Tommaso Rotunno

Experimental Study of Bond Behavior of CFRP-to-Brick Joints

AbstractCarbon fiber–reinforced polymer (CFRP) composite materials have been widely used to strengthen masonry constructions. The bond between CFRP and substrate strongly conditions the performance of reinforced masonry structures. Characterization of shear bond mechanical behavior of masonry-CFRP interface thus becomes a crucial factor. The paper presents the results of an extensive experimental investigation aimed at evaluating the bond between clay brick and CFRP sheet. Specimens with varying width and length of the bonded CFRP sheet were subjected to shear test by three different testing setups. Results allowed comparison of the effectiveness of the three types of setup and pointed out the influence of the dimensions of the bonded sheet on ultimate load and ultimate slip, load-displacement diagram, and failure modes. Measurement of local strain along the CFRP sheet also allowed an investigation on the transfer mode of the stresses from the reinforcement to the brick and the determination of the local ...

Lower Bound Limit Analysis of Masonry Arches with CFRP Reinforcements: A Numerical Method

This paper presents a numerical method to predict the ultimate load of masonry arches strengthened with carbon-fiber-reinforced polymer (CFRP) strips bonded to the intrados. The voussoirs of the arch and the CFRP strip, ideally divided into the same number of parts as the voussoirs, are modeled as rigid blocks. A finite set of stress resultants represents the stress state acting on interfaces of the rigid blocks. The local failure modes at the block interfaces are defined according to experimental evidence. The model is developed within an associated framework in such a way that the normality rule is satisfied: the upper- and lower-bound theorems of classical limit analysis apply. The ultimate load is predicted by a lower bound approach. The feasible domain is defined by the equilibrium equations and by the linear constraints imposed on the stress resultants. All the relations defining the model are linear, so that a linear programming problem is imposed. The predictions of the numerical model compare well with experimental results.

The Groin Vaults of St. John Hospital in Jerusalem: An Experimental Analysis on a Scale Model

ABSTRACT The St. John Hospital is part of a larger complex of buildings known as the Hospitallers Quarter, located south of the Holy Sepulchre in Jerusalem. At present, the hospital looks like an irregular volume both in height and in plan; it is covered by ten groin vaults resting on very stocky pillars. Each vault is formed by intersecting double curvature surfaces. In order to verify the effectiveness of continuous carbon fiber reinforced polymer sheets reinforcement, bonded at the extrados of vaults, laboratory tests were carried out on a 1:5 scale model, built with materials and construction techniques similar to those of the real building. Experimental tests were performed on the unstrengthened and strengthened vault. The experimental results shown that the strengthening system is able to increase the collapse load of the vault, without substantial variation of the initial stiffness.

Bartolomeo Ammannati’s Fountain: Comparisons Between Different Numerical Models

This paper focuses on the evaluation of the seismic performance of Venus, the central sculpture of Bartolomeo Ammannati’s Juno Fountain. A 3D geometrical model based on a laser scanner survey has been obtained and employed to build the finite element model (FEM) used in the analyses. The seismic response of the sculpture has been checked by performing different dynamic analyses, applying a spectrum-compatible ground motion and using different computer codes and assumptions. The considered numerical models differ from each other regarding the material behavior (linear and non-linear) and the connection between the statue and its base. Information useful for the seismic assessment of the artefact has been provided, thanks to the different models used.

On the modelling of infilled RC frames through strut models

Abstract Infill panels largely affect the seismic response of framed constructions. The wide variety in their mechanical and geometrical features has produced many different models and assumptions in their analytical representation. In this paper the simplest and most diffuse analytical approach, based on the introduction of equivalent struts, has been checked. An overview is presented, focusing on the strut dimensions, strength and number. Two case-studies, taken by two different experimental campaigns, have been considered and reproduced. The obtained results have been compared to the experimental ones, and some parameters have been checked for selecting the model to use for analysis.