Search results for "0201 civil engineering"
showing 10 items of 242 documents
Influence of design mistakes and material degradation on the collapse of a long-span RC roof in South Italy
2020
Abstract In 2004, during ordinary maintenance work, consisting in the waterproofing of a building located in the South of Italy, the long-span (14.50 m) in situ cast reinforced concrete (RC) roof partially collapsed. The building, constructed in 1950, was in service as a cinema up to 1967 and utilized as a school up to 1985. Finally, it was a hotel up to 2000. In 2004, when the building was not in service and underwent maintenance work, it partially collapsed under the dead load. After the collapse, which involved a large portion of the roof, several beams and two columns, the Court nominated a first Official Technical Consultant in order to investigate on the causes of failure and related …
Solutions for the Design and Increasing of Efficiency of Viscous Dampers
2016
In last decades many strategies for seismic vulnerability mitigation of structures have been studied and experimented; in particular energy dissipation by external devices assumes a great importance for the relative simplicity and efficacy. Among all possible approaches the use of fluid viscous dampers are very interesting, because of their velocity-dependent behaviour and relatively low costs. Application on buildings requires a specific study under seismic excitation and a particular attention on structural details. Nevertheless seismic codes give only general information and in most case the design of a such protection systems results difficult; this problem is relevant also in Italy whe…
Microstructural analysis (Voigt function method) of mullite in whiteware triaxial porcelains
2020
Triaxial porcelains were produced of two whiteware blends containing kaolin B (of “high-crystallinity” kaolinite) or halloysitic kaolin M (also with “low-crystallinity” kaolinite) in two different industrial firing cycles (fast or slow) with final temperatures 1270 °C, 1300 °C, 1320 °C and 1340 °C. The crystalline microstructure of mullite in all porcelain samples was studied by X-ray diffraction through analysing 110 and 001 reflections using the Voigt function method and by optical and electron microscopy. Mean crystallite sizes were determined independently for both 110 and 001 diffraction directions as principal semi-quantitative characteristics for all sixteen specimens. They illustrat…
Mechanical Behavior of Steel Fiber-Reinforced Concrete Beams Bonded with External Carbon Fiber Sheets
2017
This study investigates the mechanical behavior of steel fiber-reinforced concrete (SFRC) beams internally reinforced with steel bars and externally bonded with carbon fiber-reinforced polymer (CFRP) sheets fixed by adhesive and hybrid jointing techniques. In particular, attention is paid to the load resistance and failure modes of composite beams. The steel fibers were used to avoiding the rip-off failure of the concrete cover. The CFRP sheets were fixed to the concrete surface by epoxy adhesive as well as combined with various configurations of small-diameter steel pins for mechanical fastening to form a hybrid connection. Such hybrid jointing techniques were found to be particularly adva…
Experimental application of digital image correlation for the tensile characterization of basalt FRCM composites
2021
Abstract Composites made with inorganic matrix, namely fabric reinforced cementitious mortar (FRCM) composites are becoming widespread as strengthening materials for existing masonry structures. These composites are made of a dry grid of fibres embedded in an inorganic matrix. FRCMs can be considered a valid alternative to traditional organic composites such as fibre reinforced polymers (FRPs) because of their better compatibility with the masonry support. This work presents an experimental study for the tensile characterization of a basalt fabric reinforced cementitious mortar (BFRCM) composite. Tensile tests were carried out on coupons reinforced with one, two or three layers of grid to i…
Targeted steel frames by means of innovative moment resisting connections
2021
Abstract The present paper proposes the use of stepped cross section devices on steel frames aiming at reproducing a pre-established target push-over curve. To this aim a Limited Resistance Plastic Device (LRPD) to be inserted along selected structural members is proposed. The following two main specific features for LRPD are required: any elastic flexural stiffness variation of the original selected member must be avoided; an ultimate plastic bending moment value equal to an assigned percentage of the original limit resistance value must be ensured. Steel frames equipped with LRPD are modeled by means of an extension of a recently proposed Fibre Smart Displacement Based (FSDB) beam element…
Chemical and biological evaluation of cross-linked halloysite-curcumin derivatives
2020
Abstract Well designed and safe nano drug carrier systems are an important tool in biomedical applications. The combination of two or more drugs has been used in medicine both to enhance the therapeutic effect and to decrease the side effects of drugs. Biocompatible halloysite nanotubes, that possess two different surfaces, are a suitable nanomaterial for a simultaneous carrier and release of two drugs that can exert a synergistic effect against cancer cells. In this study, three curcumin derivatives and doxorubicin were loaded by supramolecular and covalent linkage at the lumen and external surface of the halloysite nanotubes. The obtained multifunctional systems were characterized by seve…
Parametric Hull Design with Rational Bézier Curves and Estimation of Performances
2021
In this paper, a tool able to support the sailing yacht designer during the early stage of the design process has been developed. Cubic Rational Bézier curves have been selected to describe the main curves defining the hull of a sailing yacht. The adopted approach is based upon the definition of a set of parameters, say the length of waterline, the beam of the waterline, canoe body draft and some dimensionless coefficients according to the traditional way of the yacht designer. Some geometrical constraints imposed on the curves (e.g., continuity, endpoint angles, curvature) have been conceived aimed to avoid unreasonable shapes. These curves can be imported into any commercial Computer Aide…
Strength and ductility of RC jacketed columns: A simplified analytical method
2016
Abstract Reinforced concrete (RC) jacketing is a common method for retrofitting existing columns with poor structural performance. It can be applied in two different ways: if the continuity of the jacket is ensured, the axial load of the column can be transferred to the jacket, which will be directly loaded; conversely, if no continuity is provided, the jacket will induce only confinement action. In both cases the strength and ductility evaluation is rather complex, due to the different physical phenomena included, such as confinement, core–jacket composite action, preload and buckling of longitudinal bars. Although different theoretical studies have been carried out to calculate the confin…
Testing of “Global Young's Modulus E” on a rehabilitated masonry bell tower in Venice
2017
Abstract This paper shows the effectiveness of the techniques chosen for the rehabilitation of the historic “Sant'Andrea” masonry bell-tower in Venice. The achieved rehabilitation projects based on the indenting technique consisting in removing and replacing bricks in bad conditions, and on the isolation of the bells at the belfry quote, respect all the constraints represented by the aesthetic and structural features of the building. Moreover, the experimental analyses used to define the existing state of the structure are described in detail. The tower is also an interesting case study for the validation of the proposed method to determine the global young's modulus in a rehabilitated maso…