Search results for "columns"

BFRP grid confined clay brick masonry cylinders under axial compression: Experimental results

2018

The use of composite materials for retrofitting of masonry structures has received great attention during the last two decades. For masonry buildings there are several advantages in using composite materials. Traditional techniques that were largely used and investigated in the past, may be inadequate in seismic areas where the added mass could increase seismic actions. Moreover, for historical and architectural heritage structures, the compatibility, sustainability and reversibility of the intervention is a key factor for the selection of the most appropriate strengthening system. Many investigations have shown that fibre reinforced polymers (FRP) can be effectively used to induce a passiv…

A closed form procedure for the design of longitudinal bars in RC sections subjected to axial load and biaxial bending

2020

This paper presents an analytical procedure for the design of the longitudinal reinforcement in reinforced concrete rectangular sections subjected to axial load and biaxial bending moment. The integration of the equilibrium equations is performed in analytical form for the case of uniaxial moment, including the effect of the reinforcement placed on the sides of the section and adopting code-based constitutive laws for steel and concrete. The strength domain of the section is calculated in closed form for the case of only main steel and in simplified form when including the reinforcement disposed on the side. Additionally, a formulation is proposed for the interaction domain of the two compo…

Flexural behaviour of RC columns strengthened with steel angles and strips

2011

Cyclic axial testing of columns confined with Fiber Reinforced Cementitious Matrix

2012

Steel jacketing of RC columns: Reliability of capacity laws for concrete

2016

In the seismic assessment of framed R.C. structures reinforced by steel angles and battens (steel jacketing) the use of proper confinement models for concrete is still a main topic. Really, the capacity of reinforced concrete columns under concentric and eccentric loads strongly depends on confinement exerted by the external reinforcement. Further a proper attribution of concrete stress-strain laws allows obtaining reliable estimations of inelastic capacity of reinforced elements. Moreover the presence (or not) of connections of the angles with the end joints influences their capacity to support vertical loads. In the two cases the mechanical models have to account for buckling or frictiona…

Simplified analytical models for compressed concrete columns confined by FRP and FRCM system

2017

In order to consider the response of concrete columns confined by FRP and FRCM system, proper models have to be formulated. In this context the present paper shows a generalized criterion for the determination of the increase in strength, in ductility and in dissipated energy for varying corner radius ratio of the cross section and fiber volumetric ratio. The procedure is based on the best fitting of several experimental data and unlike the usual empirical approaches available in the literature, the proposed technique relates the confinement effectiveness to a single parameter representative of the relative stiffness between the original concrete core and the reinforcement system. Furthermo…

Reliable and simple analytical methods for determination of citrulline and metabolically related amino acids by liquid chromatography after derivatiz…

2014

We describe the development of a high-performance liquid chromatography (HPLC) method for the determination of citrulline and other amino acids relevant to intestinal diseases. The amino acids were derivatized with 9-fluorenylmethylchloroformate (FMOC-Cl) and their derivatives were separated on two different columns, a core-shell column (Halo C18) and a silica-based monolith (Chromolith Performance RP-18). The derivatization reaction was optimized with respect to pH, buffer concentration and reproducibility. The optimal derivatization conditions were achieved with 0.4 M borate buffer at pH 9.20, a constant ratio of FMOC-Cl/total amino acids (10 : 1) and 75 mM tyramine after 1 min (quenching…

R/C columns strengthened by means of steel angles and battens: testing, modeling and design

2010

Some recent results on the compressive and flexural behaviour of composite members

2005

Experiemntal results from compression and flexural tests on steel tubulare columns having circular or rectangular transverse cross-section and infilled with plain or fiber reinforced concrete (FRC) are analysez. for composite members differenti lengths and different dimensions of transverse cross-section were considered in order to assess the influence on behavior in flexure and in compression.The fiber investigated with different percentage were syntetic, carbon and deformed steel fibers. The constituent materials were characterised through compressive and split tests on conconcrete cylinders. Load.shortning and load-delection curves were determined including the sotnening response. Simpli…

Photografted methacrylate-based monolithic columns coated with cellulose tris(3,5-dimethylphenylcarbamate) for chiral separation in CEC

2018

A chiral capillary monolithic column for enantiomer separation in capillary electrochromatography was prepared by coating cellulose tris(3,5-dimethylphenylcarbamate) on porous glycidyl methacrylate-co-ethylene dimethacrylate monolith in capillary format grafted with chains of [2(methacryloyloxy)ethyl] trimethylammonium chloride. The surface modification of the monolith by the photografting of [2(methacryloyloxy)ethyl] trimethylammonium chloride monomer as well as the coating conditions of cellulose tris(3,5-dimethylphenylcarbamate) onto the grafted monolithic scaffold were optimized to obtain a stable and reproducible chiral stationary phase for capillary electrochromatography. The effect o…