scholarly journals Local Retrofit of Reinforced Concrete Structures by the ACM System

Buildings ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 575
Author(s):  
Stefano Sorace ◽  
Gloria Terenzi ◽  
Elena Fuso
Keyword(s):  
Reinforced Concrete ◽  
Performance Enhancement ◽  
Concrete Structures ◽  
Time History ◽  
Substantial Improvement ◽  
Reinforced Concrete Structures ◽  
Current State ◽  
Study Characteristics ◽  
Diagnostic Investigations

During the last decades, low architectural impact strategies have been increasingly adopted in the seismic retrofit of reinforced concrete structures. Among the emerging technologies in this field, the active lateral confinement of columns, beams, and beam-to-column joints is gaining growing attention thanks to the localization of the interventions only on the members in unsafe conditions, the resulting small increase in size, and the limited demolition required for installation. The study presented herein is focused on the application of a highly performing confinement technology, named as ACM (Active Confinement of Masonry), which was conceived more than twenty years ago in Italy for masonry structures, and then successfully applied to reinforced concrete ones. A representative case study is examined in detail herein, i.e., a school built in the early 1960s in the Friuli Venezia Giulia area in Italy. A seismic assessment analysis of the building is carried out in its current state, also supported by preliminary diagnostic investigations, which highlights several seismic deficiencies, especially in terms of shear response of columns and beams. Thus, a retrofit hypothesis based on the installation of the ACM system is proposed, which allows attaining a substantial improvement in the seismic response capacities, while maintaining limited architectural intrusion. A detailed description of the case study characteristics and a synthesis of the time-history seismic analyses developed in original conditions are presented in this article, along with the design criteria, drawings of the interventions, and an evaluation of the resulting performance enhancement in retrofitted configuration.

scholarly journals Collapse rates of reinforced concrete structures during large magnitude earthquakes: case study for Romania

2021 ◽  
Vol 3 (5) ◽  
Author(s):  
Florin Pavel
Keyword(s):  
Reinforced Concrete ◽  
Seismic Event ◽  
Concrete Structures ◽  
Reinforced Concrete Structures ◽  
Large Magnitude ◽  
Rc Structures ◽  
High Rise ◽  
The Moment ◽  
Water Tanks

AbstractThis case study focuses on the evaluation of the collapse rates of various types of reinforced concrete structures (residential and industrial) as observed from the data collected in Romania after the Mw 7.4 Vrancea earthquake of March 4, 1977. The results of the analyses show that the largest collapse rates were attributed to elevated reinforced concrete silos and water tanks. Moreover, the majority of the collapsed elevated reinforced concrete water tanks were full at the moment of the seismic event. Very small collapse rates were observed for high-rise residential RC structures and for the multi-storey industrial RC structures.

Seismic Response Analysis of CFRP Retrofitted Reinforced Concrete Structures

2013 ◽  
Vol 671-674 ◽  
pp. 1445-1457
Author(s):  
Bo Jin ◽  
De Feng Zu ◽  
Han Sheng Wu ◽  
Yongwu Gao
Keyword(s):  
Reinforced Concrete ◽  
Seismic Performance ◽  
Computational Models ◽  
Concrete Structures ◽  
Time History ◽  
Relative Displacement ◽  
Shaking Table ◽  
Response Analysis ◽  
Reinforced Concrete Structures ◽  
Damage Potential

The use of carbon reinforced polymer (CFRP) to provide lateral confinement for enhanced ductility and strength of reinforced concrete structures has been increasing. The present study, attempts to analytically investigate the effect of the layout of frame columns retrofitted with different layers of CFRP on the seismic performance and damage potential of structures under strong ground motion using realistic and efficient computational models. Based on the shaking table tests of several reinforced concrete (RC) flat slab beamless construction models, the seismic performance of structures strengthened with CFRP composites are investigated. The dynamic response of CFRP retrofitted structures and the components of the model, validation of the model, force-displacement relationship, relative displacement and the time history curves are studied. Then the rational effect of different CFRP layers is found.

scholarly journals PARÂMETROS AMBIENTAIS E MATERIAIS QUE AFETAM A PENETRAÇÃO DE CLORETOS EM ESTRUTURAS DE CONCRETO – ESTUDO DE CASO DA ILHA DOS ARVOREDOS

2017 ◽  
Vol 13 (1) ◽  
Author(s):  
Carlos Eduardo Tino Balestra ◽  
Maryangela Geimba de Lima ◽  
Ronaldo A. Medeiros-Junior ◽  
Ana Julia Alves Egg Monteiro
Keyword(s):  
Reinforced Concrete ◽  
Fluorescence Spectroscopy ◽  
Marine Environment ◽  
Concrete Structures ◽  
Design Stage ◽  
Reinforced Concrete Structures ◽  
Tidal Zone ◽  
Wetting And Drying ◽  
X Ray

RESUMO: A corrosão das armaduras induzida por cloretos é um dos principais problemas relacionados à degradação de estruturas de concreto armado em ambiente marinho. Desta forma, este artigo apresenta uma compilação e discussão dos principais parâmetros ambientais e materiais que influenciam na penetração de cloretos em estruturas de concreto presentes neste ambiente. Além disso, como estudo de caso, ensaios de espectroscopia de fluorescência de Raios-X em amostras de concreto foram realizados em pontos de algumas estruturas presentes em diferentes zonas de agressividade marinha. As conclusões deste trabalho mostram que a degradação de uma estrutura pode ser evitada desde a etapa de projeto e que há um grande número de variáveis ambientais e materiais que afetam o processo. Esse trabalho contribui para a evolução do conhecimento sobre estruturas que sofrem degradação natural, expostas ao ambiente marinho. Os ensaios de espectroscopia de fluorescência de Raios-X mostraram que, sob uma perspectiva da corrosão, a zona de variação de maré é a mais agressiva às estruturas de concreto armado. Os ciclos de molhagem e secagem aos quais a zona de variação de maré está sujeita contribuem para acelerar a penetração dos cloretos no concreto. Portanto, de acordo com o tipo de zona marinha onde as estruturas podem estar presentes, o nível de agressividade quanto à corrosão induzida por cloretos é variável.
 
 ABSTRACT: The reinforcement corrosion induced by chlorides is one of the main problems related to the degradation of reinforced concrete structures in marine environment. Thus, this paper presents a compilation and discussion of key environmental and materials parameters that influence the chloride penetration in concrete structures present in this environment. Furthermore, as a case study, Fluorescence Spectroscopy X-ray testing of concrete samples were made in points of structures presents in different marine aggressive zones. The conclusions of this study show that degradation of a structure can be prevented from the design stage and that there are a large number of environmental and materials variables involved. This paper contributes to knowledge evolution about structures with natural degradation that are exposed to the marine environment. The X-ray fluorescence spectroscopy experiments showed that, from a perspective of corrosion, tidal zone is the most aggressive zone to reinforced concrete structures. The wetting and drying cycles contribute to accelerate the penetration of the chlorides into the concrete. Therefore, according to the type of marine zone where structures may be present, the level of aggressiveness for chloride-induced corrosion is variable.

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