Study On The Reinforcement Technology Hinged Joints Of Fabricated Plate Girder Bridge

With the damage of hinge joints of fabricated plate girder bridge increasing and intensifying,the strengthening technology of hinge joints was increasingly paid attention by the bridge maintenance department.There was a variety of strengthening methods of hinge joints and each of them had advantages and disadvantages.On the basis of analysis of the diseases of hinge joints,a reinforcement method of hinge joints was put forward and a series of research was made about it.The strengthening components of the method were set in the superior margin and work together with concrete bridge deck pavement.Main contents:? Combining with the disease investigation of hinge joints,disease characteristics of the hinge joints were summarized and disease causes of the hinge joints were analyzed.Hinge joints not only transferred shear but also transmitted a part of lateral bending moment.Disease and damage of hinge joints started from hinge joints or the bond interface between hinge joints and plate beam.Raising the strength of concrete of hinge joints or replace hinge joints can not fundamentally solve the problem of the disease and damage of hinge joints.Setting connection components in top or bottom plate to resist tension and pressure,changing the connection from hinged connection into a rigid or a partial rigid connection,was an effective way to improve the ability of resisting bending moment.? All kinds of reinforcement methods were summarized.According to the principle of reinforcement,those kinds of methods were divided into two types.one was enhancing the intensity of hinge joints,the other was changing the connection from hinged connection into a rigid or a partial rigid connection.The advantages and disadvantages of the reinforcement methods were analyzed.Channel steel as a kind of strengthening component was set in the superior margin of plate girder and worked together with reinforced concrete of deck pavement.The ability of resistance to lateral bending moment was improved and the malpractices of constructing under bridge were avoided by constructing on deck.? Comparative study on effect of rigid strengthening methods was made by finite element analysis.The finite element analysis was based on four methods,including setting the steel plate or channel steel in superior margin,setting the steel plate in the inferior margin of plate girder,setting channel steel working together with reinforced concrete of deck pavement in the superior margin of plate girder.It showed that,the effect of setting the steel plate in the inferior margin of plate girder was best.Concrete of hinge joint and steel plate worked together,the ability of bearing transverse bending moment and the integrity of each plate girders was improved,and the transverse normal stress of hinge joints was greatly reduced in it.The reinforcement effect of pasting the steel plate or channel steel in superior margin of plate girder was not ideal,the integrity can not be improved and the transverse normal stress can not be reduced.Improving the integrity of each plate girders and reducing the normal stress of hinge joints were carried out by the method put forward in this article.? The contrast of different rigid reinforcement methods was made through simulation experiment in the laboratory.It turns out that the diseases and damages of hinge joints started from and extended by the inferior margin of bond interface between hinge joints and plate girder.The effect of reinforcement method put forward in the article was similar to the method arranging the steel plate in the inferior margin of plate girder.