دانلود رایگان مقاله انگلیسی ارزیابی استحکام خمشی تیرآهن کامپوزیتی لوله فولادی پرشده با بتن - الزویر 2018

abstract

The flexural strength of the concrete-filled steel tube (CFST) composite girder was investigated in this study. Firstly, simple equations to evaluate the flexural strength of the CFST composite girder under both positive and negative bending moment were derived based on the plastic stress distribution method (PSDM). A series of tests was then conducted to verify the accuracy of the proposed equation, and to investigate the effect of internal shear connectors between the steel tube and concrete infill. Further, non-linear finite element analysis for each test specimen was performed to demonstrate the failure mechanism, and to set up the verified finite element analysis model. From the results, it was found that the proposed equations provided a reasonably conservative prediction of the flexural strength of the CFST composite girder under both positive and negative bending moment, and the effect of internal shear connectors between the steel tube and concrete infill on the flexural strength was negligible. A series of parametric studies was performed to investigate the effect of the D/t ratio, compressive strength of the concrete infill, and local buckling of the steel tube on the flexural strength of the CFST composite girder. Finally, some design considerations are noted based on the results of the parametric study.

Conclusion

The flexural strength of the CFST composite girder was investigated in this study. Based on the PSDM, simple equations to predict the flexural strength of the CFST composite girder were derived for both positive and negative bending moment. A series of experimental studies was then conducted. From the test results, the following observations were made:

(1) The proposed equations provided reasonable prediction of the flexural strength of the CFST composite girder, and the stress distribution obtained from the test is similar to that from the equation, even though partial interaction behavior was observed for the positive bending test.

(2) The effect of internal shear connectors between the steel tube and concrete infill on the flexural behavior of the CFST was negligible for the CFST composite girder under positive bending moment, since most of the concrete infill section experienced tension. However, the crack pattern of the concrete infill was affected by the existence of internal shear connectors.