Author: QuakeLogic

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QuakeLogic

Curated QuakeLogic articles, application notes, and technical explainers for engineering teams.

Earthquake EngineeringStructural Health MonitoringEarthquake Early WarningSeismic SensorsInfrasound MonitoringShake TablesData Acquisition SystemsInfrastructure Monitoring
Areas of expertiseSeismic monitoring, structural health monitoring, testing systems, data acquisition, and applied engineering education.
QuakeLogic dual-user VR welding simulator with two trainees practicing welding simultaneously
Technical Note

Dual-User VR Welding Simulator

Welding is a practical skill that requires precision, consistency, and continuous training. However, traditional welding education can involve significant material consumption, workshop preparation, safety considerations, and equipment costs. As training programs expand,...

Oct 23, 202610 min read

Midland Michigan Dam Failures: Lessons for Dam Monitoring

Collapsed Edenville Dam in Midland, Michigan after the May 2020 failure and flooding

In short: The Edenville Dam (built 1924, rated unsatisfactory) collapsed and the Sanford Dam (built 1925, rated fair) was breached in Midland, Michigan on May 19, 2020 after days of heavy rain, forcing evacuations. With at least 1,680 US dams rated poor or unsatisfactory and the average dam over 50 years old, QuakeLogic's SMART platform offers continuous, AI-driven sensor monitoring with threshold alerts and automated reports.

When disaster strikes, we are all at risk! But the unprepared ones get hit the hardest.

The Edenville Dam collapsed and the Sanford Dam was breached in Midland, Michigan on last Tuesday (May 19) after days of heavy rain. In the midst of the Coronavirus pandemic, residents were ordered to evacuate because of rising waters. The collapsed Edenville Dam, built-in 1924, was rated in unsatisfactory condition while the Sanford Dam, which was built in 1925, was given a fair condition rating by the state.

Are other dams safe in the US?

On average, the nation’s dams are over 50 years old. At least 1,680 dams across the U.S. are currently rated in poor or unsatisfactory condition. These all pose potential risk according to this Associated Press article. Without urgent action, aging dams may not be able to adequately handle the intense rainfall and floods of a changing climate, as happened in the case of the Michigan dams. They may fail to protect people and property in cities and towns located nearby and downstream.

Introducing SMART DAMS

QUAKELOGIC is the only company using a cloud-based, AI-powered technology platform to perform continuous, autonomous structural assessments using data from sensors on the dam structure.

Deploying the QuakeLogic’s SENSOR DATA MANAGEMENT, ASSESSMENT, AND REPOSITORY TECHNOLOGY (SMART) on dams would significantly reduce needed search and inspection efforts in future events.

The SMART integrates manually and digitally read sensor recordings into a fully-automated unified monitoring system. It facilitates the acquisition and analysis of critical sensor data needed by the dam operators for proper operations and maintenance, and most importantly for the safety assessment of the dam.

The SMART helps to collect, organize, and evaluates sensor data routinely, sends immediate notifications upon exceedance of thresholds, and generate PDF reports regularly and on-demand.

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The SMART is a cutting-edge system works with various types of sensors such as accelerometers, tiltmeters, potentiometers, strain gauges, thermocouples, weather stations, piezometers and seepage monitors. Comprehensive analytic information is visible in real-time on the mobile-friendly dashboard, providing proof and peace of mind that a dam is performing as expected.

In addition to SMART, our proprietary earthquake early warning (EEW) alerts provide a window of opportunity for action before earthquake shaking begins at the site. It can also trigger automated actions such as opening spillways, closing roads, etc. when every second counts.

Easy-to-understand, engineering-quality information about the real-time health of the dam supports operators to make informed decisions. Whether planning maintenance activities, or prioritizing critical response actions, QUAKELOGIC has you covered.

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“Dams are vital in all communities. As we move toward recovery from COVID-19, it’s important to support the resiliency of dams by realtime monitoring and ensure that the dam owners have the support, tools, and resources to outsmart disasters.”

