ABSTRACT
This work presents a methodological approach to monitor the superstructure of the cable-stayed bridge “Solidaridad” located in the state of Guerrero, Mexico, seeking to identify distorting signals through the dynamic monitoring of control points established in the superstructure of the bridge.
Geotechnological tools were involved, such as a) The Global Navigation Satellite System (GNSS) and b) The use of Unmanned Aerial Vehicles (UAV). The GNSS is a set of satellite navigation system technologies that provide geospatial positioning with global reference [1], while UAV refers to a reliable data acquisition system in inspection and photogrammetric surveillance work due to its safe handling and accessibility to risk areas [2-3].
The study case corresponds to a dynamic structure of 890 m long. Three pylons support the bridge’s superstructure with four lanes 160 m above the Mezcala River. It is a bridge of great importance due to the large number of vehicles that circulate for tourist and labor purposes and trucks to supply consumer goods in the area.
For the fulfillment of the aim, we propose a methodology made up of the following stages: 1) The establishment of a geodetic control line for georeferencing purposes, under the UTM-WGS84 system; 2) GNSS establishment and positioning of the Ground Control Points (GCP); 3) Establishment of 14 Superstructure Control Points (SCP), distributed in 3 (North-Center-South) bridge sections; 4) For each section, plan the mission and performance three simultaneous flights of 10 effective minutes duration (approximately) each with the UAV (Drone); 5) For each flight and each section, process the generation of photographs, Orthophotos, Digital Surface Models (DSM) and point clouds independently every 2 minutes; 6) Extract from the point clouds the positions (X, Y, Z) of each SCP and each section of the superstructure (5 positions for each SCP each separated by 2 minutes); 7) Record three external factors that could affect the dynamic behavior of the superstructure: a) Traffic density; b) Temperature and c) Wind speed; 8) Analyze, model and evaluate the dynamic behavior of the bridge through SCPs positions.
We believe that the proposal presented can be applied periodically to establish a reliable monitoring system at the service of the instances corresponding to user safety.
