| Spatial pipe truss steel-concrete composite girder,with advantages of high bearing capacity,stiffness,light weight,suitable for medium span continuous girder bridge,is a combination of pipe truss structure and concrete flange plate connected by shear connectors.For the research of shear lag effect of the composite beams is less,especially the shear lag effect of the truss composite beams in the negative moment region,it is necessary to study the shear lag effect in the negative moment region.The results of the research will be used as a reference for the stress analysis in the negative moment area of spatial pipe truss composite continuous beams.In order to study the shear lag effect on the flange plate of spatial pipe truss composite continuous beam in the negative moment region,the influence of this topic is studied first by test research.The load-deflection curve,load-stress curve,stress distribution curve and so on in the negative moment area of truss composite beams are measured by the test.Then through the ABAQUS finite element analysis,the loading process is simulated and the data are compared with the test.The results show that the shear lag effect on the top flange plate of spatial pipe truss composite continuous beam under the negative moment region is obvious.The finite element results are in good agreement with the test,which can be used as the basis for simplifying calculation.According to the variational principle,displacement control equations are deduced,and the simplified stress formula of the flange plate in the negative moment region is further obtained.For the particularity of structure and the effect of crack,correction coefficients are added respectively to make simplified stress formula more reasonable.Combined with the specification of other advanced countries and our country,respectively to calculate the effective width and compare with each other,which is of significance to the shear lag effect research on this kind of pipe truss composite. |
PDF Full Text Request