The Structural Effect Analysis Of Vertical Weight Forced To Closure During Construction For PC Continuous Rigid Frame Bridge After Finished

In the actual construction process, prestressed concrete continuous rigid frame bridge dueto various factors, inevitably leading large or small closure errors to appear in the full bridgeclosure, which requires forced closure sometimes, is bound to affect bridge of the linear andstress of the structure after clourse.This article is only for the vertical forced closure expands exploration and analysis, do thefollowing work and get the corresponding conclusions.(1) Through accessing to literature, to get information of prestressed concrete continuousrigid frame bridges’s characteristics and the status of their development and construction in ourcountry. To analyse a variety of factors that affecting the error of closure as well as theirmechanism of action. Thus further clarified that prestressed tension, unbalanced loads, andmeasurement bias are the main factors that leading to closure error.(2)Combined with the actual situation of closure error, if a bridge is to be closured, it canbe applied with load, tension temporary, pushing and reinforced program. For severalcommonly used measures for vertical forced closure, to analyse weight’s impact on linear andinternal force of the principles of mechanics. To derive the basic formula for the impact ofvertical forced closure pressure to continuous rigid frame bridge’ internal force from the pointof view of structural mechanics; to verify the correctness of the theoretical formula andrationality of the calculation model through a finite element analysis of regular section boxgirder.(3)Combined with two different spans prestressed concrete continuous rigid frame bridgesconstruction, by Midas/Civil finite element analysis software, numerical simulation analysis inthe ideal state and the vertical force closure two cases, to discusse the bridge structural internalforces and facade linear change rule under indifferent vertical closure error situation, under theforced closure of the initial stage of the bridge, second dead load and the time of one year andthree years later.(4)Through the impact analysis of different aggregate dragon error on the bridge linear andinternal force, discovering that heavy pressure to force co-dragon measures will cause rigidframe bridge to occur a secondary internal force in main beam and pier, compared to the idealstate of the main beam total displacement closure increases or decreases, the pier top of thebridge piers of the main span will occur a deflection. After forced to closure by the weights thebeam linear will suffer influence of closure error magnitude of the forced closure, and the top ofthe pier would occur a certain offset, the greater the error, the greater the impact; analyzing bysymmetricalbeamsection stress, heavy pressure forced closure measures on the high side of thestress is greater than the other side, but has little effect on the shear; impact of forced closuremeasures for middle span of continuous rigid frame bridge across linear and stress is greaterthan the side spans; through two kinds spans bridge analysis and comparison, finding that the effect of closure error on the greater span bridge linear effect is more obvious, and on the smallspan bridge internal forces impact is more obvious.(5) For prestressed concrete continuous rigid frame bridge, to reduce the cantileverconstruction vertical closure error can take measures from the two aspects of the design andconstruction: As for design, reasonably determine the design parameters according to the actualsituation of the construction site; for construction, to achieve the quality of construction andmake sure that process control management is in place, to ensure that the materials of variousindicators, the internal forces and linear of the structure are consistent with design parameters,in particular, to avoid unbalance load appearing on the cantilever stage in the constructionprocess on both sides.