Applications
SoundPrint® has been in use as a structural monitoring system since 1994 on a variety of structures. Cost-effective, targeted repairs have been carried out on a number of structures based on information generated by SoundPrint®. The system has saved the owners of these properties millions of dollars on repairs and premature decommissioning.
SoundPrint® offers owners of large infrastructure a tool that helps ensure the long-term integrity of post-tensioned, pre-tensioned, suspension and cable-stayed structures.
SoundPrint® is currently in use or has been used on the following structures:
| Prestressed Concrete Cylinder Pipelines (PCCP) |
Prestressed Concrete Cylinder Pipelines (PCCP)
Corrosion-induced failure in the wire wrapping of prestressed concrete cylinder pipe (PCCP) can result in ruptures with consequent interruption in service or potential flood damage. Through automated remote data acquisition and management, SoundPrint® detects and locates prestressing wire failures as they occur. Active deterioration in individual pipe spools can be identified, and rates of failure can be established for further engineering analysis.Different system configurations are available, making SoundPrint® applicable to virtually any PCCP pipeline. Hydrophone arrays are capable of monitoring up to a mile (1.6 km) of pipe from one insertion point. Large diameter pipes can be equipped with Surface Mounted Sensors or Hydrophone Stations connected via wired or wireless means. SoundPrint®® AFO, a distributed acoustic optical fibre monitoring system, is used to monitor long pipelines (up to 40 km or 26 miles with a single acquisition unit). This system is ideally suited to permananent or long-term monitoring of pipelines over 5 km (3 miles).
SoundPrint® has been successfully utilized on pipelines of 24" diameter and greater and is the only non-intrusive way to evaluate PCCP without dewatering.
Buildings and Parking Structures
Moisture can enter the tendon system of unbonded post-tensioned structures at any time.
While useful in the initial assessment of a structure, intrusive inspection of strands provides only a sampling of strand condition. SoundPrint® continuously monitors every strand in a building and will identify the time and location of wire failures. Statistical techniques can be used to estimate future rates of failure in different locations within a structure.
Moisture can enter the tendon system of unbonded post tensioned structures at any time before, during, or after construction and cause corrosion-induced failures. Resultant concerns about the presence, rate, and extent of deterioration can have a negative impact on property values. Current NDE techniques are ineffective for evaluating the condition of unbonded post-tensioned systems in their entirety. While useful in the initial assessment of a structure, intrusive inspection of strands provides only a sampling of strand condition.
SoundPrint® continuously monitors every strand in a building and will identify the time and location of wire failures. Since SoundPrint® can also determine the frequency of wire failures, statistical techniques can be used to estimate future rates of failure in different parts of the building.
Suspension Bridges
The main cables and suspender ropes (hangers) of suspension bridges are often subject to aggressive environments. Hidden corrosion of the wires in these components can occur, leading to potential reduction in structural safety factors and expensive large-scale repairs and rehabilitation.
SoundPrint® can provide complete, continuous surveillance of cable components on suspension bridges so that areas of active corrosion can be pinpointed. Engineers can now identify where cable inspections should be concentrated, and where and when repairs are required.
Cable-Stayed Bridges
The increasing use of cable-stayed technology for medium and long-span bridges presents special problems for bridge inspectors. The condition of wires in stay cables is particularly difficult to determine. It is usually not possible to visually inspect the cables due to the presence of the protective sheathing.
Non-destructive techniques such as x-ray and ultrasonic inspection have been used with limited success, but are not proven, expensive and cumbersome, as the equipment has to be winched along the free length of the cables.
The SoundPrint® acoustic monitoring system, combined with an optional complementary vibration monitoring system provides a complete continuous remote health monitoring solution for stay-cables. Corrosion or fatigue-induced failures can be detected long before they compromise the integrity of the stay. The vibration characteristics of the stays can be analyzed, and causes of excessive vibration can be identified. Changes in cable loads can also be easily derived from vibration performance. Since the system can track the actual number of dynamic cycles the stays experience, actual fatigue performance can be compared with theoretical assumptions.
Post-Tensioned Bridges
Suspect grouting practices and poor detailing has led to concerns in some countries about the durability of post-tensioned bridges.
Corrosion-induced failure of tendons has been confirmed in the United Kingdom, France, Germany, Japan, Belgium and the United States.
Conventional NDE techniques are ineffective for determining the location and extent of corrosion damage and this has led some bridge owners to de-commission suspect bridges because of structural safety concerns.
SoundPrint® has been used to provide assurance about the condition of post-tensioned bridges since 1997. Comprehensive testing of the system by the U.K.’s Transport Research Laboratory on behalf of the Highways Agency has proved that its sophisticated acquisition and event filtering capabilities can reliably detect low energy wire breaks in fully grouted tendons in noisy environments.
Water Reservoirs
Many utilities throughout the world have designed their distribution system around large diameter prestressed and post-tensioned holding reservoirs. These reservoirs are often situated at higher elevations taking advantage of the efficiencies in delivering water through gravity feed.
These tanks rely on the protective mortar coating to provide a barrier against corrosion of the wire. The high pH environment surrounding the embedded prestressed wire provides protection by passivating the steel wire. However, if the mortar coating is compromised, corrosion of the embedded wire will occur resulting in wire failure and loss of prestressing. Due to the difficulty inspecting these structures, evaluation of the embedded wire or tendons is often difficult leading to inconclusive results.
SoundPrint® uses an array of sensors surface mounted on the structure to measure the dynamic response caused by the energy released when the tensioned wires fail.
Ground Anchors
Post-tensioned anchors often come into contact with aggressive soils or groundwater. As these assemblies are generally inaccessible except for the anchor heads, engineers responsible for ensuring their integrity have had no effective way of detecting deterioration.
SoundPrint® can address this concern in a cost effective and comprehensive manner.
Cable-supported structures such as arenas, guyed towers and tent structures can be completely monitored using SoundPrint®.
Seismic Surveillance
Infrastructure owners and managers in seismically active zones with many structures distributed throughout a large geographical area must respond quickly to ensure the integrity of these structures after an earthquake. This can be a major strain on resources and the structures that need most urgent attention may not be discovered immediately.
SoundPrint® can discriminate between seismic activity and consequent structural damage. The extent and location of damage can be determined. An alarm message and event data can be transmitted to a control center by various communication methods.
Owners and managers can then prioritize their response based on the structural information provided by the system, thereby optimizing the use of resources at a critical time.
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