SIMPLIFED: "Development of a Low-Cost Passive Strain Senor for Bridge Structural Health Monitoring"

Link to original article: https://www.mdpi.com/1424-8220/26/6/1963 

Note: The image above was taken from the original article

It is obvious that if a bridge starts to stretch or collapse, then that bridge is unsafe for cars or even people to be on. This is even more clear in that in the past, there have been countless collapses in various bridges leading to countless deaths and casualties. Unfortunately, it is very difficult to see when a bridge starts stretching. To track the stretching of a bridge, one would have to create complex sensors that may not be cost-effective. However, this article investigates the potential implementation of a new sensor made from RRSM, which is retroreflective sheeting material; this sensor is passive and is cost-effective, meaning it would be able to be implemented very easily to countless bridges while keeping countless lives safer at the same time. Furthermore, this system would avoid the use of visual observations to see if a bridge is safe or not. 

RRSM may not be a material you have heard of before, but it is the same material used for highway signs. This material is useful because when it is stretched, the material reflects a significantly different amount of light. This idea is useful in that by using it as a stretching sensor on bridges, if the bridge is stretching, then this material will start reflecting a significantly different amount of light, thus indicating that the bridge is stretching and that something must be fixed. Additionally, the amount of stretching can be quantified. RR, also referred to as retroreflectivity, is a concept where light is returned back to where it came from. This entire study essentially found that as stretching increases, retroreflectivity, or RR, decreases with a linear relationship. This means that by looking at the RR, scientists are able to predict how much a bridge has stretched. 

The article also mentions that because the material is very cheap, as RRSM is used for everyday highway signs, these sensors are going to be very affordable. This means that there is potential for these sensors to be on most bridges without having to spend too much money. 

More research is needed in order to implement these new sensors. This is especially apparent in that not 100% of the trials run in the article returned the correct strain, but it was still decently high, as the percentage was between fifty and ninety. Overall, this idea is very unique and may be an innovative solution to improving bridge safety in the future.