Post-tensioning is a method of reinforcing concrete. Post-tension tendons are pre-tightening steel cables inside plastic ducts or hoses that are placed in forms before placing concrete. “The actual tension cables allow us to safely build large concrete structures. Large distances between the support parts. On-site tension is used in bridges and box girders around the world, including on our bridges, on ramps and without them. These tendons allow you to build constructs that otherwise it might not be possible. under load. Although reinforcement is used to reuse concrete to prevent the growth of cracks, concrete can still sag under increased loads. PTs or tension tendons are load bearing and can withstand large increases in load, concrete.
There are many advantages that are achieved through the use of post-stress approach. It provides design flexibility, faster construction and lower material costs. In the long run, this can reduce maintenance costs and increase workload over time.
Bridges that use tendons after stretching can contain long and transparent spans, have several beams and thin elements and thinner plates that can be used, which is impossible in the case of ordinary bridges. This method strengthens or strengthens concrete or other material with a high-strength steel rod or filament, which is known as “tendons.” This significantly reduces the weight of the building and the load on the foundation, which is very useful in seismic zones.
Constant tensile tendons help in creating complex bridges that have special geometry requirements, such as complex curves and super-height. Extremely long intermediate bridges can be built with joints after stretching. Such architectures function efficiently, without disabling the movement that moves under it, and also significantly reduce the impact on the environment.
Permanent tensile tendons are made from prestressed filaments, fasteners, ducts, and materials to protect against mashing and corrosion. Since this technology is new, there are no control systems for the tendon components. Recent cases of tendon corrosion after stresses in complex bridges have become a serious problem.
After receiving information about the tendon correlation, the transportation department checked the inventory of the structure after tension to evaluate and quantify the tendon correlation speed and estimate the remaining lifetime of the affected member.
Infrastructure Conservation Corporation (IPC) has developed a comprehensive post-stretch tendon inspection service called TendonScan®, which uses non-destructive testing and evaluation techniques that can detect corrosion and loss of cross-section in PT tendon.
What?
As we mentioned above, this is a comprehensive tendon scan system that works on the principles of non-destructive testing to find out the voids, water penetration and bleeding solution in the external tendons. This system also includes a device for detecting loss of section in the tendon.
Why was it developed?
During the construction of complex bridges, tendons are filled with a solution to prevent corrosion. But in the process of grouting, grout tends to separate depending on the quality of the grout, impurities, pumping equipment and procedures. This separation leads to the formation of a low pH solution at the tendon points and anchoring, which makes these sites susceptible to corrosion.
A comprehensive bridge check is incomplete without a tendon test, so we developed this TendonScan system to solve this problem.
How is it used?
This is a battery-powered robotic system that uses the latest non-destructive testing and advanced technology. This system connects with the tendon and moves along it to perform an MRI scan, such as examining the material inside it. The inspector stands on the mobile control unit, which moves with the sensor. The sensor works through a wireless connection to transfer the collected data. Information is transmitted to the control station to assess the state of the tendon in real time. The image of the inner tendon section is then illustrated with three-dimensional color graphics, so that any rupture, such as water penetration, void, or bleeding solution, can be easily identified and quantified.
What problem does he solve?
This tendon assessment system helps in the detection of corrosion, voids, bleeding solutions, loss of section and other problems inside and outside the tendon. In addition, it also helps in monitoring breaks for a certain period of time, which helps determine when to repair or replace a tendon after a strain.
