Model Test And Analysis On Vertical Load Transfer Mechanism In Cable-Pylon Anchorage Zone Using Steel Anchor Box

Based on the study of former research on anchorage zone composed of concrete pylon and steel anchor box,a full-scall segment experiment of cable-pylon is planned combining Huanghe No.3 bridge. This experiment is planed to research the vertical load transfer mechanism of the composed anchorage zone in all side, starting with the stress mechanism research of shear-stud. Some new results is got form this experiment.The experiment result fulfills the design theoretics of the composed anchorage zone.A simpleness formula is derived to calculate the distribution rate of vertical component force between steel anchor box and concrete pylon according to the experiment result.The shear-stud test specimen is designed to research the mechanics character of stud ,the effect of friction between the interface of steel and concrete on shear properties and the effect between the studs themselves on shear properties.Based on the result of stud test specimen, simplified model considering the effect of shear stud on the vertical load distribution is advanced to analyse the problem. Then the mathematics formula is derived upon the simplified model .The formula can be used to analyse the cable-pylon of Huanghe No.3 bridge.At the same time,the FE model is used to get the same result.After all the work is done ,the result from the two analyse method is compared to prove the exactitude of the formula that derived before.We get the vertical load transfer mechanism between the steel anchor box and the concrete pylon when these result is summarize.Besides the theory analysis and the FEM analysis,full-scall segment test is planed to study the structure.The test is design to study the mechanics character of the stud group between the steel anchor box and the concrete cable-pylon, especially the asymmetry properties and the group effect of the studs, the test is also planned to obtain the distribution rate of vertical component force between steel anchor box and concrete pylon. According to the experiment results,the conclusion get from the formula and the FEM method about the structure is believable.The bearing-load capacity and the safety factor is obtained at the same time.At last, some problems of the Huanghe No.3 bridge blue print is discussed,such as the connection method between the segment of steel anchor box and the necessity of the bearing under the bottom segment steel anchor box.Some suggestions are given according to the result after the discussion,including the value range of the parameter used in the simplified formula.