Experimental Study Andtheoretical Analysis Of Ultimate Bearing Capacity For Partially Pre-stressed High Strength Concrete Box Girder

The partially prestressed high strength concrete box girder is an engineering application girder which iscomposed of high strength concrete and partially prestressed technology.The partially prestressed high strength concrete box girderis characterized by high compressive strengh,high density,excellent durability,and economy can reduce weight,enhance the bearing capacity,and improve durability of this girder.Application of partially prestressing technique can control the deformation and cracks of this girder effectively under serviceability state,and partially prestressing technique is advantageous to the flxural ductility of this girder compared to fully prestressing technique.And this type of girder has an increasement in the flexural ductility and energy adsorption.Therefore,the partially prestressed high strength concrete box girder will be a more appropriate member applied in overload bridges.In the past,a number of research results were obtained.But few works had focused on the flexural behavior of partially prestressed high strength concrete box girder.Combining of test studies,theoretical analysis,and numerical simulation method,this paper preented an experiment study of flexural behavior of partially prestressed high strength concrete box girder under static load and fatigue load.In this paper,the research background is according to a highway project.It is based on many aspects such as ductility,crack width,deformation and ultimate bearing capacity of the prestressed concrete box girder.2 pieces of partially prestressed concrete box with C50 and C70 strength grade of concrete structure are designed to make static destruction test and compare to verificate the theoretical analysis,systematically to analyse the stress mechanism and failure process of partially prestressed high-strength concrete box girder.Besides the destructive test,the integral entity model of partially prestressed concrete box girder is createdusing large space three-dimensional finite element software ABAQUS,analysing the stress and deformation of the whole process from loading to failure analysis.In view of the code deviation due to adopt linear elastic calculation,this paper will calculate the nonlinear finite element analysis of the beam on the basis of the measured nonlinear concrete parameter,elasto-plastic stress-strainconstitutive model of reinforcing bar,and the result will be compared with the experimental value and the calculated value of standard.Furthermore,the finite strip method based on MATLAB of the prestressed concrete beam analyzes the whole stress process,and the result is compared with the experimental result.Finally the ultimate bearing capacity of prestressed high-strength concrete is obtained.Through the analysis of this paper,it can provide reference for the research on the ultimate bearing capacity of the prestressed concrete bridge.