Search results for "strength"
showing 10 items of 2415 documents
Shear and flexural strength prediction of corroded R.C. beams
2017
Abstract The purpose of the work was the study of the structural safety of R.C. beams subjected to corrosion processes though the derivation of moment-curvature diagrams and moment-to-shear interaction diagrams. Normal-strength reinforced concrete beams with longitudinal bars in the presence of transverse stirrups and subjected to corrosion processed are considered. Experimental results available in the literature related to corrosion processes, for steel bars, crack openings and bond degradation due to rust formation are reviewed. Then analytical laws relating to crack opening, bond degradation with attack penetration depth, through a rearranged form of Faraday’s law, are presented. An ana…
Advanced Strategies and Materials for Reinforcing Normal and Disturbed Regions in Brick Masonry Columns
2016
This work presents the results of an experimental investigation on the behavior of 42 solid clay brick masonry columns internally strengthened by fiber-reinforced polymer (FRP) fabrics or stainless steel grids placed in horizontal mortar joints. In some cases, every course, and in other cases, alternate courses were reinforced with steel grids, carbon, and basalt FRP fabrics. Monotonic compressive loading tests were carried out under concentric and eccentric loads. Eccentric tests were carried out by loading the specimens on a reduced area with respect to the entire cross section, producing a disturbed region (D-region). A detailed characterization of the constituent materials was made expe…
Experimental investigation on the effect of mortar grade on the compressive behaviour of FRCM confined masonry columns
2018
Abstract The use of Fiber Reinforced Cementitious Mortar (FRCM) systems for structural retrofitting of masonry structures has become increasingly popular in the last years, due to the capability of this technique in overcoming some of the drawbacks related to the adoption of resin-based composites. Recent studies investigated on the effect of FRCM wraps on the compressive behaviour of concrete members and demonstrated as the application of mortar-based composites allows increasing the strength and, above all, the ductility of the column. The main difference with FRP confined columns is related to the different post-peak behaviour, characterized by a softening branch. Differently, few studie…
Comparative experimental analysis on the compressive behaviour of masonry columns strengthened by FRP, BFRCM or steel wires
2017
Abstract In the last decade, several studies have investigated the application of Fibre Reinforced Polymer (FRP) wraps to masonry piers in order to provide a confinement effect and enhance compressive strength and ductility. Although this technique has proved to be quite effective, various drawbacks arise when organic resins are used to bind fibres. To solve these problems, different techniques have been developed to be used as alternative methods for enhancing the structural performances of weak masonry columns. Among these, the use of Basalt Fibre Reinforced Cementitious Matrix (BFRCM) wrapping, or the application of steel wires at mortar joints. This paper presents the results of an expe…
Brick Masonry Columns Externally Wrapped with Steel Wires under Concentric and Eccentric Loads
2017
This paper discusses an experimental investigation of clay brick columns that are externally strengthened by steel wire collars wrapping the horizontal mortar joints. The study aims to prove the effectiveness of the proposed strengthening technique and detect the efficiency of different numbers of steel collars. Additionally, the effect of eccentric loading is investigated. This paper proves that an analytical expression available in the previous literature can be modified to provide the strength of the equivalent homogeneous cross section in simple compression. To this aim, the biaxial strength domain of the bricks is modified to account for the lateral pressure exerted by the steel collar…
Adhesion Strength Test Comparison for HVOF Nickel-Based Superalloy Powders on Steel Substrates and Layer Characterization
2018
Thermal sprayed nickel chrome powders are known as the best materials for combined wear and corrosion applications and represent a good alternative to hard chrome plating. The coating from these materials are resistant to wear abrasion, contact with hard surfaces, particle erosion, fretting and have excellent submerged saltwater corrosion resistance. The work in this paper is focused on determining the adhesion strength for nickel powders and structural characterization of the deposited layers using metallographic analysis. The adhesion strength testing was carried out in accordance with ASTM C633 procedure. During the experimental program, an investigation was also carried out for studying…
Effect of areal weight and chemical treatment on the mechanical properties of bidirectional flax fabrics reinforced composites
2010
Abstract In this paper several bidirectional flax fibers, usually used to made curtains, were employed as reinforcement of an epoxy matrix. Four different laminates were made by a vacuum bagging process, with varying both the areal weight and the treatment of the fabric. These structures were mechanically investigated carrying out both tensile and three point flexural tests. In order to evaluate the effect of the identified variables on the mechanical parameters (i.e. Young modulus and maximum stress) a statistical analysis was performed. Finally, by comparing the flax composite with a glass one, the convenience of the replacement of glass fiber was investigated in term of cost, weight and …
Minimal intervention in dentistry: Which is the best approach for silorane composite restoration repairs?
2021
Made available in DSpace on 2021-06-25T10:28:11Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-04-01 Background: This study aimed to evaluate surface treatments, adhesives and composites for repairing silorane based restorations. Material and Methods: One hundred and twenty truncated cones (2 mm smaller diameter and 4 mm larger diameter) made of silorane composite were divided in 12 groups according with the surface treatment (diamond bur and oxide aluminum abrasion), the adhesive (Adper Scothbond Multipurpose (3M ESPE), Ecusit (Voco) and Filtek P90 Adhesive (3M ESPE)). Each group was subdivided in two according with the composite used for repair (methacrylate and silorane). The rep…
Effects of powder concentration and type of resin on the performance of marble composite structures
2009
In this work, we will expose the behaviour of a composite structure reinforced with marble powder. The attention was focused on the effects produced on the physical and mechanical properties due to different kinds of matrix (epoxy and polyester resins) and filler amounts (60%, 70%, 80%). Rheological, static flexural and Izod impact tests have been carried out. An experiment designed was defined for the mechanical tests, in order to quantify the effects of both the resin and the marble percentage on the material properties, as well as to identify a possible correlation between these factors. Moreover, water absorption and stain resistance have been evaluated to study the surface properties o…
Moisture Absorption Effects on the Resistance to Interlaminar Fracture of Woven Glass/Epoxy Composite Laminates
2012
The influence of moisture absorption on the interlaminar fracture behaviour of 8/8 harness satin weave glass/epoxy composite was investigated. Two series of specimens with 0°/0° and 90°/90° predominant interfaces immersed in water for different duration were tested under double cantilever beam (DCB mode I), single leg bending (SLB mode I + II) and end notched flexural (ENF mode II) loadings. In general, the apparent flexural modulus: E, and the fracture toughness: G C, decrease with increasing moisture content. This effect is more remarkable if mode II participation is bigger. The value of G C measured on 90°/90° specimens reveals higher than that on 0°/0° ones, but the variation in G C is …