Statistical control methods applied to structural health monitoring (SHM). The experience of infiernillo 0 Bridge

In one of the inspections carried out on Infiernillo 0 Bridge at the kilometric point 251 + 500, Cuota Federal Road "Patzcuaro-Lazaro Cardenas" in the State of Michoacan, Mexico, a remarkable inclination of the center pile was detected. Such tilting occurred, according to the responsibles of the conservation of the structure, after a discharge of the Infiernillo reservoir, located upstream of the bridge, which caused an important rotation in the pile. Among the decisions taken to reverse the damage in the bridge, monitoring of the pile was adopted, while the necessary measures to restore the bridge to its original condition were adopted. In this case, statistical control methods were used in order to see if the rotation was stabilized (continuos under control) or if they continued to evolve. These methods are suitable in view of the limited influence of temperature variation on the pile due to the reduced height and the presence of water in foundations as a thermal regulator as explained as follow.