Study On The Mechanical Behavior And Engineering Applications Of Prestressed Concrete T Beam With Fold Line Pretensioned Method

The fold line pretension method overcomes the shortcomings of the traditional prestressed concrete members,that is,the traditional pretensioned structure can not be applied to bridges with larger degrees of structure.It has the shape of the prestressed tendons that can be changed by the post-tensioning method and can be applied to the construction of concrete bridges with larger spans.At the same time,the pre-tensioning method overcomes the problem of the grouting of the tunnel,so that the prestressing tendons and the concrete are more effectively bonded together,so there is no problem of corrosion of the prestressed tendons.Compared with the post-tensioning method,the pretensioning method improves the concrete bridge.The durability has been promoted and applied in bridge construction in recent years.In this paper,combined with the engineering example of fold-line pre-tensioned prestressed concrete T-beam of Daxinhe Bridge of Dongyi Road,Jinan City,China,The systematic study and analysis of prestressed parameters,mechanical properties and local stresses of prestressed concrete T-beams with fold-line pre-tensioned lines,It provides a basis for the engineering application of pre-stressed concrete T-beam with fold-line Pretensioned method.The main research contents include:Firstly,for the problem of concrete cracking in the bending line of steel strand in the pre-stressed concrete T-beam of the fold-line Pre-tensionedmethod,the local stress of the T-beam prestressed tendon bending zone was carried out by using the finite element analysis software Abaqus.The safety analysis shows that the local stress from the bare beam state to the open state of the bridge has never exceeded the specified limit.Then,the experimental research on the bending friction loss of the pre-stressed concrete T-beam steel strand of the 23.5-meter fold line was carried out,and the calculation formula of the bending friction loss of the steel strand was obtained.Combined with the preparation process of pre-stressed concrete T-beam with 23.5m fold line pretensioning method,the prestressing loss of the tensioned steel stranded wire was calculated by the tensile test.Finally,the effective tensile stress of the steel strand is used as the prestressing parameter to establish the Midas finite element model,and the RC beam is designed for the concrete T beam.The limit state of the bearing capacity and the normal use limit state check are carried out.