ANÁLISE EXPERIMENTAL DE VIGAS ARMADAS DE CONCRETO DE ALTO DESEMPENHO COM DIFERENTES TIPOS DE FIBRAS / EXPERIMENTAL ANALYSIS OF HIGH STRENGTH CONCRETE BEAMS REINFORCED WITH DIFFERENT FIBRES

AUTOR(ES)
DATA DE PUBLICAÇÃO

2001

RESUMO

The future is directed to an increasing use of high performance concrete reinforced with fibers. The former due to its improved durability and strength, and the latter due to its ability to give ductility and tenacity to such a fragile product. Recently reviewed draft of the NBR 6118, called new NB1, was published. New constitutive laws for concrete and design procedures were incorporates. In this work, three series of steel reinforced high performance concrete beams with three types of fibers steel,polypropylene and sisal) were tested. The first series of beams attained shear rupture. In the second and third series, the beams were reinforced so as to attain the ultimate limit state by flexure. The behavior of the beams subjected to two point loads is discussed. The formulation presented by new NB1 to foresee the behavior of the structural elements is used. An analysis concerning shear and flexural moment design is also made using the procedures from Norway, Canada and New Zeland codes. Results show that fibers have low influence on resistant shear and moment in the ultimate limit states. The steel fibers presented a slightly and beneficial influence on the resistant shear force. The results also show the new NB1 code may in several cases be adequate to concrete with strength reaching more than 50MPa, with or without fibers. In other cases, as in shear design, it can be against safety. The sisal fibers promote a soft crushing of the concrete, presenting a potential which deserves further investigation.

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