The Optimization Research Of Turn Flat Cable Of Cable-stayed Bridge Construction And The Main Joist Steel Beam Construction Scheme

This paper relies on the Beijing-Qinhuangdao, Tangshan Expressway QianxiExtension LJ-2tenders on cross-Beijing-Harbin, Tianjin mountain railway overpassproject for tensioning tendons way, the construction of sunshine temperature stress on abridge construction different programs on the main girder stress and other issues,combined with on-site construction monitoring and finite element analysis softwarechecking methods, to carry out research work and came to the following conclusions:①Overall pouring a tension advantages: Liangping Shun, anchor withoutlengthening, saving anchor, short construction period, prestress loss is small.Disadvantages are: Stand Dismantling demanding and difficult, Liang cleardiscontinuity in the bracket. Overall, the whole is better than pouring a tensionedtensioning sub-sub pouring. In the main pier shorter cable-stayed bridge across therailway bridge construction, using the plane swing method is safe and reliable, and themethod of pouring cast bracket girder is convenient and feasible. For cable-stayedbridge girders cast bracket, you can choose a tension with the overall placementprograms.②By modeling analysis of different construction plans, compared to the mainbeam Cantilever stress that: the overall placement once tension, short constructionperiod, age of concrete short, shrinkage and creep is larger, but stress less, if the rushperiod, overall placement can be used once tension; if not the pursuit of speed, theoverall placement once tensioned girder stress better, you can use the overall placementprogram once tension.③In the stay cable tensioning process, because the beams of different linearexpansion coefficient Sarasota, sunshine and temperature will cause the cable-stayedtower beam at different temperatures. For cable-stayed temperature relative to the mainbeam and the main tower cable-stayed temperature40℃and relative to the main beamand the main tower reduce20℃, respectively, build the model. Drawn: cable-stayedtower temperature versus temperature decreases beam will reduce the initial cable force,causing the main beam into a bridge cable force shortage, resulting in a lower mainbeam deflection; cable-stayed tower temperature relative to the beam causes thetemperature decreases caused by an increase of the initial cable force into the bridgegirder upward vertical displacement decreases. In the design and construction shouldavoid sunlight temperature difference. ④Assumed that the lower edge of the main beam and the bottom frictioncoefficient between the mold:0.03,0.3,0.6,1.0for different friction coefficients formodeling analysis, the use of stent placement of the bridge, the lower edge of the mainbeam and the bottom die the greater the friction coefficient between the main girderstress the greater the impact.