Leading organizations use SENSR systems:

Burj Khalifa, Dubai “The CX1 is a remarkable solution; it costs less than traditional solutions and does more.  As an integrated and rugged device, it is inherently easier to deploy, more stable and more reliable than using individual components.” Tom Lawton, Systems Engineer at CPP

Lake Champlain Bridge, Crown Point “We have used SENSR products on a dozen structures in the past. Without the data we were able to obtain, many of the issues we uncovered might not have been as clearly understood during the early stages of analysis.” Ted Zoli, Technical Director at HNTB

BNSF Rail Bridge, Burlington “The SENSRnet is an incredible system that measures details the human eye just can’t see happening; it gives us insight as to how the piers are reacting to railway live loads, high water and construction.” Don Lozano, Assistant Director of Structures at BNSF

• current configuration
• materials
• condition of structure
• stability and capacity of the soil support elements
• presence of other loading

Although loads may be associated with a variety of inputs, the overall safety of a structural element can be related to its displacement capacity. Monitoring structural responses references measuring how and when a structural element moves, vibrates, tilts, twists, bends or is impacted.

Static and dynamic loads

Loads applied to a structure impart stresses, deformations and displacements. In general there are two types of loads; static and dynamic. In a static loading condition, the load is constant with respect to time. The dead weight of a structure is an example of a static load. Dynamic loads are external loads that vary with time and impart forces upon the structure that are also variable with time – this creates an interdependency between cause and effect. An example of a dynamic load is a flash flood with debris impacting the piers of a bridge.

Examples of  dynamic loads

A dynamic load’s ability to influence a structure can be significant! Dynamic loads can come from a variety of sources including human activity, working machinery, construction work, collisions, collapse of a structural element, loss of soil support, and environmental inputs such as the wind or earthquakes.

The basis for monitoring structural responses

Any structure with defined characteristics such as mass distribution, stiffness component, and inherent dampening values will respond differently to different loading conditions. Alternatively, changes in a structure’s capacity to carry a given load will produce a different response to that same load.

Monitoring structural responses

When monitoring the dynamics of a structural element, profiles are created that characterize how the structure moves, vibrates, tilts, and deforms at rest and under load. These profiles are calculated from the actual responses of the structure and are based upon the principle that for a given load, a structure’s response will be the same of the structure’s capacity to carry the load is the same. If the structure’s capacity to carry a given load changes or a new loading condition is introduced – then the response of the structure will change and these changes can be detected by sensors.

Benefits of monitoring structural responses

The measurement and monitoring of structural responses provides valuable insight into what loads are acting upon the structure, how the structure is coping with these loads, and how these loads are influencing the structure’s behavior. Structural response monitoring fosters awareness and facilitates the safe and efficient operation of the structure by allowing users to make timely, data-driven decisions that are based upon the current condition for the structure. Monitoring structural responses provides the foundation for an enhanced management program that directly supports:

1. Inspection and maintenance – Response monitoring fills in the gaps between periodic inspections by providing continuous trend data and critical measurements that are not discernible by periodic visual inspections.
2. Real-time management – By continuously monitoring  and reporting structural responses and environmental measurements, engineers have continuous awareness of their structures and can observe and react to immediate changes.
3. Early detection – Monitoring structural responses is a broad method for monitoring the health of a structure, unlike other sensing methods that can only monitor specific points on a structure, structural response monitoring can detect conditions and states influencing the entire structure. This advanced detection capability enhances coverage and increases the opportunities for the early responses that can minimize property and casualty losses.

Our Internet-enabled structural monitoring products are easy to deploy and let users monitor structures in real-time with their phones or laptops, anywhere in the world.

• simulated loads
• design
• calculated material properties
• specified support conditions

Real-world factors

When a new structure is completed and placed into service, it immediately begins responding to working and environmental loads. How the real-world structure responds is a product of the:

• actual loading
• as-built configuration
• properties of the materials used
• workmanship
• true support conditions

Comparing design vs. actual

One method for verifying the performance capabilities of the new structure is to measure how it responds to early working and environmental loads and compare those responses to the model’s calculated responses.  Measuring how a new structure responds to early loading conditions provides important indicators for how the structure will perform under more stressful conditions. If the structural responses are within the expected values then this supports the expectation that the structure will perform as expected when faced with more demanding conditions.

Benefits of comparing performance

Measuring and comparing the as-built performance of a structure with the theoretical responses helps engineers qualify the expected performance, evaluate the efficiencies of their designs, refine their level of understanding, and enhance the capabilities of their tools.

Monitoring structural response

Structural monitoring fosters awareness and facilitates the safe and efficient operation of the structure by allowing users to make timely, data-driven decisions that are based upon the current condition for the structure. Our Internet-enabled monitoring products are easy to deploy and let users monitor structures in real-time with their phones or laptops, anywhere in the world.

1. The input that produced the response needs to occur before the inspection.
2. The magnitude or cycling of the structure’s response is required to be sufficient enough to produce a visual indicator.

Beyond scheduled inspections

For structures that have an elevated risk for, or a low tolerance of being exposed to damaging inputs, it may be appropriate to supplement scheduled inspections with information driven inspections.  Information driven inspections are unscheduled inspections that occur when received data indicates that an inspection is advised.

Continuous monitoring

One option for providing this capability is to install a basic monitoring system that will provide a continuous assessment of the structure between scheduled inspections. A basic system will measure, identify and report when damaging responses occur. Monitoring how a structure responds to loading and the environment enables engineers to quickly identify significant events and abnormal changes in behavior.  Continuously monitoring structural responses and incorporating them into the management of the structure provides:

Enhanced inspections – Sensors provide continuous trend data and critical measurements that are not discernible by visual inspections.  Structural response data helps correlate inspection findings and manage loading conditions by providing a measurable link between cause and effect.

