Fiber Reinforced Cementitious Matrix (FRCM) for strengthening historical stone masonry structures: Experiments and computations

A study is presented on the evaluation of the floor deformability in the existing RC buildings and the related effects on the structural behaviour and the seismic fragility are investigated. In particular, the study of the seismic behaviour of existing RC buildings is strictly related to the initial assumptions made by practitioners on the numerical model, which usually assume the floor as rigid, according to a criterion of reducing time and computational efforts. Nevertheless, this hypothesis can provide unrealistic responses, with effect of obtaining not conservative results in the vulnerability estimation. In a view of practitioners’ necessities, a new numerical practical procedure is developed, in order to provide an a priori definition about the effective floor deformability of three-dimensional finite element models. This procedure has been tested on a couple of real existing RC school buildings, modelled with several numerical configurations and accounting for the presence of all elements that constitute the entire buildings (floor system, infill panels and elements of retrofit). Based on the evaluation of structural response and seismic fragility, some interesting observations have been provided, with the aim to define and to prevent the possible errors by assuming the floor as rigid.

A practical approach for estimating the floor deformability in existing RC buildings: evaluation of the effects in the structural response and seismic fragility

Discrete mechanical models of concrete fracture

Computational modeling of the out-of-plane behavior of unreinforced irregular masonry

This paper focuses on the simulation of irregular stone masonry by the lattice discrete particle model (LDPM), which simulates the fracture and failure behavior of quasi-brittle heterogeneo...

Lattice Discrete Particle Model for the Simulation of Irregular Stone Masonry

Seismic fragility assessment of existing masonry buildings in aggregate

Recent seismic events prompted research to develop innovative materials for strengthening and repair of both modern and historic masonry constructions (buildings, bridges, towers) and structural components (walls, arches and vaults, pillars, and columns). Strengthening solutions based on composite materials, such as the Fiber Reinforced Polymers (FRP) or the Fiber Reinforced Cementitious Matrix (FRCM), have been increasingly considered in the last two decades. Despite reinforcement made of short-fibers being a topic that has been studied for several years from different researchers, it is not yet fully considered for the restoration of the masonry construction. This work aims to experimentally investigate the enhancement of the mechanical properties of lime-based mortar reinforced by introducing short glass fibers in the mortar matrix with several contents and aspect ratios. Beams with dimensions of 160 mm × 40 mm × 40 mm with a central notch were tested in three-point bending configuration aiming to evaluate both the flexural strength and energy fracture of the composite material. Then, the end pieces of the broken beams were tested in Brazilian and compressive tests. All the tests were performed by a hydraulic displacement-controlled testing machine. Results highlight that the new composite material ensures excellent ductility capacity and it can be considered a promising alternative to the classic fiber-reinforcing systems.

https://www.mdpi.com/1996-1944/13/16/3462/pdf

Lime-Based Mortar Reinforced by Randomly Oriented Short Fibers for the Retrofitting of the Historical Masonry Structure.

Rubble stone masonry walls are widely diffused in most of the cultural and architectural heritage of historical cities. The mechanical response of such material is rather complicated to predict due to its composite nature. Vertical compression tests, diagonal compression tests, and shear-compression tests are usually adopted to investigate experimentally the mechanical properties of stone masonries. However, further tests are needed for the safety assessment of these ancient structures. Since the relation between normal and shear stresses plays a major role in the shear behavior of masonry joints, governing the failure mode, a triplet test configuration is herein investigated. First, the experimental tests carried out at the laboratory of the University of L’Aquila on stone masonry specimens are presented. Then, the triplet test is simulated by using the total strain crack model, which reflects all the ultimate states of quasi-brittle material such as cracking, crushing, and shear failure. The goal of the numerical investigation is to evaluate the shear mechanical parameters of the masonry sample, including strength, dilatancy, normal, and shear deformations. Furthermore, the effect of (i) confinement pressure and (ii) bond behavior at the sample-plate interfaces are investigated, showing that they can strongly influence the mechanical response of the walls.

https://www.mdpi.com/2075-5309/10/3/49/pdf

Michele Angiolilli

Papers

Fiber Reinforced Cementitious Matrix (FRCM) for strengthening historical stone masonry structures: Experiments and computations

Lattice Discrete Particle Model for the Simulation of Irregular Stone Masonry

Seismic fragility assessment of existing masonry buildings in aggregate

Lime-Based Mortar Reinforced by Randomly Oriented Short Fibers for the Retrofitting of the Historical Masonry Structure.

Triplet Test on Rubble Stone Masonry: Numerical Assessment of the Shear Mechanical Parameters