Simulation Analysis On Cracking Preventive Method In Bottom Flange Of Continuous Rigid Frame Bridge During Construction

In recent years, with the development of economy and traffic constructio-n, continuous rigid frame bridge has been more and more used extensively in engineering construction for combination of the advantages of T-shaped rigid frame an-d continuous beam bridge. However, our country prestressed concrete continuous rigid frame bridge are at the end of the eighties of the last century began tobuild, because of imperfect design theory, construction quality defects, overload and ineffective management of the conservation work and other reasons, a n--umber of continuous rigid frame bridge'box girder bottom plate appeared in varying degrees of disease.The crack of box girder is the usual disease of bridge construction, whichis also the researching and developing subject for the engineering circle continuously. The research on the bursting crack problems of bottom plate appeared at continuous rigid frame bridge closure segment is followed as below:①Aimed at the phenomenon that the bottom slab concrete would break up when the prestressed wires are stretched, and the prestressed curves of bottom slab layout influences on the radical force are discussed; proposes bottom line instead of curve in the actual construction and the calculation methods abo-ut radical force of bottom steel beam in the fold and the knuckle in the caseof a variety of factors. With a continuous rigid frame bridge whose middle spa-n is 200 meters as an example, set up finite element model, analysis of longitudinal prestressed bottom beams under the action of radial force of the stress state, proposing two factors of the design and construction which led to crack o-f bottom slab.②From the continuous rigid frame bridge's bottom steel beam layout parameters (space of bellow to bellow of bottom slab, cover thickness of bottom bellow, thickness of bottom slab), order of bottom steel beam tension and transverse stiffener set discusses respectively to prevent the diseases of the middle s-pan zone.③On the basis of studying domestic and abroad related literature, combined with theoretical calculations done in front of the discussion and analysis ofthe finite element model simulation, aimed the different situations on the crackproblems of appeared at continuous rigid frame bridge closure segment, summe- d up the appropriate control measures.