Real-time management – Continuous monitoring enables engineers to have real-time awareness of their structures and provides an operational platform for gauging the health of a structure between scheduled inspections.

Structural monitoring fosters awareness and facilitates the safe and efficient operation of structures by allowing users to make timely, data-driven decisions based upon the current condition of the structure. Our Internet-enabled monitoring products are easy to deploy and let users monitor structures in real-time with their phones or laptops, anywhere in the world.

The last report

Traditionally, organizations have relied on visitor feedback and periodic visual inspections to assess their remote structures; unfortunately the relevance of the last report is constantly being challenged by time, the environment and unplanned events.

Key structures demand more

For those structures that are key to an organization’s success and considered at risk, deploying a remote monitoring system to continually assess the condition and availability of the remote structure can dramatically increase efficiency, awareness and safety.  Some examples of at risk structures include those that are:

• in unknown condition
• a collision target
• in a seismically active area
• prone to the effects of flooding
• susceptible to  high winds or storm surge
• exposed to frequent and excessive loading
• targets for malicious acts
• known to have a reduced capability

New ways to monitor

In the past deploying a structural health monitoring system was difficult, expensive and frustrating. Today integrated systems like our SENSRnet are elegantly simple, extremely rugged and very affordable. Monitoring a remote structure facilitates a safe and efficient operating environment by allowing organization’s to make timely, data-driven decisions based upon the current status of the structure. Our Internet-enabled monitoring products are easy to deploy and let users monitor structures in real-time with their phones or laptops, anywhere in the world.

The challenge

As with other types of bridges, railway bridges are required to be visually inspected on a regular basis. One of the preferred objectives of the inspection is to qualify the behavior of the bridge under load.  Evaluating vibrations, superstructure movements, pier motions and span dynamics helps identify how well the different bridge elements are performing. Visually assessing and comparing the behavior of these elements under load is a very challenging task – especially for larger structures.

A new tool for inspectors

In order to provide an efficient method for assessing bridge performance under load; bridge inspectors are now being equipped with programmable accelerometers that measure and record how much the bridge element moves and vibrates.  The accelerometers measure the dynamics of the element, analyze the motion and generate reports that enable inspectors to review and compare performances. The data generated from the accelerometers is used to:

• Document inspections
• Confirm performance
• Identify bridge elements that require attention
• Create a baseline for future comparisons
• Measure the effectiveness of remedial efforts

Measuring how a bridge element responds under load gives inspectors a new tool for detecting undesirable conditions before they worsen. Our programmable accelerometers are small, portable instruments that make it easy to measure and identify how bridge elements respond under load.

Contractors are often required to measure and control how their activities will effect adjacent structures, occupants and equipment. In addition to managing these outputs; contractors also have a responsibility to ensure that work zones are safe and adjacent structures remain stable.

Damage potentials

Managing how the various elements are affected by nearby construction requires a dedicated plan that identifies susceptibilities and specifies mitigation strategies. When an adjacent building is damaged by construction the concerns are often related cracks, settlement, wall or column tilt.  The construction activities that are most associated with causing these types of damages are:

• Demolition
• Driving pile
• Excavation
• Dewatering
• Drilling
• Altering shared support members

Monitoring adjacent structures

Employing a monitoring system that can measure the vibration and pulse outputs generated by construction activities, as well as measure the settlement and tilt changes in nearby structures helps contractors minimize the damage potentials and rapidly identify undesirable responses.  Monitoring the inputs to the buildings as well as the overall stability of the structures and foundation helps ensure the worksite remains safe for workers and residents.

Benefits of monitoring

Structural monitoring fosters awareness, minimizes the potentials for damages and facilitates safe, efficient work environments. Our SENSRnet Internet-enabled monitoring systems are easy to deploy and let contractors use their phones and laptops to monitor construction sites in real-time, anywhere in the world.

Construction on or near a bridge demands enhanced management and awareness. When construction occurs on or a near a bridge great care must be taken to ensure that a bridge always remains safe for the workers and the traveling public. In the past construction activities such as blasting, pavement breaking, rock drilling, soil compaction, pile installation and material storage have inadvertently rendered bridges unsafe.

Other safety factors

In addition to potentials caused by construction activities, construction managers also need a method to evaluate whether or not other factors are influencing the safety of the bridge in their construction zone. Scour, flooding, collisions, accidents, malicious acts and earthquakes are examples of unplanned events that can dramatically impact the safety of a bridge and the construction zone.

Monitoring a bridge

One method for assessing the safety of a bridge and the effects of construction is to measure and compare how various bridge components respond to normal working loads, environmental inputs and construction activities. Measuring how and when these components move, vibrate, twist, tilt or settle helps engineers identify how the bridge is performing and whether or not it is changing in response to the various inputs. Depending on the risk potentials, monitored components may include piers, spans and superstructure elements.  For monitoring piers it is important to include provisions for measuring vibrations, impacts, collisions, tilt and position changes. For span and superstructure monitoring, responses such as motions, vibrations, attitude changes, twist and sway are measured and compared.

Benefits of monitoring

Structural monitoring fosters awareness and facilitates safe construction environments by allowing managers to make timely, data-driven decisions that are based upon the actual condition of the bridge. Our SENSRnet Internet-enabled monitoring systems are easy to deploy and let managers use their smartphones and laptops to monitor bridges in real-time, anywhere in the world.