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Steel Bars (steel + bar)

Distribution by Scientific Domains

Polymers and Materials Science	66%
Engineering	33%

Selected Abstracts

An efficient three-dimensional solid finite element dynamic analysis of reinforced concrete structures

EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 2 2006
K. V. Spiliopoulos
Abstract Most of the finite element analyses of reinforced concrete structures are restricted to two-dimensional elements. Three-dimensional solid elements have rarely been used although nearly all reinforced concrete structures are under a triaxial stress state. In this work, a three-dimensional solid element based on a smeared fixed crack model that has been used in the past mainly for monotonic static loading analysis is extended to cater for dynamic analysis. The only material parameter that needs to be input for this model is the uniaxial compressive strength of concrete. Steel bars are modelled as uniaxial elements and an embedded formulation allows them to have any orientation inside the concrete elements. The proposed strategy for loading or unloading renders a numerical procedure which is stable and efficient. The whole process is applied to two RC frames and compared against existing experiments in the literature. Results show that the proposed approach may adequately be used to predict the dynamic response of a structure. Copyright © 2005 John Wiley & Sons, Ltd. [source]

Microstructure Characterization of Tool Steel Claddings Co-Extruded on Low Alloyed Steel Substrates,

ADVANCED ENGINEERING MATERIALS, Issue 5 2009
Pedro Augusto da Souza e Silva
Low-alloyed steel bars are hot extruded with pre-sintered tool-steel powders with or without the addition of tungsten carbides (W2C/WC) as hard particles. An extrudate is formed consisting of a wear resistant coating layer and a bulk steel bar as the substrate core. The microstructure at the interface between coating and substrate of different coatings is characterized using OM, SEM and EBSD. [source]

Concrete canal lining cracking in low to medium plastic soils,

IRRIGATION AND DRAINAGE, Issue 2 2002
H. Rahimi
sol plastique; gonflement; revêtement bétonique; Iran Abstract Failure of concrete irrigation canal linings in the form of cracking, rupture, uplifting and opening of joints, causes loss of water and money in many countries. Following the appearance of extensive cracking of concrete linings in one of the Shoeybieh sugar cane industry farms in the Khoozestan province of Iran, extensive research work was conducted to identify the main causes. In this paper, the final results of the research are presented. The testing program consisted of laboratory as well as field tests, including identification, chemical and mechanical tests of soil samples taken from the borrow pits and canal embankments. Dispersivity tests were performed using pin-hole and chemical methods. Swelling tests were conducted using the ASTM standard and ISSMFE method. The field test includes measurement of deformations of the concrete lining and embankment of an actual lined canal resulting from the filling of the canal with water. The canal was 60 m in length. The deformations were recorded by surveying the elevations of steel bars driven to different depths under the canal lining and at different points in the canal and its embankment sections. The results of laboratory tests showed the soil to have low to medium plasticity with a classification of CL-ML, having less than 1% soluble content, and being nondispersive. Swelling tests conducted by the ASTM and ISSMFE methods showed completely different results. The ISSMFE method resulted in a high free swell potential, while the ASTM method indicated a low to medium potential. The results of full-scale field tests were all in favor of the ISSMFE method. The greatest difference between the results of the two methods was found to be due to the different compaction methods used during construction of the canal, as well as the moisture content of the soil sample being prepared for the swell tests. The flocculent structure and lower compaction water content of soil samples in the ISSMFE method resulted in much higher free swell. The similarity between compaction methods used in the field and the static effort used in the ISSMFE method, as well as very low soil water content of the canal embankments during lining operations, were found to be the main reasons for swelling of the soil and the eventual cracking of the concrete linings. Copyright © 2002 John Wiley & Sons, Ltd. RÉSUMÉ L'écroulement du revêtement bétonique des canaux d'irrigation en forme de fissure, de la rupture, de la sous-pression et de l'ouverture des joints, est la cause de la perte d' eau et par conséquence des fonds publics de plusieurs pays dans le monde entier. Après avoir observé ce phénomène dans des canaux d'irrigation d'un grand projet de canne à sucre à Shoeybieh dans la région de Khozestan, située au sud de l'Iran, une équipe de recherche a été engagée pour trouver les causes principales de cetécroulement. Cet article présente les résultats finaux de cette recherche. Le programme consiste de deux types d'essai, en laboratoire et sur le terrain. Les échantillons du sol pour l'essai mécanique et chimique ont été pris dans des emprunts de terre et la digue du canal. Les essais de dispersivité ont été faits par les méthodes de pin-hole et de chimique. La méthode del ISSMFE et la standard del ASTM ont été utilisés pour les essais de gonflement du sol. Le mesurage de la déformation d'un canal revêté en béton et aussi de digue du canal a été fait par rempliz le canal avee de l'eau. Le canal avait une longueur de 60 m. La déformation a été observée en examinant les élévations à plusieurs points sur la profondeur du canal en dessous de la partie revêtée et aussi la digue du canal par un instrument spécifique. Les résultats des essais de laboratoire montrent que les sols qui ont une plasticité entre petite et moyenne situés dans la classification de CL-ML ayant moins d'un pour cent de contenude soluble sont non-dispersifes. Les essais de gonflement par les méthodes de l'ASTM et l'ISSME montrent des résultats tout à fait différents. La méthode ISSMFE montre un potentiel de gonflement assez élevé, tandis que la méthode ASTM montre un potentiel entre petit et moyen. Les résultats des essais en champs d'étude confirme la méthode ISSMFE. La plus grande différence entre le résultat de deux méthodes est à cause d'usage de plusieurs méthodes de compaction dans la période de la construction du canal. La structure floculée du sol ayant une humidité moins compactée dans la méthode ISSMFE montre un gonflement plus élevée du sol. Les méthodes similaires de compaction utilisées dans le champs d'étude et énergie statique utilisée par la méthode ISSFE, et aussi une petite humidité de digue du canal en période de revêtement sont les causes principales de gonflement et éventuellement de fissure. Copyright © 2002 John Wiley & Sons, Ltd. [source]

