scholarly journals Compósitos cimentícios de alto desempenho para aplicação como substrato de transição em vigas

2016 ◽  
Vol 6 (1) ◽  
pp. 52-63
Author(s):  
V. J. Ferrari ◽  
A. P. Arquez ◽  
J. B. De Hanai
Keyword(s):  
Reinforced Concrete ◽  
Carbon Fiber ◽  
High Performance ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Fiber Reinforced Polymers ◽  
Short Fibers ◽  
Carbon Fiber Reinforced Polymers ◽  
Reinforced Polymers ◽  
Material Tests

Compuestos cementíceos de alto desempeño para su aplicación como sustrato de transición en vigasRESUMENEste estudio muestra el desarrollo y análisis del comportamiento de los materiales compuestos de cemento reforzado con fibras de alto rendimiento. El material descrito se desarrolló específicamente para su aplicación como sustrato de transición, o capa de reparación de la formación de la brida tensada vigas de hormigón reforzado con polímeros de flexión reforzado con fibras de carbono (PRFC). Diecinueve compuestos diferentes fueron producidos por el proceso de hibridación. Se varió la cantidad de fibras cortas y microfibras de acero. Para analizar el comportamiento de los ensayos de flexión en tres puntos materiales prismas se realizaron Jagged. La respuesta del material se analizó teniendo en cuenta parámetros de tenacidad a la flexión y (fractura). Materiales compuestos de alto rendimiento evidencia a través de un comportamiento pseudo- endurecimiento.Palabras clave: compuestos cementíceos; vigas de concreto; sustrato de transición. High performance cementitious compounds and their application as transition substrate for beamsABSTRACTThis study presents the development and analysis of the behavior of high performance cementitious compounds reinforced with fibers. The material described was specifically developed for its application as a transition substrate, meaning, a repair layer that forms the tensed span of the flexion reinforced concrete beams with carbon fiber reinforced polymers (CFRP). Nineteen different compounds were produced by the hybridization process. The volume of the short fibers and of the steel microfibers varied. To analyze the behavior of the flexural material, tests were done in three points in tests tubes with their notches. The response of the material was analyzed considering the tenacity parameters (to flexion and fracture). The high performance of the compounds through the behavior of pseudo-hardening was confirmed.Keywords: cementitious compounds; concrete beams; transition substrate. Compósitos cimentícios de alto desempenho para aplicação como substrato de transição em vigasRESUMONeste estudo apresenta-se o desenvolvimento e a análise do comportamiento de compuestos cementíceos de elevado desempeño reforzados com fibras. O material descrito foi especificamente desarrollado para aplicación como um sustrato de transición, ou seja, camada de reparo que forma o banzo traccionado de vigas de concreto reforçadas à flexão com polímeros reforzados com fibras de carbono (PRFC). Dezenove diferentes compuestos foram produzidos pelo processo de hibridização. Variou-se o volume de fibras curtas e de microfibras de aço. Para analisar o comportamiento do material à flexão, ensaios em três pontos em prismas entalhados foram realizados. A resposta do material foi analisada considerando-se parâmetros de tenacidade (flexional e ao fraturamento). Ficou evidenciado o elevado desempeño dos compuestos através de comportamiento de pseudo-encruamento.Palavras-chave: compuestos cementíceos; vigas de concreto; sustrato de transición.

scholarly journals Study on Thermal Stress of Concrete Beams with Carbon-Fiber- Reinforced Polymers at Low Temperature

2014 ◽  
Vol 8 (1) ◽  
pp. 182-192 ◽  
Author(s):  
Tian Shuai ◽  
Zhang Tong
Keyword(s):  
Thermal Stress ◽  
Reinforced Concrete ◽  
Carbon Fiber ◽  
Expansion Coefficient ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Fiber Reinforced Polymers ◽  
Carbon Fiber Reinforced Polymers ◽  
Reinforced Polymers ◽  
Beam Height

Concrete beams reinforced with carbon-fiber-reinforced polymers (CFRPs) are subjected to considerable thermal stress at low temperatures. To mitigate this problem, this study conducts a series of tests on three concrete specimens at various temperatures, analyzes the change rule of thermal stress in CFRP-reinforced concrete beams, and discusses the influence of CFRPs on thermal stress in terms of the elastic modulus, thickness, thermal expansion coefficient, beam height, and concrete grade. The results show that when the temperature decreases, CFRP has an obvious restraining effect on the thermal curve of concrete beams. The thermal stress on the interface of CFRP-reinforced concrete beams is sufficiently large and should not be ignored. In particular, in cold areas, thermal stress should be taken into account when reinforcing structures such as concrete bridges. The CFRP sheet’s elasticity modulus and thickness are the main factors affecting the thermal stress; in comparison, the expansion coefficient and beam height have lesser effect on the thermal stress; finally, the concrete grade has little effect on the thermal stress. Thermal stress can be prevented feasibly by using prestressed CFRP sheets to reinforce concrete beams. This study can serve as a reference for concrete reinforcement design.

