Experimental Study on Reinforcement Ratio of RCFT Columns under Axial Compression

It is clear from the former researches on reinforced concrete filled tubular steel (RCFT) structures that RCFT structures have better performance than concrete filled tubular steel (CFT) structures, in other words, because of the existence of reinforcement, the performance of RCFT differed from that of CFT. Therefore, to clarify the effect of axial reinforcement on mechanical properties of RCFT, compression tests of RCFT columns with different ratio of axial reinforcement were carried out, meanwhile, corresponding tests of CFT, reinforced concrete (RC), pure concrete, and steel tube columns were done to compare with RCFT. By a series of comparison and analysis, effect of axial reinforcement on RCFT columns were discussed, and following conclusions were drawn: reinforcement ratio has direct effect on performance of RCFT. Over arranged reinforcement will cause pre-failure of concrete without exerting strength of reinforcement, and not only may cause brittle-failure or lower performance of the structure, but also cause the increase of construction cost. On the contrary, proper ratio of reinforcement can make the RCFT possess better confined effect, improve overall performance of the RCFT structure; furthermore, whatever the ratio of reinforcement, RCFT has better performance than both CFT and RC, especially possesses more brittle-failure resistance than CFT.

Influence of the Axial Inserted Yarns on the Mechanical Properties of Multi-Angled Filament Wound Pipes

The relationship between the axial inserted yarns and the mechanical properties of the multi-angled filament wound pipes was studied by experimental investigation in this paper. Firstly, the glassfiber/epoxy pipes with different process parameters were fabricated on the specially-designed filament winding equipment under varying conditions. Then the specimens were made in terms of standard sizes and tested under axial tensile load and axial compressive load, respectively. Furthermore, the axial tensile strength and the axial compressive strength were obtained from the test data, which showed that the above two values of the specimens with the axial yarns were larger than that without the axial yarns. That is to say, the incorporation of the axial reinforcement was found to result in increased strength.

Analysis of the Axial Tensile Properties of Multidirectional Filament Wound Tubes

This paper studied the axial tensile properties of the multidirectional filament wound tubes (MFWT) both theoretically and experimentally. Based on the Classical Laminate Theory, the mechanical analysis model of the tubes was established and implemented by the program of Matlab language, from which the axial tensile strength was predicted. Then the specimens with different parameters were fabricated and tested under axial tensile load respectively. The theoretical model met the experimental results well. Furthermore, the test results, the stress-strain curve and the failure form were analyzed, which showed that the axial properties of the MFWT were obviously strengthened with the incorporation of the axial reinforcement.