Issue 46

H. Zhu et alii, Frattura ed Integrità Strutturale, 46 (2018) 361-370; DOI: 10.3221/IGF-ESIS.46.33 363 A NALYSIS ON THE FAILURE MODE OF EMBEDDED CFRP PLATE CONSOLIDATED REINFORCED CONCRETE BEAMS Bending failure hen the length of CFRP plate is enough and its binds well with concrete, strengthening beams may have bending failure, i.e, the shear bearing capacity of strengthening beams is larger than the bending bearing capacity, tensile reinforcement yields, and concrete is crushed or CFRP plate breaks. When the crushing of concrete and the fracture of CFRP plate happen simultaneously, then [11]: * 0.8 cu c y s cu fu f f f bh f A A f               where fu  stands for the ultimate strain of CFRP plate, cu  stands for the ultimate strain of concrete, b stands for the width of beam section, h stands for the height of beam section, fc stands for the design value of cube compressive strength of concrete under uniaxial stress, fy stands for the design value of tensile strength of rebars, and As stands for the cross sectional area of rebars. When * f f A A  , concrete is crushed; when * f f A A  , CFRP plate fractures. Shear failure When the stirrup ratio is not enough or shear is the first to exceed other resistances, strengthening beams are very likely to have shear failure. The shear failure of strengthening beams indicates beams have excellent bending resistance, and the values of CFRP are given full play. Debonding failure Debonding failure is a special failure mode in embedded CFRP plate reinforcement method and also the main failure mode. CFRP plate reinforcement includes the mutual contact of three materials, i.e., contact between CFRP plate and binding materials and contact between binding materials and concrete. The hardness and strength of binding materials are very likely to decrease with the increase of temperature [12]. The main manifestations of failure include failure of connection between CFRP plate and resin, failure of connection between resin and concrete, failure of resin and failure of concrete. F INITE ELEMENT ANALYSIS Establishment of finite element model inite element method which is a practical numerical calculation method has been applied in many fields. In this study ANSYS was used for simulating and analyzing embedded CFRP plate consolidated reinforced beams. Concrete SOLID65 element in ANSYS was used for simulating concrete material. The cracking of concrete was observed via the equivalent value of plastic strain. Damaged plasticity model (dilatancy angle: 45°, eccentricity ratio: 0.1, viscous parameter: 0.005) was used. During modeling, a rectangle with a size of 150 * 300 mm was drawn, and then it was stretched for 2400 mm to form a concrete beam. Rebars LINK8 element was used for simulating rebars. The rebars born under uniaxial tension and compression and could move freely in the directions of X, Y and Z. The plasticity, expansion and deformation of rebars were simulated. The parameters of rebars are shown in Tab. 1. W F