Mechanical Behavior Of Urban Wide Bridge Deck With Special-Shaped Arch-Beam Composite System

The composite arch beam system is a kind of bridge type in which the arch rib and the tie beam play their respective material characteristics,cooperate and bear the load together.This kind of bridge has great rigidity,reduces the requirement of traditional arch bridge for pier and foundation bearing capacity,and can design all kinds of beautiful shapes.The unique shape,complicated force and short design cycle are the major problems that engineers encounter in designing composite arch beam system Bridges.With the constant improvement of the landscape bridge appearance requirements,the application of the special-shaped composite arch bridge system is more and more widely,but the bridge of the corresponding theoretical research lag,such as special-shaped arch bridge is reasonable arch axis,wide bridge transverse stress distribution,derrick internal force optimization,the stability of arch rib,reasonable beam stiffness ratio,beam force improvement measures of combining site still less,the stress of composite arch system research and put forward the optimization measures are very necessary.This paper takes the Kedu Bridge,a composite system of special-shaped arch beams on wide bridge deck,as the engineering background,and conduct relevant research,the main results are as follows:(1)The mechanical analysis method is used to simplify the stress mode of the special-shaped arch and the reasonable arch axis equation of special-shaped arch bridge is put forward after comparing different derrick angles;(2)The simplified influence matrix method,that is,the minimum bending energy method,is used to solve the dead load cable force of the bridge,and the secondary adjustment of the cable force is carried out by using the optimization toolbox in MATLAB,compared with the cable force value of one-time completed bridge,the error is controlled within 5%;(3)According to the actual construction stage,the whole bridge pole model is established to check the indexes of the completed bridge state,moving load condition and operation state of the Kedu Bridge,and according to the standard method,the stability of the arch bridge is determined to meet the operation requirements.(4)The ANSYS plate-shell model is established to study the distribution of longitudinal stress and transverse stress under dead load and temperature of the wide deck Kedu Bridge.The results of the bar model are compared,and the conclusion that the transverse stress should be checked when designing the wide concrete box girder is obtained.(5)The influence of suspender equivalent stiffness,beam-arch bending stiffness ratio and beam-arch tension stiffness ratio on the load ratio of arch beams is studied by using the idea of control variable method,and the influence of different parameters of beam-arch axial stiffness ratio and bending stiffness ratio on the dynamic characteristics of the structure is studied.(6)The solid model of ANSYS local analysis of steel-concrete joint of Kedu Bridge is established,and the displacement,equivalent stress,principal tensile stress and principal compressive stress index of each part under the most unfavorable conditions are extracted,and the optimization suggestions of adding chamfering and strengthening stiffener are given.