Key Takeaways

  • Edenville Dam (1924, rated unsatisfactory) collapsed and Sanford Dam (1925, rated fair) was breached after days of heavy rain.
  • At least 1,680 US dams are rated poor or unsatisfactory; the average American dam is over 50 years old.
  • SMART (Sensor Data Management, Assessment and Repository Technology) runs cloud-based, AI-powered continuous structural assessment.
  • SMART ingests accelerometers, tiltmeters, potentiometers, strain gauges, thermocouples, weather stations, piezometers and seepage monitors.
  • Threshold exceedance triggers immediate notifications; EEW alerts can automatically open spillways or close roads.

Frequently Asked Questions

What caused the dam failures in Midland, Michigan?

The Edenville Dam collapsed and the Sanford Dam downstream was breached on May 19, 2020 after days of heavy rain raised reservoir levels beyond what the aging structures could handle. Edenville, built in 1924, had been rated in unsatisfactory condition by the state and Sanford, built in 1925, was rated fair. Residents were ordered to evacuate as waters rose during the coronavirus pandemic.

How many dams in the United States are in poor condition?

According to an Associated Press analysis cited in the article, at least 1,680 dams across the United States are rated in poor or unsatisfactory condition, and the nation's dams average more than 50 years old. Without urgent action these aging dams may not handle the intense rainfall and floods of a changing climate, putting downstream communities at risk.

What is QuakeLogic SMART for dams?

SMART, short for Sensor Data Management, Assessment and Repository Technology, is QuakeLogic's cloud-based, AI-powered platform that performs continuous, autonomous structural assessments from sensors on a dam. It integrates manually and digitally read sensors into one unified system, evaluates data routinely, sends immediate notifications when thresholds are exceeded, generates PDF reports on schedule or on demand, and shows analytics on a mobile-friendly dashboard.

Which sensors can a dam monitoring system use?

QuakeLogic SMART works with accelerometers for vibration and earthquake response, tiltmeters for rotation, potentiometers for displacement, strain gauges, thermocouples, weather stations, piezometers for pore pressure and seepage monitors. Combining these data streams lets operators verify that the dam is performing as expected, plan maintenance and prioritize response actions after storms or earthquakes.

Can earthquake early warning protect a dam?

Yes. QuakeLogic's earthquake early warning alerts provide a window of seconds to tens of seconds before strong shaking reaches the dam site. In that window the system can trigger automated actions such as opening spillways or closing downstream roads, and notify operators, so protective measures begin before the shaking rather than after damage is observed.

Need help with a project? QuakeLogic designs and supplies seismic monitoring, earthquake early warning, structural health monitoring, infrasound, and shake table systems. Browse QuakeLogic products or contact our engineering team with your site, structure, or test requirements.

Monitoring Tunnels for Seismic Safety and Risk Management

Highway tunnel interior with structural health monitoring sensors for seismic safety assessment

In short: Tunnels are not automatically safe in earthquakes: liquefaction, slope failure, fault crossings and near-fault pulses damaged or collapsed tunnels in the 1906 San Francisco, 1952 Kern County and 1999 Duzce earthquakes, and the 2012 Sasago ceiling collapse showed components fail even without shaking. Tunnel seismic monitoring with real-time structural health monitoring measures accelerations, displacements and strains in the lining so officials can close a tunnel before it becomes deadly.

Monitoring tunnels for vibrations and deformations is not only critical during the construction phase but also their service life.

In 2012, the Tokyo-bound Sasago Tunnel suffered significant damage when nearly 150 concrete ceiling panels collapsed and crushed three vehicles, including a van carrying six people that caught fire. The deficiencies in mounting components of the ceiling panels were to blame.

But, are tunnels safe during an earthquake?

