Experimental assessment of an innovative strengthening material for brick masonry infills

Abstract

The vulnerability of masonry infill walls has been highlighted in recent earthquakes in which severe in-plane damage and out-of-plane collapse developed, justifying the investment in the proposal of strengthening solutions aiming to improve the seismic performance of these construction elements. Therefore, this work presents an innovative strengthening solution to be applied in masonry infill walls, in order to avoid brittle failure and thus minimize the material damage and human losses. The textile-reinforced mortar technique (TRM) has been shown to improve the out-of-plane resistance of masonry and to enhance its ductility, and here an innovative reinforcing mesh composed of braided composite rods is proposed. The external part of the rod is composed of braided polyester whose structure is defined so that the bond adherence with mortar is optimized. The mechanical performance of the strengthening technique to improve the out-of-plane behaviour of brick masonry is assessed based on experimental bending tests. Additionally, a comparison of the mechanical behaviour of the proposed meshes with commercial meshes is provided. The idea is that the proposed meshes are efficient in avoiding brittle collapse and premature disintegration of brick masonry during seismic events.

Optimal Design and Additive Manufacturing of Novel Reinforcing Elements for Composite Materials

“…Table 2 gives the toughness index I of the examined mortar specimens, and the mean values of such a quantity that we recorded for each different material. [20]. It is worth noting, however, that most of specimens analyzed in the present work exhibit flexural collapse under deflections lower than  5 .…”

Experimental Assessment of Strengthening Strategies Against the Out-of-Plane Collapse of Masonry Infills in Existing Rc Structures

“…The authors also pointed out the reduction of the displacement at the maximum strength and allowed reaching a controlled failure mode. Martins et al [8] tested an innovative strengthening technique based on TRM technique with meshes based on composite rod composed by an external polyester protection. The idea of the authors was that the core provides the reinforcement and the external polyester braided rod contribute with the residual strength and deformation capacity which controls the damage and avoids brittle failure of the masonry units.…”

In-Plane Behavior of Infills using Glass Fiber Shear Connectors in Textile Reinforced Mortar (TRM) Technique

“…3a. The bond between the external braid and the reinforcing fibers can be ensured in the manufacturing process by adding polyester resin during the braiding process or after the production of the composite braided rods by adding the resin over the external polyester manually (Martins et al, 2015). For the application on the masonry infills, the composite rod was composed of a braided structure with 15 multifilament of polyester with 11 Tex and one braided element with a simple structure consisting of 8 braided polyester yarns produced at the maximum speed of the production equipment (1.07 m/min).…”

“…The developed mesh is composed of a set of composite rods with an external polyester helicoidally braided with a reinforcing nucleus of glass fibers. The idea is that the braided rod can protect the reinforcing fibers and provide ductility after the rupture of the fibers (Martins et al, 2015), Fig. 3a.…”

“…An innovative strengthening technique was proposed by Martins et al (2015) by performing some bending tests on masonry wallets. Based on the results the strengthening material is designated as Braided Composite Rod (BCR) which results from a braiding process.…”