Search results for "CONSTRUCTION"
showing 10 items of 2670 documents
3D buckling analysis of multidelaminated composite specimens
2007
The behaviour of thin composite laminates (unidirectional, cross-ply and angle-ply) under compressive loads has been examined in cases where multiple delaminations are present. The problem is solved using the Finite Element Method (FEM) both with linear analyses, based on the eigenvalues research problem, and with nonlinear analyses, based on incremental-iterative procedures. In particular, the role of the delamination length, of the angle of the plies and of the stacking sequence on the critical load is investigated. Results are compared with those found in literature derived from experimental or numerical 2D analyses.
Experimental in situ behaviour of unreinforced masonry elements retrofitted by pre-tensioned stainless steel ribbons
2014
Abstract The results of in situ tests carried out on unreinforced and reinforced poor rubble masonry full-scale walls in the earthquake prone Messina (Italy) area are presented and discussed. This experimental research was aimed at the assessment of the in plane shear behaviour of ancient masonry strengthened with an innovative system for masonry and retrofitting of reinforced concrete element constituted by three-dimensional pre-tensioned stainless steel ribbons. A comparison between different strengthening configurations was made in order to characterise the behaviour of masonry panels under shear-compression load, focusing attention on the diagonal cracking failure mode. The effectivenes…
Improvements in aggregate-paste interface by the hydration of steelmaking waste in concretes and mortars
2019
[EN] The objective of the experimental work is to study the mechanical properties in self-compacting concretes (SCC) in which part of the limestone aggregate has been replaced by granulated blast furnace slag (GBFS) in different percentages ranging from 0% to 60%. The results show that at early ages the SCC with the largest content in slag tend to have lower compressive strengths due to the poor compacting of the aggregates, although in the long-term their strength increases due to the reactivity of the slag. In fact, at the age of 365 days, the mortars made with the substitution of 50% of cement by ground GBFS reach compressive strength similar to that of the mortar made with 100% of cemen…
In-process calibration of a non-destructive testing system used for in-process inspection of multi-pass welding
2020
Abstract In multi-pass welding, there is increasing motivation to move towards in-process defect detection to enable real-time repair; thus avoiding deposition of more layers over a defective weld pass. All defect detection techniques require a consistent and repeatable approach to calibration to ensure that measured defect sizing is accurate. Conventional approaches to calibration employ fixed test blocks with known defect sizes, however, this methodology can lead to incorrect sizing when considering complex geometries, materials with challenging microstructure, and the significant thermal gradients present in materials during the inter-pass inspection period. To circumvent these challenge…
Physical activation and characterization of tannin-based foams enforced with boric acid and zinc chloride
2019
In this study, tannin-furanic-based foams enforced with H3BO3 and ZnCl2 are investigated, as well as their properties such as mechanical strength, specific surface area, and pore size distribution. From an industrial point of view, the aforementioned properties of these foams play a key role when used as catalyst, adsorbent, or gas storing materials. Therefore, this study aims to prove that such enforced tannin-furanic foams are promising materials for these types of applications. According to the results, materials that are up to five times stronger can be achieved by carbonizing the foams in comparison to maturing them. With physical activation, it was possible to obtain a specific surfac…
Induced Modification of Flexural Toughness of Natural Hydraulic Lime Based Mortars by Addition of Giant Reed Fibers
2020
Abstract Nowadays, there is a growing need to reduce the environmental impact generated by the use of inorganic materials for building applications. The aim of this work is to investigate the bio-lime based mortar flexural toughness improvement due to the addition of common reed fibers (Arundo donax L.) in order to evaluate their possible application as ductile eco-compatible prefabricated bricks or laying and joint mortars for masonry. Different sets of specimens were tested by varying the fiber weight content and the fiber length. Moreover, chemical treatments with Linseed Oil and Polyethylene glycol (PEG) were performed to improve the physical and mechanical properties of the fibers as w…
Masonry columns confined with fabric reinforced cementitious matrix (FRCM) systems: A round robin test
2021
Abstract The conservation and the preservation of existing masonry buildings, most of them recognized as cultural heritage, require retrofitting techniques that should reduce the invasiveness and assure reversibility and compatibility with the substrate. In this perspective, the strengthening system should be able to improve the bearing capacity of the structural member and, at the same time, to assure mechanical and material compatibility. The use of Fabric Reinforced Cementitious Matrix (FRCM) composites is now recognized to be suitable for these purposes. Indeed, the inorganic matrix has comparable properties with respect to the existing historical mortars while the fabric has relevant t…
Behavior of fiber-reinforced concrete columns under axially and eccentrically compressive loads
2010
An experimental investigation into the behavior of 16 short, confined, reinforced concrete columns with and without steel fibers was carried out. The columns with square sections had a concrete core 165 x 165 mm (6.49 x 6.49 in.) at the midsection and were hunched at the ends to apply eccentric loading and prevent boundary effects. The specimens were tested to failure at different strain rates under two loading schemes: concentric compression and eccentric compression with a constant eccentricity. The axial load and axial strains were obtained to evaluate the effects of the presence of steel fibers, the thickness of the cover concrete, and the eccentricity of the applied axial load. The com…
Numerical simulations of the mechanical characteristics of glass fibre reinforced C-profiles
2006
A mechanical characterisation analysis on pultruded glass fibre reinforced C-shaped profiles, developed as modular construction elements to assemble fastening systems, such as doors, window frames and shutters is presented. The key idea is to perform the analysis, and all the related identification procedures of the material parameters, via a coupled approach, based on a limited number of standard laboratory tests and on the numerical finite element simulations of the same tests. The proposed approach allows one to identify all those material parameters which are difficult to detect, by means of simple laboratory experiments on specimens that are extracted from commercial products. It also …
Stainless steel grids for confinement of clay brick masonry columns
2016
This work presents the results of an experimental investigation on the behavior of 21 solid clay brick columns internally strengthened by stainless steel grids placed in the horizontal joints of mortar. This reinforcing technique can be applied as a constructive technique for new construction or as a retrofitting technique for existing structures (old structures to be reconstructed by original constructive method and internal reinforcement). Monotonic compressive loading tests were carried out under concentric and eccentric load. The effects of different numbers of steel grids and eccentricity of the external load were examined. Also, a detailed characterization of the constituent materials…