A common belief that underground structures are safer because they move with the soil, while structures above ground sway back and forth during the earthquakes appears to be misleading. The impact of earthquakes on tunnels can be severe due to ground failures such as liquefaction, strong ground shaking, and fault crossing.

Liquefaction takes place when saturated soft soil deposits loose load-carrying capacity during strong shaking. This phenomenon can cause the ground surrounding tunnels to deform and shift, with potentially severe impacts. The slope instability and fault crossings may also create permanent deformations leading to a collapse of the tunnel.

After the 1906 San Francisco earthquake, the Wrights railway tunnel in southern Santa Cruz mountains was closed for more than a year due to the collapse of approximately 100-m-long part crossing the San Andreas Fault Zone. Another railway tunnel crossing the White Wolf Fault was seriously damaged during the 1952 magnitude 7.5 Kern County earthquake associated with this fault (Kontogianni and Stiros, 2003).

In 1999 a magnitude 7.2 hit the Duzce region in Turkey. Close to the fault rupture, twin highway tunnels on the major highway connecting Ankara to Istanbul were under construction. The tunnels were partially collapsed due to intense pulses of earthquake motion (near-fault effects) as their lines cross the shear zone of the North Anatolian Fault.

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The excavation process during tunnel construction may itself trigger microearthquakes. The vibrations, therefore need to be monitored to identify such seismic activity whether they create any movements or cracks on the tunnel surface. The monitoring vibrations is also needed to estimate the rock formations ahead of the tunnel face to optimize the excavation parameters. Besides, the infrastructure surrounding the tunnel including buildings must be monitored especially in case of construction of new subway (metro) lines.

Structural health monitoring (SHM) system is essential for the seismic resilience of tunnels. A robust real-time SHM system not only allows for assessment of accelerations and deformations (displacements and strains) in tunnel linings but also facilitates the implementation of adaptive risk management. Such a system can assist the officials to make informed and timely decisions to protect people (such as drivers or construction workers) from life-threatening conditions. For example, the highway tunnel can be closed to traffic before any severe consequences take place. Such pro-active actions would not only save lives but also avoid liabilities.

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QuakeLogic is the only company providing cloud-based AI-powered disaster risk management solutions to prevent and reduce human and economic losses risen during and after earthquakes. Our cutting-edge technology platform performs real-time autonomous structural assessments using sensor data and sends rapid notifications after an event with the level of shaking intensity and whether structural integrity is compromised. For tunnels, our platform provides meaningful and easy-to-understand information immediately after an earthquake. This timely and critical information helps the officials to plan their emergency response. We also provide a web-based display where the sensor information can be monitored in real-time. This solution can provide great benefits especially for tunnels under construction phase.

For emergency measures and safety of tunnels, QuakeLogic provides advanced monitoring systems together with real-time and autonomous data analytics.

Key Takeaways

  • In 2012 about 150 concrete ceiling panels fell in Japan's Sasago Tunnel, crushing three vehicles, due to deficient mounting components.
  • The Wrights railway tunnel lost roughly 100 m where it crossed the San Andreas Fault in the 1906 San Francisco earthquake.
  • Twin highway tunnels near Duzce partially collapsed in the 1999 M7.2 earthquake from near-fault pulses on the North Anatolian Fault.
  • Tunnel excavation itself can trigger microearthquakes, so vibrations should be monitored during construction.
  • Real-time SHM of accelerations, displacements and strains enables closing a tunnel to traffic before severe consequences.

Frequently Asked Questions

Are tunnels safe during an earthquake?

Not necessarily. The belief that underground structures are safer because they move with the surrounding soil is misleading. Tunnels can suffer severe damage from liquefaction of saturated soft soils, slope instability, strong shaking and especially fault crossings, where permanent ground deformation can collapse the lining. Historic failures include the Wrights tunnel in 1906, a White Wolf Fault railway tunnel in 1952 and the Duzce highway tunnels in 1999.

Why should tunnels be monitored during construction?

