H R Manjunath, R Prabhakara
Abstract: The nature of fracture in high strength concrete (HSC) is brittle. High strength concrete due to its very high compressive strength, is less ductile and as such creates a less ductile response in the structural members. The paper describes the nonlinear finite element modeling and analysis of doubly reinforced HSC beams for flexural behavior. The finite element method is an analytical tool which is able to model RCC and calculate the non linear behavior of the structural members. The concrete was modeled with 8-noded SOLID-65 element that can translate either in the x, y or z-axis directions and longitudinal and transverse steels were modeled as discrete elements using 3D-LINK8 bar element available in the ANSYS elementary library. Concrete and reinforcing steel are represented by separate material models which are combined together to describe the behavior of the reinforced concrete material. A total of nine beams were modeled of size 100mm X 170mm and overall length of 2000mm, 2600mm, and 3200mm with an effective length of 1800mm, 2400mm, and 3000mm so that l/d ration is 15, 20 and 25.The beams are analyzed by varying the l/d ratio and percentage of reinforcement of HSC beams. The beams were simply supported and tested under two point loading. Analyses were carried out by calculating the cracking load, deflection and ductility using IS and ACI codes. The comparisons between analytical, experimental and calculated results using IS and ACI are observed with the objective to establish the validity of the proposed models.
Keywords: High Strength Concrete, Doubly reinforced beam, ANSYS