Effect of Web Key Tooth Inclination on Mechanical Properties of a Segmental Assembled Box Girder
This study explored the effect of web key tooth inclination on the mechanical characteristics of a segmental box girder and elucidated the corresponding damage mechanism and damage mode.Two sets of tests on segmental box girders with different types of key teeth(vertical and horizontal)were conducted under different loading modes(pure bending and bending shear)to analyze the resulting deformation,crack emergence,crack expansion patterns,change in tendon prestress,girder stress,and crack width change law.A finite element numerical analysis model was subsequently established to analyze the stress state of each key tooth according to the inclination of the joint in detail.The results show that prior to joint cracking,the concrete stress-strain relationship,the girder deformation and prestressing tendon stress are linearly related to the load and the concrete stress-strain relationship and beam deformation are both nonlinear to the load after joint cracking.Under pure bending load,both types of girders exhibit joint cracking damage in the pure bending section with different main crack locations:the primary crack in the vertical key-tooth girder is close to the mid-span position whereas that in the horizontal key-tooth girder is closer to the loading position.Under bending-shear load,the joint cracking damage is near the loading point.Under both loads,the concrete at the top of the joint is crushed and the web key teeth are broken in shear.The type of key tooth and load effect both have a significant influence on the damage pattern of the segmental girders,with the vertical key tooth providing a superior load-carrying capacity and flexural stiffness compared to the horizontal key tooth.The loading method and type of key tooth have a negligible impact on the change in prestressing tendon stress;the internal tendons consistently exhibit a higher stress increase than the external tendons.The numerical analysis model established in this study is in agreement with the test results and can effectively analyze the stress distribution state of the key tooth to reveal the stress damage mechanism of the segmental box beam.Finally,this study presents an equation for calculating the flexural load capacity based on the current code and test data.The accuracy of this equation is confirmed as its results agree well with the test values.
bridge engineeringsegmental assembled box girdermodel testmechanical proper-tieskey tooth type
NETL
NSTL
万方数据
维普
