santi urso - Academia.edu (original) (raw)

Papers by santi urso

Lecture notes in civil engineering, 2021

Despite the current awareness of the high seismic risk of earthen structures, little has been don... more Despite the current awareness of the high seismic risk of earthen structures, little has been done so far to develop proper strengthening solutions for the rammed earth heritage. Based on the effectiveness of TRM for masonry buildings, the strengthening of rammed earth walls with externally bonded fibers using earth-based mortar is being proposed as a compatible solution. In this context, the investigation of bond behavior was conducted by means of direct tensile tests, pull-out tests and single lap-shear tests. The specimens were prepared using earth-based mortars and two different types of meshes (glass and nylon) while considering different-bonded lengths. The direct tensile tests on TRM coupons showed the high capacity of the nylon mesh in transferring stresses after cracking of the mortar. The pull-out tests highlighted that in the case of glass fiber mesh, the bond was granted by friction, while the mechanical anchorage promoted by the transversal yarns granted the bond of the nylon mesh. Finally, the single lap-shear tests showed that the adopted earth-based mortar seems to limit the performance of the strengthening.

Key Engineering Materials, Apr 7, 2022

This paper presents a comprehensive experimental campaign performed on natural stone masonry wall... more This paper presents a comprehensive experimental campaign performed on natural stone masonry wallettes jacketed with 14 different combinations of mortars, meshes, and connectors. After characterizing the mortars and the bare masonry, diagonal compression tests were performed on three specimens for each jacketing solution. The performance of a fiber-reinforced, high-performance mortar without reinforcing mesh was investigated, considering its application to one or both sides of the wall, with and without connectors. Then, two different fabric reinforced cementitious matrix solutions were tested, using unidirectional or bidirectional textiles. Finally, the effects of FRP mesh spacing, mortar composition, and connector type and density were explored on reinforced plaster applications. The test outcomes were analyzed in terms of failure mode, tensile strength, and corresponding shear deformation capacity. All combinations proved effective at increasing the tensile strength compared to the bare masonry, with ratios between 1.9 and 4.7.

Procedia structural integrity, 2023

Soil Dynamics and Earthquake Engineering, Nov 1, 2019

In seismic areas one of the most important problems for engineers is to characterize in the most ... more In seismic areas one of the most important problems for engineers is to characterize in the most correct way the future ground motion accelerations. Building codes allow the practitioners to use artificial time-history compatible with a target pseudo-acceleration spectrum. The spectrum compatible seismic accelerations are usually represented by samples of stationary processes, even if it is well know that the ground motion accelerations should be modelled as samples of fully non-stationary processes. Moreover, the spectrum compatible accelerograms are not able to catch the site intensity of seismic events. In this paper methods able to catch the main features of recorded earthquakes, generating both spectrum compatible fully non-stationary accelerograms and artificial fully non-stationary accelerograms compatible with the site intensity of recorded accelerograms, are presented. In order to quantify the influence of the input model on the structural response, several numerical applications will be carried out and the results will be compared with the Monte Carlo simulation method.

Key Engineering Materials

Procedia Structural Integrity

Sensors, 2021

Digital Image Correlation (DIC) provides measurements without disturbing the specimen, which is a... more Digital Image Correlation (DIC) provides measurements without disturbing the specimen, which is a major advantage over contact methods. Additionally, DIC techniques provide full-field maps of response quantities like strains and displacements, unlike traditional methods that are limited to a local investigation. In this work, an experimental application of DIC is presented to investigate a problem of relevant interest in the civil engineering field, namely the interface behavior between externally bonded fabric reinforced cementitious mortar (FRCM) sheets and concrete substrate. This represents a widespread strengthening technique of existing reinforced concrete structures, but its effectiveness is strongly related to the bond behavior between composite fabric and underlying concrete. To investigate this phenomenon, a set of notched concrete beams are realized, reinforced with FRCM sheets on the bottom face, subsequently cured in different environmental conditions (humidity and temp...

International Journal of Adhesion and Adhesives, 2021

Temperature effects on failure mode of double lap glass-aluminum and glass-gfrp joints with epoxy... more Temperature effects on failure mode of double lap glass-aluminum and glass-gfrp joints with epoxy and acrylic adhesive,

Construction and Building Materials, 2020

Bond behavior of CFRP and PBO-FRCM systems comparatively analyzed. Different environmental condit... more Bond behavior of CFRP and PBO-FRCM systems comparatively analyzed. Different environmental conditions in terms of temperature and humidity. Novel notched beam test setup with externally bonded composite systems adopted. Analytical procedure to determine stress-global slip curve as in direct shear test. Different sensitivity of FRP and FRCM to high temperature conditions.

