Analysis Of Mechanical Behavior On Rc Beam Reinforced By External Prestressing

External prestressing is an important branch of post-tensioning system,it has been widely used in new buildings and reinforcement of old buildings.The thesis introduced the reinforcement mechanism to the simple supported beams by the means of external prestressed,the calculation methods of carrying capacity of the normal section of the external prestressed simple supported beams,stress increment of the external prestressed tendons, stress loss,which was recommended both at home and abroad.For the external prestressed simple supported beams,because the deformation of prestressing tendon and the beam is not compatible, and considering both material and geometrical nonlinearity,it is difficult to calculate. Finite element analysis is a common calculational method.lt was used to simulate the whole process of the external prestressed simple supported beams.Modeling of finite element analysis of external prestressed concrete beam has its particularity. How to build the model is the basis of the proper analysis. In this thesis,how to build the model of the external prestressed concrete beam by ANSYS was introduced in detail, including how to select element, how to select constitutive relation, division of lattice, setting of calculation etc.The thesis built nineteen models,including seventeen external prestressed simple supported beams and two reinforced concrete simple supported beams,which was intended for contrast.It was taken into consideration,such as the nummber of the deviators,span-to-depth,the area of the ordinary tension steel bars,the initial stress of the external tendons,which was the main influential factors to the structure carrying capacity. Known by the numerical simulation calculation, the ultimate state carrying capacity of the reinforced simple beams was enormous improved. The Load-displacement curve was plotted for every models,before crush of the concrete,the curve showed up obvious nonlinear characteristic,but after the crush of the concrete,as the yileding of the general tensile steel bars,the curve developed linear feature but not nonlinear until the failure of the external prestressed simple supported beams.