| In recent years,assembled T-girder bridges have been playing an increasingly important role in our engineering construction activities,but on the one hand their bridge widths are increasing,and on the other hand many in-service T-girder bridges have cracked flanges,webs,and diaphragms to varying degrees.In view of this,there is an urgent need to conduct an in-depth study on the spatial force behavior of wide assembled girder bridges from the perspective of improving and improving their long-term service performance.In this paper,the effect of span and bridge width on the spatial distribution characteristics of live load effect,live load internal force and live load stress distribution characteristics of assembled simple-supported T-beam bridge under vehicle load is investigated by combining numerical simulation with ANSYS,a large general-purpose finite element software,and practical spatial theory for beam bridges,using the 2008 edition of "General drawings for highway bridges and culverts"(T-beam series)issued by the Ministry of Transportation as background,and deriving The spatial distribution algorithm of T-girder bridges under the consideration of flexible deformation of cover girders is derived,and the influence of pier and girder connection mode on the live load tensile stress in the negative moment zone of simply supported continuous T-girder bridges is also discussed,and the main research results obtained are as follows.(1)In order to study the spatial distribution characteristics of the automobile load effect of simply supported T-girder bridges,the vertical/transverse load response of Tgirder bridges is analyzed by using numerical simulations and traditional theoretical calculations,and the influence of bridge span and bridge width on the spatial distribution of its live load effect is discussed,and the applicability and accuracy of the traditional theoretical methods are also explored,and suggestions are made from the perspective of crack resistance.The results show that: the lateral load effect of T-girder bridge is influenced by various factors such as bridge span,width and distribution form under the action of vehicle load;the designed live load effect of side girder of T-girder bridge can envelop the live load lateral deflection effect of T-girder,but its lateral bending will significantly increase the tensile stress near the neutral axis,and it is approximately linearly related to the span diameter;the distribution reinforcement on the outside of the T-girder web should preferably be designed according to the lateral bending moment of the web.The distribution reinforcement on the outside of the T-beam web should preferably be designed as stressed reinforcement according to the transverse bending moment of the web,and the spacing of the reinforcement should be reduced to better prevent the vertical cracking of the web.(2)In order to explore the load transverse distribution of simply supported T-girder bridges under flexible deformation conditions of large span/long cantilevered cover girders,the load transverse distribution algorithm is derived based on the rigid beam method for urban wide span bridges with integral cover girders,and its calculation results for three different wide span ratios are compared with those of the traditional theoretical method and the solid finite element method.The calculation results are closer to the solid model and are safer.(3)In order to study the distribution of the live load effect of the cross-sectional plate of simply supported T-girder bridge under the action of automobile load,ANSYS was used to build several solid models of T-girder bridge with different spans,bridge widths and radii of curvature,and the span and quarter-point cross-sectional plate were analyzed in depth.The percentage of vertical moment difference between the span diaphragm and the span diaphragm decreases linearly with the increase of span diameter,while the influence of bridge width and radius of curvature is not significant;for the span diaphragm live load stress of T-girder bridge,symmetrical loading produces greater tensile stress than eccentric loading,in which the maximum tensile stress under eccentric loading is 85.7% higher than that under 5 pieces of T-girder bridge width,indicating that the diaphragm should be designed with symmetrical loading.The stress magnitude and stress location(distance between the maximum stress and the main beam)of the T-girder bridge span are influenced by the span diameter and bridge width,where the tensile stress decreases linearly with increasing span diameter,but the stress location increases approximately linearly with increasing span diameter.The effect of curvature and radius of curvature on the live load tensile stresses in the span span span is small.(4)In order to investigate the effect of automobile load on simply supported continuous T-girder bridge,ANSYS was used to simulate the construction process of simply supported continuous T-girder bridge with different pier and girder connection methods and establish a solid model to analyze the tensile stresses in the negative moment zone and load transverse distribution in two dimensions considering different loading conditions.The results of the analysis are as follows: under the consideration of selfweight,the car load applied to the double span causes more tensile stresses in the negative moment zone of the T-girder bridge than the car load applied to the single span,and the tensile stresses in the negative moment zone of the T-girder bridge are the smallest when the middle pier is set to double support,and the effect of rigid or flexible double support on the tensile stresses in the negative moment zone of the T-girder bridge is not significant;the setting of the middle pier to double support not only has a peak shaving effect on the maximum tensile stresses in the negative moment,but also shifts the location of the maximum tensile stresses.For the two-span simply supported T-girder bridge,for the eccentric loading,the center pier is set as single support for the side girders to be more favorable. |
PDF Full Text Request