Excavation can itself trigger microearthquakes, and vibration monitoring reveals whether that seismic activity is causing movement or cracking in the tunnel surface. Vibration data also helps estimate rock conditions ahead of the tunnel face to optimize excavation parameters. In addition, surrounding infrastructure such as buildings above a new subway line must be monitored for settlement and vibration effects.

What does a structural health monitoring system measure in a tunnel?

A tunnel structural health monitoring system measures accelerations and deformations, meaning displacements and strains, in the tunnel lining in real time. QuakeLogic's cloud platform processes this sensor data autonomously, reports the shaking intensity after an earthquake, indicates whether structural integrity is compromised, and offers a web display so officials can watch conditions continuously, including during construction.

What happened in the Sasago Tunnel collapse?

In 2012 nearly 150 concrete ceiling panels in Japan's Tokyo-bound Sasago Tunnel collapsed, crushing three vehicles, including a van carrying six people that caught fire. Investigators blamed deficiencies in the components mounting the ceiling panels. The event shows that monitoring tunnels for deformation matters throughout their service life, not only during construction or earthquakes.

How does tunnel seismic monitoring help emergency response?

Real-time tunnel seismic monitoring gives officials immediate, easy-to-understand information after an earthquake about shaking intensity and whether the structure is compromised. With that data they can close a highway tunnel to traffic before severe consequences occur, protect drivers and construction workers, plan emergency response, and avoid liabilities. This adaptive risk management turns the monitoring system into a decision tool rather than a passive record.

Need help with a project? QuakeLogic designs and supplies seismic monitoring, earthquake early warning, structural health monitoring, infrasound, and shake table systems. Browse QuakeLogic products or contact our engineering team with your site, structure, or test requirements.

Bridge Monitoring for Early Damage Detection and Intervention

Highway bridge instrumented with accelerometers and strain gauges for structural health monitoring

In short: Proper bridge monitoring means installing a structural health monitoring (SHM) system of accelerometers, potentiometers, inclinometers, strain gauges, thermocouples and weather stations that reports a bridge's real-time condition and flags changes in performance before they become failures. With about 56,000 structurally deficient US bridges carrying 188 million trips a day, and collapses such as I-35W in Minneapolis and the FIU pedestrian bridge, continuous SHM gives officials the data to intervene early.

There are about 56,000 structurally deficient bridges in the U.S., and these bridges accommodate on average 188 million trips each day according to data from the Federal Highway Administration.

The nation’s transportation infrastructure is aging. More than 200,000 bridges are now more than 50 years old, and many are approaching the end of their design life. Although the seismic construction requirements are aimed to protect the lives of those crossing bridges. The number of bridges that are in such poor condition as to be considered structurally deficient is increasing and posing potential risk.

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Fourteen years ago, the Interstate 35 bridge over the Mississippi River in downtown Minneapolis collapsed. The cars, trucks and even a school bus were driving in bumper-to-bumper traffic across in the evening rush hour. Bridge’s failure plummeted them into the water and onto the rocky river banks. This disaster left a death toll of thirteen and injured 145. The officials were warned that the bridge was structurally deficient due to significant corrosion in its bearings. A federal inspection also rated the bridge structurally deficient, giving it a 50 on a scale of 100 for structural stability.

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In 2018, another horrific bridge collapse occurred in the Florida International University campus in Miami. The failed pedestrian bridge killed six and injured eight people. The bridge was under construction and the errors in the design overestimated how much stress the structure could take.

The question arose about the cause of the collapse of bridges and whether they could have been prevented.

Emergent technologies in sensing, artificial intelligence (AI), and cloud computing are now remedying engineers to construct stronger bridges and also improve bridge maintenance for longer life-span. To provide continuous feedback on the bridge’s structural conditions, sensors supporting structural health monitoring (SHM) systems are being installed into both new and existing bridges.

