Assessment of the TRM Reinforcement of Windowed Masonry Walls Through Oma Identification

Abstract

Masonry constructions compose the majority of the Architectural Heritage worldwide, thus, their preservation is of great importance. Nevertheless, they usually show a great vulnerability to seismic and dynamic loads. Several reinforcement techniques can be used in order to improve their dynamic behaviour. The Textile Reinforced Mortar (TRM) material appears as very suitable, since it meets the requirements of compatibility and reversibility of the retrofitting. Moreover, it avoids some problems related to permeability. And strongly reduces adhesion and debonding issues. In this paper the effectiveness of the TRM reinforcement for dynamic loads for windowed brick masonry walls is evaluated through vibration testing and operational modal analysis. To this aim, two scaled brick masonry walls were built at the "Laboratorio de Grandes Estructuras" of the University of Alicante. Only one of them was reinforced with the TRM. Both were damaged with a cyclic in-plane lateral force for simulating damage due to seismic actions. Structural vibrations of the two walls were measured in the presence of a white noise excitation. Modal parameters were evaluated through Operational Modal Analysis (OMA) before and after the damage. Finally, changes in modal parameters due to damage were compared and investigated in both the unreinforced and reinforced cases. The results suggest that TRM reinforcement can be considered effective for improving the mechanical behaviour of a brick windowed masonry wall.

Modal testing of masonry constructions by ground-based radar interferometry for structural health monitoring: A mini review

“…In general, neither higher natural frequencies nor full threedimensional mode shapes can be obtained. The estimation of modal damping ratios is not explored in the literature, albeit information about the energy dissipation could be useful for damage detection (Ivorra et al, 2020).…”

Dynamic Identification of Tensile Force in Tie-Rods by Interferometric Radar Measurements

“…, is necessary for determining ϕ, γ and δ, related to the unknown parameters EJ, k and N. Specifically, a system of three nonlinear equations should be solved through numerical techniques. However, this procedure may be affected by significant instabilities; therefore, in [3], it is suggested to determine the three unknown parameters through the minimization of an error function G defined as follows:…”

“…One of the possible applications of NDT for historical masonry constructions is the assessment of the effectiveness of past or recent strengthening interventions [3,4]. In particular, a very diffused traditional reinforcing technique is represented by the introduction of tie-rods [5].…”

Dynamic changes on a masonry cross vault after a forced damage

“…This is so because masonry structures are specially designed to work under compressive stresses, being usual to consider as practically null the tensile strength. In this sense, since the dynamic response of the structure is directly related to its dynamic properties, the generation of damage on the structure due to a cracking of the masonry by vertical displacement of any of the supports should be reflected in a change in the vibration frequencies of the structure [2,3]. On the other hand, once the structures have been damaged, several authors have proposed the reinforcement of the structures by means of composite materials, fiber reinforced polymers (FRP) [4], or also by means of cement-based polymers, textile reinforced mortar (TRM) [5].…”