SHM of a stayed bridge during a structural failure, case study: the Rio Papaloapan Bridge

The Rio Papaloapan Bridge in Mexico is a stayed structure that has reported structural problems; it has required extra rehabilitation works besides a SHM system for continuous remote monitoring. The main problems were identified as structural deficiencies in the upper anchoring elements of the cables and up till now, these have caused two fractures and loosening of cables. The first failure, reported in 2000, was produced by deficiencies of the constitutive material and, in June 2015; a second failure took place due to a defective weld. In 2013 a SHM system was installed in the bridge for permanent remote monitoring, and although it did not have the ability to prevent the second failure, it was possible to measure, reproduce and evaluate the structural behavior of the bridge during and after this event; this information was very valuable to assess the overall structural integrity of the bridge and to quantify the effect of the failure to decide immediate preventive actions and to verify the effectiveness of the rehabilitation to recuperate the initial condition. This case study describes how the problem was addressed using the information collected from the monitoring system, and from the point of view of cost effectiveness of the SHM system, an initial evaluation of the costs and benefits has been done to estimate the value of having the information in almost real time for decision-making and to assure the bridge safety and integrity, versus the initial investment cost for the SHM system. As an initial conclusion, SHM are cost effective when structures are under many external or structural uncertainties affecting the bridges reliability.