The Bending Performance Test Research Of Spatial Pipe Truss Composite Beams In The Negative Bending Moment

Spatial pipe truss composite beams is a section of triangular truss structure,it composed of steel tube truss and concrete plate formed by perforated plate connector,it has the advantages of high bearing capacity,large stiffness,light weight and so on.It suitable for long-span continuous girder bridge,and it can give full play to the compressive performance of concrete and the tensile performance of steel.At present many countries are mainly concentrated on the study of the structure in the positive bending moment.However,some related researches about the continuous beam in the detriment of the concrete in the negative bending moment are very few.So it is necessary for the structure in the negative bending moment to study.Bearing in the negative moment area stress analysis has great value in engineering application.This topic first through the experiment of two truss beam in the negative bending moment to study the stress performance,this experiment adopts cross reverse concentration in loading,to simulate the force bearing condition of a continuous beam.Stick some strain gauge in concrete plate,steel bar and steel pipe.Through the test,got the load-deflection curve of spatial pipe truss composite beam,load-slip curve,the curve of shear lag,load-strain curve and so on.The experimental results show that the concrete has very early cracking,then steel bar and truss bear the load.Through ABAQUS finite element software to simulate pipe truss composite beams,then extract data compared with the experimental value.The simulation results and the experimental results are in good agreement,which proved the accuracy of the experiment.Finally,change the width and thickness of the concrete slabs and calculation models of the three parameters to analysis and study of the structure of the flexural bearing capacity.According to the results,the concrete slab width had a little effects on flexural bearing capacity of composite beams in the negative bending moment,but concrete thickness and span is one of the main factors affecting bearing capacity of composite beams in the negative bending moment.