scholarly journals Seismic Retrofitting of a Bridge Pier with Ultra High Performance Fibre Reinforced Concrete

2018 ◽  
Vol 199 ◽  
pp. 09015
Author(s):  
Reggia Adriano ◽  
Alessandro Morbi ◽  
Giovanni A. Plizzari

The increasing number of road infrastructures needing repair and retrofit is raising the problem of how to improve seismic behaviour for all those structures for which substitution is unlikely. This work deals with the application of a retrofitting technique for Reinforced Concrete (RC) elements based on the use of Ultra High Performance Fibre Reinforced Concrete (UHPFRC). A thin layer of UHPFRC, cast around an existing RC element, can both improve its structural performance and enhance its durability against environmental actions. This kind of rehabilitation intervention may represent, in many practical cases, a cost effective solution compared with the replacement of the entire structure. The aim of this paper is the definition of a reinforcement strategy and the presentation of a 1:4 scale laboratory test of a highway bridge pier reinforced with a 30 mm layer of UHPFRC.

2018 ◽  
Vol 199 ◽  
pp. 01004
Author(s):  
Giovanni A. Plizzari

Enhancement of seismic behaviour of existing structures, both masonry or reinforced concrete, is a key issue for future technical activities in many Western Countries, since construction of new buildings has decreased in favour of an increased attention to the structural rehabilitation and re-use of existing buildings. The development of innovative repairing, strengthening, and retrofitting techniques is, therefore, a crucial topic to improve the structural safety of existent constructions. Fibre Reinforced Concrete (FRC) may now be particularly efficient in these cases, due to the high toughness provided by fibres that may reduce or avoid the use of conventional reinforcement.This paper presents the results of two experimental research studies carried out at the University of Brescia, concerning the use of FRC as the principal reinforcing material. The first study aims at assessing the structural response, under cyclic horizontal loads, of a full scale (1:1) Unreinforced Masonry (URM) building retrofitted with Steel Fibre Reinforced Mortar (SFRM) as external plaster. The second study concerns the seismic retrofitting of a scaled (1:4) reinforced concrete bridge pier by means of a High Performance Fibre Reinforced Concrete (HPFRC) jacketing. In both cases, repair material is applied in thin layers, due to the high mechanical properties compared to those of the respective substrates, with the addition of a limited amount of traditional reinforcement, placed only on the most stressed sections.


2018 ◽  
Vol 183 ◽  
pp. 02005
Author(s):  
Ezio Cadoni ◽  
Matteo Dotta ◽  
Daniele Forni

The paper presents the results obtained on cylindrical Ultra High Performance Fibre Reinforced Concrete specimens with diameter of 30mm and a height of 60mm under compression at high stress rate (1.7–2.3 TPa/s). Four different percentages of fibre reinforcement are considered (1, 2, 3, and 4% fibre content) and compared with the results of the matrix (UHPC). A slight reduction of the strength and fracture time with the introduction of fibres is observed. The experimental results are analysed and discussed with the intent to better understand the mechanical behaviour of UHPFRC materials in case of dynamic event under service loading conditions.


2008 ◽  
Vol 17 (11) ◽  
pp. 316-317
Author(s):  
Daniel de MATTEIS ◽  
Pierre MARCHAND ◽  
Aude PETEL ◽  
Thierry THIBAUX ◽  
Nicolas FABRY ◽  
...  

Materials ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 1372 ◽  
Author(s):  
Krzysztof Ostrowski ◽  
Łukasz Sadowski ◽  
Damian Stefaniuk ◽  
Daniel Wałach ◽  
Tomasz Gawenda ◽  
...  

When understanding the effect of the morphology of coarse aggregate on the properties of a fresh concrete mixture, the strength and deformability of self-compacting high-performance fibre-reinforced concrete (SCHPFRC) can be seen to be critical for its performance. In this research, regular and irregular grains were separated from granite coarse aggregate. The morphology of these grains was described while using digital image analysis. As a result, the aspect ratio, roundness and area ratio were determined in order to better understand this phenomenon. Then, the principal rheological, physical, and mechanical properties of SCHPFRC were determined. The obtained results indicated that the morphology of the grains of coarse aggregate has an impact on the strength and stiffness properties of SCHPFRC. Moreover, significant differences in the transverse strain of concretes were observed. The morphology of the coarse aggregate also has an impact on the rheological parameters of a fresh concrete mixture. To better understand this phenomenon, the hypothesized mechanism of the formation of SCHPFRC caused by different morphology of coarse aggregate was proposed at the end of the article.


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