Motorway Bridge A8: Moisture and Corrosion from the New Build

Challenge

Detecting damage before it becomes visible

The aim of the design was to detect damage in time, before it becomes visible. Whoever only reacts once the damage can be seen pays more for the concrete repair and needs longer closures. Three areas of the structure were critical here: the caps, the joints and the technologically induced weak points.

This project ran as a PPP project, which adds a second point: a very long warranty period was agreed for the structure. Over such a long period, it had to remain observable whether the surface protection systems used are working and how the technologically induced weak points develop.

Solution

Sensors that go into the concrete with the new build

The concessionaire of the PPP project planned and installed the sensors, in the new-build section. Moisture and corrosion sensors were placed specifically where the damage is expected: in the cap area, at the joints and at the technologically induced weak points.

The positions were chosen according to the damage expected there in future. The sensor therefore sits exactly where the damage will later occur.

Readout

From handheld reader to remote readout

Initially, the sensors were read out with a handheld reader, directly at the structure. That works, but it costs a site visit every time. With the CorroDec 2G sensor generation, the same measurement is conveniently possible remotely.

For the operator, this changes less about the readings themselves than about how they are handled. Inspection intervals can be steered by the data instead of by the calendar, repairs can target specifically the points where the surface protection system actually fails, and closures for later measures become shorter because the scope is known in advance.

Result

A measurement series that begins with the structure

The critical points of the structure have carried sensors since the new build. Over the warranty period, this makes it possible to observe how moisture and corrosion develop at caps and joints.

The project shows how concrete monitoring and moisture and corrosion monitoring work in bridge monitoring when they are planned in already during construction. If you are planning a structure or a repair and want to be able to prove its condition afterwards, describe your project to us through our project inquiry.