A field study of critical chloride content in reinforced concrete with blended binder

MATERIALS AND CORROSION/WERKSTOFFE UND KORROSION, Issue 8 2009
L. Tang
Abstract This paper presents the results from the investigation of chloride-induced reinforcement corrosion in concrete slabs after over 13 years exposure in the marine environment. In the beginning of 1990s over 40 reinforced concrete slabs with different types of binder and water/binder ratios were exposed in a marine environment at Swedish west coast. In this study a new rapid technique was used for non-destructive measurement of corrosion. Based on the results from the non-destructive measurement, the actual corrosion of steel bars in five concrete slabs was visually examined and the chloride profiles in the penetrating direction as well as at the cover level were measured. The results show that the visible corrosion normally occurred about 10,20 cm under the seawater level, where the oxygen may be sufficiently available for initiating the corrosion. It is also found that chloride may easily penetrate through a poor interface between concrete and mortar spacer and initiate an early corrosion. As a conclusion, although the chloride level 1% by mass of binder may not be the same as the conventionally defined threshold value, it can be taken as the critical level for significant on-going corrosion that is visible by destructive visual examination, despite types of binder. [source]

Investigations of an ethanolamine-based corrosion inhibitor system for surface treatment of reinforced concrete

MATERIALS AND CORROSION/WERKSTOFFE UND KORROSION, Issue 7 2004
V. T. Ngala
Abstract Laboratory investigations were performed to assess the efficacy of a proprietary ethanolamine-based corrosion inhibitor system when applied to the surface of reinforced concrete specimens that were chloride-contaminated to varying extents in the presence or absence of carbonation. The corrosion responses of embedded steel bars at various depths of cover were monitored electrochemically during a controlled programme of cyclic wetting and drying undertaken for several months prior to the inhibitor treatment and for approximately eighteen months thereafter. Gravimetric measurements of the quantities and distribution of corrosion on the steel were also made on completion of the exposure tests. Analysis of aqueous extracts from treated concrete revealed that the ethanolamine component of the inhibitor system penetrated to depths of more than 15 mm within the concrete. It was found that, for inhibitor-treated specimens, there was some reduction in the corrosion rate of pre-corroding steel at low cover depths in non-carbonated concrete with modest levels of chloride contamination. At higher levels of chloride contamination and in carbonated specimens, however, the ethanolamine-based inhibitor was apparently ineffective under the conditions investigated. [source]