Non-destructive identification of the mechanical response of FRP strengthened brickwork walls with modal analysis

Abstract

Techniques for the non-destructive identification of the materials and structures properties have been recently developed and are rapidly improving their performance now. One of the main advantages of these testing procedures is their possible application for studying historical buildings without damaging these heritage elements, which is one of the basic requirements of conservation interventions. Among non-destructive testing techniques, the vibration analysis or modal analysis outstands because of its easy implementation, quick data acquisition and reliable result. Hundreds of buildings and civil engineering structures have been studied with this technique to assess their performance through the elastic dynamic response. This testing technique is able to provide essential information for the safety study of existing structures or to evaluate the structural effectiveness of a strengthening system once it is applied. Focusing the research on the historical buildings, brickwork walls are one of the most common structural elements. However, it has been noticed that there is a growing strengthening tendency which might change the structural behavior of these elements. Applying FRP laminates bonded on the wall’s surface has turned to be a common practice in retrofitting structures. Nevertheless, this actuation shows several drawbacks which have been deeply studied. The elastic properties of the FRP strengthened walls are expected to be different from the ones of unreinforced walls. This strengthening system has been experimentally analyzed with destructive tests but using a nondestructive technique is still a new investigation branch.The proposed tasks are aimed to perform an experimental campaign in order to evaluate the changes in the dynamic response of brickwork walls when strengthened with different patterns of FRP by using a modal analysis.