A robust SHM system, including various sensors and data analytics to monitor the bridge’s real-time integrity, can provide officials and engineers with the knowledge and “peace of mind” that the bridge is performing as expected, and the ability to detect a change in its performance. This knowledge and ability are critical because they are directly responsible for the consequences of failure. To prevent catastrophic collapses, especially the bridges that require significant maintenance, rehabilitation, or replacement can significantly benefit from the SHM system to monitor its elements founds to be in poor condition due to deterioration or damage.

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At QuakeLogic, we provide the most comprehensive SHM system for bridges. We are the only company with a cloud-based, AI-powered technology platform performing autonomous structural assessments using sensor data. Our platform sends rapid notifications with the level of shaking intensity in case of an earthquake and whether the bridge’s integrity is compromised. This system can not only monitor for earthquakes but also utilize data from various sensors such as accelerometers, potentiometers, inclinometers, strain gauges, thermocouples, and weather stations. Our platform sends meaningful and easy-to-understand information. This timely and critical information helps the bridge officials and engineers to give informed decisions and plan their responses appropriately.

Our structural health monitoring platform response matches for the first time the timing of the earthquake impact, which was impossible before. This platform can provide timely information that is needed for an understanding of the performance of a bridge and address problems earlier to improve public safety.

Key Takeaways

  • About 56,000 US bridges are structurally deficient and carry roughly 188 million trips per day, according to FHWA data.
  • More than 200,000 US bridges are over 50 years old and approaching the end of their design life.
  • The I-35W collapse in Minneapolis killed 13 and injured 145 after inspectors rated the bridge 50 out of 100 for structural stability.
  • The 2018 FIU pedestrian bridge collapse in Miami killed six; design errors overestimated the stress the structure could take.
  • SHM systems combine accelerometers, potentiometers, inclinometers, strain gauges, thermocouples and weather stations with cloud AI analytics.

Frequently Asked Questions

What is structural health monitoring for bridges?

Bridge structural health monitoring (SHM) installs sensors on a new or existing bridge and analyzes their data continuously to report the bridge's real-time integrity. Typical sensors are accelerometers, potentiometers, inclinometers, strain gauges, thermocouples and weather stations. The system confirms the bridge is performing as expected and detects changes in performance so engineers can intervene before deterioration leads to failure.

How many bridges in the US are structurally deficient?

According to Federal Highway Administration data cited in the article, about 56,000 US bridges are structurally deficient, and together they carry an average of 188 million trips every day. More than 200,000 bridges are over 50 years old, so the number in poor condition is rising as the transportation infrastructure approaches the end of its design life.

Could the I-35W and FIU bridge collapses have been prevented?

Both collapses had warning signs. The I-35W bridge in Minneapolis was rated structurally deficient with a 50 out of 100 stability score because of significant bearing corrosion before it fell, killing 13 and injuring 145. The FIU pedestrian bridge in Miami failed in 2018 after design errors overestimated its capacity. Continuous SHM data could have exposed abnormal behavior and prompted earlier intervention.

How does an SHM system respond to an earthquake?

QuakeLogic's cloud-based, AI-powered platform performs autonomous structural assessments from sensor data. During an earthquake it sends rapid notifications with the level of shaking intensity and an indication of whether the bridge's integrity is compromised, timed with the event itself. Officials get plain-language information to decide whether to close, inspect or reopen the bridge.

Which sensors are used to monitor a bridge?

A comprehensive bridge monitoring system uses accelerometers for vibration and earthquake response, potentiometers for displacement, inclinometers for tilt, strain gauges for stress in members, thermocouples for temperature effects and weather stations for wind and environmental loads. Combining these data streams in a cloud platform allows the structure's behavior to be assessed continuously rather than only during periodic inspections.

Need help with a project? QuakeLogic designs and supplies seismic monitoring, earthquake early warning, structural health monitoring, infrasound, and shake table systems. Browse QuakeLogic products or contact our engineering team with your site, structure, or test requirements.