scholarly journals Experimental assessment of different strengthening techniques for opening in reinforced concrete beams

2021 ◽  
Vol 16 (59) ◽  
pp. 549-565
Author(s):  
Fatma Agag ◽  
Seleem S. E. Ahmad ◽  
Hossam El-Din M. Sallam
Keyword(s):  
Reinforced Concrete ◽  
Carrying Capacity ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Fiber Reinforced Polymers ◽  
Load Carrying Capacity ◽  
Carbon Fiber Reinforced Polymers ◽  
Reinforced Polymers ◽  
Cfrp Sheets ◽  
Load Carrying

The present experimental study includes testing thirteen reinforced concrete beams with openings at different locations to investigate the efficiency of strengthening such openings. Different strengthening techniques around the opening after and before casting include diagonal bars, upper and lower steel, and carbon fiber reinforced polymers (CFRP), were examined. All beams were made from 30 MPa compressive strength and tested under four-point loading.  The cross section of the beams is 400 mm depth x 160 mm width and beam length 2400 mm. The dimensions of the opening are 200 mm x 200 mm. The stiffness, deflection, failure load, and failure mode of the strengthened beams were discussed. Experimental results showed that the beams strengthened with upper and lower steel around opening at mid-span increase the load-carrying capacity by 16.59%. However, beams strengthened by CFRP sheets around the opening in the shear zone increase the load carrying capacity by 47.7% compared to opened beam.

scholarly journals Structural Behavior of Strengthened RC Beams in Shear using CFRP Strips

2017 ◽  
Vol 11 (1) ◽  
pp. 205-215
Author(s):  
Amer M. Ibrahim ◽  
Ahmed Abdullah Mansor ◽  
Muthafer Hameed
Keyword(s):  
Reinforced Concrete ◽  
Ultimate Load ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Fiber Reinforced Polymers ◽  
Failure Model ◽  
Carbon Fiber Reinforced Polymers ◽  
Reinforced Polymers ◽  
Concrete Members ◽  
Theoretical Investigations

Carbon fiber reinforced polymers (CFRP) were widely used in strengthening of reinforced concrete members in the last few years. Experimental and theoretical investigations were carried out to find the behavior of reinforced concrete beams strengthened in shear by CFRP strips. Six beams measured of 200x300x2000mm were investigated. The variables investigated in this work are orientation (vertical and inclined) and the spacing between CFRP strips. It was found that the strengthening by CFRP strips increased the crack, yield and ultimate load by 10%, 71% and 77% respectively on average. Inclined CFRP strips show a better performance than vertical CFRP strips with same distances and increase the yield and ultimate load by 11% and 13% respectively on average. By covering all faces of specimen with CFRP strips, the yield and ultimate load increased by 82% and 95% respectively. Using the CFRP strips changed the failure model from shear to flexural by increasing the shear strength, so the ductility was increased by 198% on average. CFRP increased the strain in compression face of concrete and the value was greater than (0.003). For all strengthened specimens, there was no effect on CFRP strips.

scholarly journals Analysis of reinforced concrete beams strengthened with different CFRP lengths

2019 ◽  
Vol 42 ◽  
pp. e44212
Author(s):  
Ricardo José Carvalho Silva ◽  
Antônio Eduardo Bezerra Cabral ◽  
Francisco Eudázio Suriano da Silva Júnior ◽  
José Leonézio Lopes de Vasconcelos Filho ◽  
David Ermerson Farias Eugênio
Keyword(s):  
Reinforced Concrete ◽  
Computational Analysis ◽  
Concrete Beams ◽  
Reference Beam ◽  
Reinforced Concrete Beams ◽  
Steel Plates ◽  
Fiber Reinforced Polymers ◽  
Carbon Fiber Reinforced Polymers ◽  
Reinforced Polymers ◽  
Element Simulation

The application of carbon fiber reinforced polymers (CFRP) as method of strengthening for concrete structures is replacing the conventional strengthening through the bonding of steel plates. However, since it is a recent technique, several codes from different countries still do not consider this type of strengthening. In this work, seven reinforced concrete beams were tested and analyzed. One was used as a reference beam and six were strengthened through the application of CFRP, with some variations regarding the strengthening, with the aim of verifying the efficiency of each system compared to the reference beam. For the computational analysis, the software ANSYS was used along with the plugin ACP (ANSYS Composite PrepPost), by comparing the results obtained in the simulation of the experimental results. Through the laboratory tests and the finite element simulation, it was concluded that the strengthening was efficient in all situations, but it was less efficient in cases where the strengthening was extended to the regions of simple flexure without proper anchorage. It was also possible to notice that the behavior of the simulated beams properly represented the reality, with the beams behaving comparably to the beams of the experimental test.

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