Research On Deform Regularity Of Concrete Beam After Cracking

Due to the influence of wind, rain, floods, freezing, temperature, humidity and othernatural factors, the microscopic components of concrete bridge materials evolve duringuse, and that results in reduction of mechanical parameters such as material strength anddeformation modulus, and accumulation of damage such as cracking, corrosion anddeformation; the structure could be damaged also by earthquake, hurricane, explosionand other unpredictable disasters. Therefore the bearing capacity of the structurecomponents decreases. When outer loads changes, the components, of which the bearingcapacity decrease the most, are most likely to lose function first, then the functionfailure goes to other components due to the unbalance in the structure, and finallycollapse occurs. More life and property can be saved if weakness in structure can befound timely and accurately.Cracking in concrete beam causes structural internal force redistribution, variationof structural maximum displacement and change of structural deform regularity whichleads to decrease of serviceability, movement of weak area and increase of risk onstructural failure.In this paper, the deform regularity of concrete beam after cracking was studied. TheFE models of a simple-supported beam and a continuous beam were built by usingANSYS. The cracks with different widths, depths and locations were set by deletingsome elements in these models. The distributed load was applied to the beams and thenthe maximum displacement and deform regularity were observed. The results of FEsimulation show that:(1) the width of crack has little effect on the maximumdisplacement of beam;(2) the depth of crack obviously affects the maximumdisplacement and the deeper the crack is, the bigger the extent of the effect is;(3) thelocation of crack has quite effect on the maximum displacement of beam and thelocation of the maximum displacement in beam changes by the occurrence of crack, andthe change cleared by the depth.