teknomekanik, 7(1), pp.85–100. https://doi.org/10.24036/teknomekanik.v7i1.26772

Vancouver Style

Apdeni R, Citra Z, Rifwan F, Putri PY, Sandra N, Malinda Y, Wibowo PD, Ashadi RF, Melinda AP. Application of ground penetrating radar for evaluating foundation structure condition after earthquake. Teknomekanik. 2024;7(1):85–100. doi:10.24036/teknomekanik.v7i1.26772.

Chicago (Author–Date)

Apdeni, Risma, Zel Citra, Fitra Rifwan, Prima Yane Putri, Nevy Sandra, Yosie Malinda, Paksi Dwiyanto Wibowo, Reza Ferial Ashadi, and Annisa Prita Melinda. 2024. "Application of Ground Penetrating Radar for Evaluating Foundation Structure Condition After Earthquake." Teknomekanik 7 (1): 85–100. https://doi.org/10.24036/teknomekanik.v7i1.26772.

MLA (9th Edition)

Apdeni, Risma, et al. "Application of Ground Penetrating Radar for Evaluating Foundation Structure Condition After Earthquake." Teknomekanik, vol. 7, no. 1, 2024, pp. 85–100. Crossref, https://doi.org/10.24036/teknomekanik.v7i1.26772.

Editorial Note

Editorial Note: This blog post is an independent scholarly review intended for educational and scientific communication purposes. It summarizes and discusses the published article in the author's own words while providing full attribution to the original publication, consistent with the principles of the CC BY 4.0 license.

Engineering Research Insights

Search This Blog