SYSTEM IDENTIFICATION AND NONLINEAR MODELING OF THE RETROFITTED NAVAL HOSPITAL HOSNAG DAMAGED AFTER THE 2016 ECUADOR EARTHQUAKE

The Naval Hospital "HOSNAG" is a seven-story reinforced concrete (RC) frame building located in Guayaquil, Ecuador. The structure suffered significant structural and nonstructural damage and service interruption due to the 2016 Muisne earthquake. The structure has RC frames with masonry infill, which were severely damaged during the earthquake. The building was repaired and retrofitted shortly after the seismic event. The strengthening involved the addition of steel X-braces and steel frames. A three-dimensional model of the building was prepared to simulate the seismic performance calibrated with a novel approach based on a recently proposed simplified analytical tool for infilled frames. After the completion of the strengthening efforts, this structure was instrumented with accelerometers and its ambient vibration was recorded. The recordings have been used to identify the dynamic properties of the repaired and retrofitted structure. The obtained natural frequencies and modal shapes were compared with those from a nonlinear finite element model of the structure, as being developed following a novel modeling methodology, which is expanded in order to account for the retrofit scheme. The current study presents the comparison of the model-estimated modal parameters with those obtained from the recorded data and will provide insight for the development of accurate, yet efficient, numerical models for actual buildings. Finally, the behavior of the building after being retrofitted indicates drift values above the ASCE 7-2010 code specificities, which could damage nonstructural elements after events similar to the 2016 Muisne earthquake.