## 4 Discussion--Challenges and Opportunities for the Bridges of Peru
### Challenges in New Digital Technology Tools to Support Bridge Construction
These sensors are complemented with sensors that measure seismic accelerations and also the level of vibrations, called accelerometers, which measure seismic accelerations and vibration levels by the induction of loads in different directions in structural elements, both horizontal and vertical, thus indicating a trend in the level of damage that an earthquake can develop in the bridge infrastructure [40; 41]. Currently, there are studies where low-cost inclinometer and accelerometer-type sensors are combined with Arduino or Raspberry Pi controller boards alongside the IoT and artificial intelligence to improve the accuracy in vibration level measurements [40]. Finally, the use of UAVs or drones allows for inspecting structural elements of bridges that are difficult to access after an earthquake, thus allowing for assessing the level of damage, including cracks, explosions of elements, and landslides, among others. This allows for the identification of critical structural elements that require the application of conservation measures and thus guarantees the structural stability of the bridge. The use of UAVs avoids traffic disruptions on bridge infrastructures both day and night, as well as significant time savings for the engineering team in charge of repairing the bridge. In addition, the use of images obtained with UAVs avoids falling into biases or subjective criteria for the identification and level of failures in the bridge infrastructure. Finally, it is possible to combine the use of UAVs with artificial intelligence tools to manage aerial images and thus, through CNNs, analyze, process, and study large volumes of data more quickly and accurately, automating the inspection process in bridge infrastructure [24; 25; 26]. Opportunities for Structural Health Monitoring of Bridges Against Deterioration Due to Use of Materials  
An important issue that must be monitored through continuous monitoring over time is the effect of the deterioration of materials due to environmental conditions in the bridge infrastructure project. Cycles of night and day temperature changes, cycles of temperature changes from winter to summer, moisture content, liquid and solid precipitation, among others, cause internal changes and alterations in the construction materials used in bridges, such as wood, concrete, and steel. These environmental conditions induce deformations, displacement, rotations, sulfation, and corrosion, among others, in bridge infrastructure [38; 42; 43]. By combining wireless sensors with the use of the IoT and artificial intelligence, it is possible to measure different parameters and monitor changes in the key properties of structural elements in bridges in real time [42; 44]. The use of UAVs or drones that have thermal cameras allows for obtaining heat maps of the structural elements of bridges and identifying areas of cracking and fracture in reinforced concrete structures and excessive corrosion in steel structures. The use of UAVs allows the bridge to continue providing normal operation to the public without traffic interruptions day or night [22; 23]. Nevertheless, creep and shrinkage effects have to be considered in terms of long-term behavior for the structural health monitoring of bridge infrastructures. In this sense, pre-cast deck systems also have several advantages from a construction point of view, such as superior concrete quality, the possibility of implementing a modular construction scheme, and the fact that there are fewer weather constraints, since the volumes of cast-in-place concrete are significantly reduced. For example, for the Nanay bridge, pre-cast slab panels with dimensions of 3.20 m \(\times\) 7.30 m, cured at least 60 days before their installation on the bridge, were used to minimize creep and shrinkage effects. Structural health monitoring for bridge structures generally refers to the process of designing, developing, and implementing a damage detection or characterization strategy for the real-time assessment of structural conditions.