Key Engineering Materials, 2019

The use of externally-bonded composite materials for strengthening and rehabilitation of existing... more The use of externally-bonded composite materials for strengthening and rehabilitation of existing structures is among the most popular reinforcement techniques. Technologies, such as Fabric Reinforced Cementitious Matrix (FRCM) have been recently developed to address some of the issues of Fiber Reinforced Polymers (FRP), such as sensitivity to elevated temperatures and UV, impermeability, restricted application in presence of moisture or uneven substrate. For a detailed strengthening design with FRCM composites, the mechanical properties of the materials are required. Analytical models in literature discuss the interaction between the FRCM matrix and fabric using a fracture mechanics approach. These analytical laws were simplified using a trilinear curve in which a constant branch correlated to the friction is added. In the United States, “Acceptance Criteria AC434” includes the test methods to evaluate the mechanical properties of the FRCM through a direct tensile test which uses c...

International Journal of Adhesion and Adhesives, 2018

In this experimental study the mechanical performance of the adhesive joints in a steel-glass con... more In this experimental study the mechanical performance of the adhesive joints in a steel-glass connection is investigated. The aim of this work is to verify the applicability of the adhesive bonds on the "Tensegrity floor" (Patent no 0001426973); "Tensegrity floor" is a hybrid system characterized by a particular steel-glass adhesive junction that permits an effective cooperation between the two structural elements (a glass panel and a steel subframe). The innovation of this structure is related to the cooperation of the above mentioned elements; in fact, in those applications where the glass represents the floor decking, the adhesive glass-metal junctions have already been used, but the glass panel has not been considered as a cooperating element. For this reason, several adhesives-four epoxy, one silicone and one acrylic-have been herein tested in order to study the opportunity of using this connection to increase the stiffness of the system. Two types of characterization test, compression and tensile tests, have been carried out to obtain the mechanical properties of the adhesives. After this step some suitable component tests have been performed with a stepwise cyclic loading; the results showed the effectiveness of the system in terms of stiffness increasing and consequent reduction in terms of deformations. As a result of these experimental investigations the epoxy adhesives have shown a better behavior, both in compression and in flexion, in term of stiffness, than the acrylic and silicone ones, which, instead, have got highest deformability. A numerical validation of the whole system has been done through a Finite Element Model of the tested samples; the analytical results confirmed the stiffness increase due to the adhesive joint compare to the simplysupported model.

Journal of Composites for Construction, 2016

Steel Reinforced Polymer (SRP) systems have recently emerged as an attractive solution for the ex... more Steel Reinforced Polymer (SRP) systems have recently emerged as an attractive solution for the external strengthening of reinforced concrete structures. They entail unidirectional fabrics made out of high tensile strength steel cords that can be externally bonded to the substrate via wet lay-up, using either epoxy or polyester resin. Currently, research about the behavior of SRP strengthening systems for concrete structures is evolving but further systematic and comprehensive studies are still needed to ensure the consistency and reliability of the studies performed to date. The present paper contributes to expanding the existing knowledge by presenting the results of an extensive experimental program devoted to investigate the bond behaviour between SRP and concrete substrate. To this purpose, a number of SRP strips were bonded to concrete blocks by a thixotropic organic matrix and the lap joint was subsequently subjected to direct shear tests performed in displacement control. Besides the concrete strength, the following study parameters were considered: (a) the concrete surface roughness in the bonded region, (b) the density of the steel fabric, (c) the ratio of the epoxy covered concrete surface width to the SRP strip width, and (d) the bonded interface length.

Journal of Building Engineering, 2020

Abstract The present work is based on an experimental campaign in which the mechanical properties... more Abstract The present work is based on an experimental campaign in which the mechanical properties of a set of adhesive painted aluminum-cloudy glass joint are investigated; the obtained results can be appropriately used for practical problems, since this particular junction is suitable in civil engineering applications. For the conducted experimental campaign, a commercial epoxy structural adhesive was selected. Since the performance of the adhesive depends on temperature, tensile test on dog bone specimens and double-lap joints were conducted at three different temperatures (representing laboratory conditions, work conditions and maximum service temperature). The work aims to verify the applicability and the compatibility of the tested junction on a building component, such as window frames, by reproducing the effective work conditions of both glass and aluminum. The obtained results show that the analyzed junction can be suitable used for practical applications up to work temperature, since a good performance in term of maximum load capacity and maximum displacement is maintained if compared with laboratory condition. Instead, a drastic reduction of mechanical properties is observed at maximum service temperature.