Experimental Study On Stress Increment Of External Prestressed And Model Of Box Girder With Corrugated Steel Webs

The waveform folded steel box girders used as web, from a cross-sectional form is an innovative combination of structure, namely a combination of box girder with corrugated steel webs. Composite box girder bridge with corrugated steel webs have many traditional box girder bridges do not have the advantages,and there are some inherent disadvantages. With the improvement of research to improve technology and construction of such stru ctures, this type of bridge builders and design by domestic and foreign researchers of all ages. However, from the available information, the less the combination of corrugated steel webs externally prestressed box beam research. In this paper, a large number of experimental studies refer to the basis of domestic and foreign materials, design specifications and relevant literature, were analyzed in combination with corrugated steel webs Girder tendons in vitro tests, deduced stress increment of external tendons based on deflection formula.In addition, with a large finite element software MIDAS/FEA of composite box girder with corrugated steel webs establish finite element model and finite element model of the beam test values of composite box girder with corrugated steel webs were compared, carried out the entire process of loading stress increment analysis, and analysis of composite box girder with corrugated steel webs prestressed increment factors influencing in vitro.The main work includes the following aspects:(1)The relevant literature to understand externally prestressed concrete box beam combination of structural configuration and the status of the corrugated steel webs and the development of research at home and abroad.(2)The basic mechanical properties of composite box girder bridge with corrugated steel webs and the externally prestressed tendons stress related theories.(3)Wll-designed model test beam with corrugated steel web, production and static load test.Test data collected mainly stress cross in vitro tendon deflection and beam under different conditions, and the test results were analyzed.Test results show that the elastic stage, stress increment deflection and beam span in vitro tendon and load line or approximate linear relationship was.(4)Changes in the relationship between in vitro prestressed concrete structure in accordance with the deflection and externally prestressed tendons stress increment,derived straight fold fabric reinforcement fabric reinforcement and tendons stress increment separately under different loads formula.Calculated using the derived stress increment externally prestressed beams formula this trial and comparison with the measured data, comparing findings is very close, which is calculated on a combination of in vitro prestressed box beam steel web incremental computing waveform is effective feasible.(5)By selecting appropriate element type and material properties, a finite element model is made with MIDAS/FEA and the model test beam.Finite element calculation results show that the experimental data analysis software and test beam results in good agreement with each other, such modeling composite box girder bridge with corrugated steel webs is more accurate.(6)Software to simulate changes in the test beam load from the beginning to the structural failure of the entire process of in vitro prestressed stress increment.The results showed that: elastic stage structure before concrete cracking, in vitro prestressed stress increment and span deflection and load linear relationship.With increasing load, concrete cracking, deflection and span externally prestressed stress increment increase rapidly, structural rigidity significantly reduced the tension zone of reinforced still in the elastic range, in vitro and span prestressed stress increment deflection and load also linearly.Structure into the shaping stage, yielding the tension zone of reinforced, prestressed deflection and stress increment increases rapidly in vitro, in vitro prestressed stress increment and span defl ection and load into a curvilinear relationship.(7)Establish influence with corrugated steel webs externally prestressed tendons stress increment with different parameters of the model MIDAS/FEA, through the analysis of the shows: big influences on increment of prestressing steel yield strength, tensile zone ordinary steel reinforcement ratio and concrete strength, while steel web thickness, yield strength of steel, and prestressed tendons tension reinforcement ratio of corrugated steel webs externally prestressed stress increment little effect.