Long-term monitoring of concrete bridge failures

Remote monitoring with SENSECOM-SK2 series

Case

A significant number of bridges are currently in a state of disrepair. Many of them were constructed from prefabricated post-tensioned beams. If their construction leaks, water penetrates to the metal reinforcement, which gradually corrodes. The most risky place is the transverse assembly joint, where cracks occur. Here it is important to detect the degradation in time to prevent the possible collapse of the bridge.

How this was done in the past

The manager of the prestressed bridge carried out frequent inspections with auxiliary tools to detect degradation because its permanent presence, often at heights, was not possible. The detection of bridge degradation is made possible by slides taped over the joint. Using binoculars, the administrator monitored them for cracks caused by the widening of the joint.

What it looks like today

The length of time from the first signs of a crack in the beam to the collapse of the structure is usually more than a few seconds, but rather on the order of hours or days. In these circumstances, it is of great importance to catch the first symptoms as soon as they arise and to inform the bridge manager so that he can carry out an emergency inspection as soon as possible. 

The solution was designed so that even a hairline crack as small as 0.05mm wide can be electronically detected on the slide and an SMS or email sent immediately.

The devices with detection slides have been successfully tested on several motorway road bridges in Czech Republic. In two cases, a microcrack was already detected through a cracked slide. The bridge manager was informed within 1 minute. The installation of these devices is practically no different from gluing conventional detection slides through joints and cracks, only the communication device is additionally attached and connected to the slides with a thin two-wire cable. 
 

Conclusion

The communication and detection device SENSECOM-SK2 is a significantly cheaper solution compared to the deployment of probes that continuously measure the width of the already formed joint. The SENSECOM-SK2 is easy to install, and its operating costs are minimal.

With SENSECOM-SK2, long-term electronic crack monitoring can reduce the risks of serious bridge failures and avoid the often-excessive costs of bridge repair in many cases. This solution represents low investment and operating costs, easy installation, and almost maintenance-free long-term operation. It can therefore be applied to a much larger number of problem or older bridges.

Use in different sectors

The same SENSECOM-SK series devices are also used on other types of structures and buildings, where detection slides are used to detect cracks in order to inform the building manager of possible structural damage.

Remote monitoring and detection of of cracks